Some Aspects of Local Anaesthesia.

Satisfactory as local anaesthesia can be, when the anaesthetic limits are trespassed by the operator, the distress produced may have more far-reaching effects than is generally supposed. Success d"pends as much upon a knowledge of the regional nerve supply as upon an appreciation of the extent to which it can be effectively blocked. A spinal subarachnoid block up to the level of the fourth or fifth dorsal segment does not adequately protect the stomach from traumatic impulses, for although the splanchnic nerves are given off below this the vagi remain intact. While these may be blocked in this area by infiltrating the anterior and posterior parts of the oesophagus with novocain, it may be that other organs in the peritoneal cavity require to be dealt with. If the operator is capable of such gentle handling as not to cause vagal distress, then much can be achieved inside the abdomen with local methods. It may be that this is the only possible way for a successful issue. Broadly speaking, local analgesia is not a good method for operations on the abdominal viscera in which much trauma is anticipated. 'When adequate control is not possible, then general anaesthesia is indicated. There are circumstances when the pathology is such that a certain amount of handling of the tissues is necessary which could hardly be described as gentle. It is in these cases that local analgesia fails. Premedication allays nervous apprehension and may even result in amnesia. Omnopon grains 2/3rds, and scopolamine, grains I/I5oth, serves in the case of healthy adults of over twelve stones weight; ormnopon, grains I/3rd, and scopolamine, grains 1/150th, for those between this and seven stones; while for adult patients under this the doses are reduced to I/6th and I/3ooth grain respectively (and in the case of children morphine is given by body weight, i/4oth grain per stone). If little or no drowsiness results a further injection of omnopon may be given intravenously. The administration must be made slowly and in fractional doses of I/6th grain till the required effect is obtained. Basal narcosis with local'analgesia is unsatisfactory as it is unreliable, and may result in a state in which the patient becomes unmanageable, moving about, and possibly requiring restraint, with danger to the sterile field. Amnesia does not mean that there has not been any mental shock, nor does it signify that nocciceptive impulses have been blocked. It is not uncommon, however, for a patient to ask when his operation is to be done after it has actually been accomplished. I have on record the case of a man,, aged forty-five years, who had a palliative gastroenterostomy for a carcinoma. He was small in stature and pale, but there was no apparent cachexia. After omnopon and scopolamine he was drowsy, but not asleep, and a field block of the abdominal wall was carried out. The peritoneum was also infiltrated with novocain, but this was all. Nothing unt6ward occurred except at critical phases, such as when the stomach was delivered out of the peritoneal cavity, and towards the end of the operation when the viscera were returned before suture of the abdominal wall. At these times the patient groaned out loud, and there was some distress. There was a moderate but temporary fall in blood pressure. Two days later he complained bitterly that he had been in hospital long enough, and that it was time his operation was done. Three days later he died after a period in which the pulse rate kept rising, but nothing else abnormal was detected. There was no autopsy, but the impression at the time was that the myocardium had failed. In this type of fatality, where the diagnosis is uncertain, the question of internal haemorrhage, or extravasion of blood under cover of a serous membrane, must be considered. In the case described, the abdomen was soft and not distended, and there was no increase in pallor. An examination of this case reveals two points: