Comparison of controlled respiration by the manual technique and with a respirator during general anaesthesia for abdominal operations

These studies investigating the difference between controlled respiration performed by manual technique and controlled respiration applied by means of a respirator during general anaesthesia, and assessing the influence of these methods on the immediate post-operative condition of the patient were carried out on 75 patients during abdominal operations. Gasometric tests in arterial blood were performed before premedication, at intervals of 30 min from the beginning of operation, and 10 min. after the removal of the endotracheal tube. Controlled respiration with a respirator is a more favourable method of pulmonary ventilation during general anaesthesia given for a long-lasting surgical operation. The manual technique of controlled respiration leads to respiratory alkalosis. The best results were obtained using a respirator with inspiratory volume of 10 ml/kg and respiratory frequency 10/min., which ensured normocapnia. It was observed that oxygenation of arterial blood was reduced postoperatively in all patients but the value of PaO2 was the lowest in patients on manual controlled respiration. Disturbances in acid-base balance and oxygenation had an unfavourable effect and delayed the regaining of consciousness.