Canadian Anaesthetists' Society journal最新文献

The commonly used vasodilators sodium nitroprusside and nitroglycerin increase intracranial pressure (ICP) and cause tachycardia. Since diltiazem is also a vasodilator, we designed this experiment in cats to study its effect on intracranial pressure and heart rate (HR). Twelve cats were assigned to two equal groups. One group had normal ICP (N-ICP), while in the other the ICP was raised artificially (AR-ICP) by placing a balloon into the intracranial extradural space. Both groups received an infusion of diltiazem to decrease the mean blood pressure (BP), which was maintained 30 per cent below the baseline value for 15 minutes. Diltiazem caused no significant change in ICP (5.7 +/- 1 to 6.7 +/- 1.5 mmHg, p less than 0.01) in cats with N-ICP while in cats with AR-ICP, the increase from 26.9 +/- 0.5 to 34.0 +/- 1.9 mmHg was significant (p less than 0.006). HR decreased significantly during the diltiazem infusion in both groups.

This report describes the absence of gas flow despite the apparent proper mounting of a Canadian Liquid Air nitrous oxide quick-mount connector to its wall outlet. A similar but potentially more dangerous malfunction can occur with oxygen quick-mount connectors. The nature and cause of this defect are examined.

Previous studies have reported that elevation of the pH of local anaesthetics is associated with enhanced quality and duration of block. This study investigated the effect, on time to onset and duration of analgesia, of pH adjustment of 0.25 per cent bupivacaine immediately prior to injection into the epidural space in parturients. Addition of 0.1 ml of 8.4 per cent sodium bicarbonate to 20 ml of 0.25 per cent bupivacaine consistently raised the pH of the local anaesthetic from 5.65 to 7.26 (mean values). Thirty parturients received an epidural injection of 8 ml of pH-adjusted 0.25 per cent bupivacaine and a control group of 30 parturients received 8 ml of the standard commercial preparation of 0.25 per cent bupivacaine. Elevation of the pH of the local anaesthetic significantly increased the speed of onset of analgesia from 6.0 minutes to 3.2 minutes and the duration of analgesia was significantly lengthened from 79.4 minutes to 96.5 minutes. There was no significant influence on time to peak effect, nor on mean maternal plasma levels of bupivacaine.

Atracurium is a new intermediate-acting muscle relaxant, relatively devoid of cardiovascular effect in the clinical dose range. Histamine release is reported in a dose-dependent fashion, but below the threshold for haemodynamic effect within the recommended dose limits. We report a case of an anaphylactoid reaction to a low dose (0.2 mg X kg-1) of atracurium, and discuss the peculiar aspects of this case that predisposed the patient to this event.

The detailed clinical response of a patient with absent plasma cholinesterase (genotype E1s E1s) who received tubocurarine (3 mg), succinylcholine (120 mg), pancuronium (2 mg), and reversal with neostigmine (3 mg) is reported. The patient's responses were compared to the responses of a group of patients with genotype E1a E1a evaluated prospectively, and with eight other genotype E1s E1s patients reported in the literature. The present patient demonstrated evidence of a phase II block before and after attempted reversal, suggesting that free succinylcholine was present in her plasma and a mixed block was present at that time. Conservative supportive therapy was continued and a complete recovery resulted five hours and 30 minutes after the succinylcholine administration.

Epidural meperidine (1 mg X kg-1) was administered for relief of sternal pain to ten patients, at a mean of 24.8 hours after infusion of high dose fentanyl for cardiac surgery. Lung function, cough, pain score, somnolence, respiratory rate, PaCO2, pulse and blood pressure were studied before and for six hours after analgesic administration. Following epidural meperidine, four of ten patients were pain-free, and three had only minimal pain. Duration of analgesia was 8.8 +/- 4.9 hours. Cough score was significantly improved for five hours. Postoperatively vital capacity was approximately 40 per cent, and FEV1 was approximately 55 per cent of the preoperative value. There was no significant change in FEV1 or vital capacity, following analgesia with epidural meperidine. The somnolence score increased in seven patients. In the first two hours after epidural meperidine, three patients exhibited a fall in their respiratory rate, one had a PaCO2 greater than 45, and two of these patients had marked hypotension. These side effects are easily treated without mechanical or pharmacological support, and do not preclude the use of epidural meperidine after a high dose fentanyl anaesthetic.