Canadian Anaesthetists' Society journal最新文献

A patient with a longstanding history of mild hypertension undergoing elective coronary artery bypass grafting exhibited extreme and paroxysmal elevations of systemic blood pressure immediately after separation from cardiopulmonary bypass. Conventional antihypertensive therapy (nitroprusside, hydralazine, propranolol) was ineffective, whereas phentolamine infusion produced a decrease in systemic blood pressure. These observations led to the discovery of a predominantly norepinephrine-secreting phaeochromocytoma. This case is noteworthy in that cardiopulmonary bypass may have served as a stimulus for tumour secretion of catecholamine. Possible mechanisms for this effect are discussed.

A 30-year-old female patient presented in a comatose state with clinical and radiographic signs of aspiration pneumonia 16 hours following elective surgery. Subsequent clinical assessment and investigations revealed the characteristic facies, proximal muscle weakness, lenticular opacities, pulmonary function defects, arterial desaturation and abnormal breathing during rapid eye movement (REM) sleep often associated with myotonia dystrophica. Although these characteristic features were evident on clinical examination postoperatively they were not noted in the preoperative assessment. The aspiration pneumonia and coma were unusual presenting features of this disease. Unsuspected myotonia dystrophica should be considered in the differential diagnosis of unexplained respiratory depression, aspiration or comatose state following surgery. Recognition of the disorder during the preoperative assessment is the key to avoiding complications during the perioperative management of such patients.

The severity of epidural morphine-induced pruritus was evaluated following the addition of epinephrine to the local anaesthetic solution used for Caesarean section anaesthesia. The local anaesthetic solutions used were: Group I--0.5 per cent bupivacaine plain--20 patients. Group II--0.5 per cent bupivacaine with 1:400,000 epinephrine--25 patients. Group III--0.5 per cent bupivacaine with 1:200,000 epinephrine for the 3 ml "test dose" followed by 0.5 per cent bupivacaine plain for anaesthesia--21 patients. The severity of the pruritus, as measured by completion of a visual analogue "itch scale" and by requests for medication for pruritus, was statistically significantly greater in both groups in which epinephrine was added. This effect was not dose-related, as the "test dose" group (15 micrograms epinephrine) experienced the most severe itch. This latter difference was also statistically significant (p less than 0.05).

A clinical trial involving ten anaesthetized adult patients was conducted during controlled ventilation using the Humphrey A.D.E. system in the Mapleson "E" mode (lever down). With each patient acting as his or her own control, the parallel (non-coaxial) and coaxial versions of the single lever Humphrey A.D.E. system were compared, using capnography, to the Bain system (Mapleson D/E). All three systems behaved similarly with predictable patient normocarbia when a fresh gas flow of 70 ml X kg-1 X min-1 was used. The A.D.E. system has the added advantage that the switch from controlled to spontaneous ventilation (or vice versa) is achieved quickly and simply. Spontaneous, assisted or automatic controlled ventilation could be instituted at any time merely by the appropriate lever position.

Treatment of MH was studied in 21 pigs, using an isolated perfused caudal body preparation (L1 transection). Halothane one per cent triggered MH; data included oxygen consumption, blood/muscle lactate levels, plasma potassium, acid-base balance. Three treatment protocols had two phases each: A-1, discontinue halothane, inject dantrolene 7.5 mg X kg-1; A-2, inject HCO3- (113 +/- 6 mEq). B-1, Discontinue halothane, inject HCO3- (118 +/- 13 mEq); B-2, inject dantrolene 7.5 mg X kg-1; X C-1, Continue halothane, inject dantrolene 7.5 mg X kg-1; C-2, discontinue halothane, inject HCO3- (101 +/- 8 mEq). Dantrolene and HCO3- acted separately and differently: dantrolene reversed the hypermetabolism, both aerobic and anerobic, and HCO3- reversed the extracellular metabolic acidosis. Semitendinosus muscle biopsies demonstrated that both red and white muscle are involved in MH, that muscle lactate (to 35 mumol X g-1) consistently exceeded blood lactate (to 22 mumol X ml-1), and that blood lactate levels were slow to diminish following treatment. One could expect continued release of muscle lactate into blood, despite adequate therapy of MH; this might suggest a recurrence even when such is not the case.

A prospective analysis of the cost of intensive care was carried out on 67 admissions to a multidisciplinary ICU. Admissions were grouped and investigated according to various criteria such as admitting diagnosis, admission status (elective vs emergency), severity of illness and outcome. Total ICU admission costs, total per diem ICU costs and per diem costs divided into fixed and variable cost items for the patient groups are reported. Lower total and per diem ICU charges were observed for elective surgical patients, patients with lower severity of illness as assessed by the Therapeutic Intervention Scoring system and survivors. Emergency admissions were more expensive than elective admissions when compared for total ICU admission costs. Length of stay was a significant factor in overall ICU costs. Within the variable cost items, the diagnostic laboratory was the single most costly item per day. As a result of this analysis, the authors propose several suggestions for reducing ICU costs independent of case-mix or diagnosis-related groupings of ICU patients.

A case report is presented of a seven-year-old boy who developed ventricular fibrillation during general anaesthesia with atracurium, O2, N2O and halothane, following tracheal intubation for hypospadias revision. He spontaneously defibrillated and the surgery was cancelled. Echocardiography done two days later was normal. The patient returned two weeks later for the same procedure. He developed nodal tachycardia, and premature ventricular contractions, which responded to lidocaine. A second echocardiographic examination done postoperatively while the child was crying showed mitral valve prolapse.