Oxygenation during electroconvulsive therapy. A comparison of two anaesthetic techniques.

Oxyhaemoglobin saturation was monitored continuously during electroconvulsive therapy in two groups of patients. All patients were anaesthetised using methohexitone (40-100 mg) and suxamethonium (25-50 mg). In group 1 (n = 48), the patients' lungs were ventilated manually with oxygen in air (40-50%) during the modified convulsion. In group 2 (n = 47), the convulsion was allowed to subside before recommencing manual ventilation with a similar gas mixture. Eight patients in group 1 and seven patients in group 2 received more than one shock and were excluded, leaving 40 patients in each group. In group 1, one patient had a minimum oxygen saturation of less than 90% after the electric shock as opposed to 11 in group 2 (p less than 0.01). Five of the patients in group 2 had a saturation of less than 80%. It is concluded that patients undergoing electroconvulsive therapy should be ventilated with an oxygen-enriched gas mixture during the convulsion induced by the electric shock in order to avoid hypoxaemia.