APPARATUS AND METHOD FOR MONITORING AN AIRWAY DEVICE SUCH AS AN ENDOTRACHEAL TUBE

• US 20100252048A1
• Filed: 09/16/2008
• Published: 10/07/2010
• Est. Priority Date: 09/17/2007
• Status: Active Grant

• Current Assignee: Indian Ocean Medical Inc.
• Original Assignee: Indian Ocean Medical Inc.
• Inventors: Young, Peter, Zocca, Mario
• Granted Patent: US 9,233,219 B2
• Time in Patent Office: Days
• US Class Current: 128/207.150
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 16/0409 with mean for closing the oesophagus
• CPC Class Codes: A61M 16/0434 Cuffs
• CPC Class Codes: A61M 16/044 External cuff pressure control or supply, e.g. synchronisation with respiration
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: G02B 6/4459 Ducts; Conduits; Hollow tubes for air blown fibres

Abstract

An airway device (14), that is used to maintain a clear airway in a patient, e.g. for artificial ventilation during surgery, comprises an inflatable cuff (26), which is inflated when in position in a patient'"'"'s airway (24). The inflated cuff (26) provides a seal to maintain the device (14) in position in a patient'"'"'s airway (24), and to prevent leakage of infected oropharangeal secretions into the patient'"'"'s lungs. A method and apparatus (10) for monitoring and controlling the pressure in the inflatable cuff (26) is described, which, in one embodiment, controls the pressure about a setpoint pressure, whilst preventing loss of sealing pressure during a patient'"'"'s respiratory cycle. In other embodiments, the method and apparatus monitors for: leaks in the pressure system of the device (14) that includes the cuff (26); blockage in the pressure system, and/or malpositioning of the airway device (14) during use.

Claims

1. A method for monitoring a pressure of an inflatable seal of an airway device, the method comprising the steps of:

receiving a pressure value indicative of the pressure of the inflatable seal;

comparing the received pressure value with a preselected, desired pressure value, and

if a difference between the received pressure value and the preselected pressure value is greater than a predefined tolerance, changing the pressure of the inflatable seal, to reduce the difference;

wherein the step of changing the pressure is carried out at a rate dependent upon a difference between the received pressure value and the desired pressure value.

2. A method as claimed in claim 1, wherein the step of receiving a pressure value is carried out periodically at predefined time intervals.

3. A method as claimed in claim 2, wherein the predefined time intervals are in the range of 0.1 to 2.0 seconds.

4. A method as claimed in claim 1, wherein the step of changing the pressure is carried out at a rate that is dependent on the square of the difference between the received pressure value and the preselected pressure value.

5. A method as claimed in claim 1, wherein the step of changing the pressure is carried out by changing a volume of closed volume pressure system, wherein the change in volume is carried out at a rate that is proportional to:

$\frac{\left({\left(P_1-S\right)}^2*S\right)}{\left(R\right)}$

Where;

N is the rate of change of volume

P₁ is the actual measured pressure

S is the set point or desired pressure

* is the multiplier operation

R is a regulation constant.

6. A method as claimed in claim 1, wherein the step of changing the pressure is carried out at a rate that is further limited to a predetermined threshold rate.

21. A computer readable medium comprising program instructions which, when executed, perform the method of claim 1.

22. An apparatus comprising processor means, configured for carrying out the method of claim 1.

7. A method for detecting a change in position of an airway device with an inflatable seal, the method comprising:

comparing a received pressure value indicative of the pressure of the inflatable seal with a predefined pressure value to determine a difference, and, if the difference is greater than a predetermined amount for a predetermined time period, indicating a detected change in position of the airway device.

8. A method as claimed in claim 7, wherein the predefined pressure value is a previous pressure value that is within predefined tolerances of a preselected, desired pressure value.

9. A method as claimed in claim 7, wherein the predetermined amount is a proportion of the predefined pressure value.

10. A method as claimed in claim 9, wherein the predetermined amount is in the range of 15% and 25% of the predefined pressure value, preferably 20%.

11. A method as claimed in claim 7, wherein the predetermined time is in the range of 15 seconds to 1 minute.

12. A method as claimed in claim 7, further comprising:

receiving a first pressure value indicative of a pressure of the inflatable seal, the pressure value within predefined tolerances of a preselected desired pressure value;

thereafter, periodically receiving further pressure values at predetermined time intervals;

comparing each received pressure value with a predetermined pressure value to determine a difference;

if the difference is greater than a predetermined amount, starting a timer for a predetermined time period, and

if the further, periodically received pressure values are not within the predefined tolerances of the preselected pressure value before the timer has expired, indicating a detected change in position of the airway device.

13. A method as claimed in claim 12, wherein the predetermined pressure value is either the preselected pressure value or the first pressure value.

14. A method for detecting a change in position of an airway device with an inflatable seal, the method comprising:

periodically comparing a received pressure value indicative of the pressure of the inflatable seal with a predefined threshold value, and, if the pressure value exceeds the threshold value for a predetermined time period, indicating a detected change in position of the airway device.

15. A method of detecting a leak of fluid from an inflatable airway device, the method comprising:

receiving a pressure value for the inflatable airway device;

calculating a statistical average of a values calculated using the received pressure value and a predetermined number of previously received pressure values; and

if the statistical average exceeds a threshold average, indicating a leak of fluid from the airway device.

16. A method as claimed in claim 15, wherein the values calculated using the received and previously received pressure values are values representing a rate of change in volume or pressure of fluid within the inflatable airway device.

18. A method as claimed in claim 16, wherein the predefined minimum pressure value is a predetermined proportion of a preselected, desired pressure value, for example 50% of the preselected pressure value.

17. A method for detecting a leak of fluid from an inflatable airway device, the method comprising:

periodically receiving a pressure value for the inflatable airway device;

comparing the received pressure value with a predetermined, minimum pressure value, and

if the received pressure value is less than the predetermined minimum pressure value, indicating a leak of fluid from the airway device.

19. A method for detecting a blockage in a pressure system of an inflatable airway device, the method comprising:

receiving a pressure value for the inflatable airway device and calculating a current activity, and, if the current activity is below a threshold for activity for a predetermined time period, indicating a blockage in the pressure system of the airway device.

20. A method for detecting a blockage in a pressure system of an inflatable airway device, the method comprising:

comparing a received pressure value for the inflatable airway device, with a predetermined or average pressure value to calculate a difference;

calculating a statistical average of the difference and a predetermined number of differences calculated using previously received pressure values;

comparing the statistical average with a threshold average, and, if the statistical average is less than the threshold for a predetermined time period indicating a blockage in the pressure system of the airway device.