The use of nitrous oxide in anaesthetic practice: a questionnaire survey

Abstract

SummaryWhere practicable, exposure to a hazardous substance should be eliminated or adequately controlled. A postal questionnaire survey was sent to 10% of consultants from the Association of Anaesthetists of Great Britain and Ireland, to identify the level of use of nitrous oxide in current anaesthetic practice and identify any change of practice over the last 5 years. Details of anaesthetic practice were requested in three areas: nitrous oxide usage, availability of medical air on anaesthetic machines and the use of total intravenous anaesthesia. Replies were received from 320 consultants (75%). Of these, 49% felt that, over the last 5 years, their use of nitrous oxide had decreased. Twenty per cent of anaesthetists felt that there should be some restriction in availability of nitrous oxide. Where medical air was available, 32% felt that they would use it frequently. A total of 263 (83%) stated that they use total intravenous anaesthesia to some extent. The results showed that, although 49% of consultant anaesthetists had reduced their use of nitrous oxide, this was due to medical considerations rather than concerns over health and pollution issues arising from the use of nitrous oxide. Studies have identified levels of pollution generated from the use of nitrous oxide in clinical procedures [1][2][3][4]. One of the contributing factors may be the lack of provision of medical air on the anaesthetic machine, and therefore the greater use of nitrous oxide as a carrier gas [5].There are potential health risks associated with occupational exposure to nitrous oxide. The problem of addiction has been reported [6,7]. Associated with this is the development of myeloneuropathy [8,9], but these problems have not been investigated recently. A number of epidemiological studies has linked occupational exposure to nitrous oxide with spontaneous abortions, reduced rates of fertility and congenital abnormality. Both supportive and negative studies exist and there is much conflicting information surrounding the existence of the problem [10][11][12][13][14][15][16]. Again there is little recent work.In the UK, the Control of Substances Hazardous to Health (COSHH) Regulations 1999 state that exposure to anaesthetic agents must be reduced to as low as is reasonably practicable. Where practicable, exposure to a hazardous substance should be eliminated or adequately controlled [17]. Nitrous oxide has an occupational exposure limit (OEL) of 100 parts per million (p.p.m.) over an 8-hr time weighted average (TWA). This is based on personal exposure. There are varying exposure limits across the world; in the USA the limit for nitrous oxide is as low as 25 p.p.m. and internationally, there is no agreed standard.With the recent increased provision of medical air on anaesthetic machines and greater interest in the use of total intravenous anaesthesia [18], it was decided to look at the usage of nitrous oxide in anaesthetic practice and try to assess whether its usage has increased, decreased or stayed the same over the past 5 years. The c...

The use of nitrous oxide in paediatric anaesthetic practice in the United Kingdom: a questionnaire survey*

“…This contrasts with a previous UK survey of the use of nitrous oxide in anaesthetic practice published in 2002 (including both adult and paediatric anaesthetists), in which only 16% of responders felt that operating theatre pollution by nitrous oxide was a problem [18]. In the previous questionnaire, 80% of senior anaesthetists felt that nitrous oxide should remain freely available.…”

A comparative evaluation of nitrous oxide-isoflurane vs isoflurane anesthesia in patients undergoing craniotomy for supratentorial tumors: A preliminary study

“…[31,32] Some authors believe that although there may be specific situations where nitrous oxide be avoided, not only its routine use be questioned but also its routine avoidance. [33] Further studies are needed to address this issue before discarding the only anesthetic drug that has withstood the test of time.…”

Anesthesia and Pain Management: Techniques and Practice

“…Nitrous oxide diffusion causes an increase in the middle ear pressure and distension of the bowel, possibly resulting in increases in postoperative nausea and vomiting. The results of a questionnaire proposed by the Association of Anesthesist of Great Britain and Ireland indicate that 49% of anesthesist had reduced their use of nitrous oxide (Henderson et al, 2002). According to Baum, nitrous oxide should not be used routinely as a carrier gas and the safer mixture of oxygen/medical air is able to replace this old anesthetic with some economical advantages (Baum, 2004).…”