The Effect of N2O Administration on Arterial Oxygenation

NCT ID: NCT00146250

Last Updated: 2018-01-11

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: PHASE4
• Total Enrollment: 20 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2005-03-01
• Study Completion Date: 2005-09-30

Brief Summary

Nitrous oxide is a standard part of most anaesthetic breathing mixtures. It has often been assumed that it reduces the amount of oxygen reaching the lower parts of the lung. However the results of previous studies and of some computer modelling suggests the opposite may be true, and that oxygen levels in the blood are actually higher with nitrous oxide. This study seeks to determine whether nitrous oxide increases or decreases blood oxygen levels in anaesthetized patients.

Detailed Description

The concentrating and second gas effects of nitrous oxide (N2O) uptake have been well described, and are produced by rapid uptake of N2O during the first several minutes of an inhalational anesthetic. This significantly increases alveolar and arterial O2 partial pressure. Theoretical modelling of alveolar gas exchange has predicted that these effects may not be transient but may be a persisting phenomenon. However, N2O is known to promote absorption atelectasis in poorly ventilated lung units.

This study, carried out pre-cardiopulmonary bypass in 20 patients undergoing coronary artery surgery, measures change in PaO2 after a minimum of 30 minutes of relaxant general anesthesia with a FIO2 of 30%. Patients are randomised to two groups. The intervention group has N2O introduced following baseline blood gas measurements, while the control group continued breathing an identical FIO2 in N2. The change in PaO2 in the two groups is the primary endpoint for comparison.

Conditions

Anesthesia

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

Nitrous oxide

Nitrous oxide 70% as balance gas in inspired mixture

Group Type: EXPERIMENTAL

Nitrous oxide

Intervention Type: DRUG

Substitution of Nitrous oxide for Nitrogen as balance gas in inspired gas mixture

Nitrogen

Nitrogen instead of nitrous oxide 70% as balance gas in inspired mixture

Group Type: EXPERIMENTAL

Nitrous oxide

Intervention Type: DRUG

Substitution of Nitrous oxide for Nitrogen as balance gas in inspired gas mixture

Interventions

Nitrous oxide

Substitution of Nitrous oxide for Nitrogen as balance gas in inspired gas mixture

Intervention Type: DRUG

Other Intervention Names

N2O

Eligibility Criteria

Inclusion Criteria

• Patients undergoing elective coronary artery bypass surgery

Exclusion Criteria

• Age under 18 years, emergency surgery

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Monash University

OTHER

Sponsor Role: collaborator

La Trobe University

OTHER

Sponsor Role: collaborator

The Alfred

OTHER

Sponsor Role: collaborator

University of Melbourne

OTHER

Sponsor Role: collaborator

Austin Health

OTHER_GOV

Sponsor Role: lead

Responsible Party

Dr Philip Peyton

Doctor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Philip J Peyton, MD FANZCA

Role: PRINCIPAL_INVESTIGATOR

Dept of Anaesthesia, Austin Health

Other Identifiers

H99/00835

Identifier Type: -

Identifier Source: org_study_id