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

NCT ID: NCT02003300

Last Updated: 2013-12-06

Basic Information

• Recruitment Status: COMPLETED
• Total Enrollment: 30 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2005-04-30
• Study Completion Date: 2006-11-30

Brief Summary

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

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

E03.155.197; E03.155.253

Study Design

• Study Time Perspective: PROSPECTIVE

Eligibility Criteria

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

Sponsors

Bayside Health

OTHER_GOV

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

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

The Alfred

Melbourne, Victoria, Australia

Countries

Australia

References

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

GE/ASA Research Grant, 2004

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

177/03

Identifier Type: -

Identifier Source: org_study_id