Lung inflection point monitor apparatus and method

• US 6,355,002 B1
• Filed: 05/22/2000
• Issued: 03/12/2002
• Est. Priority Date: 05/22/2000
• Status: Expired due to Term

• Current Assignee: Comedica Incorporated
• Original Assignee: Comedica Technololigies Incorporated
• Inventors: Fish, Philip E., Faram, Joseph Dee
• Primary Examiner(s): Winakur, Eric F.
• Assistant Examiner(s): Natnithithadha, Navin
• Application Number:
  US09/575,268
• Time in Patent Office: 659 Days
• Field of Search: 600/529, 600/531, 600/532, 600/533, 600/534, 600/538, 128/204.23, 128/203.14, 128/204.18, 128/204.21
• US Class Current: 600/529
• CPC Class Codes: A61B 5/03 Detecting, measuring or recording fluid pressure within the body other than blood pressure, e.g. cerebral pressure; Measuring pressure in body tissues or organs A61B5/205 takes precedence
• CPC Class Codes: A61B 5/085 Measuring impedance of respiratory organs or lung elasticity
• CPC Class Codes: A61M 16/0006 with means for creating vibrations in patients' airways
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/021 operated by electrical means A61M16/202 – A61M16/205 take precedence
• CPC Class Codes: A61M 16/04 Tracheal tubes catheters in general A61M25/00
• CPC Class Codes: A61M 16/0452 following the inspiration and expiration pressure
• CPC Class Codes: A61M 16/0459 one cuff behind another
• CPC Class Codes: A61M 16/08 Bellows; Connecting tubes having means for taking samples G01N1/22; Water traps; Patient circuits
• CPC Class Codes: A61M 16/0833 T- or Y-type connectors, e.g. Y-piece
• CPC Class Codes: A61M 16/085 Gas sampling
• CPC Class Codes: A61M 16/0858 Pressure sampling ports
• CPC Class Codes: A61M 16/12 by mixing different gases
• CPC Class Codes: A61M 16/206 Capsule valves, e.g. mushroom, membrane valves
• CPC Class Codes: A61M 16/208 Non-controlled one-way valves, e.g. exhalation, check, pop-off non-rebreathing valves
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2205/3569 sublocal, e.g. between console and disposable
• CPC Class Codes: A61M 2205/3576 with non implanted data transmission devices, e.g. using external transmitter or receiver

Abstract

A monitoring device and method for finding the critical opening pressure, the critical closing pressure and the over distention pressure of the lungs by first, delivering pulses of gas to the lungs without allowing the gas to escape, and then, allowing the gas to escape, all the while, monitoring the resulting pressure change. By looking at a simple pressure-over-time depiction of these pressure changes, the critical opening pressure, the critical closing pressure and the over distention pressure can be determined by observing the overall pressure change and the incremental pressure changes.

Claims

1. A method for determining the critical opening pressure of a patient'"'"'s lungs, comprising the steps of:

immobilizing the patient'"'"'s lungs;

closing an exhalation valve to prevent gas from escaping from the patient'"'"'s lungs;

introducing gas into the patient'"'"'s lungs in pulsatile increments through the patient'"'"'s airway, beginning at a pressure lower than the critical opening pressure;

measuring the resulting pressures as the gas is introduced into the lungs in pulsatile increments, and displaying those measurements in the form of a pressure-over-time line-graph;

stopping when the pressure-over-time line-graph gradient first indicates that a stepwise pressure increment differs substantially from the previous stepwise pressure increment; and

displaying the final pressure.

2. The method according to claim 1, further comprising a step of electronically transmitting the final pressure to a ventilator.

3. A method for determining the critical closing pressure of the lungs, comprising the steps of:

immobilizing the patient'"'"'s lungs;

closing an exhalation valve or any opening which would otherwise allow gas to escape from the patient'"'"'s lungs;

introducing gas into the patient'"'"'s lungs in pulsatile increments through his or her airway and stopping at a pressure greater than the critical closing pressure;

allowing the gas to passively escape from the patient'"'"'s lungs by partially opening an exhalation valve;

measuring the resulting pressures as the gas escapes from the lungs in a decreasing manner, and displaying those measurements in the form of a pressure-over-time line-graph;

stopping when the pressure-over-time line-graph gradient first indicates that a stepwise pressure decrement differs substantially from the previous stepwise pressure decrement; and

displaying the final pressure.

4. The method according to claim 3, further comprising the step of electronically transmitting the final pressure to a ventilator.

5. A method for determining the over distention pressure of a patient'"'"'s lungs, comprising the steps of:

immobilizing the patient'"'"'s lungs;

closing an exhalation valve or any opening which would otherwise allow gas to escape from the patient'"'"'s lungs;

introducing gas into the patient'"'"'s lungs in pulsatile increments through his or her airway beginning at a pressure lower than the over distention pressure;

measuring the resulting pressures as the gas is introduced into the lungs in pulsatile increments, and displaying those measurements in the form of a pressure-over-time line-graph;

stopping when the pressure-over-time line-graph gradient first indicates that a stepwise pressure increment differs substantially from the previous stepwise pressure increment; and

displaying the final pressure.

6. The method according to claim 5, further comprising the step of electronically transmitting the final pressure to a ventilator.

7. A device for determining critical opening, critical closing and over distention pressures of a patient'"'"'s lungs, comprising:

a gas controlling apparatus for regulating both the pulsatile delivery of gas to and the evacuation of gas from the patient;

an interface apparatus for connecting the gas controlling device to the patient'"'"'s airway;

a valve for preventing or allowing the escape of gas from the patient, and a port for measuring gas pressures;

a graphic device for measuring, and displaying the measurement of gas pressures; and

a computing device for analyzing gas pressures, programming the gas controlling device and transmitting data to a ventilator.