GB2453371A

GB2453371A - A method of weighing a patient using a fluid-fillable mattress

Info

Publication number: GB2453371A
Application number: GB0719478A
Authority: GB
Inventors: Andrew Robinson
Original assignee: HARVEST HEALTHCARE
Current assignee: HARVEST HEALTHCARE
Priority date: 2007-10-05
Filing date: 2007-10-05
Publication date: 2009-04-08
Anticipated expiration: 2027-10-05
Also published as: GB0719478D0; GB2453371B; WO2009044201A1; AU2008306594A1; EP2203092A1

Abstract

A method of weighing a patient is disclosed comprising a system that is provided with mattress pump apparatus controller (108, figure 1) arranged to monitor pressure of a fluid in the mattress (100, figure 1). The controller (108, figure 1) detects a change in the pressure due to placement of patient on the mattress, measures a load pressure of the fluid (such as air) contained in the mattress and determines the weight of the load from the load pressure.

Description

MATTRESS PUMP APPARATUS CONTROLLER, MATTRESS PUMP APPARATUS, MATTRESS AND METHOD OF CONTROLLING A

MATTRESS

Field of the Invention

Embodiments of the present invention relate to a mattress pump apparatus controller, mattress pump apparatus, mattress and method of controlling a mattress.

Background to the Invention

Inflatable mattresses may be used, for example, within medical premises such as hospitals on hospital beds for the use of patients. The weight of a patient may affect the performance and/or perceived comfort of the mattress by the patient as well as the pressure area care when the mattress is filled (inflated) with fluid (such as a gas, for example air) to a predetermined and/or varying pressure. S... * S S...

It is an object of embodiments of the invention to at least mitigate one or more of the

: problems of the prior art.

* : * Summary of the Invention

According to a first aspect of embodiments of the invention, there is provided a mattress pump apparatus controller, wherein the controller is arranged to monitor pressure of a fluid in at least some parts of the mattress; detect a change in the pressure due to placement of a load on the mattress; measure a load pressure of the fluid; and determine a weight of the load from the load pressure.

Thus a mattress can be controlled by the mattress pump apparatus controller (for example, using a mattress pump apparatus) to automatically measure the weight of a load, such as a patient, when the load is placed on the mattress.

In certain embodiments, the controller is arranged to determine an initial pressure before the detecting. Determining the weight may comprise determining the weight from the initial pressure and the load pressure.

In certain embodiments, the controller is arranged to fill the mattress with a predetermined volume of fluid or to a predetermined pressure before the detecting.

Thus, the mattress is inflated to a certain level (for example, a level that is comfortable for a patient mounting the mattress and/or takes into account the patient's fragility and tissue vulnerability) before the load is placed on the mattress.

In certain embodiments, the controller is arranged to add fluid to or remove fluid from the mattress after the measuring. Therefore, the pressure within the mattress is set to, for example, a predetermined level once the load pressure is measured. The predetermined pressure may be selected automatically according to the weight of the : *.* 15 load and/or the treatment that a patient on the mattress may receive. Alternatively, the predetermined level may be selected by a user such as, for example, a patient on the mattress or a member of medical staff.

S...., * According to a second aspect of embodiments of the invention, there is provided a :.:::. 20 mattress pump apparatus comprising means for adding and/or removing fluid from a * * fluid tillable mattress and a controller, wherein the controller is arranged to monitor pressure of a fluid in at least some parts of the mattress; detect a change in the pressure due to placement of a load on the mattress; measure a load pressure of the fluid; and determine a weight of the load from the load pressure.

According to a third aspect of embodiments of the invention, there is provided fluid tillable mattress comprising a mattress pump apparatus, the mattress pump apparatus comprising means for adding and/or removing fluid from a fluid fillable mattress and a controller, wherein the controller is arranged to monitor pressure of a fluid in at least some parts of the mattress; detect a change in the pressure due to placement of a load on the mattress; measure a load pressure of the fluid; and determine a weight of the load from the load pressure.

According to a fourth aspect of embodiments of the invention, there is provided a method of controlling a fluid-fihlable mattress, the method comprising monitoring pressure of a fluid in at least some parts of the mattress; detecting a change in the pressure due to placement of a load on the mattress; measuring a load pressure of the fluid; and detrmining a weight of the load from the load pressure.

Brief Description of the Drawings

Embodiments of the invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a mattress and mattress pump apparatus according to embodiments of the invention; I. :.: 15 Figure 2 shows a method of controlling a mattress according to embodiments of the invention; * I *.. * Figure 3 shows a graph of pressure against time during a method according to : embodiments of the invention; * : Figure 4 shows a graph of weight against pressure according to embodiments of the invention; Figure 5 shows a first alternative embodiment of a mattress; Figure 6 shows a second alternative embodiment of a mattress; and Figure 7 shows a third alternative embodiment of a mattress.

Detailed Description of Embodiments of the Invention An embodiment of the invention shown in figure 1 comprises a mattress 100 and mattress pump apparatus 102. The mattress pump apparatus 102 comprises a pump 104 for pumping a fluid (for example, air) into the mattress 100, a pressure sensor 106 for measuring the pressure of the fluid in the mattress 106 and a mattress pump apparatus controller 108 for controlling the mattress pump apparatus 102. The apparatus 102 may also comprise an interaction device 110 that includes a display and/or an input device. The mattress 100 is connected to the apparatus 102 via a fluid conduit 112. The conduit 112, which is, for example, a flexible tube, may be pennanently or removably connected to the mattress 100 and/or apparatus 102. In alternative embodiments of the invention, however, the apparatus may be integrated with (for example, attached directly to or located within) the mattress 100, and as such the conduit 112 may not be required.

In embodiments of the invention, the apparatus 102 can be used to inflate the mattress to an initial fluid pressure, detect when a load is placed on the mattress, calculate the weight of the load and then inflate or deflate the mattress 100 to a selected pressure level. A load being placed on the mattress 100 may include, for example, a patient mounting the mattress and lying down on the mattress.

*::* Embodiments of the mattress 100 are arranged such that fluid pumped into the mattress 100 fills the entire internal volume 114 of the mattress 100. However, in alternative embodiments of the mattress, the internal volume 114 may be partitioned :.:: 20 into two or more sections that may be inflated and deflated independently.

* : * Embodiments of such mattresses are described later in this description.

Figure 2 shows a method of controlling a mattress pump apparatus according to embodiments of the invention. The method 200 starts at step 202 where the mattress is inflated to an initial pressure. For example, air is pumped into the mattress using the pump 104 via the conduit 112 such that the pressure of the air within the internal volume 114 of the mattress 100 is an initial pressure of 15 mm Hg, as indicated by the pressure sensor 106. Figure 3 shows an example of a graph of pressure (in mm Hg) against time during the method 200. The initial pressure A is shown to be 15 mm Hg, although other initial pressures may be used.

Once the mattress reaches the initial pressure A, the method continues to step 204 where the pressure of the mattress is monitored using the pressure sensor 106. At step 206, placement of a load on the mattress 206 is detected. As shown in figure 3, a load is placed on the mattress at time TI. The pressure of the fluid in the mattress typically reaches a peak at time T2 and then falls, causing a spike at time T2. The placement of the load on the mattress is detected, for example, by detecting when the pressure of the fluid in the mattress exceeds a threshold value. For example, as shown in figure 3, the threshold value is set at 30 mm Hg. The peak at time T2 exceeds the threshold value, and thus the mattress pump apparatus 102 detects the placement of the load on the mattress.

When placement of the load is detected in step 206 shown in figure 2, the method 200 continues to step 208 where the mattress pump apparatus 102 waits for a settling lime Tw (for example, 10 seconds) for the pressure in the mattress to settle. The pressure settles at a pressure B as shown in figure 3. After the settling time Tw, the pressure B inside the mattress 100 is measured in step 210 at time 13. Then, in step 212, the weight of the load placed on the mattress is determined as explained below. In step *,: 15 214 of the method 200, which follows from step 212, the mattress pump apparatus * 102 inflates or deflates the mattress to a selected pressure, and then the method ends at step 216 once the pressure reaches the selected pressure at time T4. ***.* * *

An example of a method of determining the weight of the load on the mattress : 20 comprises using the following formula: **.*.* * S w=cB+ A (1) where w is the weight of the load; A is the initial pressure within the mattress; B is the measured pressure measured at time T3 in step 210; and c is a scalar.

Therefore, the weight is determined according to a linear relationship between the weight of the load and the measured pressure B, as shown in figure 4. The scalar c may be dependent on the initial pressure A andlor the type of mattress. The scalar c may be determined, for example, experimentally or may be specified with the mattress (for example, specified by the manufacturers of the mattress). In alternative embodiments of the invention, however, there may be other relationships between the weight and the measured pressure B. Additionally or alternatively, other calculations may be performed, such as, for example, determining the weight from both the measured pressure B and the initial pressure A. Once the weight of the patient is determined, in embodiments of the invention the weight may be displayed on a display device, if any, associated with the mattress pump apparatus 102.

The selected pressure, to which the mattress is inflated in step 214 of the method 200 shown in figure 2, may be specified manually by a user using, for example, an input device associated with the mattress pump apparatus 102. The selected pressure may be specified before or after the weight of the load is determined. For example, a :.:::: 15 member of medical staff may specif' the selected pressure according to the weight of the patient (being the load on the mattress). S... * *

* :...: In alternative embodiments, the selected pressure may be determined automatically based on the weight of the load on the mattress. For example, the selected pressure *.::. 20 may be determined according to the following table: *.... * a

Weight of load Selected pressure Above 100kg Heavy setting 75-100kg Medium setting Below 75kg Light setting For example, the heavy setting may be a high pressure, the medium setting may be a medium setting and the light setting may be a low pressure. The selected pressure may be specified or determined based on the weight of the patient, for example, to improve the comfort of the patient on the mattress. In embodiments of the invention where the selected pressure is automatically determined based on the weight of the load, there is no requirement for a user to specif' the selected pressure, whether or not in response to the measured weight of the load.

Figure 5 shows an example of an alternative embodiment of a mattress 500. The mattress 500 comprises a plurality of first chambers 502 that are connected together in such a way that fluid may flow freely between the chambers 502. The mattress 500 also comprises a plurality of second chambers 504 that are similarly connected together. The chambers 502 are not connected to the chambers 504. Therefore, for example, if one of the chambers 502 is filled with fluid, then the other chambers 502 are also filled with fluid, and the chambers 504 are not filled with fluid (although the chambers 504 may be filled separately, for example by filling one of the chambers 504).

The chambers 502 are connected together, for example, by a first conduit 506, and the chambers 504 are connected together using a second conduit 508. The mattress 500 may be controlled in a ioop such that in a first period of time, the chambers 502 are filled with fluid to the selected pressure, and the chambers 504 are empty or are filled or deflated to a lower pressure. Then, the chambers 504 are filled to the selected pressure, and the chambers 502 are deflated to a lower pressure, for a second period of :.::: 20 time before returning to the beginning of the loop. Such an arrangement may benefit * : a patient on the bed, for example, by reducing the occurrence of bed sores.

Figure 6 shows another embodiment of a mattress 600 comprising first chambers 602 connected together using a first conduit 604, and second chambers 606 connected together using a second conduit 608. The mattress 600 also comprises a head rest section 610 comprising first head rest chambers 612 and a second head rest chamber 614 (in alternative embodiments of the invention, the mattress 600 may have any number of head rest chambers). The first conduit 604 comprises a valve 616 such that when the first chambers 602 are inflated to a certain pressure, the first head rest chambers 612 are inflated to the same pressure, and when the first chambers 602 are subsequently deflated, the first head rest chambers are not deflated. Thus, the pressure inside the first head rest chambers 612 is maintained at a certain pressure.

Similarly, the second conduit 608 includes a valve 618 such that the second head rest chamber 614 is maintained at a certain pressure. Therefore, the mattress 600 has a head rest section 610 that is permanently inflated to a certain pressure once the first and second chambers 602 and 606 have been inflated to a certain pressure, which may improve the comfort of a patient on the mattress 600. The mattress 600 can be controlled in a loop in a manner similar to that described in respect of the mattress 500 shown in figure 5.

Figure 7 shows another embodiment of a mattress 700. The mattress 700 includes a first mattress section 702 that is similar to the mattress 500 shown in figure 5. The mattress also includes a second mattress section 704 comprising first chambers 706 located underneath the first mattress section, and also comprising second chambers 708 being a head rest section. The first and second chambers 706 and 708 of the second mattress section are connected together using a conduit 710. The second mattress section 704 is maintained at a certain pressure, while the first mattress section is controlled in a loop in a manner similar to that described above with reference to the mattress 500 shown in figure 5. Therefore, there is always an inflated section of the mattress underneath the patient on the mattress 700, which may improve the comfort of the patient.

I

* In the example mattresses described above, chambers may be connected together by : .::: 20 reason of the internal structure of the mattresses instead of using conduits between *:: chambers.

In embodiments of the invention, the fluid used to fill the mattress may be a gas, such as, for example, air. Thus the mattress may be filled by inflating the mattress with the gas.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. The claims should not be construed to cover merely the foregoing embodiments, but also any embodiments which fall within the scope of the claims. * * * *** **** * * **e* * * S

*5***S * S S *S * S S * I.. * S

Claims

1. A mattress pump apparatus controller, wherein the controller is arranged to: monitor pressure of a fluid in at least some parts of the mattress; detect a change in the pressure due to placement of a load on the mattress; measure a load pressure of the fluid; and determine a weight of the load from the load pressure.

2. A controller as claimed in claim 1, arranged to determine an initial pressure before the detecting.

3. A controller as claimed in claim 2, wherein determining the weight comprises determining the weight from the initial pressure and the load pressure. S.

4. A controller as claimed in any of the preceding claims, arranged to fill the mattress with a predetermined volume of fluid or to a predetermined pressure before the detecting. *5**

*.S...

*

5. A controller as claimed in any of the preceding claims, arranged to add fluid to :: 20 or remove fluid from the mattress after the measuring.

S..... * S

6. A mattress pump apparatus comprising: means for adding and/or removing fluid from a fluid fihlable mattress; and a controller as claimed in any of the preceding claims.

7. A fluid fihlable mattress comprising a mattress pump apparatus as claimed in claim 6.

8. A method of controlling a fluid-fillable mattress, the method comprising: monitoring pressure of a fluid in at least some parts of the mattress; detecting a change in the pressure due to placement of a load on the mattress; measuring a load pressure of the fluid; and determining a weight of the load from the load pressure.

9. A method as claimed in claim 8, comprising determining an initial pressure before the detecting.

10. A method as claimed in claim 9, wherein determining the weight comprises determining the weight from the initial pressure and the load pressure.

11. A method as claimed in any of claims 8 to 10, comprising filling the mattress with a predetermined volume of fluid or to a predetermined pressure before the detecting.

12. A method as claimed in any of claims 8 to 11, comprising adding fluid to or removing fluid from the mattress after the measuring.

13. A method as claimed in any of claims I to 12, wherein the fluid comprises a : . 15 gas, for example air. *0** * * ****

14. A mattress pump apparatus controller, mattress pump apparatus, mattress S...

and/or method of controlling a mattress substantially as described herein with : reference to the accompanying figures. S...