Ann Acad Med Singap
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Ann Acad Med Singap · Nov 1994
ReviewRecent advances in the understanding and management of postoperative nausea and vomiting.
Postoperative nausea and vomiting (PONV) is a common distressing complication of surgery and anaesthesia. The multifactorial aetiology of PONV gives rise to an incidence that varies widely among different patient groups. ⋯ Current research is concentrated on a new class of drugs, the serotonin (5-HT3) receptor antagonists. This review summarizes the experience with these drugs and other recent advances in PONV.
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Extracorporeal life support (ECLS), which is prolonged cardiopulmonary bypass with an artificial membrane lung, is one of the most efficient life support means for patients with severe cardiopulmonary failure. Its practice will become much simpler, safer and popular in the near future. In this article, the history of ECLS and the acronyms related to it, together with its present status in the world are introduced. ⋯ Heparin-bonded hollow-fibre lungs made of non-microporous membrane are recommended for prolonged cardiopulmonary bypass to prevent gas embolism and fluid leakage from the artificial lungs. Several special clinical cases where patients were saved from moribund cardiopulmonary failure, such as severe barotrauma after excessive ventilator therapy and prolonged cardiac standstill after myocardial infarction, are described to explain the life-support effects and indications of ECLS. Research on ECLS, now taking place, such as the use of an intravenacaval oxygenator, manually operated cardiopulmonary bypass system for emergency resuscitation and transportation of the patient, as well as respiratory care of a premature newborn in artificial amnion fluid, is also introduced.
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Continuous spinal anaesthesia is an established technique in which renewed interest has been generated by the availability of small bore catheters suitable for use in the subarachnoid space. Problems include technical difficulty, post dural puncture headache and maldistribution of local anaesthetic, the latter being implicated in the development of caudal equina lesions. Maldistribution of local anaesthetic may possibly be reduced by attempting to place the tip of the catheter at the apex of the lumbo-sacral curve and the use of local anaesthetic solution that is only marginally hyperbaric. This article is in the form of a short review together with an account of the authors' own studies of continuous spinal anaesthesia, conducted to assess the technique for peripheral vascular surgery.
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Ann Acad Med Singap · Nov 1994
ReviewClinical pearls in the anaesthetic management of elderly patients.
Recently published information is changing the approach of anaesthetists to pulmonary aspiration prophylaxis, drug dosing, hypertension during general anaesthesia, hypotension during spinal and epidural anaesthesia, intraoperative hypothermia, and postoperative ileus in elderly patients. Routine aspiration prophylaxis is no longer recommended. Lower drug doses are required to achieve the same endpoints in the elderly as in younger patients. ⋯ The adverse effects of inadvertent intraoperative hypothermia are discussed, including the conversion of vecuronium from an intermediate to a long-acting neuromuscular blocking agent. Spinal or epidural local anaesthetics with or without spinal or epidural opioids and ketorolac are associated with less postoperative ileus than postoperative analgesia based on opioids administered intravenously or intramuscularly. Finally, improving postoperative care will reduce perioperatively mortality to a greater extent than reducing intraoperative anaesthesia-related complications.
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Malignant hyperthermia (MH) is a pharmacogenetic disorder of skeletal muscle. In humans, MH is inherited in an autosomal dominant fashion; in swine, the principal model for MH, it is in a recessive fashion. Those with MH susceptibility usually are asymptomatic except in the presence of certain "triggering" anaesthetic agents such as isoflurane, enflurane and the muscle relaxant succinylcholine. ⋯ The pathophysiology of MH centres around a defect in calcium flux in skeletal muscle. A specific base pair change in the gene that codes for the ryanodine receptor calcium channel in muscle has been demonstrated in susceptible swine, but occurs rarely in humans. It is hoped that the understanding of the molecular genetics of MH will lead to a simpler diagnostic test than is currently available, and enhance our understanding of MH and its relation to other myopathies.