Method and apparatus for controlled flow sampling from the airway

• US 6,067,983 A
• Filed: 09/19/1997
• Issued: 05/30/2000
• Est. Priority Date: 09/19/1997
• Status: Expired due to Term

• Current Assignee: Sensormedics Corporation (Becton Dickinson & Co)
• Original Assignee: Sensormedics Corporation (Becton Dickinson & Co)
• Inventors: Stenzler, Alex
• Primary Examiner(s): Lewis, Aaron J.
• Application Number:
  US08/934,175
• Time in Patent Office: 984 Days
• Field of Search: 128/201.18, 128/204.23, 128/205.19, 128/206.29, 600/532, 600/543
• US Class Current: 128/204.23
• CPC Class Codes: A61B 5/097 Devices for facilitating collection of breath or for directing breath into or through measuring devices
• CPC Class Codes: A61M 16/0493 with means for protecting the tube from damage caused by the patient's teeth, e.g. bite block
• CPC Class Codes: A61M 16/08 Bellows; Connecting tubes having means for taking samples G01N1/22; Water traps; Patient circuits
• CPC Class Codes: A61M 16/085 Gas sampling
• CPC Class Codes: A61M 16/0858 Pressure sampling ports
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2202/0275 Nitric oxide [NO]
• CPC Class Codes: A61M 2205/75 with filters
• CPC Class Codes: A61M 2230/43 Composition of exhalation

Abstract

An apparatus and method for controlled flow sampling from the airway includes a mouthpiece, or a connector attached to a tube inserted in the subject'"'"'s trachea, either of which is used to capture gases from the subject'"'"'s airway. Attached to the mouthpiece or the connector is a total airway occlusion. A pump or vacuum source, maintained at a lower pressure than the pressure inside the airway, is connected to the total airway occlusion, pulling gas out of the airway independent of the subject'"'"'s volition. The flow is maintained at a substantially constant rate chosen by the operator through control over the source of low pressure. As gases flow out of the airway, they flow through a gas analyzer which measures desired properties of the gas.

Claims

1. An apparatus for controlled flow sampling of gases from a living subject'"'"'s airway, comprising:

(a) a gas supply;

(b) a total airway occlusion which receives gas from said gas supply;

(c) a collector connected to said total airway occlusion, for transferring gas received by said total airway occlusion from said gas supply to such a living subject and for capturing gases from such a living subject'"'"'s airway;

(d) a pressure generator which generates a pressure lower than that of such a living subject'"'"'s airway and which is connected to said total airway occlusion to produce a substantially controlled gas flow rate from such a living subject'"'"'s airway;

(e) a regulator for setting the pressure produced by said pressure generator;

(f) a pressure transducer which measures the pressure generated by such a living subject in said total airway occlusion when said total airway occlusion blocks exhalation;

(g) a gas analyzer which measures properties of the gases collected from such a living subject'"'"'s airway; and

(h) a display which outputs the data collected from said gas analyzer.

2. The gas analysis apparatus of claim 1, wherein said collector comprises a mouthpiece, said gas analysis apparatus further comprising a nasal block.

3. The gas analysis apparatus of claim 1, wherein said collector comprises a tracheal tube adaptor.

4. The gas analysis apparatus of claim 1, wherein said pressure generator comprises a pump.

5. The gas analysis apparatus of claim 1, wherein said pressure generator comprises a vacuum source.

6. An apparatus for controlled flow sampling of gases from a living subject'"'"'s airway, comprising:

a mouthpiece adapted for insertion into the mouth of such a living subject, the mouthpiece allowing for the passage of gases therethrough into and out of the airway of such a living subject;

a nasal block adapted for attachment to such a living subject such that the nasal block substantially blocks the nostrils of such a living subject;

a pressure transducer in flow communication with the mouthpiece;

a pressure generator connected to the pressure transducer and in flow communication with the mouthpiece the pressure generator adapted to generate a pressure lower than the pressure of a living subject'"'"'s airway to create and control an outward flow from the living subject'"'"'s airway independent of the living subject'"'"'s volition; and

a gas analyzer in flow communication with the pressure generator and the mouthpiece, the gas analyzer receiving substantially all of the outward flow from the living subject'"'"'s airway and adapted to measure properties of the gases removed from the airway of such a living subject through the mouthpiece.

7. A method for controlled flow sampling of gases from a living subject'"'"'s airway, comprising:

inserting a mouthpiece into the mouth of a living subject;

providing breathable gas of known composition to the living subject;

monitoring such a living subject'"'"'s exhalation pressure to ensure it remains above approximately 3.7 mmHg for sealing the soft palate of a living subject;

generating a pressure outside the mouthpiece lower than the pressure within such a living subject'"'"'s airway to create and control and outward flow from the living subject'"'"'s airway independent of the living subject'"'"'s volition;

measuring the properties of the gas induced outward from such a living subject'"'"'s airway.

8. The method of claim 7, further comprising the step after the inserting a mouthpiece step of blocking such a living subject'"'"'s nostrils substantially completely.