1/4. Idiopathic orthostatic hypotension, midodrine, and anaesthesia.A patient with idiopathic orthostatic hypotension receiving chronic oral midodrine therapy required anaesthesia for coronary artery bypass grafting. A perioperative infusion of phenylephrine was substituted for midodrine, an alpha-2 agonist, enabling hypotension resulting from low systemic vascular resistance to be controlled easily. Anticipated adrenergic receptor denervation hypersensitivity was noted. The only significant perioperative problem was one episode of syncope from orthostatic hypotension during the reambulation period.- - - - - - - - - - ranking = 1keywords = anaesthesia (Clic here for more details about this article) |
2/4. Anaesthetic considerations in idiopathic orthostatic hypotension and the shy-drager syndrome.Orthostatic hypotension due to autonomic failure may occur secondary to systemic disease states (notably diabetes) or as a disease entity in its own right with a variable degree of neurological involvement that has resulted in a confused classification. The diagnosis, classification and treatment of these latter forms of orthostatic hypotension is reviewed. The pathology is in the central and efferent autonomic pathway, resulting in a disordered baro-receptor reflex, postural hypotension, abnormal responses to tilting and the Valsalva manoeuvre, an inappropriately fixed heart rate and other autonomic features. Anaesthesia may be associated with profound hypotension and some of the signs of anaesthesia may be absent. The response to cardiac depressant drugs and reduction of circulating blood volume may be exaggerated due to absence of compensatory mechanisms. The response to vasoactive agents is unpredictable. The importance of preoperative evaluation, monitoring during operation and the careful selection of anaesthetic agents and techniques is discussed.- - - - - - - - - - ranking = 0.2keywords = anaesthesia (Clic here for more details about this article) |
3/4. shy-drager syndrome. A review and a description of the anaesthetic management.Autonomic failure in patients with the shy-drager syndrome may produce cardiovascular instability during anaesthesia and surgery. The syndrome is reviewed and the anaesthetic management of a case is described. The choice between general and regional anaesthesia seems to be less important than adequate cardiovascular monitoring and the maintenance of blood pressure with intravenous fluids. Sympathomimetic drugs, if used at all, should be administered in very dilute solutions to avoid hypertension from denervation hypersensitivity. In the postoperative period, symptoms from orthostatic hypotension may be severe and their control requires prolonged postural training, by elevation of the head of the bed, and therapy with 9-alpha-fludrocortisone.- - - - - - - - - - ranking = 0.4keywords = anaesthesia (Clic here for more details about this article) |
4/4. Cardiorespiratory arrest and diabetic autonomic neuropathy.Twelve cardiorespiratory arrests in eight neuropathy are reported. Only one patient died at the time, but two others subsequently died suddenly at home. There was no evidence of myocardial infarction, cardiac arrhythmia, or hypoglycaemia at the time of arrest. In most of the episodes there was some interference with respiration, either by anaesthesia, drugs, or bronchopneumonia. Five of the episodes occured during or immediately after anaesthesia. It is suggested that the arrests were caused by defective respiratory rather than cardiovascular reflexes. Cardiorespiratory arrest appears to be a specific feature of diabetic autonomic neuropathy and may contribute to the mortality of this condition.- - - - - - - - - - ranking = 0.4keywords = anaesthesia (Clic here for more details about this article) |