Trial | NCT00146250  Report issue

Title

The Effect of N2O Administration on Arterial Oxygenation
Relationship of Oxygenation During Anaesthesia in the Presence of N2O or N2 to Mode of Ventilation

  • Phase

    Phase 4

  • Study Type

    Interventional

  • Status

    Completed No Results Posted

  • Study Participants

    20
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.
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.
Study Started
Mar 01
2005
Primary Completion
Jul 20
2005
Study Completion
Sep 30
2005
Last Update
Jan 11
2018

Drug Nitrous oxide

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

  • Other names: N2O

Nitrous oxide Experimental

Nitrous oxide 70% as balance gas in inspired mixture

Nitrogen Experimental

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

Criteria 

Inclusion Criteria:

Patients undergoing elective coronary artery bypass surgery

Exclusion Criteria:

Age under 18 years, emergency surgery
No Results Posted