An Improved Method for the Measurement of Oxygen and Anaesthetic Agent Uptake in Patients Using the Foldes-Biro Equation

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Total Enrollment

30 participants

Study Classification

OBSERVATIONAL

Study Start Date

2005-04-30

Study Completion Date

2006-11-30

Brief Summary

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The primary aim is to confirm the efficacy of a new non-invasive method for measuring the oxygen uptake during general anesthesia of patients undergoing surgery under cardiopulmonary bypass. The method has already been successfully tested in the laboratory under controlled conditions. In the patient group chosen, oxygen uptake is simultaneously calculated, for comparison purposes, from monitoring measurements made routinely as part of normal patient care in these cases, using a pulmonary artery catheter - an invasive technique from which severe complications occasionally arise, including death.

A secondary aim is to elucidate the time course of uptake of the anaesthetic vapor, isoflurane, during this kind of surgery.

Detailed Description

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In a series of 30 patients undergoing cardiopulmonary bypass, the change in nitrogen concentration between fresh gas entering the anesthetic breathing system and the exhaust gas leaving it in an otherwise closed system is used to determine total gas uptake by the principle of insoluble gas dilution. Oxygen and anaesthetic agent uptakes are then automatically determined by a computer directly linked to a rapid gas analyzer, every 15 seconds.

As a control, oxygen is calculated using the reverse Fick method. Measured arterial and mixed venous oxygen saturations were used to do this, and the cardiac output which was determined by thermodilution.

Conditions

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E03.155.197 E03.155.253

Keywords

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Oxygen uptake Anesthetic gas uptake

Study Design

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Study Time Perspective

PROSPECTIVE

Eligibility Criteria

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Inclusion Criteria

* Patients undergoing non-emergency procedures using cardiopulmonary bypass in whom pulmonary artery catheterization was to be performed for routine monitoring purposes, including mixed venous oxygen determinations and thermodilution cardiac output determinations.

Exclusion Criteria

* High risk patients (ASA 4+)
* Acute lung injury, sepsis
* Tricuspid regurgitation
* Patients under 18 years of age
* Patients unable to give informed consent

Minimum Eligible Age

18 Years

Maximum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Brian J Lithgow, MESc BE BSc

Role: STUDY_DIRECTOR

Monash University Department of Electrical Engineering

Gavin JB Robinson, MB BS FANZCA

Role: PRINCIPAL_INVESTIGATOR

The Alfred, Bayside Health

Philip J Peyton, MB BS FANZCA

Role: STUDY_DIRECTOR

The Austin Hospital

Locations

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The Alfred

Melbourne, Victoria, Australia

Site Status

Countries

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Australia

References

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Biro P. A formula to calculate oxygen uptake during low flow anesthesia based on FIO2 measurement. J Clin Monit Comput. 1998 Feb;14(2):141-4. doi: 10.1023/a:1007413018732.

Reference Type BACKGROUND

PMID: 9669452 (View on PubMed)

Other Identifiers

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GE/ASA Research Grant, 2004

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

177/03

Identifier Type: -

Identifier Source: org_study_id