Anaesthetic considerations for microsurgical repair of limbs.

With the advent of surgery under the operating microscope microvascular surgical techniques requiring prolonged anaesthesia have greatly increased in number. Local anaesthetic techniques, whilst often producing excellent surgical conditions, are limited by the duration of action of the anaesthetic agents and by the ability of the patient to remain still, often in uncomfortable positions, for periods of up to twenty hours. The use of indwelling catheters as a means of prolonging the duration of nerve blocks is discussed along with methods of sedation or general anaesthesia to enable the patient to tolerate lengthy surgical intervention. Present general anaesthetic techniques may not be ideally suited to long surgical procedures. The problems and possible alternatives are discussed. Sympathetic ganglion blockade, intravenous regional blockade and systemic vasodilator therapy are discussed as a means of improving the success rate of these procedures. The general principles of patient management such as fluid balance, temperature control, patient positioning and control of the operating room environment assume a much greater significance when related to the provision of prolonged general anaesthesia, whilst the effect of extended periods of work on operating personnel must also be considered.