Evaluation of Nitrous oxide In the Gas Mixture for Anaesthesia: a randomised controlled Trial (The ENIGMA Trial) [ 2003 - 2005 ]

Research Grant

Researchers: Prof Paul Myles (Principal investigator) ,  A/Pr Brendan Silbert ,  Prof Kate Leslie ,  Prof Michael Paech ,  Prof Philip Peyton

Brief description There are about 2 million anaesthetics given each year in Australia (1:10 Australians), with more than 1 million Australians being exposed to nitrous oxide (laughing gas). Despite being around for more than 150 years, there has yet to be a large trial of the safety and benefits of nitrous oxide, particularly when compared with newer (safer?) anaesthetic drugs. Nitrous oxide is not a particularly strong anaesthetic and so it must be mixed with other drugs. Current practice in Australia and around the world is to give 70% nitrous oxide in oxygen along with another anaesthetic gas in order to produce a depth of anaesthesia sufficient for surgery. This is despite knowledge that nitrous oxide interferes with the production of DNA. DNA is used to programme cell division and function - it is the building block of cell and tisue growth. It is known that nitrous oxide can impair some tissue functions, such that anaemia and, possibly birth defects can occur. Such effects are rare, but recent evidence suggests that milder abnormalities may occur more commonly than previously thought. There is also good evidence that nitrous oxide increases the risk of severe nausea and vomiting after surgery. The adverse effects on DNA production raises the possibility of nitrous oxide causing immune deficiency, heart ischaemia, (angina), nerve and spinal cord damage, and increased cancer risk in hospital staff chronically exposed to low levels of nitrous oxide. The prevailing view is that nitrous oxide is a cheap, relatively safe drug that can reduce the exposure to other anaesthetic drugs. However, the development of many new anaesthetic drugs demands a re-evaluation of the role of nitrous oxide in current anaesthetic practice.

Funding Amount $AUD 490,125.00

Funding Scheme NHMRC Project Grants

Notes Standard Project Grant