SE532701C2 - Device for setting mandatory mechanical ventilation parameters based on patient physiology - Google Patents

Description

l5 20 25 30 35 40 45 monitoring and interpretation of ventilator parameters move to empirical assessment and thereby lead to a treatment that is less than optimal, even by doctors with the best intentions.

The situation is further complicated by the fact that ventilator support should be individually arranged for each patient's existing pathophysiology instead of using a generalized approach for all patients with potentially different needs for ventilation.

Pragmatically, the overall efficiency of assisted ventilation will ultimately continue to depend on mechanical, technical and physiological factors, with the interaction between the clinician, the ventilator and the patient always continuing to play a key role. Thus, technology is needed that demystifies these complex interactions and that provides appropriate information to effectively ventilate patients.

In accordance with the above, it remains desirable to achieve maximum effective mechanical ventilation parameters and to thereby specifically engage clinics to provide appropriate amounts and qualities of ventilator support to patients, arranged for each individual patient's specially ventilated pathophysiology.

SUMMARY OF THE INVENTION The above problems are solved with a device for adjusting the size of the breath of an individual in controlled mechanical ventilation. The device comprises: means arranged to vary the tidal volumes of an individual during a predetermined inhalation time and a predetermined exhalation time, with for determining final tidal gas concentrations associated with said tidal volumes and means for curve fitting a relationship between said tidal volumes and said end time.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS A clear idea of the advantages and features which form arrangements according to the invention and of different design and operating aspects of typical mechanisms provided by such arrangements is obtained by looking at the following illustrations, for example serving, representative and / or non-limiting urer clocks which form an integral part of this description, wherein like numerals generally indicate the same elements in the views arising in a number, where Figure I shows a front perspective view of a medical system comprising a valve Figure 2 is a block diagram of a medical system that provides ventilator support to a patient, Figure 3 shows a block diagram of a ventilator that provides ventilator support to the patient, Figure 4 shows a fate diagram of the patient's inhalation time (TI), exhalation time (TE) and natural exhalation time (TEXH) for single breaths, especially during regulated mechanical ventilation (CMV), Figure 5 shows a fl schedule of a simplified arrangement for setting the patient's exhalation time (TE) based on the patient's natural exhalation time (TEXH), Figure 6 shows a fl schedule of a simplified arrangement for setting the patient's exhalation time (TEEX). TE) based on when the patient's natural exhalation fl ceases, Figure 7 shows a fl fate chart of a simplified arrangement for setting the patient's exhalation time (TE) based on the time when the patient's tidal volume has ceased, Figure 8 shows a response curve over the patient's exhaled time (dTl) and the COE (F ECOZ) levels that the patient has when exhaling, Figure 9 illustrates the response curve for the delivered inhalation time (dTI) shown in Figure 8 and graphically shows an arrangement for identifying the patient's optimal inhalation time (TEOETIMAE), 10 15 20 Figure 10 shows a response curve of the patient's delivered inhalation time (dT1) and exhaled VCO 2 levels, ii Figure I] v shows a response curve over the patient's emitted tidal volume (dVT) and exhaled CO; - DÅVåCI '(FETCOQ), Figure 12 shows the relationship between the patient's emitted inhalation pressure (dPINSp) and delivered tidal volumes (dVT) and Figure 13 shows a patient response curve (dVT) dPINSP) and patient levels (FETCO2) of exhaled C02. DETAILED DESCRIPTION OF DIFFERENT PREFERRED EMBODIMENTS Referring now to Figures and particularly to Figures 1-3, a medical system 10 is shown for mechanically ventilating a patient 12. More specifically, an anesthetic device 14 includes a ventilator 16 having suitable connections 18, 20. for connection to an inhalation branch 22 and an exhalation branch 24 in a breathing circuit 26 leading to the patient 12. As will be explained in more detail below, the ventilator 16 and the breathing circuit 18 cooperate to form breathing gases to the patient via the inhalation branch 22 and to receive gases that the patient 12 exhales via the exhalation branch 24.

If desired, the ventilator 16 may also be provided with a bag 28 for manual convergence relative to the patient 12. More specifically, the bag 28 may be filled with breathing gases and manually compressed by a clinician (not shown) to provide suitable breathing gases to the patient 12. The use of this bag 28 or “bag treatment of the patient” is often required and / or preferred by the clinicians, since the person in question can thereby manually and / or immediately regulate the release of the respiratory gases to the patient 12. It is equally important that the clinician can sense conditions in the breathing and / or lungs 30 of the patient 12 in accordance with how the bag 28 feels and can then perform adaptation in connection therewith. Although it may be difficult to accurately obtain this feedback during mechanical ventilation of the patient 12 using the ventilator 16, it may also tire the clinician if the clinician has to treat the patient 12 with the bag for an excessive period of time. Thus, the fan 16 can also be provided with a rocker 32 for switching and / or switching between manual and automated ventilation.

In any case, the ventilator 16 may also receive input signals from sensors 34 associated with the patient 12 and / or the ventilator 16 at a treatment terminal 36 for subsequent treatment thereof and which may be displayed on a monitor 36 which may be provided by the medical system 10 and / or or similar. Representative data received from the sensors 34 may include, for example, inhalation time (TI), exhalation time (TE), natural exhalation time (TEXH), respiration rates (f), conditions liE, positive final exhalation pressure (PEEP), fraction of inhaled oxygen (FIOZ), fraction exhaled oxygen (F E02), respiratory gas flow (F), tidal volumes (VT), temperatures (T), lu fi road pressure (Pm), saturation levels of arterial blood oxygen (S302), blood pressure information (BP), heart rate (PR), pulse oximetry levels (SpOz), exhaled COZ levels (F ETCOZ), concentration of inhaled anesthetic (C1), concentration of exhaled anesthetic (CE), arterial blood oxygen partial pressure (PaOZ), arterial carbon dioxide pressure (PaCO 2) and the like.

Referring now specifically to Figure 2, the ventilator 16 provides breathing gases to the patient 12 via the breathing circuit 26. Thus, the breathing circuit 26 usually includes the aforementioned inhalation branch 22 and the exhalation branch 24. Usually, the single end of each of the inhalation branch 22 and the exhalation branch 24 is connected to the fan 16 while their other ends are usually connected to a Y-connector 40, which can then be connected to the patient 12 through a patient branch 10 [20 fr: | 42 which may also include a boundary portion 43 for securing the patient's airway connection to the respiratory circuit 26 and / or preventing gas leakage therefrom.

Referring now more closely to Figure 3, the fan 16 may also include an electronic control circuit 44 and / or a compressed air circuit 46. More specifically, compressed air elements in the compressed air circuit 46 supply the patient 12's lungs 30 with breathing gases through the inhalation branch 22 of the breathing circuit 26 during inhalation. Upon exhalation, the respiratory gases are discharged from the patient's 12 lungs 30 and into the exhalation branch 24 of the respiratory circuit 26. The process can be activated repeatedly by the electronic control circuit 44 and / or the compressed air circuit 46 in the ventilator 16, which may establish different control parameters such as breaths per minute that the patient 12 is to be given, tidal volumes (VT), maximum pressure, etc. that can characterize the mechanical ventilation that the ventilator 16 provides the patient 12 with. As such, the ventilator 16 may be microprocessor-based and drivable in conjunction with a suitable memory for controlling the compressed air gas exchanges in the breathing circuit 26 which is connected to and between the patient 12 and the ventilator 16.

More specifically, the various compressed air elements in the compressed air circuit 46 usually comprise a source of pressurized gas (not shown), which can operate through a gas concentration subsystem (not shown) to supply the breathing gases to the patient's 12 lungs 30. This compressed air circuit 46 can supply the breathing gases directly to the patient's 12 lungs 30 as is typical in a chronic application and / or a critical care application, or else it may feed a propellant to compress a bellows 48 (see Figure 1) which contains the breathing gases and which in turn may supply the breathing gases to the patient's 12 lungs as is typical in one application. with anesthesia. In both cases, the breathing gases repeatedly pass from the inhalation branch 22 to the Y-connection 40 and to the patient 12 and then back to the ventilator 16 via the Y-connection 40 and the exhalation branch 24. In the embodiment shown in Figure 3, one or more of the sensors 34, which are located in the breathing circuit 26, also supply feedback signals back to the electronic control circuit 44 of the fan 16, in particular via a feedback loop 52. More specifically, a signal in the feedback loop 52 could, for example, be proportional to gas fl fate and / or airway pressure in patient branch 42 leading to the patient's 12 lungs 30. Inhaled and exhaled gas concentrations (such as, for example, oxygen 02, carbon dioxide CO 2, nitrous oxide N 2 O and inhalants for inhalation), flow rates (including, for example, spirometry), and gas pressure levels, etc., are also representative. feedback signals that could be captured by the sensors 34, which also applies r for the periods of time between when the ventilator 16 allows the patient 12 to inhale and exhale as well as when the patient 12's natural inhalation and exhalation fates cease.

The electronic control circuit 44 of the ventilator 16 may also control the display of numerical and / or graphical information from the breathing circuit 26 on the monitor 38 of the medical system 10 (see Figure 1) as well as other patient 12 and / or system parameters from other sensors 34 and / or the treatment terminal 36 (see Figure 1). In other embodiments, different components can be integrated and / or separated as required and / or as desired.

By means of methods known in the art, the electronic control circuit 44 can also coordinate and / or regulate e.g. other fan setting signals 54, fan control signals 56 and a processing subsystem 58, for example for receiving and processing signals such as from the sensors 34, display signals for the monitor 38 and / or the like, alarms 60 and / or an operator connection 62 which may include one or more input devices 64, etc, all as required and / or desired and interconnected in an appropriate manner (see eg figure 2). These components are functionally shown for clarity, in which some may also be integrated and / or separated as required and / or as desired. For 10 15 20 25 30 35 40 45 further improved clarity, other functional components could also be easily understood but are not shown - e.g. one or more voltage supplies for the medical system 10 and / or the anesthesia machine 14 and / or the ventilator 16, etc. (not shown).

Against this background, the arrangements according to the invention establish ventilation parameters according to patient physiology. These arrangements, which will now be described, enable clinicians to regulate patient ventilation parameters throughout the patient's 12 breathing cycle and enable individually optimized ventilation treatments for patients 12 exposed to regulated mechanical ventilation (CMV).

To facilitate the following discussion, please refer to the following generalized and / or representative explanations and / or definitions: 1. TI is the inhalation time. More specifically, the TI is the time span, measured in seconds, which is set by the ventilator 16 by the clinician and which lasts from the beginning of the patient's 12 inhalation to the beginning of the patient's 12 exhalation. Thus, TI is the patient's 12 inhalation time.

Inhalation times TI can be further degraded to a set inhalation time sTI, a given inhalation time dTI and a measured inhalation time mTI. More specifically, the set inhalation time sTI is the time that the clinician sets on the ventilator 16 to deliver gases to the patient 12 during inhalation, while the delivered inhalation time dTI is the time that gases may actually be delivered to the patient 12 from the ventilator 16 during inhalation. Similarly, the measured inhalation time mTI is the time that the ventilator 16 measures to allow gases to be delivered to the patient 12 during inhalation. Ideally, the set inhalation time sTI, the delivered inhalation time dTI and the measured inhalation time mTI are equal or substantially equal. However, if the clinician or ventilator 16 is looking for an optimal inhalation time TIOPIIMAE, as will be explained in more detail below, each of these inhalation times TI may be different or slightly different. For example, the clinician and / or ventilator 16 may have established a set inhalation time sTI, but the delivered inhalation time dTI may still deviate therefrom during the course then, it looks for, for example, the patient's 12 optimal inhalation time TIOEIIIIAI. 2. TE is the exhalation time.

More specifically, TE is the time, measured in seconds, that the clinician sets on the ventilator 16 and that runs from the beginning of the patient's 12 exhalation to the beginning of the patient's 12 exhalation. Thus, TE is the patient's 12 exhalation time.

(In the same way as the inhalation times TI, the exhalation times TE can be further broken down to a set exhalation time sTE, a given exhalation time dTE and a measured exhalation time mTE. More specifically, the set exhalation time sTE is the time that clinicians set on ventilator 16 to allow patient 12 exhale gases during exhalation while the delivered exhalation time dTE is the time that gases may be exhaled by the patient 12 during exhalation. Similarly, the measured exhalation time mTE is the time that the ventilator 16 measures to have allowed the patient 12 to exhale ideally, the set exhalation time sTE, the delivered exhalation time dTE and the measured exhalation time mTE are equal or substantially equal, however, if the clinician or ventilator 16 is looking for an optimal exhalation time TE, which will be discussed in more detail below, For example, each of these exhalation times TE may be different or slightly different h / or the ventilator 16 has established a set exhalation time sTE, but the delivered exhalation time dTE can still deviate from it during the process when, for example, the patient's natural exhalation time TEXII is sought. 10 15 20 25 30 35 40 533? 'Ü'1 3. I: E ratios are ratios between T; and TE.

More specifically, the conditions I: E measure inhalation times divided by exhalation times - ie TI / TE, which is usually expressed as a ratio. Usual I: E ratios are 1: 2, which means that patients 12 can inhale for a certain time (x) and then exhale for twice as long (2x). However, since some patients 12 may have obstructive pathologies (Lex. Chronic obstructive pulmonary disease (COPD)) and / or prolonged exhalation, which means that the clinician must set longer exhalation times TE, conditions I: E can also be set to conditions that are closer 1: 3 and / or 1: 4, in particular to provide the required exhalation time TE for a given patient 12 to be able to exhale completely, even if conditions I: E from 1: 8 and 2: 1 are not are unusual, with standard fans 16 giving 0.5 ratings in between. 4. TEXE is a natural exhalation time.

More specifically, the TEXH time, measured in seconds, is required for the patient's 12 natural exhalation fate to cease. Thus, TEXE is the patient's 12 natural exhalation time.

Often the patient's 12 exhalation time TE is not equal to the patient's 12 natural exhalation time TEXE, ie the patient's 12 exhalation time TE set by the clinician on the ventilator 16 often does not coincide with the patient's 12 natural exhalation time TEXE. Furthermore, in accordance with many incorrect settings on many fans 16, breathing rates f (see below) are usually set between 6-10 breaths / minute, whereas the conditions I: E are usually set to 1: 2, which results in many clinics setting exhalation times TE between 4.0 and 6.6 seconds in contrast to typical natural exhalation times TEXH, which amount to less than or equal to about 0.8 - 1.5 seconds. On the other hand, several of the arrangements according to the invention set the patient's 12 exhalation times TE approximately equal to the patient's 12 natural exhalation times TEXE (ie 2 * TEEX 2 TE 2 TEXE).

If the clinician or ventilator 16 sets the patient 12's exhalation time TE to less than or equal to the patient's 12 natural exhalation time TEXE, the time 12 may be insufficient for the patient 12 to expel the gases in the patient's 12 lungs 30. This may result in respiration stacking in the patient's 12 lungs 30. (ie so-called “breathing stacking”), whereby the patient's 12 lung pressure is increased unintentionally and / or unknowingly.

Thus, the arrangements of the invention set the patient's 12 exhalation time TE approximately equal to the patient's 12 natural exhalation time TEXE, preferably with the patient's 12 exhalation time TE set so that it is longer or equal to the patient's natural exhalation time TEXE. 5. PEEP is positive final breathing pressure.

More specifically, the PEEP is the patient's 12 positive final exhalation pressures, which are often measured in cm H20. Thus, PEEP is the magnitude of the pressure in the patient's 12 lungs 30 at the end of the patient's 12 exhalation time TE, as indicated by the ventilator 16.

Like inhalation times TI and exhalation times TE, positive final exhalation pressure PEEP can also be degraded to a set positive final exhalation pressure sPEEP, a measured positive final exhalation pressure mPPEP and a given positive final exhalation pressure dPEEP. More specifically, the set positive final exhalation pressure sPEEP is the magnitude of the pressure the clinician sets on the ventilator 16 for the patient 12, while the measured positive final exhalation pressure mPEEP is the magnitude of the pressure in the patient's 12 lungs 30 at the end of the patient's 12 exhalation time TE. Similarly, the delivered positive final exhalation pressure dPEEP is the magnitude of the pressure delivered by the ventilator to the patient 12. Typically, the set positive final exhalation pressure is sPEEP, the measured positive final exhalation pressure mPEEP, and the positive final exhaled pressure emitted are substantially equal to or dPEEP. However, the measured positive final exhalation pressure mPEEP may be greater than the set positive final exhalation pressure sPEEP when, for example, respiratory stacking occurs. 6. F10; is a fraction of the oxygen fed.

More specifically, F10; the concentration of oxygen in the patient's 12 inhalation gas, often expressed as a fraction or a percentage. Thus, FTOg is the patient's 12 fraction of oxygen that is inhaled. 7. FEO, is a fraction of oxygen that is exhaled.

More specifically, F50; the concentration of oxygen in the patient's 12 exhaled gas, often expressed as a proportion or fraction. Thus, FEO; the patient's 12 fraction of exhaled oxygen. 8. f is the rate of respiration.

More specifically, the patient's 12 breathing rate, measured in breaths / minute, is set on the ventilator 16 by the clinker. 9. VT is the tidal volume.

More specifically, VT is the total volume of gases, measured in millimeters, delivered to the patient's 12 lungs during inhalation. Thus, VT is the patient's 12 tidal volume. _ In the same way as inhalation times TT and exhalation times TF, tidal volumes VT can also be broken down to a set tidal volume sVT, a given tidal volume dVT and a measured tidal volume mVT. More specifically, the set tidal volume sVT is the volume of gases that the clinician sets on the ventilator 16 to deliver gases to the patient 12 during inhalation, while the delivered tidal volume dVT is the volume of gases actually delivered to the patient 12 from the ventilator 16 during inhalation. Similarly, the measured tidal volume mVT is the volume of gases that the ventilator 16 measures to have delivered gases to the patient 12 during inhalation. Ideally, the set tidal volume sVT, the emitted tidal volume dVT and the measured tidal volume mVT are equal or substantially equal. However, if the clinician or ventilator 16 is looking for a set optimal tidal value sVT, as will be mentioned more below, each of these set tidal volumes sVT may be different or slightly different. * 10. FETCO, the end time carbon dioxide is C02.

More specifically, the FETCOT is the concentration of carbon dioxide C02 in the patient's 12 gas exhaled, o fi a expressed as a fraction or a percentage. Thus, FETCOZ is the amount of carbon dioxide CO2 that patient 12 has exhaled at the end of a given breath. 15 25 30 35 40 45 50 533? Ü'å ll. VCO; is the volume of carbon dioxide CO2 per breath.

More specifically, VCO; the volume of carbon dioxide CO2 that patient 12 exhales in a single breath.

Thus, VCO; patient's 12 volume of CO; which the person in question exhales per breath.

Clinics usually begin ventilation by selecting an originally set tidal volume sVT, respiratory rate f, and ratio I: E. The respiration rate f and the ratio I: E usually determine the originally set inhalation time STI and the originally set exhalation time sTE that the clinician sets on the ventilator 1.6. In other words, the actual set inhalation time sTl and the actual inhaled time sTE that the clinician typically uses are determined according to the following equations: _: JL sT fi- STE nEJ-'ÃI- STK Klinikem usually makes these initial determinations based on generic gymnastics rules. positions taking into account such factors as, for example, the patient's age 12, weight, height, sex, geographical location, etc. Once the clinician has made these initial determinations, the arrangements according to the invention can now be understood. Referring to Figure 4, a graph is shown of the relationship between delivered inhalation time dTI, delivered exhalation time dTE and natural exhalation time TEXH in the case of a single breathing cycle for a patient 12 exposed to controlled mechanical ventilation (CMV). As can be seen in the figure, the patient's exhaled exhalation time dTE is longer than the patient's 12 natural exhalation time TEXH, as shown by the measured exhalation time mTE.

Referring now to Figure 5, a simple arrangement for setting the patient's set 12 exhalation time sTE based on the patient's 12 natural exhalation time TEXH is displayed. More specifically, a method begins in a step 100, during which the patient's 12 natural exhalation time TEXH is determined. The patient's 12 natural exhalation time TEXH is preferably determined using the patient's 12 airway fate wave, especially when its preexisting derivative approaches zero, as is well known in the art. Alternatively, other arrangements are also well known in the art and may also be used to determine the patient's 12 natural exhalation time TEXH in step 100, such as, for example, analysis of the patient's 12 lu fi path fl fate, tidal volume VT analysis of the patient 12, acoustic analysis of patient 12, vibration analysis of patient 12, airway pressure analysis Pm of patient 12, capnographic morphology analysis of patient 12, respiratory mechanics analysis of patient 12, and / or chest excursion corresponding to gases exhaled from patient 12's lungs 30 (e.g. imaging of patient analysis 'of the patient 12 and / or electrical impedance tomography (analysis of the patient and / or the like), etc.

Then, the patient's 12 natural exhalation time TEXH can be used to set the patient's 12 set exhalation time sTE on the ventilator 16. More specifically, the patient's 12 set exhalation time sTE can be set based on the patient's 12 natural exhalation time TEXH and, for example, set equal to or substantially equal to the patient's 12 natural exhalation time TEXH as shown in step 102 in Figure 5, after which this method ceases.

In accordance with the above, the patient's set 12 exhalation time sTE is preferably set equal to or slightly greater than the patient's 12 natural exhalation time TEXH. However, if the patient's 12 natural exhalation flow does not cease at the end of the patient's 12 ventilated set exhalation time sTE, as this time is set by the clinician and / or ventilator, the clinician may increase the patient's 12 exhaled exhalation time. STB until the patient's 12 natural exhalation fl ceases.

As mentioned earlier, the spontaneous breathing of the patient 12 is regulated by many stimuli that control the patient's 12 breathing rates f and tidal volumes VT. Especially during regulated mechanical ventilation (CVM), these reflexes are either subdued and / or overwhelming. One of the only aspects of ventilation that usually remains during the patient's 12 regulation is in fact the patient's 12 natural exhalation time TEXT, which is required for a given volume as mentioned above. This is why it can be used to set the patient's set set exhalation time sTE on the ventilator 16 accordingly.

The arrangements specified according to the invention utilize the patient's 12 natural exhalation time TEXH and / or physiological parameters to determine and / or set the patient's 12 set exhalation time sTE, set inhalation time sTT and / or set tidal volume sVT, either directly and / or indirectly. For example, the patient's 12 inhalation time TT can be set directly or otherwise it can be determined from the breathing rate f for a certain set exhalation time sTE. Likewise, the patient's set 12 tidal volume sVT can also be set directly or the arms can be determined by adjusting the patient's 12 inhalation pressure (PTNSP) in, for example, pressure control ventilation (PCV). Adding the patient's set 12 inhalation time sTT to the patient's 12 set exhalation time sTE results in a breath time which, when divided by 60 seconds, gives the patient's 12 breathing rate f Thus, the patient's 12 set inhalation time sTT, set exhalation time sTE and respiration rate f do not is integer. Referring now to Figure 6, a flow chart shows a simplified arrangement for setting the patient's set 12 exhalation time sTE based on when the patient's 12 natural exhalation flow ceases. More specifically, a method begins in step 104, during which the cessation of the natural fate of the patient's 12 expirations is determined. Preferably, the cessation of the patient's 12 natural exhalation fate is determined using the patient's 12 air flow wave, especially as its precursor derivative approaches zero, as is well known in the art. Alternatively, other arrangements are well known in the art and may also be used to determine when the patient's 12 natural exhalation fate ceases. Thereafter, the patient 12 cessation of natural exhalation fl fate can be used to set the patient 12's set exhalation time sTE on the ventilator 16. More specifically, the patient 12's set exhalation time sTE can be set based on the patient 12 cessation of natural exhalation de fate and ii for example set equal to or substantially equal to when the natural exhalation fate of the patient 12 ceases, as shown in a step 106 in Figure 6, after which the mode is terminated.

Referring now to Figure 7, a fate diagram shows a simplified arrangement for setting the patient's set 12 exhalation time sTE based on when the patient's 12 tidal volume VT ceases. More specifically, a method begins in step 108, during which the cessation of the patient's 12 tidal volume VT is determined.

Preferably, the termination of the tidal volume VT of the patient 12 is determined using an fl fate sensor. Alternatively, other arrangements are well known in the art and can be used to determine when the patient's 12 tidal volume VT ends.

There, the patient's 12 exhalation with the tidal volume VT can be used to set the patient's 12 set exhalation time sTE on the ventilator 16. More specifically, the patient's 12 exhaled time sTE can be set based on the patient's 12 exhalation with the tidal volume VT and, for example, set equal to or generally seen equal to when the patient's 12 tidal volume VT ceases as shown in a step 110 in Figure 7, after which the method ceases. 15 20 25 30 35 40 50 55 532? 'Ü'l 10 As previously stated, the following applies: __ 60 _ sT, + .sTE El sTE whereby knowledge of the patient's 12 breathing rate f and ratio I: E allows determination of the patient's 12 set inhalation time. sTI and set exhalation time sTE with knowledge that the patient's I: E = 'of the 12 set inhalation time sT, and set exhalation time sTE inversely allow determination of the patient's 12 respiration rate f and ratio I: E. Preferably, the clinician and / or ventilator sets the patient's 12 breathing rate f and set exhalation time sTE, for which the patient's 12 set inhalation time sT, and ratio I: E can then be determined using the equations above.

Although various mandatory mechanical ventilation methods can be used with the techniques of the invention, volume guaranteed pressure control ventilation (ie PCV-VG) will be further described below as a representative example, as it has a retarding fate profile based on the patient's natural respiration. the inhalation pressure emitted by the fan, and the set tidal volume SVT is guaranteed by the fan on the basis of breath to breath. However, the arrangements according to the invention are equally applicable to other pressure control ventilation (PCV) and / or other fan operating methods for fan control ventilation (V CV).

In any case, fl era of the primary control settings on a typical fan 16 include controls for one or more of the following: setting exhalation time sTE, setting inhalation time STI, setting tidal volumes sVT and / or fraction of oxygen FIOZ that has been inhaled.

According to the patient's 12 physiological measurements in a state of permanence, the following applies: Våo; = FL., Co, * Mt; where VÖOz is the volume of CO2 per minute exhaled by the patient 12 and MV is the minute volume which is the total volume exhaled per minute by the patient 12. As used in these terms the index A indicates "alveolar", which is part of the patient's 12 lungs which participates in gas exchanges with the patient's 12 blood as opposed to dead space (VD) such as the patient's 12 airway.

In this state of permanence and for a short time, the patient's 12 blood reservoir is such that »VCOz is a constant (blood reservoir effects will be treated below) and in accordance with this equation, as MVA increases, the patient's 12 end time carbon dioxide FETCO; to decrease when VÖÛZ is constant. Thus substitution of MV A = VA * f gives the following: 60 = FmCO2 * VA * f = F¿-TC0¿ * V¿ * V1. = V¿ + VD Thus, the same VÖOZ can be achieved by increasing the patient's 12 VA and / or decreasing the patient's 12 respiratory rate f Decreasing the patient's 12 respiratory rate f has the same effect as increasing the patient's 12 exhaled time dT1 on the ventilator 16. Many respiratory rates f- and emitted respiration time- dTI combinations can actually result in equivalent or almost equivalent VCOZ production. Thus, an optimal combination is desired. 10 15 20 25 30 35 40 532 TÜå ll As described above, the patient's 12 natural exhalation time TEXH measures the period of time when the patient's' natural exhalation gas fl ceases during mechanical ventilation - ie the patient's 12 natural exhalation time TEXH includes the duration of gas flow during the patient's 12 delivered exhalation time dTÉ. If flow ceases, this indicates that the patient's 12 lungs are at their final expiratory lung volume (EELV). Continued gas exchange after the EELV could be less efficient, largely as a result of the reduced volume of gases in the patient's 12 lungs 30, leading to a reduced gas exchange gradient between the lung and the blood. As a result, initiation of a new breath (ie patient 12 begins a new breath) may be more effective.

Referring now to Figure 8, the clinician may also increase or decrease the patient 12 set inhalation time STI on the ventilator 16 until the patient 12's resulting end-time carbon dioxide FETC02 is or becomes stable to changes in the patient's 12 exhaled time dT1. More specifically, this identifies the patient's 12 optimal inhalation time TLOPTIMAL. Preferably, the clinician and / or ventilator 16 will be able to determine this optimal inhalation time TLOPTIMAL within a few breaths of the patient 12 for any given inhalation cycle. For example, when a stable end-time carbon dioxide FETCO 2 is reached, the preferred equalization of carbon dioxide CO 2 during a given emitted inhalation time dT; is achieved, since little or no more carbon dioxide CO 2 can be extracted efficiently from the patient's 12 blood at all by increasing the patient's 12 exhaled inhalation time dT; further. Thus, the patient's 12 optimal inhalation time TLOmMAL can be ascertained and / or set. More specifically, the patient's final endpoint carbon dioxide F ETC02 can be considered stable or more stable at or after a point A on a dTI gene response curve 150 in the (gure (see, e.g., a first portion 150a of the dT1 gene response curve 150) and not at all stable or less stable or unstable at or before that point A (see Lex. a second part 150b of the dTI response curve 150). Thus, point A on the dTI response curve 150 can be used to determine the patient's 12 optimal inhalation time TLOPUMAL as indicated in the figure.

Physiologically, when the patient's 12 end total carbon dioxide FETCO2 is equal to the patient's 12 capillary carbon dioxide FcCO2, diffusion and removal of carbon dioxide CO2 from the patient's 12 blood stops. Ideally, the patient's 12 optimal inhalation time TLOPTIMAL is set where this definition becomes ineffective or stops. Otherwise, a less given inhalation time would dT; be able to suggest that additional carbon dioxide CO 2 could be effectively removed from the patient's 12 blood during a longer inhaled time dT; could indicate that no additional carbon dioxide C02 could be effectively removed from the patient's 12 blood.

Preferably, the patient's 12 stable end-to-end carbon dioxide FETC02 is found without interference from the patient's 12 blood chemistry results. A preferred technique for finding the patient's 12 stable end time carbon dioxide FETCO2 can increase or decrease the patient's 12 inhalation time dTI, which can minimally disrupt the patient's 12 blood reservoir of carbon dioxide CO2. Changes in the patient's 12 delivered inhalation time dTI will affect how the patient's 12 blood buffers the patient's 12 carbon dioxide CO 2, and whether that blood circulates back to the patient's 12 lungs 30 before the patient's 12 set inhalation time sT; has been optimized, the patient's 12 end time carbon dioxide FETC02 will be different for a given inhalation time dTI. In this case, optimization of the patient's set 12 inhalation time sT1 can become a dynamic process. Under all conditions, the time available to find the patient's 12 optimal inhalation times can be TI. oNmnAL be approximately one (1) minute for an average adult patient 12.

One way to reduce the likelihood of disturbances from the patient's 12 blood chemistry results is to change the patient's 12 delivered inhalation time dT; for two (2) or fl of your inhalations and then using the patient's 12 resulting endpoint carbon dioxide FETCO 2 was extrapolated using an a priori function, such as an exponential friction, by methods known in the art. 10 15 20 25 30 35 40 532? Ü'l 12 If, for example, the patient's 12 first end time carbon dioxide FETCO; originally determined at a point B on a dT1 response curve 152 in the figure and then at a point C and then at a point D and then at a point E and further at a point F and then at a point G etc. the data points ( eg points BG) can be collected and a dT1 response curve 1502 with best fit is obtained with extrapolation if required. Preferably, the dTI response curve 152 is piecewise continuous.

For example, a first portion 152a of the dTI gene response curve 152 may comprise a stable horizontal or substantially horizontal portion (e.g., points BD) while a second portion 152b thereof may comprise a polynomial portion (e.g., points EG ). Where this first part 152a and second part 152b of the dT1 response curve 152 intersect (see, for example, point A of the dTI response curve 152), it can be used to determine the optimal inhalation time TLOPTIMAL of the patient 12 as indicated in ñguren. For example, with reference now to Figure 9, an arrangement for identifying the patient's optimal inhalation time TLOPTIMAL based on a repeated course will now be described. More specifically, a preferred arrangement for determining an optimal inhalation time collects TI QPTIMAL FETCOZ data in equal or nearly equal inhalation time increments ATI. If, for example, the patient's 12 first sluttidal carbon dioxide FETCO; originally found to be within the first portion 152a of the dT1 gene response curve 152 (see, e.g., points BD), the clinician and / or ventilator 16 could reduce the patient's 12 delivered inhalation times dT] until the patient's 12 endpoint carbon dioxide FgTCO within the second part l52b of the dTI response curve 152 (see eg EC points).

If e.g. patient's 12 end valve carbon dioxide FETCO; originally found to be at point C on the dTI response curve 152 (ie, within the first portion 15a of the dT1 response curve 152), the patient's 12 exhaled inhalation time dT; could be reduced until the patient's 12 next end-time carbon dioxide -FETCO2 was found to be at a point D on the dTI response curve 1.52, at which point the patient's 12 end-time carbon dioxide F ETCOZ would still be found to be within the first part 152a of the dTI response curve 152. Thus, the patient's exhaled time dT] can be reduced again until patient 12's next end time carbon dioxide FETCO2 had been found to be at a point E on the dTI response curve 152, at which point patient 12's end time carbon dioxide PECO; would now be found to be within the second part l52b of the dTI gene response curve 152 (ie the patient's 12 end time carbon dioxide FETCO; would have dropped and thus not settle at the patient's 12 optimal inhalation time TLOPTIMAL). Thus, a less delivered inhalation time increment of ATI / x could be made to determine when the patient's 12 end valve carbon dioxide FETCO; would start at point A on the dT1 response curve 152 - ie at the intersection of the first part 152a of the dTI response curve 152 and the second part l52b of the dT; response curve 152. In this repeated manner, successively less time increments and / or decrement AT] is determined to determine the patient's optimal inhalation time TLOPTIMAL as indicated in the figure.

If similarly the patient's 12 end valve carbon dioxide FETCO; initially would be found to be at point F on the dTI response curve 152 (ie, within the second portion 152b of the dTI response curve 152), the patient's 12 exhaled time dT would be released; be able to be increased until the patient's 12 next end time carbon dioxide F ETCO; would have been determined to be at point E of the dTI response curve 152, at which point the patient's 12 endpoint carbon dioxide FETCOZ would still be found to be within the second portion l52b of the dTI response curve 152. Thus, the patient's 12 exhaled inhalation time dT; be able to be increased again until the patient 12's next end valve carbon dioxide FETCO; would have been found to be at point D on the dTI response curve 152, at which point the patient's 12 endpoint carbon dioxide FETCOZ would now be found to be within the first part 152a of the dTI response curve 152 (ie the patient's 12 endpoint carbon dioxide FETCO; would not have increased and thus not patient's 12 optimal inhalation time TLOPTIMAL). 10 20 25 30 35- 40 45 FB? Thus, a smaller release inhalation time decrement ATI / x could be made to determine when the patient's end time carbon dioxide FETCOZ would be at point A of the dTI response curve 152 - I, i.e. at the intersection of the first portion 152a of the dT1 response curve 152 and the second portion 152b. of the dTI response curve 152. In this repeated manner, successively less emitted time increments and / or decrements are brought AT; again to determine the patient's 12 optimal inhalation time TLOPTIMAL as marked in the clock.

In addition, when the patient's 12 optimal inhalation time TwpnMAL is determined, it is found that this can be dynamic, whereby the above-mentioned arrangements can be repeated as needed and / or as desired.

A lower limit for the patient's 12 set inhalation time sT1 should be directly related to the minimum time required to deliver the patient's 12 minimum set tidal volume SVT.

A lower limit for the patient's 12 set and delivered tidal volume sVT, dVT should be higher than VD, preferably within a predetermined and / or clinically selected safety margin. A rearrangement of the Enghoff-Bohr equation can preferably be used to appoint the CEO or the following variation: mg FrfCÛs Once the patient's 12 end time carbon dioxide FETCOZ has been determined, the patient's 12 set time volume sVT can be set accordingly, but it must not be set yet. to an optimal value. O fi a för- g = a-n = m- _ the clinician and / or the ventilator 16 seek to determine this desired value. For example, the clinician may consider the desired value as the patient's final endpoint carbon dioxide FETCO; before determination. The clinician can then adjust the patient's set 12 tidal volume sVT until the desired end-time carbon dioxide FETCOZ has been reached. Alternatively or in conjunction therewith, a predetermined methodology may also be used to adjust the patient's delivered tidal volume dVT until the desired end tidal carbon dioxide FETCOZ is obtained. For example, such a methodology can use a linear way to achieve a desired final carbon dioxide FETCOZ. Preferably, the clinician can work with a dialog box on the monitor 38, which, for example (see Figure 1), indicates that the current and / or updated optimal settings of the ventilator 16 should be accepted or discarded. Preferably, these settings can be presented to the clinician in the acceptance or rejection dialog box, whereby the person can accept them, discard them and / or change them before the person in question accepts them. Alternatively, the settings can also be accepted automatically without using such a dialog box. .

As stated above, various techniques can also be used to search for optimal settings for the fan 16. If desired, the values given can also be changed periodically to see if, for example, the settings are still optimal.

These changes may follow one or more of the above methodologies and may be determined on the basis of a predetermined and / or clinician-selected time interval, at the request of the physiologist and / or determined by other regulatory parameters, based for example on clinical events, such as rings in the patient's 12 end total carbon dioxide FETCO; or on clinical events such as changes in drug dosages, changes in the patient's physical condition, surgical events and the like. For example, the patient's delivered inhalation time dT, may vary around its current value-set inhalation time sT1, in addition to the resulting end-time carbon dioxide FETCO; can be compared with the current end-time carbon dioxide FETCO; to assess how optimal the current settings are If, for example, a longer given inhalation time dT1 leads to a larger end time carbon dioxide F ETCO; the currently set inhalation time sTI could be too short. In an alternative embodiment, the dT1 response curve 154 could be expressed in terms of VCO; instead of FETCO; as shown in Figure 10. The morphology of the response curve 154 becomes similar to that shown in Figure 9. Without loss of generality, the above techniques can be used to firm TI.

OPTIMAL using VCO; as opposed to FETC02. VCO; is equal to the internal product over a breath between a volume curve and a CO 2 curve. The flow and COZ curves should be synchronized in time. As a representative summary of potential inputs to and outputs from, such a methodology is given below: 'Clinical inputs The patient's age 12, weight, height, sex, position and / or desired FETCOZ, etc. Measured inputs End time carbon dioxide FETCOQ, flow wave data, etc. Output The patient's 12 set exhalation time sTE, set inhalation time, and / or set tidal volume sVT By creating a closer match between the patient's 12 set exhalation time sTE and the patient's 12 natural exhalation, average ventilation. In addition, there is further optimal removal of carbon dioxide CO 2, improved oxygenation and / or more equalization of anesthetics, whereby ventilated gas exchanges become more efficient with respect to the use of lower set tidal volume dV-f compared to conventional settings. Small ventilations and respiratory resistance may be reduced, and a decrease in volumes may result in a decrease in the patient's 12 airway pressure Paw, thereby reducing the risk of inadvertently overextending the lung.

In addition, the arrangements of the invention facilitate ventilation for patients 1-2 with acute respiratory distress syndrome, and they can be used to improve the usefulness during both single and double lung ventilations as well as transitions between them.

As a result of the above, the arrangements of the invention according to the invention set the patient's set exhalation time sTE equal to the time period between when the ventilator 16 allows the patient 12 to exhale and when the patient's 12 exhalation upph ceases - ie the patient's 12 natural exhalation time TEXH. This facilitates the breathing of the patient 12 by ensuring that ventilated air currents are suitable for the patient 12 at that time in the treatment. In addition, ways to set optimal patient-inspired time TwmMAL and the desired tidal volume are presented. Referring now to Figure 11, this shows a response curve to the patient's emitted tidal volume (dVT) and CO 2 levels (F EICO 2) that have been exhaled. More specifically, for a given and / or predetermined inhalation time T; and exhalation time TE that the patient's 12 delivered tidal volumes dVT can be caused to vary, for which the patient's corresponding end tidal gas concentrations FETCO; associated with it can be determined. For example, a first emitted tidal volume lstdCT may correspond to a first final idle gas concentration ISTETCOQ (see for example point H in the clock) while a second emitted tidal volume 2 "ddVT may correspond to a second final idle gas concentration ZMFETCOQ (see eg point I in the figure) while a third emitted tidal volume TddVT may correspond to a third final tidal gas concentration WFETCO; (see Lex. point I in the figure) etc. Once two or more of these data points are known, a curve 160 can be fitted between them to define a first relationship between the patient's 12 delivered tidal volumes dVT and end-tidal gas concentrations FETCOQ.Therefore, a desired delivered tidal volume 10 15 20 25 30 35 532? Û * l 15 xdTT can be determined for the patient 12 based on a desired end-time concentration XFHCOZ and curve 160 (see for example point X in the fi clock Similarly, after the relationship has been established, the curve 160 can be displayed on the monitor 38 and / or the like, whereby a clinician can determine the desired time delivery. lyme xdVT for patient 12 based on the desired X-FETCO tidal gas concentrations; and the display.

Referring now to Figure 12, a second relationship between patient 12 delivered inhalation pressure dPfNsp and delivered tidal volumes dVT can also be established according to a second curve 162, for which the clinician can then determine the desired delivered inhaled pressure xdPmsp for patient 12 based on the desired the final gas concentrations xFETCO2, the first relationship (eg curve 160) and the second relationship (eg curve 162). Referring now to Figure 13, this shows a response curve of the patient's exhaled pressure dPmSp and exhaled CO 2 levels (FETCOZ). More specifically, for a given and / or predetermined inhalation time TI and exhalation time TE, the patient's 12 exhaled pressure dPmSPs can be caused to vary, for which the patient's corresponding end-time gas concentrations FETCO; associated with it can be determined. For example, a first emitted inhaled pressure lstdPmsp may correspond to a first final idle gas concentration lStFETCO2 (see, for example, point K in the) clock), while a second emitted inhaled pressure ZMdPINSP may correspond to a second final idle gas concentration ZMFETCO; (see for example point L in the figure) while a third emitted inhalation pressure 3 "dPmsp can correspond to the third final valley gas concentration BMFETCO; (see for example point M in the figure) etc. Once two or fl of these data points are known, a curve 164 can be fitted between them to define an initial relationship between the patient's 12 inhaled pressure dPmsp and final end gas concentrations FETCOZ, then a desired exhaled pressure ydPINSP can be determined for the patient 12 based on a desired end time concentration yFE-CO; and curve yFE-CO; see eg point Y in the figure) Once the relationship has been established, the curve 164 can be similarly displayed on the monitor 38 and / or the like, whereby a clinician can determine the desired exhaled pressure ydPmsp for the patient based on the desired end total gas concentrations yFgyCO and the display.

Referring again to Figure 12, the second relationship between the patient's delivered inhalation pressure dPINSp and the delivered tidal volumes dVT can be re-established according to the second curve 162, for which the clinician can then determine the desired delivered tidal volume ydVT for the patient 12 based on the desired final endogenous gas concentration. , the first relationship (eg curve 164) and the second relationship (eg curve 162).

It should be quite obvious that this description shows illustrative, exemplary, representative and non-limiting embodiments of the arrangements according to the invention.

Thus, the scope of the arrangements of the invention is not limited to any of these embodiments. Instead, various details and features of the embodiments have been described as required. Thus, many changes and modifications, as will be readily apparent to those skilled in the art, are within the scope of the arrangements of the invention without departing from the spirit of the invention, the arrangements of the invention including these. In order to clarify to the public the scope and concept of the arrangements specified according to the invention, the following patent claims are set forth.

Claims (10)

10 15 20 25 30 35 53.? ? Û'i lb PATENTKRAV An apparatus for adjusting the amount of respiration of an individual (12) in controlled mechanical ventilation, comprising means arranged to vary the tidal volumes of an individual and a predetermined exhalation time, means for determining final tidal gas concentrations associated with said tidal volumes and (12) during a predetermined inhalation time means for curve fitting of a relationship between said tidal volumes and said final tidal gas concentrations. The device of claim 1, wherein said gas concentrations include one or more gases exhaled by said individual (12). The device of claim 2, wherein at least one of said gases includes at least one of inhaled carbon dioxide, oxygen, nitrous oxide or anesthetic. The device of claim 1, further comprising means for determining a desired tidal volume for said individual (12) based on a desired end tidal gas concentration and said relationship. The apparatus of claim 1, further comprising means for displaying said relationship and determining a desired tidal volume for said individual (12) based on a desired end-time gas concentration and said display. Apparatus for adjusting the size of breaths of an individual (12) in controlled mechanical ventilation, comprising means for varying the inhalation pressures of an individual (12) during a predetermined inhalation time and predetermined exhalation time, means for determining final end gas concentrations associated with said inhalation pressure, and means for adjusting the curve of a relationship between said inhalation pressure and said final tidal gas concentrations. The device of claim 6, wherein said gas concentrations include one or more gases that said individual (12) exhales. The device of claim 7, wherein at least one of said gases includes at least one inhaled carbon dioxide, oxygen, nitrous oxide or anesthetic. The device of claim 6, further comprising determining a desired inhalation pressure for said individual (12) based on a desired end valve gas concentration and said relationship. The device of claim 9, further comprising means for displaying said connection and determining a desired inhalation pressure for said individual (12) based on a desired end valve gas concentration and said display.