US5320093A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rapid anesthesia emergence system using closed-loop PCO2 control
Assignee: The Brigham and Women's Hospital Inc
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Filing: 1990-12-21
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Granted: 1994-06-14
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Expires: 2010-12-21
Abstract
Abstract A system is disclosed for rapidly restoring ventilatory drive to an anesthetized patient after surgery. The end-expired carbon dioxide partial pressure is used as feedback to determine the amount of CO 2 to be added to the inspired breathing mixture of the patient's breathing circuit. The CO 2 added to the patient's breathing circuit increases CO 2 within the blood stream to a level sufficient to stimulate the central ventilatory center in the brain, thereby rapidly restoring ventilatory drive to the patient.
Inventors
- 👤 Dan Raemer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:11
CPC Classifications
A; A61; A61M; A61M16/00; A61M16/08; A61M16/0816; A61M16/0841; A61M16/085; A61M16/021; A61M16/022; A61M16/024; A61M16/026; A61M16/0045; A61M16/0057; A61M16/0075; A61M16/0081; A61M16/22; A61M2202/00; A61M2202/02; A61M2202/0225; A61M2230/00; A61M2230/40; A61M2230/43; A61M2230/432; Y; Y10; Y10S; Y10S128/00; Y10S128/914
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
77 words
A method for restoring ventilatory drive to an anesthesized patient, the method comprising: (a) measuring the end-tidal value of the respiratory PCO 2 of the patient; (b) comparing said measurement of the end-tidal value of the respiratory PCO 2 with a reference value as feedback to determine the amount of CO 2 to be added to a patient's breathing circuit; and (c) adding said amount of CO 2 to the inspired mixture of the patient's breathing circuit.
Claim 2
Independent Claim
77 words
A method for restoring ventilatory drive to an anesthesized patient, the method comprising: (a) measuring the end-tidal value of the respiratory PCO 2 of the patient; (b) comparing said measurement of the end-tidal value of the respiratory PCO 2 with a reference value as feedback to determine the amount of CO 2 to be added to a patient's breathing circuit; and (c) adding said amount of CO 2 to the inspired mixture of the patient's breathing circuit.
Claim 3
Dependent Claim
18 words
The method of claim 1 wherein a device is used to detect the phases of a respiratory cycle.
Claim 4
Dependent Claim
21 words
The method of claim 2 wherein the CO 2 gas is added only during the inspired phase of the respiratory cycle.
Claim 5
Dependent Claim
13 words
The method of claim 3 wherein phases are detected by a flow meter.
Claim 6
Dependent Claim
54 words
The method of claim 1 further comprising the step of differentiating between the expired end-tidal CO 2 value and a inspired peak CO 2 value produced by the addition of CO 2 into the breathing mixture such that the effect of the inspired peak CO 2 value on the CO 2 addition is minimized.
Claim 7
Dependent Claim
30 words
The method of claim 1 wherein said feedback is determined by a term which is a function of difference between a desired and a measured P ET CO 2 .
Claim 8
Dependent Claim
34 words
The method of claim 1 wherein said feedback is determined by a term which is proportional to the time integral of the difference between a desired and a measured P E TCO 2 .
Claim 9
Dependent Claim
37 words
The method of claim 1 wherein said feedback is determined by a term which is proportional to the derivative with respect to time of the difference between a desired and a measured P ET CO 2 .
Claim 10
Dependent Claim
35 words
The method of claim 1 further comprising the step of controlling the time or the proportion of time a valve is left open to introduce the correct flow of CO 2 into the breathing mixture.
Claim 11
Dependent Claim
43 words
The method of claim 1 further comprising the step of measuring the total fresh gas flow into the subject's breathing circuit and inhibiting the addition of CO 2 gas into the circuit when the fresh gas flow is less than a particular value.
Claim 12
Dependent Claim
37 words
The method of claim 1 further comprising the step of measuring O 2 concentration within the breathing circuit and inhibiting CO 2 addition into the circuit when the O 2 concentration is less than a particular value.
Claim 13
Dependent Claim
40 words
The method of claim 1 further comprising the step of measuring the average inspired CO 2 concentration within the breathing circuit and inhibiting CO 2 addition into the circuit when the average inspired CO 2 concentration exceeds a particular value.
Claim 14
Dependent Claim
30 words
The method of claim 1 further comprising the step of detecting an absence of breathing for a particular duration of time and triggering an alarm upon said absence of breathing.
Claim 15
Dependent Claim
16 words
The method of claim 5 wherein the inspired peak value is greater than 2 mm Hg.
Claim 16
Independent Claim
101 words
A device for restoring ventilatory drive to an anesthetized subject comprising: (a) means for determining the partial pressure of CO 2 in the blood stream of a subject; (b) feedback means utilizing said determination of the partial pressure of CO 2 in the blood stream of a subject; and (c) means for adding CO 2 into the breathing circuit as determined by the feedback means; (d) wherein said feedback means differentiates between the expired peak value of CO 2 from the inspired peak value of CO 2 which may be produced by the addition of CO 2 to the breathing mixture.
Claim 17
Independent Claim
101 words
A device for restoring ventilatory drive to an anesthetized subject comprising: (a) means for determining the partial pressure of CO 2 in the blood stream of a subject; (b) feedback means utilizing said determination of the partial pressure of CO 2 in the blood stream of a subject; and (c) means for adding CO 2 into the breathing circuit as determined by the feedback means; (d) wherein said feedback means differentiates between the expired peak value of CO 2 from the inspired peak value of CO 2 which may be produced by the addition of CO 2 to the breathing mixture.
Claim 18
Dependent Claim
29 words
The method of claim 1 further comprising estimating the partial pressure of CO 2 within the patient's bloodstream by measuring the end-tidal value of the respiratory PCO 2 .
Claim 19
Dependent Claim
36 words
The method of claim 1 wherein said feedback computes feedback compensation as a function of the difference between a desired value of P ET CO 2 and the measured value of P ET CO 2 .
Claim 20
Dependent Claim
36 words
The method of claim 1 further comprising the step of comparing said added amount of CO 2 with a reference value to determine the amount of CO 2 to be added to the patient's breathing circuit.
Claim 21
Dependent Claim
42 words
The method of claim 1 further comprising the step of measuring the inspired PCO 2 and comparing the inspired amount of CO 2 with a reference value to determine the amount of CO 2 to be added to the patient's breathing circuit.
Claim 22
Independent Claim
105 words
A device for restoring ventilatory drive to an anesthetized subject comprising: (a) means for determining the partial pressure of CO 2 in the blood stream of a subject; (b) feedback means utilizing said determination of the partial pressure of CO 2 in the blood stream of a subject; and (c) means for adding CO 2 into the breathing circuit as determined by the feedback means; (d) means for measuring the inspired PCO 2 of a subject and second feedback means for comparing said measured inspired PCO 2 with a reference value for determining the amount of CO 2 to be added into the breathing circuit.
Claim 23
Independent Claim
105 words
A device for restoring ventilatory drive to an anesthetized subject comprising: (a) means for determining the partial pressure of CO 2 in the blood stream of a subject; (b) feedback means utilizing said determination of the partial pressure of CO 2 in the blood stream of a subject; and (c) means for adding CO 2 into the breathing circuit as determined by the feedback means; (d) means for measuring the inspired PCO 2 of a subject and second feedback means for comparing said measured inspired PCO 2 with a reference value for determining the amount of CO 2 to be added into the breathing circuit.
Claim 24
Independent Claim
91 words
A device for restoring ventilatory drive to an anesthetized subject comprising: (a) means for determining the partial pressure of CO 2 in the blood stream of a subject; (b) feedback means utilizing said determination of the partial pressure of CO 2 in the blood stream of a subject; and (c) means for adding CO 2 into the breathing circuit as determined by the feedback means; (d) means for comparing said added CO 2 with a reference value for determining the amount of CO 2 to be added into the breathing circuit.
Claim 25
Independent Claim
91 words
A device for restoring ventilatory drive to an anesthetized subject comprising: (a) means for determining the partial pressure of CO 2 in the blood stream of a subject; (b) feedback means utilizing said determination of the partial pressure of CO 2 in the blood stream of a subject; and (c) means for adding CO 2 into the breathing circuit as determined by the feedback means; (d) means for comparing said added CO 2 with a reference value for determining the amount of CO 2 to be added into the breathing circuit.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-06-13 | 1997-12-13 | 1998-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-06-13 | 2001-12-13 | 2002-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-06-13 | 2005-12-13 | 2006-06-14 | $7700.00 | Window Closed / Lapsed |