Medical indications for regional anaesthesia

Abstract

Although many specialists in internal medicine think that they should help influence the choice of anaesthetic technique, the decision between regional and general anaesthesia in any given medical condition and surgical procedure is best left to the attending anaesthetist. Many factors influence the choice of anaesthesia.* These include patient attitude, size and metabolic-physiologic status, anaesthetist skills, accessory personnel and facilities, operative site and duration of operation, and therapeutic and diagnostic considerations. Recent additions and advances in anaesthetic drugs and techniques for general anaesthesia, the increasing number of otherwise well-trained anaesthetists who have limited experience with regional techniques, and the inherent suspicion and fear of surgeons and their patients toward blocks have conspired to limit the use of regional anaesthesia, l As a result, appropriate and optimal use of local anaesthetics is often neglected, resulting in even less inclination to consider regional techniques. The economic pressure to use operating theatre time for the maximum number of cases also mitigates against regional anaesthesia, which, especially in less experienced hands, often takes longer than general anaesthesia. It is interesting to note that among anaesthetists, 68 per cent of 3,498 respondents in a survey preferred regional anaesthesia for themselves} Reasons cited by them for choosing regional anaesthesia included ease of administration, lower incidence of major intraoperative or postoperative complications, avoidance of the toxic effects of some general anaesthetic agents, provision of excellent operating conditions, pleasant recovery, and less difficulty in the recovery room. Regional anaesthesia may be preferred in outpatients, emergency surgery without extensive haemorrhage, patients with a full stomach, surgery in the prone position, geriatric patients, hot and dry climates or high altitude, and surgery where patient co-operation is required. 3 Local techniques may also be selected in patients with certain disease states: diabetes, hypertension, coronary artery disease, congestive heart failure, cerebrovascular accidents, respiratory disease, and urinary tract disease. In contrast, preference may be given to general anaesthesia in young, unco-operative or uncomprehending patients, hysterical patients, patients with a history of malingering, certain nervous system diseases, anaemias, coagulopathies, skin infections, and septicaemia. There are few controlled scientific studies which attempt to determine the relative advantages of either form of anaesthesia. Recent data have demonstrated the merits of regional anaesthesia with respect to haemodynamic considerations, metabolic effects, postoperative patient care, and relative morbidity and mortality. 4 Cardiovascular depression is less and metabolic stress responses are better obtunded. 5 Postoperatively there is improved pulmonary function, better pain control, and earlier ambulation and discharge. 6 Mortality rates have been shown to be slightly lower in regional anaesthesia. 7,s Nevertheless, large scale epidemiologic studies need to be done to further elucidate the relative advantages of regional and general anaesthetic techniques.