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Thoughts and opinion from the wards
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Environmental Anaesthesia
Environmental anaesthesia If you are in the UK, your local council insists that you sequester your household waste for recycling. In other European countries they have done so for much longer. But what about medical wastes? The AAGBI’s web page about the environment, http://www.aagbi.org/about-us/environment includes much good sense about how the concerned citizen, let alone doctor and anaesthetist should behave to minimise our damage to the environment. More specifically to anaesthesia, the site points out that all the inhaled anaesthesia vapours are halogen-substituted hydrocarbons, just like the refrigerants and aerosol propellants that have knocked a hole in our ozone layer. Although they are far less chemically stable than those, and break down much more rapidly after they are released, like CO2 they have a potent effect on solar heat and contribute to global warming. In fact last year, a paper (1) estimated that the global use of such vapours had the global warming potential (GWP) of a coal-fired power station or one million cars!What that article and the AAGBI does not mention is the contribution of nitrous oxide. Like the vapours, N2O is a far more potent global warming gas than CO2, that over a 100 year period has a GWP100 nearly 300 times more than CO2. This may be compared with the GWP100 of the vapours, which span that figure, but will not last anything like that long in that atmosphere. It may be reassuring to anaesthetists still using it that the release of N2O through the theatre scavenging systems of the world is at least a hundred times less than that from industrial processes, the use of nitrogenous fertilisers and from the excreta of animals, and us. But when the only possible clinical use in anaesthesia for this out moded agent is the second gas effect to speed vapour induction, they should ask themselves if they really need to use it any more. http://www.aagbi.org/about-us/environment/should-i-use-nitrous-oxide So what is available that doesn’t have a global warming impact? Xenon is an element, a noble gas, that exists in the atmosphere and can be concentrated. It has no environmental effects beyond the CO2 impact of making it available for clinical use, the concentration process and transporting it to the user. But so far, it is used only for research and experimental purposes, and it is expensive and difficult to use without special equipment. Propofol is an attractive alternative. Since it was introduced into clinical practice more than twenty years ago, the cost of the drug and equipment has fallen to one comparable to the vapours. It is not released into the atmosphere, but is excreted unchanged, as quinols and in glucuronated, hydrolysed and sulphated forms, all of which still contain the phenol ring of di-isopropyl phenol. While phenol is an environmental pollutant, I know of no work that shows what propofol in waste water breaks down into, and so far no one has pointed blame at the drug. Like any drug, propofol must have a cost to the environment in synthesis but again, I do not know and the manufactureres do not tell what that is. But what else could we do to help the environment? Quite a lot, and even more to help our cash-strapped NHS and hospitals! As the AAGBI web pages show, the disposal of theatre waste is an expensive business. Sharps and other items cost about £750 a tonne to be incinerated, when disposal of domestic waste costs a tenth of that, and paper and other recyclables can be sold, for money! Do you throw all that paper wrapping from your disposables in the same bag as bloody swabs, or small plastic items in the sharps bin? Do you have separate bins and bags at all? The AAGBI recommends the 5Rs approach, of REDUCE, REUSE, RECYCLE, RETHINK and RESEARCH. Anaesthesia has lead the way in many aspects of modern hospital management, from analgesia and audit right down the alphabet. You, your theatre and your hospital could save a lot of money, if you can get all the staff to be environmentally minded! References
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