WO2021248110A1

WO2021248110A1 - Respiratory ventilator

Info

Publication number: WO2021248110A1
Application number: PCT/US2021/036098
Authority: WO
Inventors: Keith P. ROMANO; James D. RICHARDS III; Tyler B. DAILY
Original assignee: The Brigham And Women's Hospital, Inc.; The Aerobreath Project, Inc.
Priority date: 2020-06-05
Filing date: 2021-06-07
Publication date: 2021-12-09

Abstract

A respiratory ventilator is provided. The ventilator comprises a bellows configured to be compressed to deliver a selected tidal volume to a patient. A connecting rod is operably connected to the bellows to compress the bellows by a selected stroke distance that corresponds to the selected tidal volume. A crank arm has an elongated slot into which a pin extends to connect the connecting rod to the crank arm. A control wheel is for selectively adjusting an effective crank arm length. The effective crank arm length directly corresponds to the stroke distance of the connecting rod. The control wheel has a slot into which the pin extends. Selective rotation of the control wheel relative to the crank arm urges the pin to move along an elongated slot of the crank arm toward and away from a drive axis to selectively adjust the effective crank arm length.

Description

RESPIRATORY VENTILATOR

Related Application

[0001] This application claims priority from U.S. Provisional Application No. 63/035,031 , filed 5 June 2020, the subject matter of which is incorporated herein by reference in its entirety.

Technical Field

[0002] This disclosure generally relates to respiratory ventilation and, more particularly, to a reciprocating bellows-type respiratory ventilator.

Background

[0003] Standard-of-Care ventilators are complex and expensive machines, generally operable only in a resource-rich health care context by medical specialists.

Summary

[0004] In order to simplify operation, reduce cost, and reduce resource dependencies, the present disclosure comprises a simple respiratory ventilator specifically designed and controlled to reduce the cost of accomplishing core and essential operating capabilities and characteristics.

[0005] In an aspect, a respiratory ventilator is provided. The ventilator comprises a bellows configured to be compressed to deliver a selected tidal volume to a patient and decompressed to draw gas into the bellows. A connecting rod is operably connected to the bellows to compress and decompress the bellows by reciprocation along an axis of reciprocation. The connecting rod compresses the bellows by a selected stroke distance that corresponds to the selected tidal volume. A pin extends through the connecting rod. A crank arm is configured to be selectively rotated about a drive axis. The crank arm has an elongated slot into which the pin extends to connect the connecting rod to the crank arm. Selective rotation of the crank arm about the drive axis responsively causes the connecting rod to compress and decompress the bellows. The pin is selectively moveable along the elongated slot toward and away from the drive axis. An effective crank arm length is a distance between the pin and the drive axis. The effective crank arm length directly corresponds to the stroke distance of the connecting rod. A control wheel is for selectively adjusting the effective arm length. The control wheel has a slot into which the pin extends. The control wheel is selectively rotatable relative to the crank arm. Selective rotation of the control wheel relative to the crank arm urges the pin to move along the elongated slot toward and away from the drive axis to selectively adjust the effective crank arm length. The ventilator is configured to be selectively adjusted to deliver the selected tidal volume to the patient by selectively adjusting the effective crank arm length with the control wheel to provide the selected stroke distance that corresponds to the selected tidal volume.

[0006] In an aspect, alone or in combination with any other aspect, a method for delivering a selected tidal volume to a patient is provided. The method comprises providing the respiratory ventilator. The effective crank arm length is adjusted by rotating the control wheel relative to the crank arm to provide the selected stroke distance that corresponds to the selected tidal volume. With the effective crank arm length adjusted, the crank arm is rotated about the drive axis to responsively cause the connecting rod to compress the bellows by the selected stroke distance. Compression of the bellows by the selected stroke distance responsively causes bellows to deliver the selected tidal volume to the patient.

[0007] In an aspect, alone or in combination with any other aspect, a respiratory ventilator is provided. The ventilator comprises a bellows configured to be compressed to deliver a selected tidal volume to a patient and decompressed to draw gas into the bellows. A connecting rod is operably connected to the bellows to compress and decompress the bellows by reciprocation along an axis of reciprocation. The connecting rod compresses the bellows by a selected stroke distance that corresponds to the selected tidal volume. A drive shaft is selectively rotatable about a drive axis. Selective rotation of the drive shaft about the drive axis responsively causes the connecting rod to compress and decompress the bellows. The drive shaft is configured to be switchable between being rotated manually and automatically. Brief Description of the Drawings

[0008] The foregoing and other features of the present disclosure will become apparent to those skilled in the art to which the present disclosure relates upon reading the following description with reference to the accompanying drawings, in which:

[0009] Fig. 1 is a front view of a portion of a respiratory ventilator according to one aspect of the present disclosure;

[0010] Fig. 2 is a side view of the aspect of Fig. 1 ;

[0011] Fig. 3a is a perspective view of a portion of the respiratory ventilator according to an aspect of the present disclosure;

[0012] Fig. 3b is an exploded view of a portion of the aspect of Fig. 3a;

[0013] Fig. 4 is a front view of an element of the aspect of Fig. 1 ;

[0014] Fig. 5 is a front view of an element of the aspect of Fig. 1 , including the element in a first condition;

[0015] Fig. 6 is a front view of the element of the aspect of Fig. 5, including the element in a second condition;

[0016] Fig. 7 is a front view of the element of the aspect of Fig. 5, including the element in a third condition;

[0017] Fig. 8 is a perspective view of an element of the aspect of Fig. 1 ;

[0018] Fig. 9 is a front view of an element of the aspect of Fig. 1 ;

[0019] Figs. 10-12 depict an example sequence of operation of a portion of the aspect of Fig. 1 , including the ventilator in a plurality of operating modes and cycles;

[0020] Fig. 13 depicts example flow waveform curves of the various operating modes and cycles of the ventilator;

[0021] Figs. 14-16 depict an example sequence of operation of a portion of the aspect of Fig. 1 ;

[0022] Figs. 17-19 depict an example sequence of operation of a portion of the aspect of Fig. 1 ; [0023] Fig. 20 is a front view of a portion of the aspect of Fig. 1 , including a portion of the ventilator in an example condition;

[0024] Fig. 21 depicts a plan view of an element of the aspect of Fig. 3; and

[0025] Fig. 22 depicts a plan view of an element that may be used in conjunction with the ventilator of the aspect of Fig. 1 .

Description of Embodiments

[0026] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which the present disclosure pertains.

[0027] As used herein, the term “patient” can refer to any warm-blooded organism including, but not limited to, human beings, pigs, rats, mice, birds, cats, dogs, goats, sheep, horses, monkeys, apes, rabbits, cattle, farm animals, livestock, etc.

[0028] As used herein, the term “user” can be used interchangeably to refer to an individual who prepares for, assists with, and/or performs a procedure.

[0029] As used herein, the term “tidal volume” can refer to the volume of gas displacement during a compression stroke, and delivered to the patient during inspiration.

[0030] As used herein, the term “inspiratory time” can be used to mean the time interval of the compression cycle delivering tidal volume to the patient.

[0031] As used herein, the term “expiratory time can be used to mean the time interval of the decompression cycle and the dwell time, allowing for the patient to exhale the tidal volume.

[0032] As used herein, the singular forms “a,” “an” and “the” can include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” as used herein, can specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. [0033] As used herein, the term “and/or” can include any and all combinations of one or more of the associated listed items.

[0034] As used herein, phrases such as “between X and Y” can be interpreted to include X and Y.

[0035] As used herein, the phrase “at least one of X and Y” can be interpreted to include X, Y, or a combination of X and Y. For example, if an element is described as having at least one of X and Y, the element may, at a particular time, include X, Y, or a combination of X and Y, the selection of which could vary from time to time. In contrast, the phrase “at least one of X” can be interpreted to include one or more Xs.

[0036] It will be understood that when an element is referred to as being “on,” “attached” to, “connected” to, etc., another element, it can be directly on, attached to or connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being, for example, “directly attached” to, or “directly connected” to another element, there are no intervening elements present. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed “adjacent” or “adjacent to” another feature may not have portions that overlap or underlie the adjacent feature.

[0037] Spatially relative terms, such as “below” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the Figures. It will be understood that the spatially relative terms can encompass different orientations of a device in use or operation, in addition to the orientation depicted in the Figures. For example, if a device in the Figures is inverted, elements described as “below” other elements or features would then be oriented “above” the other elements or features.

[0038] It will be understood that, although the terms “first,” “second,” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, a “first” element discussed below could also be termed a “second” element without departing from the teachings of the present disclosure. The sequence of operations (or steps) is not limited to the order presented in the claims or Figures unless specifically indicated otherwise. [0039] The invention comprises, consists of, or consists essentially of the following features, in any combination.

[0040] Figs. 1 -3b depict a respiratory ventilator 100. The respiratory ventilator 100 includes a bellows 102. The bellows 102 may be a compressible duct, or equivalent chamber that is configured to be compressed and decompressed by reciprocation substantially in a longitudinal direction. The term “longitudinal” is used herein to indicate a substantially vertical direction, in the orientation of Figs. 1 -2, and is indicated at “LO” in Figs 1-2. The bellows 102 has a first end 104 attached, e.g., directly and/or fixedly attached, to a head 106. The bellows 102 includes an opposite, second end 108 that is longitudinally spaced from the first end 104. The second end 108 of the bellows 102 is attached, e.g., directly and/or fixedly attached, to a diaphragm 110. The head 106 may have a gas inlet check valve 112, at least one gas outlet check valve 114, and a pressure relief valve 116. As shown in Figs. 3a-b, the head may also have a manometer port 318 to which a manometer 320 is attached. As shown in Figs. 1-3a, the head 106, bellows 102 and diaphragm 110 together define an airtight or low leakage chamber 122 when the valves 112, 114,

116 are closed.

[0041 ] The head 106, the bellows 102, and the diaphragm 110 also collectively form a head assembly 124. The head assembly 124 can be attached to and supported by a supporting framework 126. The supporting framework 126 may be or may include a support post 128, a support base 330, a cabinet, any other framework configured to support the head assembly 124, or any combination thereof. In the example configuration of Figs. 1-2, the supporting framework 126 is a support post or “backbone” 128. As shown in Figs. 3a-b, the backbone 128 can be selectively attached to and supported by a support base 330. As shown in Figs. 1 -3b, the head 106 may be selectively attached to the backbone 128 to connect the head assembly 124 to the supporting framework 126. The head assembly 124 is also removable from the supporting framework 126, such as by removing the head 106 from the backbone 128, and collapsible for compact transport of the head assembly 124 along with the disassembled framework 126.

[0042] The head 106, the bellows 102, and the diaphragm 110 may be permanently attached to one another to permit the head assembly 124 to be attached to/removed from the supporting framework 126 as one-piece. This one- piece configuration, when present, permits the head assembly 124 to be quickly attached to/removed from the supporting framework 126.

[0043] The ventilator 100 may include at least one guide 132 that at least partially surrounds at least one of the bellows 102 and the diaphragm 110, and longitudinally extends along a perimeter of at least one of the bellows 102 and the diaphragm 110 to help guide the reciprocating motion of the bellows 102. In the example ventilator shown in Figs. 1 -3b, the at least one guide 132 may be formed as a longitudinally extending rod and the device may have a plurality of guides 132 (e.g., two, three, four, or more guides) that surround the bellows 102 and the diaphragm 110. Alternatively, the at least one guide 132 may be a cylindrical constraint cage or shell that surrounds at least one of the bellows 102 and the diaphragm 110. The bellows 102 and/or the diaphragm 110 may be loosely constrained within the guides 132 to permit at least a portion of the bellows 102 and/or the diaphragm 110 to sway relative to a longitudinal axis of reciprocation 434 (see Fig. 4) of the bellows 102, or may be tightly constrained to substantially prevent the bellows 102 and/or the diaphragm 110 from swaying relative to the axis of reciprocation 434.

[0044] As shown in Figs. 1 -3b, the guides 132 may longitudinally extend between the head 106 and a clamp 136, when the clamp 136 is present. The guides 132 may be fixedly attached to the head 106, fixedly attached to the clamp 136, or fixedly attached to both the head 106 and the clamp 136. The clamp 136, when present, may be selectively attached to the supporting framework 126, such as to the backbone 128, and longitudinally spaced from the head 106 so that the bellows 102 and the diaphragm 110 are longitudinally positioned between the head 106 and the clamp 110.

[0045] The bellows 102 may be alternately compressed and decompressed by reciprocation of a connecting rod 138 that may longitudinally extend through the clamp 110, when present. The connecting rod 138 has longitudinally spaced first and second ends 140, 142. The first end 140 of the connecting rod 138 is attached (e.g., directly attached) to the diaphragm 110. The connecting rod 138 may be fixedly attached to the diaphragm 110 to prevent the connecting rod 138 from pivoting relative to the diaphragm 110. In this fixedly-attached configuration, the bellows 102 and/or the diaphragm 110 is loosely constrained within the guides 132 and is permitted to sway relative to the axis of reciprocation 434. Alternatively, connecting rod 138 may be pivotably attached to the diaphragm 110. In this pivotable configuration, the bellows 102 and/or the diaphragm 110 may be tightly constrained within the guides 132 to substantially prevent the bellows 102 and/or the diaphragm 110 from swaying relative to the axis of reciprocation 434. The second end 142 of the connecting rod 138 includes an aperture 144 laterally extending therethrough. The term “lateral” is used herein to indicate a direction substantially perpendicular to the “longitudinal” direction, is shown as the horizontal direction in the orientation of Fig. 2, and is indicated at “LA” in Figs. 1 -3a.

[0046] As shown in Figs, 1 -3b, a pin 146 may laterally extend through the aperture 144 in the connecting rod 138. The connecting rod 138 may at least partially pivot about pin 146 during use. As shown in Fig. 4, when the bellows 102 and/or the diaphragm 110 are swayed relative to the axis of reciprocation 434, the connecting rod 138 may be pivoted about the pin 144 so that a longitudinal axis 448 of the connecting rod 138 is offset from the axis of reciprocation 434 by an angle a.

[0047] As shown in Figs. 1 -3b and 5-7, the pin 146 may connect the connecting rod 138 to a crank arm 150. For example, the pin 146 may laterally extend through both the aperture 144 in the connecting rod 138 and an elongated slot 552 in a first portion 154 of the crank arm 150 to connect the connecting rod 138 to the crank arm 150. As shown in Figs. 5-7, the elongated slot 552 may extend along the first portion 154 of the crank arm 150 in a transverse direction, in the orientation of Figs. 5-7.

The term “transverse” is used herein to indicate a direction substantially perpendicular to both the “longitudinal” and “lateral” directions, is shown as the horizontal direction in the orientation of Figs. 5-7, and is indicated at “TFT in Figs. 1- 3a and 5-7.

[0048] As shown in Figs. 1 -3b and 5-7, the crank arm is configured to be rotated about a laterally extending drive axis 256. As the crank arm 150 rotates, a periphery 558 of the elongated slot 552 may engage the pin 146 and cause the pin 146 to responsively rotate about the drive axis 256. The rotating pin 146 responsively causes the connecting rod 138 to rotate about the drive axis 256. The connecting rod 138 moves in the longitudinal direction as it rotates about the drive axis 256. The longitudinally moving connecting rod 138 responsively causes the bellows 102 to compress (for example, when the connecting rod 138 moves longitudinally upwards, in the orientation of Fig. 1) and decompress (for example, when the connecting rod 138 moves longitudinally downwards, in the orientation of Fig. 1) by reciprocation along the axis of reciprocation 434 (shown in Fig. 4).

[0049] The ventilator 100 is configured to deliver gas to a patient by compressing the bellows 102 by a certain stroke distance dependent on a selected tidal volume, wherein the tidal volume corresponds to a displaced volume of gas equal to the area of the diaphragm 110 times the stroke distance. The stroke distance may be equal to the longitudinal distance the connecting rod 138 longitudinally moves when compressing the bellows 102 and/or the longitudinal distance the bellows 102 longitudinally compresses when being compressed by the longitudinally moving connecting rod 138. The stroke distance may be dependent (e.g., directly dependent) on and directly correspond to an effective crank arm length 560, i.e., the distance (e.g., perpendicular distance) between the drive axis 256 and the pin 146 positioned in the elongated slot 552. This is because the effective crank arm length 560 may be substantially equal to the radius at which the pin 146 and/or the connecting rod 138 rotate about the drive axis 256 (see, for example, Figs. 5-7), and thus substantially equal to half the stroke distance. A larger effective crank arm length 560 equates to a larger radius for the rotation of the pin 146 and/or the connecting rod 138 about the drive axis 256 and a greater stroke distance.

[0050] As shown in Figs. 1 -3b and 5-7, the ventilator 100 may include a control wheel 162 for moving the pin 146 along the elongated slot 552 of the crank arm 150 in order to adjust the effective crank arm length 560. The control wheel 162 includes a spiral slot 164 through which the pin 146 extends. As shown in Figs. 5-7, the spiral slot 164 has a first end 566 adjacent to the drive axis 256 and spirals away from the drive axis 256 so that a second end 568 of the spiral slot 166 is spaced further from the drive axis 256 than any other portion of the spiral slot 164 is spaced from the drive axis 256. It is contemplated, though, that the structure referenced herein as a “spiral slot” may have any appropriate configuration to achieve desired results, in a particular use environment of the ventilator 100. [0051] The control wheel 162 may be selectively rotated about the drive axis 256 relative to the crank arm 150. As the control wheel 162 rotates, the pin 146 moves along the spiral slot 164 from one of the first and second ends 566, 568 of the spiral slot 164 to the other of the first and second ends 566, 568. For example, Fig. 5 shows a first effective crank arm length 560 (shown here as the first effective crank arm length 560a) where the pin 146 is adjacent to the first end 566 of the spiral slot 164 and a first end 570 of the elongated slot 552. Selective clockwise rotation of the control wheel 162 causes the pin 146 to travel along the spiral slot 164 toward the second end 568 of the spiral slot 164. As shown in Figs. 5-7, as the pin 146 travels along the spiral slot 164 toward the second end 568, a periphery 572 of the spiral slot 164 urges the pin 146 to move along the elongated slot 552 toward the second end 574 of the elongated slot 552. Fig. 7 shows a second effective crank arm length 560 (shown here as the first effective crank arm length 560b), which is greater than the first effective crank arm length 560a, where the pin 146 is adjacent to the second ends 574, 568 of both slots 552, 164. Fig. 6 shows a third effective crank arm length 560 (shown here as the first effective crank arm length 560c), which is greater than the first effective crank arm length 560a and less than the second effective crank arm length 560b, where the pin 146 is positioned between the first and second ends 570, 566, 574, 568 of both slots 552, 164.

[0052] Therefore, rotary positions of the control wheel 162 about the drive axis 256 correspond to predetermined effective crank arm lengths 560. The effective crank arm length 560, and correspondingly the stroke distance and tidal volume (i.e., the volume of gas displacement during the compression stroke), thus can be selected and/or adjusted by rotating the control wheel 162 clockwise and counterclockwise relative to the crank arm 150 as desired. As shown in Figs. 5-8, in order to help select a desired effective crank arm length 560, the control wheel 162 may have a plurality of detents 576 extending about the circumference of the control wheel 162. A user can selectively lock the crank arm 150 to the control wheel 162 at a selected detent 576 in order to set the effective crank arm length 560, stroke distance, and tidal volume as desired. In other words, once the user rotates the control wheel 162 to a position in which a desired effective crank arm length 560 is selected, the user can selectively lock the crank arm 150 to the control wheel 162 to selectively fix the effective crank arm length 560. [0053] The first portion 154 of the crank arm 150 may include a detent lock 578 for selectively locking the crank arm 150 to the control wheel 162. In particular, the detent lock 578 may be selectively engaged to a selected one of the detents 576 to lock the crank arm 150 to the control wheel 162. When locked (see Figs. 5 and 7-8), the control wheel 162 is rotationally fixed relative to the crank arm 150 (i.e., the control wheel 162 cannot rotate relative to the crank arm 150) so that the effective crank arm length 560 is maintained during use, until changed by a user. Because the crank arm 150 is configured to rotate about the drive axis 256, the control wheel 162 rotates about the drive axis 256 with the crank arm 150 when locked to the crank arm 150.

[0054] To adjust the effective crank arm length 560, the detent lock 578 can be selectively disengaged from the detents 576 to unlock the control wheel 162 from the crank arm 150. When unlocked (see Fig. 6), the control wheel 162 may be rotated about the drive axis 256 relative to the crank arm 150 and the detent lock 578. A user can thus disengage the detent lock 578 from one detent 576 to unlock the control wheel 162, rotate the control wheel 162 relative to the crank arm 150, and then re-engage the detent lock 578 to a desired detent 576 to lock the control wheel 162 to the crank arm 150 at the selected detent 576.

[0055] As shown in Figs. 5-8, the detent lock 578 may be a spring loaded detent lock. That is, a user may press a driving portion 580 of the detent lock 578 to pivot/move an engaging portion 582 of the detent lock 578 away from the detents 576 against the bias of a spring. Once the user releases the driving portion 580 of the detent lock 578, the engaging portion 582 of the detent lock 578 may spring back to engage a selected detent 576. Alternatively, the detent lock 578 may be any other locking feature that is configured to be selectively moved into and out of engagement with the detents 576 of the control wheel 162 and maintained in a desired engagement for a predetermined period of use of the ventilator 100.

[0056] As shown in Figs. 5-8, the control wheel 162 may include markings 584 arrayed circumferentially about the control wheel. Each marking 584 of the control wheel 162 may correspond to a specific effective crank arm length 560 causing a specific stroke distance and tidal volume (i.e., the volume of gas displacement during the compression stroke). Therefore, each marking may also correspond to a specific position of the pin 146 along the spiral and/or elongated slots 164, 552. Each marking may be written in customary units relating to a specific effective crank arm length 560, stroke distance, and/or tidal volume. In the example shown in Fig. 8, the markings 584 are provided in medically customary units. In particular, as shown in Fig. 8, the markings 584 are provided as tidal volumes in milliliters.

[0057] As shown in Fig. 8, the ventilator 100 may have an indicator 886 adjacent to the control wheel 162 for helping to select a desired effective crank arm length 560, stroke distance, and/or tidal volume. A user may rotate the control wheel 162 until the indicator 886 is adjacent to a desired marking 584, and then engage detent lock 578 to a detent 576 that is adjacent to the detent lock 578 to lock the control wheel 138 to the crank arm 150. For example, if the user desires to deliver a tidal volume of 250 ml_ to a patient, the user may rotate the control wheel 162 until the indicator 886 is adjacent to the 250 ml_ marking 584 and then engage the detent lock 578 to a detent 576 to lock the control wheel 138 to the crank arm 150.

[0058] In view of the above, it should be appreciated that, the effective crank arm length 560, the stroke distance, and/or the tidal volume may be adjusted without having to disassemble the ventilator 100. For example, a user familiar with the procedure can complete the adjustment of the effective crank arm length 560, the stroke distance, and/or the tidal volume of the ventilator in a very short period of time, such as five seconds or less. The ventilator 100 can be either on and in operation, or off, during adjustment of the effective crank arm length 560, the stroke distance, and/or the tidal volume. However, it may be preferable to have turn the ventilator 100 off or briefly pause the operation of the ventilator 100 when adjusting the effective crank arm length 560, the stroke distance, and/or the tidal volume.

[0059] Although the user can select a tidal volume for patient delivery, the user may also adjust the pressure relief valve 116 so that the selected tidal volume is delivered to a patient below a certain set relief pressure. For example, as shown in Fig. 9, the pressure relief valve 116 may have a thumbscrew 990 with a thumbscrew head 992, a spring 994, a cap 996 that is biased by the spring 994 to close off an opening 198 (see Figs. 1 and 3b) in the head 106 that is in fluid communication with the bellows 102 and the chamber 122, and at least one pressure relief scale 9100 that corresponds to a biasing force of the spring 994. The pressure relief valve 116 of Fig. 9 is shown as having two pressure relief scales 9100 that provide for redundancy and indicate the same values. The thumbscrew head 992 may be adjusted to select a desired relief pressure by aligning a bottom 9102 of the thumbscrew head 992 with a selected relief pressure on the pressure relief scale 9100. If the gas pressure during delivery of the selected tidal volume reaches the selected relief pressure, the gas pressure will responsively cause the pressure relief valve 116 to open by urging the cap 996 longitudinally away from the opening 198 against the bias of the spring 994. Gas from the chamber 122 is released through the open pressure relief valve 116, thereby releasing a portion of the gas and preventing the gas pressure in the chamber 122 from exceeding the selected relief pressure. The gas released may also result in a reduction of the selected tidal volume being delivered to the patient. Therefore, the selected tidal volume may be configured to be delivered to a patient unless a user selected relief pressure is reached.

[0060] As shown in Fig. 2, a second portion 2104 of the crank arm 150 is connected to a drive shaft 2106. For example, as shown in Fig. 2, a first end 2108 of the drive shaft 2106 may be inserted into the second portion 2104 of the crank arm 150. The drive shaft 2106 is configured to be selectively rotated about the drive axis 256. The crank arm 150 may be rotationally fixed relative to the drive shaft 2106 so that the crank arms 150 responsively rotates about the drive axis 256 with the rotating drive shaft 2106. As shown in Fig. 2, the drive shaft 2106 may extend at least partially through the backbone 128 and may be at least partially supported for rotation on the backbone 128.

[0061] The drive shaft 2106 is positioned within the ventilator 100 so that it may be easily accessed and connected to a manual, mechanical, and/or motorized power source that operably rotates the drive shaft about the drive axis. Manual power may be provided by the patient for self-administration of breathing assistance, or by another person or persons. For example, as shown in Fig. 2, a hand-crank 2110 may be attached a second end 2112 of the drive shaft 2106. The hand-crank 2110 may be selectively rotationally fixed relative to the drive shaft 2106 so that manual rotation of the hand-crank 2110 about the drive axis 256 responsively causes the drive shaft 2106 to rotate with the hand-crank 2110 about the drive axis 256. Instead of, or in addition to, utilizing the hand-crank 2110 to manually rotate the drive shaft 2106, the ventilator 100 can have a hand-lever, a foot treadle, any other means configured to manually rotate the drive shaft 2106, or any combination thereof.

[0062] Mechanical power sources for rotating the drive shaft may include, but is not limited to, a stationary bicycle, a water powered mechanical device, a wind powered mechanical device, a solar powered mechanical device, or any combination thereof. For example, one or more ventilators 100 could be mechanically attached to a stationary bicycle for rotation of the drive shaft(s) 2106 thereof, particularly in a situation where electrical power is unreliable. Whether as a backup or main power source, a manual or mechanical power source could be connected to the drive shaft 2106 of the ventilator 100 as-needed at the time of use, or could stay connected to the drive shaft 2106 (or to a coupler for quick attachment) for use in an emergency or other short-notice situation, as noted below.

[0063] As shown in Fig. 2, a motorized power source can take the form of a motor 2114 that is operably connected (e.g., directly connected) to the drive shaft 2106 and configured to rotate the drive shaft 2106 upon selective actuation. The motor 2114 may be an electric motor (e.g., an electric alternating current motor, an electric direct current motor, an electric stepper motor, or an electric variable frequency drive motor), a hydraulic motor, a pneumatic motor, or any combination thereof. In the case of an electric motor, the electric motor may be powered from mains, a battery, or both. The energy required for operating the motor 2114 and any associated control circuits may be harvested from the action of the patient walking during self administration of breathing assistance, from other human mechanical input (e.g., from a hand-crank 2110 or stationary bicycle that is operably connected to the motor 2114), from an electrical power source (e.g., battery and/or a main), from hydropower, from wind power, from solar power, or from any combination thereof.

[0064] Wearable or portable energy storage means, including batteries and other storage devices, e.g., super capacitors, may also be provided for powering the rotation of the drive shaft 2106. The ventilator 100 may be configured to accept multiple sources of power either sequentially or concurrently.

[0065] The ventilator 100 may be configured to be selectively switched between power sources for rotating the drive shaft 2106. For example, the ventilator 100 may be selectively switch between a manual drive (i.e., a manual power source) and an automatic drive (i.e., a mechanical or motorized power source). In the example ventilator 100 shown in Fig 2, the drive shaft 2106 may be manually rotated by the hand-crank 2110, and automatically rotated by the motor 2114. Therefore, a user can switch between rotating the drive shaft 2106 manually with the hand-crank 2110 and rotating the drive shaft 2106 automatically with the motor 2114 as desired.

[0066] The switch between manual power and automatic power may be accomplished without mechanically disconnecting any parts of the ventilator 100.

For example, when the user desires to manually operate the ventilator 100, the user can grasp and rotate the hand-crank 2110 to operate the ventilator 100, while the motor 2114 remains unactuated and in a condition that does not prevent or inhibit the manual rotation of the drive shaft 2106. When the user desires to operate the ventilator 100 automatically, the user can simply disengage the hand-crank 2110 and then actuate the motor 2114 to rotate the drive shaft 2106 automatically. The switch between the power sources can thus be performed very quickly, e.g. 5 seconds or less, by a user familiar with the procedure.

[0067] During automatic operation, the hand-crank 2110 (or any other structure used as a manual power source) may be collapsed or folded into a stowed position. Alternatively, the hand-crank 2110 can be unattached from the drive shaft 2106 during automatic operation, and then reattached when manual operation is desired.

[0068] Fig. 3a depicts an example situation in which the manual power source has been disconnected from the drive shaft 2106. Fig. 3a also depicts an example configuration for powering the motor 2114. Fig. 3a includes an uninterruptible power supply 3116 that has a main power cord 3118 for connecting to an electrical outlet. An alternating current power cord 3120 provides power to a power supply 3122 from the uninterruptible power supply 3116. A direct current power cord 3124 provides power to a control unit 3126 from the power supply 3116. A wiring cord 3128 extends from the control unit 3126 to provide power to the motor 2114.

[0069] It is contemplated that the motor 2114 may be a flex-powered motor. The flex-powered motor may be at least partially powered by electricity but may also be configured to have a manual power source, such as a hand-crank, removably attached thereto. During manual operation, the user can turn the hand-crank to cause the mechanical features of the motor to rotate the drive shaft 2106 without having to energize the motor with electricity. During automatic operation, the user can disconnect the hand-crank from the motor and energize the motor with electricity to rotate the drive shaft 2106.

[0070] As shown in Figs. 2-3b, at least one of the drive shaft 2106, the motor 2114, the connecting rod 138, the pin 146, the crank arm 150, and the control wheel 162 may be directly or indirectly connected to a drive mount 2129. At least one of the drive shaft 2106, the motor 2114, the connecting rod 138, the pin 146, the crank arm 150, and the control wheel 162 may be at least partially supported on the backbone 128 of the supporting framework 126 by the drive mount 2129. The drive mount 2129 may be removably connected to the backbone 128 to allow for at least partial deconstruction of the ventilator 100.

[0071 ] The ventilator may have a patient circuit 1130 removably attached to the head 106. Figs. 1 -3a depict an example patient circuit 1130. The patient circuit 1130 can include more or fewer features than shown and described in relation to the example patient circuit 1130 of Figs. 1 -3a. For example, the patient circuit 1130 shown in Figs. 1-3a may include one or more of: a long breathing tube 1132 removably connected to the gas outlet check valve 114; an in-line inhalation filter 3134 connected to the long breathing tube 1132; an exhalation check valve 3136 connected to the long breathing tube 1132; a exhalation filter 3138 connected to the exhalation check valve 3136; a positive end-expiratory pressure (PEEP) valve 3140 connected to the exhalation filter 3138; an exhalation control tube 3142 connected to the exhalation check valve 3136 and to an exhalation control port 3144 on the head 106; a short breathing tube 3146 connected to the exhalation check valve 3136; a respiratory profile monitor sensor 3148 connected to the short breathing tube 3146; and a patient airway pressure tube 3150 connected to the control unit 3126 and to an in-line patient airway pressure filter 3152 of the ventilator 100. Instead of, or in addition to, the PEEP valve 3140, the ventilator 100 may have any other source of PEEP. For example, expiration tubing after the exhalation filter 3138 may extend to a predetermined distance below a water level in a water trap. The PEEP applied by this water-trap system may equal a distance between an end of the expiration tubing and the water level. The expiration tubing may be the short breathing tube 3146, a portion of the short breathing tube 3146, or another tubing of the ventilator 100.

[0072] The exhalation control tubing 3142 creates fluid communication between the chamber 122 and the exhalation check valve 3136. During inspiration, the chamber 122 is charged with pressure, which communicates to close the exhalation check valve 3136 via the exhalation control tube 3142. The patient airway pressure tube 3150 creates fluid communication between the short breathing tube 3146 and the control unit 3126. The respiratory profile monitor sensor 3148, when present, can be connected to a patient mask or endotracheal tube. When the respiratory profile monitor sensor 3148 is not present, the short breathing tube 3146 can be directly connected to the patient mask or endotracheal tube. For installation requiring Fi02 therapy, the ventilator 100 can include a mixing venturi 3154 connected to the gas inlet check valve 112, a flow regulator 3156, and a Fi02 supply line 3158 connecting the mixing venturi 3154 to the flow regulator 3156.

[0073] As shown in Figs. 10-12, in use, ambient air (oxygen-enriched as appropriate) is drawn from the environment through the gas inlet check valve 112 by decompression of the bellows 102 and expelled into the patient circuit 1130 through the gas outlet check valve 114 during subsequent compression of the bellows 102. As shown in Fig. 10, during bellows 102 decompression, the gas inlet check valve 112 is open while the gas outlet check valve 114 remains closed. As shown in Figs. 11-12, during the subsequent bellows 102 compression and pressurization, the gas inlet check valve 112 is closed while the gas outlet check valve 114 is open to pressurize the patient circuit 1130. Pressurization of the bellows 102 may also be in fluid communication with the exhalation check valve 3136 located on the patient circuit 1130 via the exhalation control tubing 3142, holding the exhalation check valve 3136 closed to allow the patient circuit 1130 to become pressurized during inspiration of air to the lungs. During the subsequent decompression of the bellows 102, the exhalation check valve 3136 may be released to allow expiration from the patient’s lungs. The gas outlet check valve 114 may be closed during patient expiration to prevent exhalations from entering the ventilator 110.

[0074] The ventilator 100 may support a plurality of ventilation modes. For example, the ventilator 100 may support, but is not limited to, a continuous mandatory ventilation (CMV) mode and an assist-control ventilation (ACV) mode. In CMV mode, the ventilator 100 may automatically reciprocate at regular intervals based on any combination of the selected inspiratory time, selected expiratory time, the l:E ratio, and the respiratory rate/BPM. In ACV mode, the patient is able to trigger each reciprocation of the ventilator 100 at desired, possibly irregular intervals, triggered by decreased pressure caused by patient respiratory effort at the beginning of spontaneous inspiration. In ACV mode, the patient airway pressure tube 3150 creates fluid communication between the short breathing tube 3146 and the control unit 3126, allowing the control unit to detect pressure changes caused by patient respiratory effort.

[0075] The ventilator 100 may also support a plurality of ventilation cycles. Example cycle types are, but are not limited to, a volume-controlled (VC) cycle and a pressure-limited (PL) cycle. For the VC cycle, the user selects a desired tidal volume using the control wheel 162 as described above, and the ventilator 100 delivers that volume to a patient. An example illustration of the VC cycle is shown in Figs. 10-11. For the PL cycle, the user may select a desired relief pressure by adjusting the pressure relief valve 116 as described above to help prevent the pressure of the selected tidal volume from exceeding the desired relief pressure when being delivered to the patient. An example illustration of the VC cycle is shown in Figs. 12. In Fig. 12, gas is shown as exiting the chamber 122 through the opened pressure relief valve 116 to maintain the pressure of the gas being delivered to the patient at or below the desired relief pressure.

[0076] Prior to, or during use, a user may select a desired combination of ventilation mode and ventilation cycle. For example, the user may select between one of a CMV-VC mode, a CMV-PL mode, an ACV-VC mode, and an ACV-PL mode. In a CMV-VC mode, the ventilator 100 delivers a selected volume of gas within a selected inspiratory time. The flow waveform is substantially sinusoidal due to the reciprocation geometry. Peak flow will occur approximately halfway through the inspiratory time. Pressure will vary with lung compliance and is limited by the adjustable pressure relief valve 116. In the event pressure relief occurs, volume delivery will decrease. The selected inspiratory time is immediately followed by the full selected expiratory time. [0077] In a CMV-PL mode, the ventilator 100 delivers gas as achievable without exceeding a selected relief pressure, which may be set with the adjustable pressure relief valve 116. In the CMV-PL mode, delivered volume is expected to be less than the selected volume. The selected inspiratory time is immediately followed by the full selected expiratory time.

[0078] In an ACV-VC mode, the ventilator 100 operates substantially identical to the CMV-VC mode, except that the selected expiratory time will end prematurely, and the next inspiration begins upon detection of patient effort. If no patient effort is detected, the ventilator 100 will continue to the end of the selected expiratory time, as described for the CMV mode above.

[0079] In an ACV-PL mode, the ventilator 100 operates substantially identical to the CMV-PL mode, except that the selected expiratory time will end prematurely, and the next inspiration begins upon detection of patient effort. If no patient effort is detected, the ventilator 100 will continue to the end of the selected expiratory time, as described for the CMV mode above. The ACV-PL mode may be used for spontaneous breathing trials or for patients weaning from ventilation.

[0080] As discussed above, the ventilator 100 delivers gas to the patient by compressing the bellows 102 a certain stroke distance dependent on the selected tidal volume. Adjustment of the tidal volume control changes the effective crank arm length 560 of the crank arm 150 and thus the length of the stroke resulting in change in displaced volume. For a given stroke, flow of gas through the patient circuit 1130 is the result of the displaced volume divided by the inspiratory time within which the bellows compression occurs. The flow waveform shape is substantially sinusoidal because the ventilator 100 operates based on reciprocation using the drive shaft 2106, the crank arm 150, and the connecting rod 138. During the inspiratory time, flow starts at zero, rises to peak at approximately midway through the inspiratory time, and returns to zero in the second half of the inspiratory time, as is depicted in Fig 13. All modes share this characteristic flow waveform, with the only difference between CMV and ACV modes being when the next inspiration begins. The only difference for pressure-limited modes, such as modes that use the PL cycle, is that peak flow, and thus delivered volume, are reduced by allowing gas to escape via the pressure relief valve. [0081] As illustrated in Figs. 14-16, an operating cycle of the ventilator 100 may include a compression stroke of the bellows 102 (Fig. 14) to deliver the inspiratory gas through the patient circuit 1130, followed by a decompression stroke of the bellows 102 (Fig. 15) to reposition the bellows 102 for the next compression stroke.

A dwell time may occur after the decompression stroke (Fig. 16). Duration of the compression stroke may be controlled to correspond to a selected inspiratory time. Duration of the decompression stroke and/or the dwell time may be controlled to correspond to a selected expiratory time. Expiratory time thus may be the combination of the duration of the decompression stroke and any dwell time. A respiratory rate, which is the inverse of the combination of durations of the compression stroke, the decompression stroke, and any dwell time, may be controlled by controlling the inspiratory time, the expiratory time, the duration of the decompression stroke, and/or the dwell time,. The cycle illustrated in Figs. 14-16 may not require directional control of the drive shaft 2106 as rotation of the drive shaft 2106 may be in a single direction (i.e., clockwise or counterclockwise). Figs. 14-15 show the rotation of the drive shaft 2106 being in the counterclockwise direction throughout the operating cycle, though it is contemplated that a clockwise rotation could be provided as desired for a particular use environment.

[0082] A diaphragm 110 initial velocity at the start of the compression stroke may be increased by using a starting position of the crank arm 150 that is beyond bottom- dead-center 17160 for better trigonometric advantage. Fig. 17 depicts the starting position of the crank arm 150 being beyond bottom-dead-center 17160. A bottom- dead-center line 17160 indicates the where the crank arm 150 would start if the crank arm 150 were to start at the bottom-dead-center. As depicted, the bottom- dead-center 17160 may be at least partially longitudinally below the drive axis 256.

In Fig. 17, the starting position of the crank arm 150 is shown by starting position line 17162 that extends in line with the crank arm 150. The starting position 17162 of the crank arm 150 in Fig. 17 is set at an angle b (e.g., a 90 degree angle) with respect to the bottom-dead-center 17160, such that the starting position 17162 of the crank arm 150 extends transversely beyond the bottom-dead-center 17160. Starting the crank arm 150 transversely beyond the bottom-dead-center 17160 may allow for better control over the inspiratory flow. For example, by extending the starting position 17162 of the crank arm 150 transversely beyond the bottom-dead-center 17160, peak flow occurs relatively early in the flow waveform, and declines along a sinusoidal path thereafter. This flow waveform at least partially mimics how patients breath naturally - flow may be “fast” at first, and slows down near-linearly as the breath is entrained.

[0083] When the crank arm 150 is adjusted to extend transversely beyond the bottom-dead-center 17160 at the start of the compression stroke, drive shaft rotation must oscillate direction either between compression and decompression strokes, or after each cycle. For example, as shown in Fig. 18, the drive shaft 2106 may rotate in the counterclockwise direction, and correspondingly rotate the crank arm 150 in the counterclockwise direction from the starting position 17162, during a compression stroke. As shown in Fig. 19, the drive shaft 2106 may then rotate in the clockwise direction, and correspondingly rotate the crank arm 150 in the clockwise direction back to the starting position 17162, during a decompression stroke. If the rotational direction of the drive shaft 2106 is not reversed, a dump valve may be provided to avoid pressurization of the bellows 102 while the crank arm 150 continues from bottom-dead-center 17160 back to the starting position 17162 of the crank arm 150 to avoid undesirably causing positive airway pressure or closure of the exhalation check valve 3136 during patient exhalation. The gas inlet check valve 112 may function as the dump valve through selective actuation that causes the gas inlet check valve 112 to open during the decompression stroke continuation beyond bottom-dead-center.

[0084] Returning to Fig. 13, the flow waveform may be sinusoidal due to reciprocation by conversion of circular motion corresponding to single direction constant rotational speed of the crank arm 150. In an example embodiment, this sinusoidal flow waveform phase may be translated to a front-loaded deescalating inspiratory waveform by any combination of (a) relocation of the starting position 17162 of the crank arm 150 as illustrated in Fig. 17, but wherein the drive axis 256 intersects the axis of reciprocation 434 (b) transversely offsetting the drive axis 256 from the axis of reciprocation 434 as illustrated in Fig. 20, such that the drive axis and axis of reciprocation no longer intersect, and/or (c) variable speed control of a velocity of the bellows 102 and/or diaphragm 110 along the axis of reciprocation 434. Shown in Fig. 20, offsetting the drive axis 256 comprehends that the shape of the flow waveform may be driven by the shape of two sinusoidal waves. One of these waves is the vertical velocity component of a pivot between the crank arm 150 and the connecting rod 138. The second wave is the vertical translation of the diaphragm 110 relative to the aforementioned pivot as a consequence of connecting rod 138 sway. The flow waveform is the sum of these two velocities. When the axis of reciprocation 434 intersects the drive axis 256, the sway of the connecting rod 138 subtracts from the first half of the compression cycle and adds to the second half of the cycle resulting in a peak flow rate that occurs after the halfway point of the compression cycle. Offsetting the drive axis 256 from the axis of reciprocation 434 shifts the phasing of these two waves causing peak flow to occur at or before the halfway point of the compression cycle. Therefore, the drive axis 256 may be transversely offset from the axis of reciprocation 434 by a distance 20164 (see Fig. 20) to phase shift the peak of the sinusoidal flow waveform.

[0085] The ventilator 100 may utilize precise timing means for controlling reciprocation speed and frequency in order to select and provide a desired inspiratory time, a desired expiratory time, a desired ratio of inspiratory and expiratory time (i.e., a desired inspiratory-expiratory ratio), and a desired respiratory rate. User controls and circuitry for accomplishment of timing means may be attached fixedly to the supporting framework 126 or located remotely by hard wired or wireless connection. For example, as described above, the ventilator 100 may have the control unit 3126 that controls the operation of the ventilator 100, such as by controlling the motor 2114 when the ventilator 100 is automatically driven. The control unit 3126 may be located exterior to a pathogen containment space containing the ventilator 100 and patient allowing for monitoring and operator control without entering the pathogen containment space.

[0086] The inspiratory time, the expiratory time, the duration of the decompression stroke, the dwell time, the inspiratory-expiratory ratio, the respiratory rate, or any combination thereof, may be controlled by a timing means that is manually powered or automatically powered. Timing means for manual power may simply be, for example, the action of turning the hand-crank 2110 at different speeds during different portions of the operating cycle. It can be seen that aspects of the ventilator 100 are readily configurable for use in a “field hospital” setting, or another locale with intermittent or unreliable electric power.

[0087] Timing means for automatic power may include the motor 2114 being controlled as desired by the control unit 3126. The control unit 3126 can operate the motor 2114 to have a single-speed corresponding to an inspiratory-expiratory ratio of 1 at a specific respiratory rate, two-speeds for inspiratory-expiratory ratio other than 1 at a specific respiratory rate, or three-speeds, where the bellows 102 is decompressed quickly and a third speed of zero is used to wait until detection of spontaneous inspiratory effort by the patient or the end of the desired expiratory time, whichever occurs first, allowing breath-to-breath variation in respiratory rate triggered by the spontaneous inspiratory effort of the patient. Speeds may be constant during respective strokes or variable to effect specific pressure waveforms during the respective strokes.

[0088] Timing means for when the ventilator 100 is driven automatically (e.g., by the motor 2114) or manually (e.g., by the hand-crank 2110) may use switches or sensors to indicate one or more reference positions for the stroke. The switches or sensors may be electromechanical, optoelectrical, capacitive, or magnetic. A rotary encoder may be provided to detect the rotary position of the crank arm 150, the connecting rod 138, and/or the drive shaft 2106. Timing control means for automatic embodiments may use multi-level voltage, variable voltage, pulse width modulation, stepped or variable frequency control for electric motors, or multi-speed or variable speed control means applicable to other motor types.

[0089] Timing means may provide for three or more distinct operating cycle portions including the compression stroke, the decompression stroke, and the dwell time before a subsequent compression stroke. Timing means may cause different diaphragm velocities during different portions of the operating cycle to accomplish specific operating characteristics which may include desired inspiratory-expiratory ratio, desired inspiratory pressure curves, desired inspiratory flow curves, and desired respiratory rates. Compression stroke diaphragm velocity along the axis of reciprocation may be fixed or variable. Decompression stroke duration may be selected to consume the entire balance of the desired expiratory time, or to end earlier to ensure the bellows 102 is refilled and ready for next compression stroke whenever triggered by patient spontaneous inhalation.

[0090] Timing means may accommodate different combinations of inspiratory time, expiratory time, decompression stroke duration, dwell time, inspiratory- expiratory ratio, and respiratory rate by asserting a dwell time between the decompression and compression strokes. Timing means may use adjustable dwell timeout to effect a minimum mandatory respiratory rate. Timing means may cause dwell to terminate in the event of a spontaneous breathing trigger from the patient circuit.

[0091] In an example embodiment, the decompression stroke is at the maximum diaphragm velocity possible for the given motor 2114 and control unit 3126 allowing for maximum potential increase in respiratory rate from cycle-to-cycle in the case the next compression stroke is initiated in response to spontaneous patient inhalation.

[0092] Timing means may use a single direction of drive shaft rotation or alternating direction of rotation. For single direction embodiments, timing means may include the dump valve to help prevent pressurization of the bellows 102 and patient circuit 1130 during any decompression stroke of the connecting rod 138 continuing beyond bottom-dead-center to the dwell position.

[0093] The motor 2114 may have electric, magnetic, or mechanical brakes that are controllable by the control unit 3126 to reduce overshooting the position at which motor drive power is removed.

[0094] The ventilator 100 may include a plurality of controls and indicators used by the user when operating the ventilator 100 as desired. The below includes an example list of possible controls and indicators for using the ventilator 100. The controls and indicators of the ventilator 100 of the present disclosure may include more or less than what is listed below.

[0095] · Tidal Volume. As described above and shown in Fig. 5-8, a tidal volume may be selected through the use of the control wheel 162, the crank arm 150, and the detent lock 578. For example, a tidal volume may be selected by pressing the detent lock 578 to unlock the control wheel 162 from the crank arm 150, rotating the control wheel 162 to align a desired tidal volume with the indicator 886, and releasing the detent lock 578 to lock the control wheel 162 to the crank arm 150.

[0096] · Relief Pressure. As described above and shown in Fig. 9, a relief pressure may be set by adjusting the thumbscrew 990 of the pressure relief valve 116 to align the bottom 9102 of the thumbscrew head 992 with the desired pressure on the scale 9100.

[0097] · Inspiration Time. When the ventilator 100 is powered by a manual power source, such as the hand-crank 2110, the inspiration time (i.e., the inspiratory time) may be selected and controlled by the rotating the hand-crank 2110 at a desired speed. When the ventilator 100 is powered by an automatic power source, such as the motor 2114, the user can utilize the control unit 3126 to set the inspiratory time as desired. Fig. 21 depicts an example control/indicator configuration for the control unit 3126. As illustrated in Fig. 21 , the control unit 3126 can include an inspiration time control 21166. Using the inspiration time control 21166, the inspiratory time can be set in seconds by aligning an indictor line 21168 of a knob 21170 with a desired duration on a scale 21172. In response, the control unit 3126 sends a signal to the motor 2114 that controls the motor 2114 to provide the desired inspiratory time. This results in the selected tidal volume being delivered to the patient over the selected inspiratory time in seconds.

[0098] · Expiration Time. When the ventilator 100 is powered by a manual power source, such as the hand-crank 2110, the expiration time (i.e., the expiratory time) may be selected and controlled by the user rotating the hand-crank 2110 at a desired speed. When the ventilator 100 is powered by an automatic power source, such as the motor 2114, the user can utilize the control unit 3126 to set the expiratory time as desired. As illustrated in Fig. 21 , the control unit 3126 can include an expiration time control 21174. Using the expiration time control 21174, the expiratory time can be set in seconds by aligning an indictor line 21176 of a knob 21178 with a desired duration on a scale 21180. In response, the control unit 3126 sends a signal to the motor 2114 that controls the motor 2114 to provide the desired expiratory time. Although the control unit 3126 is shown as controlling the expiratory time instead of separately controlling decompression stroke duration and dwell time, the control unit 3126 may include explicit controls for controlling the duration of the decompression stroke and/or the dwell time in addition to, or instead of, the expiration time control 21174.

[0099] · Inspiratory-Expiratory Ratio (“l:E ratio”) and Respiratory Rate in Breaths per Minute (BPM). There may be no explicit controls for setting the l:E ratio or the BPM, in some embodiments of the ventilator 100. Instead, the inspiratory time and expiratory time may be selected to implicitly set the l:E ratio and/or BPM as desired. The l:E ratio and the BPM may thus be the result of the selected inspiratory and expiratory times. Fig. 22 depicts example cue cards 22182 that a user may use to set the l:E ratio and/or the BPM as desired. In the absence of the cue cards, the l:E ratio may be computed by dividing the expiratory time by the inspiration time. In the absence of the cue cards, the BPM (i.e., the respiratory rate) can be calculated by dividing sixty (60) by the sum of the inspiratory and expiratory times. Other embodiments of the ventilator 100 may include explicit controls for setting the l:E ratio and/or the BPM.

[00100] · Assist Pressure Threshold and Indicators. As shown in Fig. 21 , the control unit 3126 may include an assist pressure threshold controller 21184. Using the assist pressure threshold controller 21184, a pressure threshold can be selected in cmH20 (hPA) by aligning an indicator line 21186 on a knob 21188 with a desired pressure on a scale 21190. When the set pressure threshold is achieved in the patient airway pressure tube 3150, the control unit 3126 sends a signal to the ventilator 100 to deliver a desired assisted breath to the patient. When using positive end-expiratory pressure (PEEP) therapy, the assist pressure threshold may be set below the PEEP. Early during a patient-initiated respiratory effort, pressure within the patient airway pressure tube 3150 drops below the PEEP. Once the pressure drops low enough to equal the set pressure threshold on the assist pressure threshold controller 21184, the control unit 3126 sends a signal to the ventilator 100 to deliver a desired assisted breath to the patient. For CMV modes, the assist pressure threshold may be set to a desired minimum. An assisted indicator 21192 may illuminate during each pressure-triggered inspiration cycle. A mandatory indicator 21194 may illuminate during each inspiration cycle initiated by reaching the end of the expiratory time settings without receiving a pressure- triggered assisted breath by the patient. [00101] · High-Pressure Alert and Indicator. The control unit 3126 may include a high-pressure alert controller 21196. A pressure level for causing a visual (e.g., through a visual indicator 21198), and audible (e.g., through a speaker 21200), and/or other user-perceptible high-pressure alert may be set in cmH20 (hPA) by aligning an indicator line 21202 on a knob 21204 with a desired pressure on a scale 21206. The control unit 3126 may include an alarms controller 21208 for setting alerts, such as the high-pressure alert, to be audible (e.g., by moving a switch 21210 to an audible position 21212) or silenced (e.g., by moving the switch 21210 to a silent position 21214). The speaker 21200 may sound when the patient airway pressure is at or above the high-pressure alert setting and may sound until a reset button 21216 is pressed. The visual indicator 21198 may illuminate when the patient airway pressure, for example, in the patient airway pressure tube 3150, is at or above the high-pressure alert setting and may remain illuminated until the reset button 21216 is pressed. The visual and/or audible alert may immediately recur unless the condition is alleviated, or the pressure setting is changed.

[00102] · Reset (High Pressure Alert). The reset button 21216 may be used to cancel the high-pressure alert. Pressing the reset button 21216 will only stop the alert if the condition has been alleviated or the high-pressure alert setting is changed.

[00103] · Pressure Activity Alert (inactivity alert). There may be no user control for the pressure activity alert on the control unit 3126. This alert may be caused by a continuing positive pressure of less than 10 cmH20 variation longer than 15 seconds. Therefore, this alert may be helpful for signaling when the patient has been disconnected from the ventilator 100. The alert condition may be silenced by setting the alarms switch 21210 in the silent position 21214.

[00104] · Pressure Activity Alert Indicator. The pressure activity alert indicator 21218 may illuminate while the pressure activity alert is active.

[00105] · Alarms. The high-pressure and pressure activity alerts may be silenced by setting the alarms switch 21210 in the silent position 21214. To return the alarms to audible, the switch 21210 may be set in the audible position 21212. [00106] · Power. The control unit 3126, and thus the ventilator 100, may be started by setting a power switch 21220 to an On (“I”) position 21222 and stopped by setting the switch 21220 to an Off (“0”) position 21224. An audible alarm may sound if control unit/ventilator 3126/100 power is lost while the power switch 21220 is in the On (I) position 21222. This alert may be terminated by providing power to the control unit/ventilator 3126/100 or turning the control unit/ventilator 3126/100 off. The control unit 3126 may not need to be turned on using the power switch 21220 when the ventilator 100 is operating with manual power.

[00107] · Post-Inspiratory Hold Button. The control unit 3126 may include a post- inspiratory hold button 21226. When the hold button 21226 is held, the ventilator may deliver the set volume and then pause, allowing for lung pressures to equilibrate so that pulmonary mechanics can be calculated. The addition of this hold button 21226 may be helpful for patients with ARDS on lung-protective ventilation protocols.

[00108] · Delivered Volume Sensor. The control unit 3126 may include a qualitative delivered volume sensor. The control unit 3126 may include a series of light indicators 21228, 21230, 21232 that are configured to “light up” at certain delivered volume increments. For example, at a low delivered volume increment, a first light indicator 21228 may light up. At a moderate delivered volume increment, a second light indicator 21230 may light up instead of or in addition to the first light indicator 21228. At a high delivered volume increment, a third light indicator 21232 may light up instead of or in addition to the first and second light indicators 21228,

21230. The light indicators 21228, 21230, 21232 may allow a provider to “look” at a sedated patient, or a patient receiving pressure-limited ventilation, and know that the set volumes are being delivered to the patient. For obtaining the volume measurement, the ventilator 100 may have a volume sensor located in a similar location as the patient airway pressure tube 3150, connecting the short breathing tube 3146 and the control unit 3126. There are various kinds of volume sensors that can be used by the ventilator 100. The volume sensor can be electronic and directly wired to the control unit 3126. Alternatively, the volume sensor may comprise two pressure sensors with intervening resistor tubing within the short breathing tube 3146, having a connection to the control unit 3126 with tubing. A volume sensor configured in this manner may sense the pressure drop across the resistor tubing to calculate flow, which would be integrated by the control unit 3126 to generate volume. Although the control unit 3126 has been shown as having three light indicators 21228, 21230, 21232 for the qualitative delivered volume sensor, the control unit 3126 may have any number of lights each configured to light up at a certain delivered volume increment.

[00109] An example operation of the ventilator 100 using at least the control unit 3126, the control wheel 162, and the pressure relief valve 116 is described below. This description is not meant to limit the operation of the ventilator 100. Using the control wheel 162, the detent lock 578, and the crank arm 150 as described above, a desired tidal volume can be selected responsive to, for example, the height, weight, and/or condition of a patient. Using the pressure relief valve 116 as described above, a relief pressure may be set to the maximum limit for the CMV-VC or the ACV-VC modes. Alternatively, the relief pressure may be set lower than the maximum, as desired, for the CMV-PL or the ACV-PL modes. Using the control unit 3126, the inspiratory time, expiratory time, the l:E ratio, and the respiratory rate/BPM may be selected. The high-pressure alert may be set. The alarms may be turned to audible. The assist pressure threshold may be set to -5 or lower for CMV modes or to the desired assist pressure threshold for ACV modes. The patient circuit 1130 may be connected to the ventilator 100. The ventilator 100 may be turned on. The manometer 320 may be checked to verify pressure is not exceeding the selected relief pressure. Ventilatory parameters may be adjusted in accordance with patient requirements and treatment protocol.

[00110] It is contemplated that the bellows 102 may be oriented at any angle, vertical, horizontal, or otherwise, and may be oriented with the head 106 at the top, the bottom, or in any other position. For example, although the bellows 102 has been shown as extending in the longitudinal direction and described as being compressed and decompressed by reciprocation substantially in the longitudinal direction, the bellows may extend in any desired direction, such as, for example, the longitudinal, lateral, or transverse direction, and may be correspondingly compressed and decompressed by reciprocation substantially in the desired direction, such as, for example in the longitudinal, lateral, or transverse direction. [00111] It is contemplated that the portions of the ventilator 100 may be collapsible for transport, portable, or wearable, may be used for self-administered breathing assistance, and may use single bellows 102, or multiple bellows 102 in parallel, opposing or radial arrangements to contain a given total gas displacement capability within a particular packaging aspect ratio, to accomplish desired flow waveforms, or both. The flow waveform may be continuous, in particular use environments.

[00112] It is contemplated that biocompatible materials may be used for each of the head 106, the bellows 102, the diaphragm 110, the gas inlet check valve 112, the gas outlet check valve 114, and the pressure relief valve 116, in some use environments. For example, each of the head 106 and the valves 112, 114, 116 may be formed at least partially from polycarbonate, while each of the bellows 102 and the diaphragm 110 may be formed at least partially from polypropylene. Each of the clamp 132, the connecting rod 138, and the drive mounts 2129 may be at least partially formed from acrylonitrile butadiene styrene or polycarbonate/acrylonitrile butadiene styrene for greater rigidity. Each of the control wheel 162 and the crank arm 150 may be formed at least partially from aluminum. Each of the backbone 128, the support base 330, and the guides 132 may be formed at least partially from polyvinyl chloride. Other appropriate materials may be used. The plastic parts may be injection molded. Other appropriate fabrication methods may be used.

[00113] While aspects of this disclosure have been particularly shown and described with reference to the example aspects above, it will be understood by those of ordinary skill in the art that various additional aspects may be contemplated. For example, the specific methods described above for using the apparatus are merely illustrative; one of ordinary skill in the art could readily determine any number of tools, sequences of steps, or other means/options for placing the above-described apparatus, or components thereof, into positions substantively similar to those shown and described herein. In an effort to maintain clarity in the Figures, certain ones of duplicative components shown have not been specifically numbered, but one of ordinary skill in the art will realize, based upon the components that were numbered, the element numbers which should be associated with the unnumbered components; no differentiation between similar components is intended or implied solely by the presence or absence of an element number in the Figures. Any of the described structures and components could be integrally formed as a single unitary or monolithic piece or made up of separate sub-components, with either of these formations involving any suitable stock or bespoke components and/or any suitable material or combinations of materials. Any of the described structures and components could be disposable or reusable as desired for a particular use environment. Any component could be provided with a user-perceptible marking to indicate a material, configuration, at least one dimension, or the like pertaining to that component, the user-perceptible marking potentially aiding a user in selecting one component from an array of similar components for a particular use environment. A “predetermined” status may be determined at any time before the structures being manipulated actually reach that status, the “predetermination” being made as late as immediately before the structure achieves the predetermined status. The term “substantially” is used herein to indicate a quality that is largely, but not necessarily wholly, that which is specified-a “substantial” quality admits of the potential for some relatively minor inclusion of a non-quality item. Though certain components described herein are shown as having specific geometric shapes, all structures of this disclosure may have any suitable shapes, sizes, configurations, relative relationships, cross-sectional areas, or any other physical characteristics as desirable for a particular application. Any structures or features described with reference to one aspect or configuration could be provided, singly or in combination with other structures or features, to any other aspect or configuration, as it would be impractical to describe each of the aspects and configurations discussed herein as having all of the options discussed with respect to all of the other aspects and configurations. A device or method incorporating any of these features should be understood to fall under the scope of this disclosure as determined based upon the claims below and any equivalents thereof.

[0001] Other aspects, objects, and advantages can be obtained from a study of the drawings, the disclosure, and the appended claims.

Claims

We claim:

1 . A respiratory ventilator, comprising: a bellows configured to be compressed to deliver a selected tidal volume to a patient and decompressed to draw gas into the bellows; a connecting rod operably connected to the bellows to compress and decompress the bellows by reciprocation along an axis of reciprocation, the connecting rod compressing the bellows by a selected stroke distance that corresponds to the selected tidal volume; a pin extending through the connecting rod; a crank arm configured to be selectively rotated about a drive axis, the crank arm having an elongated slot into which the pin extends to connect the connecting rod to the crank arm, selective rotation of the crank arm about the drive axis responsively causing the connecting rod to compress and decompress the bellows, the pin being selectively moveable along the elongated slot toward and away from the drive axis, an effective crank arm length being a distance between the pin and the drive axis, the effective crank arm length directly corresponding to the stroke distance of the connecting rod; and a control wheel for selectively adjusting the effective crank arm length, the control wheel having a slot into which the pin extends, the control wheel being selectively rotatable relative to the crank arm, selective rotation of the control wheel relative to the crank arm urging the pin to move along the elongated slot toward and away from the drive axis to selectively adjust the effective crank arm length; wherein the ventilator is configured to be selectively adjusted to deliver the selected tidal volume to the patient by selectively adjusting the effective crank arm length with the control wheel to provide the selected stroke distance that corresponds to the selected tidal volume.

2. The respiratory ventilator of claim 1 , wherein the slot of the control wheel is a spiral slot, the spiral slot having a first end adjacent to the drive axis, the spiral slot spiraling away from the drive axis so that a second end of the spiral slot is spaced further from the drive axis than any other portion of the spiral slot is spaced from the drive axis.

3. The respiratory ventilator of claim 2, wherein selective rotation of the control wheel responsively causes the pin to move along the spiral slot from one of the first and second ends of the spiral slot to the other of the first and second ends of the spiral slot, the pin being urged to move along the elongated slot of the crank arm by a periphery of the spiral slot as the pin moves along the spiral slot.

4. The respiratory ventilator of claim 2, wherein when the pin is adjacent to both the first end of the spiral slot and a first end of the elongated slot, the effective crank arm length is a first effective crank arm length, when the pin is adjacent to both the second end of the spiral slot and a second end of the elongated slot, the effective crank arm length is a second effective crank arm length, and when the pin is positioned between the first and second ends of both the spiral and elongated slots, the effective crank arm length is a third effective crank arm length, the third effective crank arm length being greater than the first effective crank arm length and less than the second effective crank arm length.

5. The respiratory ventilator of claim 1 , wherein the control wheel has a plurality of detents extending about the circumference of the control wheel, the respiratory ventilator further comprising: a detent lock being selectively engaged to a selected one of the detents to selectively lock the crank arm to the control wheel, the control wheel being rotationally fixed relative to the crank arm when the crank arm and control wheel are selectively locked together to prevent the effective crank arm length from being adjusted.

6. The respiratory ventilator of claim 1 , wherein the control wheel includes markings arrayed circumferentially about the control wheel, each marking corresponding to a specific tidal volume, the respiratory ventilator further comprising: an indicator adjacent to the control wheel, the selected tidal volume being selected when the indicator is positioned adjacent to a marking that corresponds to the selected tidal volume.

7. The respiratory ventilator of claim 1 , further comprising a head attached to an end of the bellows, the head having a gas inlet check valve through which gas is drawn into the bellows by decompression of the bellows, the head having a gas outlet check valve through which gas from the bellows is delivered to a patient.

8. The respiratory ventilator of claim 7, further comprising a diaphragm attached to an end of the bellows that is opposite the head, the connecting rod being attached to the diaphragm and operably connected to the bellows through the diaphragm.

9. The respiratory ventilator of claim 8, further comprising: a support post for supporting each of the head, the bellows, and the diaphragm, the head being selectively attached to the support post; a clamp selectively attached to the support post; and at least one guide extending between the head and the clamp, the at least one guide at least partially surrounding at least one of the bellows and the diaphragm to help guide the reciprocating motion of the bellows along the axis of reciprocation.

10. The respiratory ventilator of claim 7, further comprising an adjustable pressure relief valve on the head for selecting a relief pressure in the ventilator, gas pressure during deliver of the selected tidal volume reaching the selected relief pressure responsively causing the pressure relief valve to open to release a portion of the gas pressure, a tidal volume less than the selected tidal volume being delivered to the patient upon opening of the pressure relief valve.

11. The respiratory ventilator of claim 10, wherein the pressure relief valve includes a thumbscrew with a thumbscrew head, a spring, a cap that is biased by the spring to close off an opening in the head that is in fluid communication with the bellows, and a pressure relief scale that corresponds to a biasing force of the spring, the thumbscrew being adjustable to the selected relief pressure by aligning a bottom of the thumbscrew head with the selected relief pressure on the scale, the gas pressure during delivery of the selected tidal volume reaching the selected relief pressure responsively causing the pressure relief valve to open by urging the cap away from the opening against the bias of the spring.

12. The respiratory ventilator of claim 1 , further comprising a drive shaft configured to be selective rotated about the drive axis, the crank arm being connected to and selectively rotated by the drive shaft about the drive axis.

13. The respiratory ventilator of claim 12, further comprising: a hand-crank selectively attached to the drive shaft, manual rotation of the hand-crank about the drive axis responsively causing the drive shaft to rotate about the drive axis; and a motor operably connected to the drive shaft and configured to rotate the drive shaft upon selective actuation; wherein the drive shaft is configured to be switchable between being rotated manually by the hand-crank, and automatically by the motor.

14. The respiratory ventilator of claim 1 , wherein the effective crank arm length is substantially equal to half the stroke distance of the connecting rod.

15. A method for delivering a selected tidal volume to a patient, the method comprising: providing the respiratory ventilator of claim 1 ; adjusting the effective crank arm length by rotating the control wheel relative to the crank arm to provide the selected stroke distance that corresponds to the selected tidal volume; and with the effective crank arm length adjusted, rotating the crank arm about the drive axis to responsively cause the connecting rod to compress the bellows by the selected stroke distance, compression of the bellows by the selected stroke distance responsively causing bellows to deliver the selected tidal volume to the patient.

16. A respiratory ventilator, comprising: a bellows configured to be compressed to deliver a selected tidal volume to a patient and decompressed to draw gas into the bellows; a connecting rod operably connected to the bellows to compress and decompress the bellows by reciprocation along an axis of reciprocation, the connecting rod compressing the bellows by a selected stroke distance that corresponds to the selected tidal volume; and a drive shaft selectively rotatable about a drive axis, selective rotation of the drive shaft about the drive axis responsively causing the connecting rod to compress and decompress the bellows, the drive shaft being configured to be switchable between being rotated manually and automatically.

17. The respiratory ventilator of claim 16, further comprising: a hand-crank selectively attached to the drive shaft, manual rotation of the hand-crank about the drive axis responsively causing the drive shaft to rotate about the drive axis; and a motor operably connected to the drive shaft and configured to automatically rotate the drive shaft upon selective actuation; wherein the drive shaft is configured to be switchable between being rotated manually by the hand-crank, and automatically by the motor.

18. The respiratory ventilator of claim 16, further comprising: a crank arm connected to the connecting rod and to the drive shaft, the crank arm being selectively rotated by the drive shaft about the drive axis, selective rotation of the crank arm about the drive axis responsively causing the connecting rod to compress and decompress the bellows.

19. The respiratory ventilator of claim 18, further comprising: a pin extending through the connecting rod; wherein the crank arm has an elongated slot into which the pin extends to connect the connecting rod to the crank arm, the pin being selectively moveable along the elongated slot toward and away from the drive axis, an effective crank arm length being a distance between the pin and the drive axis, the effective crank arm length substantially equaling half the stroke distance of the connecting rod.

20. The respiratory ventilator of claim 19, further comprising: a control wheel for selectively adjusting the effective crank arm length, the control wheel having a slot into which the pin extends, the control wheel being selectively rotatable relative to the crank arm, selective rotation of the control wheel relative to the crank arm urging the pin to move along the elongated slot toward and away from the drive axis to selectively adjust the effective crank arm length; wherein the ventilator is configured to be selectively adjusted to deliver the selected tidal volume to the patient by selectively adjusting the effective crank arm length with the control wheel to provide the selected stroke distance that corresponds to the selected tidal volume.

21 . The respiratory ventilator of claim 20, wherein the slot of the control wheel is a spiral slot, the spiral slot having a first end adjacent to the drive axis, the spiral slot spiraling away from the drive axis so that a second end of the spiral slot is spaced further from the drive axis than any other portion of the spiral slot is spaced from the drive axis.

22. The respiratory ventilator of claim 21 , wherein selective rotation of the control wheel responsively causes the pin to move along the spiral slot from one of the first and second ends of the spiral slot to the other of the first and second ends of the spiral slot, the pin being urged to move along the elongated slot of the crank arm by a periphery of the spiral slot as the pin moves along the spiral slot.

23. The respiratory ventilator of claim 21 , wherein when the pin is adjacent to both the first end of the spiral slot and a first end of the elongated slot, the effective crank arm length is a first effective crank arm length, when the pin is adjacent to both the second end of the spiral slot and a second end of the elongated slot, the effective crank arm length is a second effective crank arm length, and when the pin is positioned between the first and second ends of both the spiral and elongated slots, the effective crank arm length is a third effective crank arm length, the third effective crank arm length being greater than the first effective crank arm length and less than the second effective crank arm length.

24. The respiratory ventilator of claim 21 , wherein the control wheel has a plurality of detents extending about the circumference of the control wheel, the respiratory ventilator further comprising: a detent lock being selectively engaged to a selected one of the detents to selectively lock the crank arm to the control wheel, the control wheel being rotationally fixed relative to the crank arm when the crank arm and control wheel are selectively locked together to prevent the effective crank arm length from being adjusted.

25. The respiratory ventilator of claim 21 , wherein the control wheel includes markings arrayed circumferentially about the control wheel, each marking corresponding to a specific tidal volume, the respiratory ventilator further comprising: an indicator adjacent to the control wheel, the selected tidal volume being selected when the indicator is positioned adjacent to a marking that corresponds to the selected tidal volume.

26. The respiratory ventilator of claim 16, further comprising a head attached to an end of the bellows, the head having a gas inlet check valve through which gas is drawn into the bellows by decompression of the bellows, the head having a gas outlet check valve through which gas from the bellows is delivered to a patient.

27. The respiratory ventilator of claim 26, further comprising a diaphragm attached to an end of the bellows that is opposite the head, the connecting rod being attached to the diaphragm and operably connected to the bellows through the diaphragm.

28. The respiratory ventilator of claim 27, further comprising: a support post for supporting each of the head, the bellows, and the diaphragm, the head being selectively attached to the support post; a clamp selectively attached to the support post; and at least one guide extending between the head and the clamp, the at least one guide at least partially surrounding at least one of the bellows and the diaphragm to help guide the reciprocating motion of the bellows along the axis of reciprocation.

29. The respiratory ventilator of claim 26, further comprising an adjustable pressure relief valve on the head for selecting a relief pressure in the ventilator, gas pressure during delivery of the selected tidal volume reaching the selected relief pressure responsively causing the pressure relief valve to open to release a portion of the gas pressure, a tidal volume less than the selected tidal volume being delivered to the patient upon opening of the pressure relief valve.

30. The respiratory ventilator of claim 29, wherein the pressure relief valve includes a thumbscrew with a thumbscrew head, a spring, a cap that is biased by the spring to close off an opening in the head that is in fluid communication with the bellows, and a pressure relief scale that corresponds to a biasing force of the spring, the thumbscrew being adjustable to the selected relief pressure by aligning a bottom of the thumbscrew head with the selected relief pressure on the scale, the gas pressure of the selected tidal volume reaching the selected relief pressure while being delivered to the patient responsively causing the pressure relief valve to open by urging the cap away from the opening against the bias of the spring.