Effects of Nitrous Oxide Following Anaesthesia Clinical Trial
Official title:
Evaluation of Nitrous Oxide In the Gas Mixture for Anaesthesia: a Randomised Controlled Trial
We aim to investigate the effectiveness and safety of nitrous oxide (N2O) in anaesthesia.
Hypothesis In patients undergoing anaesthesia for major surgery, avoidance of N2O will
reduce hospital length of stay when compared with otherwise identically managed surgical
patients receiving N2O as a component of their anaesthesia.
There are some compelling reasons to question the routine use of nitrous oxide (N2O), also
known as "laughing gas". Despite being the first anaesthetic drug introduced, and still
widely used, there is sufficient doubt as to the risk-benefit profile.
There is strong evidence that N2O is a major risk factor for postoperative nausea and
vomiting. It is clear that (even) brief exposure to N2O impairs methionine synthetase, an
enzyme required for DNA production, red and white blood cell formation. Tissue hypoxia may
be more common. These adverse effects are enhanced in "sick" patients (ie. those at highest
risk, increased hospital length of stay and healthcare expenditure), and will be more likely
in longer surgery. The extent of wound infection and cardiac morbidity associated with N2O
is not known.
Large outcome trial data are lacking. When considering its widespread use in about 90% of
all surgery around the world, small differences in outcome would have major implications for
healthcare delivery. A large randomised controlled trial is necessary to answer this
question.
We have recruited 2000 patients from about 25 centres around the world (mostly Australasia),
who are undergoing major surgery.
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Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Single Blind, Primary Purpose: Prevention