Anaesthetists

An anaesthetist administers chemicals such as halothane (HI) to a patient before and during an operation to promote unconsciousness. Medical procedures such as operations would be impossible for the surgeon if the patient were awake and could move and they would also be traumatic for a patient who was aware of what the surgery entailed. 

A really deep sleep requires a large amount of anaesthetic and a shallower sleep requires less material. A trained anaesthetist knows just how much anaesthetic to administer to induce the correct depth of sleep, and achieves this by varying the relative pressures of the gases breathed by the patient. 

In effect, the anaesthetist relies on Henry s law, which states that the equilibrium amount of gas that dissolves in a liquid is proportional to the mole fraction of the gas above the liquid. Henry published his studies in 1803, and showed how the amount of gas dissolved in a liquid is directly proportional to the pressure (or... 

The site http //www.oyston.com/history has afascinating history of the topic, mentioning such early anaesthetics as ether, chloroform and nitrous oxide. Local anaesthetics are often injected in the form of liquids or solutions, see the article pharmacology of local anaesthetic agents by a British anaesthetist, Dr J. M. Tuckley, may be found... 

Wilcox, R.A. and Owen, H. (2000) Variable cytochrome P450 2D6 expression and metabolism of codeine and other opioid prodrugs implications for the Australian anaesthetist. Anaesthesia and Intensive Care, 28 (6), 611-619. 

Maintaining cleanliness and sterility is involved in everyday practice but, for the most part, is not under the direct control of anaesthetists. Nevertheless, a familiarity will be expected with the main definitions and methods of achieving adequate cleanliness. 

The most important type to the anaesthetist is type B, which encompasses both anaphylactic and anaphylactoid reactions. 

Consultant Anaesthetist, Royal Hampshire County Hospital, Winchester, UK... 

Department of Anaesthesiology Academic Medical Centre Amsterdam The Netherlands John P Howe Consultant Anaesthetist Belfast City Hospital Belfast... 

For inhalational induction of anaesthesia in children, 6% sevoflurane in 50% nitrous oxide and oxygen is probably optimal. However, some anaesthetists consider it to be inferior to halothane for the management of the irritable or constricted airway and for anaesthesia for bronchoscopy. Sevoflurane is preferred for dental procedures as there is a lower risk of cardiac arrhythmias than with halothane, especially in children. In children with congenital heart disease, whereas the cardiac index is reduced by halothane it is preserved with sevoflurane. In adults, 8% sevoflurane is well tolerated and, provides rapid induction of anaesthesia without adversely affecting haemodynamic stability. 

There are now few indications for etomidate, aithough many anaesthetists stiii use the drug for induction in patients with compromised car-diovascuiar function. 

Whittaker M. Plasma cholinesterase variants and the anaesthetist. Anaesthesia 1980 35 174-97. Zhang M-Q. Drug-specific cyclodextrins the future of rapid neuromuscular block reversal Drugs of the Future 2003 28 347-54. 

Prophylaxis of stress ulceration in intensive care units is the major interest to the anaesthetist. Here, it is given in a dose of 1 g every 6 hours via nasogastric tube. Several studies have shown sucralfate to be comparable in efficacy to H2 blockers. It has been claimed, but not proved, to result in a reduction in morbidity and mortality from nosocomial pneumonias in comparison to H2 antagonists. The latter, by raising gastric pH, eliminate the acid barrier to colonisation of the gut by pathogens, which sucralfate does not do. 

The treatment of constipation and questions of use and abuse of laxatives are not normally of major interest to the anaesthetist. However, constipation is a particular problem in terminal care patients, especially where they are receiving opioid drugs for pain relief, and its prevention and management must be an integral part of their treatment. Both constipation and diarrhoea are problems in the intensive care patient. 

Idio ncrasy. This is a response that is qualitatively different from the action of the drug in normal individuals, again often genetically determined. Of importance to anaesthetists are abnormal responses to several drugs in patients with acute intermittent porphyria, and in those susceptible to the malignant hyperpyrexia syndrome. 

Many of the pharmacodynamic interactions of most interest to the anaesthetist occur in pathways associated with the various divisions of the nervous system, central and autonomic, and thus influence the control of the cardiovascular system. 

Gander PH, Merry A, Millar MM, Weller J. Hours of work and fatigue-related error a survey of New Zealand anaesthetists. Anaesth Intens Care 2000 28 178-183. 

We thank the British Technology Group and the Association of Anaesthetists for sponsoring the University Research Program, Professor G. Smith and Dr. C. Hanning of Leicester University, Department of Anaesthesia, for their joint interest and clinical results, and our laboratory technicians P. Keating and R. Cameron for careful preparations and assays. 

The words anaesthesia and anaesthetic were first used by Oliver Wendell Holmes in a letter to the surgeon William Morton dated 21st November 1846. The Association of Anaesthetists of Great Britain and Ireland have a museum in central Lon-... 

Nitrous oxide is still used because of its rapid action and adding a little of this to other anaesthetics makes less likely another type of accident, that happens when the supply of anaesthetic runs out during the course of an operation and the anaesthetist is unaware of it. As a result, the patient starts to recover consciousness during the operation and consequently suffers extreme pain and trauma. Financial compensation in such cases can be particularly high. Nitrous oxide keeps the patient unaware of what is happening. 

Dr Karalliedde was formerly Senior Lecturer and Honorary Consultant Anaesthetist at the United Medical Dental Schools of Guy s St Thomas Hospitals, London, UK and Medical Toxicologist at Guy s Poisons Unit and National Poisons Information Service, Guy s St Thomas NHS Foundation Trust, London, UK. 

CalveyTN,WilUams NE. Principles and practice of pharmacology for anaesthetists. St. Louis Blackwell Scientific Publications, 1982. 

The anaesthetist ensures that the effects of neuromuscular blocking agents and opioid-induced respiratory depression have either worn off or have been adequately reversed by an antagonist the patient is not left alone until conscious, with protective reflexes restored, and a stable circulation. 

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