British journal of anaesthesia
-
Jet ventilation, through a bronchoscope, was evaluated using a lung model (normal compliance and increased airway resistance). Three I/E ratios (0.25, 0.43, 0.67) and seven rates of ventilation (from 20 to 230 cycles per min (c min-1) were studied with the bronchoscope either unoccluded or partially occluded by a telescope. ⋯ The introduction of the telescope reduced minute ventilation, as a result of a decrease in the amount of air entrained, and increased end-expiratory pressure and lung volume. The risk of barotrauma as a result of high peak pressure is reduced during high frequency jet ventilation, but the increase in lung volume, particularly when the telescope is introduced, may be of clinical importance.
-
Comparative Study
Effect of intrathecal diamorphine on the adrenocortical, hyperglycaemic and cardiovascular responses to major colonic surgery.
The effect of the intrathecal administration of diamorphine on the hyperglycaemic, adrenocortical and cardiovascular responses to major colonic surgery were investigated, and the results compared with those obtained in a similar group of patients receiving low doses of fentanyl. In the group receiving intrathecal diamorphine, the hyperglycaemic response was delayed, and the adrenocortical response decreased significantly both during and following surgery; there were no significant cardiovascular responses to incision, and analgesia was prolonged after operation.
-
Neurotoxicity after subarachnoid infusion of bupivacaine, lignocaine and 2-chloroprocaine was studied in a chronic rat model. Hartmann's solution 100 microliter h-1 was infused as a control, and 0.5% bupivacaine, 1.5% lignocaine and 2.0% 2-chloroprocaine were infused at 100 microliter h-1 for 3, 6 or 24 h, to five rats in each group. ⋯ Abnormal histology, in the form of neuronal vacuolation, was not a sensitive index, being present in control rats, but more intense in those receiving lignocaine and 2-chloroprocaine than in those given bupivacaine; no correlation with clinical findings could be established. The neurotoxic effects of each local anaesthetic tested as a continuous intrathecal infusion were dose related in the rat, which may be a useful model for screening other local anaesthetics.
-
Rat and mouse were utilized as models to study the spinal (subarachnoid) anesthetic effects of five commonly used local anaesthetic agents. Duration and frequency of motor and sensory blockade, and onset time were determined after injection of 5.0% lignocaine, 0.75% bupivacaine and 1.0% amethocaine to the same groups of rats with chronically implanted catheters in the lumbar subarachnoid space. ⋯ The relative potency and other characteristics of the compounds investigated were in agreement with results obtained in other species, including man. The techniques described may provide useful adjuncts to methods in larger animals for the evaluation of potential new spinal anaesthetic agents, and the study of various factors that may influence spinal anaesthesia.
-
Randomized Controlled Trial Clinical Trial
Fentanyl by constant rate i.v. infusion for postoperative analgesia.
Fentanyl by continuous i.v. infusion (1.5 microgram kg-1 min-1 or 0.5 microgram kg-1 min-1) was compared with placebo infusion as an analgesic regimen for 24 h after hysterectomy. The drugs were infused using a new disposable device which required no external power source. All patients were allowed morphine i.m. if they experienced pain. Patients in the higher dose fentanyl group demanded less i.m. morphine and had better pain relief after operation, without important respiratory depression.