Anaesthesia in the elderly. Special considerations

The physiological effects of aging may alter the pharmacokinetics and pharmacodynamics of many anaesthetic drugs. Premedicants should be avoided in the very old, and intravenous induction agents given in reduced dosage. The new inhalational agents, desflurane and sevoflurane, may be useful in this patient group; sevoflurane can also be administered to induce anaesthesia. However, both these agents can have adverse cardiovascular effects at high concentrations. The nondepolarising neuromuscular blocking drug, atracurium, is useful in the elderly because it does not undergo organ disposition. It may, however, cause histamine release, with resultant hypotension and tachycardia. It is as yet uncertain whether the isomer of atracurium, cisatracurium, will have any advantages in this age group, but it appears to be free from histamine-releasing effects. If residual neuromuscular block is antagonised in the elderly, then the dosage of anticholinesterase should be titrated using neuromuscular monitoring, as these agents can have adverse effects in this age group. Postoperative analgesia requires careful control in the elderly. Several methods of administration exist for relieving pain in this age group, but each has disadvantages. Anaesthesia in the elderly therefore requires skill and judgement based on these physiological and pharmacological considerations.