British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Remifentanil reduces auditory and somatosensory evoked responses during isoflurane anaesthesia in a dose-dependent manner.
We studied 60 patients during stable isoflurane anaesthesia (0.4 MAC) after premedication with temazepam. Patients were allocated randomly to one of three dose regimens of remifentanil: 1 microgram kg-1 i.v. over 1 min and an infusion of 0.2 microgram kg-1 min-1 (low dose); 2.5 micrograms kg-1 and 0.5 microgram kg-1 min-1 (medium dose); and 5 micrograms kg-1 and 1 microgram kg-1 min-1 (high dose). The auditory (AER) and median nerve somatosensory (SER) responses were elicited throughout, and recorded before and after tracheal intubation, and surgical incision, together with systolic and diastolic arterial pressure and heart rate. ⋯ After intubation, P15-N20 and N35-P45 amplitudes increased at the low dose, did not change at the medium dose and decreased at the high dose (P = 0.001, P = 0.027). After remifentanil, systolic and diastolic arterial pressure and heart rate decreased in a linearly dose-related manner (P = 0.033, P < 0.001, P < 0.001). At all doses the three variables increased after intubation (P = 0.001, P < 0.001, P < 0.01), and systolic and diastolic arterial pressure increased after incision (P = 0.027, P = 0.039).
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Randomized Controlled Trial Clinical Trial Controlled Clinical Trial
Effect of systemic N-methyl-D-aspartate receptor antagonist (ketamine) on primary and secondary hyperalgesia in humans.
Ketamine reduces nociception by binding noncompetitively to the N-methyl-D-aspartate (NMDA) receptor, activation of which increases spinal hypersensitivity. We studied 19 healthy, unmedicated male volunteers, aged 20-31 yr. Burn injuries were produced on the medial surface of the dominant calf with a 25 x 50 mm rectangular thermode. ⋯ In contrast, ketamine did not alter phasic heat pain perception (perception of transient, painful, thermal stimuli) in undamaged skin. The analgesic effects of ketamine in the burn injury model are in agreement with results from experimental studies, and can be distinguished from those of local anaesthetics and opioids. Side effects caused by continuous infusion of ketamine 0.15 and 0.30 mg kg-1 h-1 were frequent but clinically acceptable.
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Randomized Controlled Trial Comparative Study Clinical Trial
Removal of the laryngeal mask airway in children: anaesthetized compared with awake.
We studied 60 children, aged 12 months to 8 yr, undergoing plastic surgery under general anaesthesia supplemented by regional anaesthesia. Patients were allocated randomly to have the laryngeal mask airway removed either on awakening or while anaesthetized. ⋯ There were no differences in the incidences of laryngospasm, desaturation (< 95%) and excess salivation between the groups. Removed of the laryngeal mask airway during deep anaesthesia reduced coughing in the immediate postoperative period.
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Randomized Controlled Trial Comparative Study Clinical Trial
Spinal clonidine produces less urinary retention than spinal morphine.
We have conducted a double-blind, randomized study in two groups of 20 patients each, undergoing hip surgery during spinal anaesthesia, to compare the incidence of urinary retention after spinal morphine or clonidine. Patients received 0.5% spinal bupivacaine 15 mg combined with either clonidine 75 micrograms or morphine 0.2 mg. ⋯ Naloxone was given in 16 and one, and a catheter was placed in one and six patients in the morphine and clonidine groups, respectively (P < 0.001). We conclude that spinal clonidine impaired bladder function to a lesser extent than morphine.
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Clinical Trial
Continuous extrapleural paravertebral infusion of bupivacaine for post-thoracotomy analgesia in young infants.
We have studied the efficacy of a continuous paravertebral infusion of bupivacaine for the management of post-thoracotomy pain in 20 infants with a median age of 5.3 weeks (range 2 days to 20 weeks). Immediately before chest closure, 0.25% bupivacaine 1.25 mg kg-1 was injected into an extrapleural paravertebral catheter, inserted under direct vision. A continuous infusion of 0.25% bupivacaine 0.5 mg kg-1 h-1 was commenced 1 h later and terminated after 24 h. ⋯ The technique provided effective postoperative pain relief in 18 (90%) patients and the failure in two (10%) infants was attributed to catheter block. Mean maximum serum concentrations of bupivacaine after the loading dose and during infusion were 1.03 (SD 0.56) and 2.00 (0.63) microgram ml-1, respectively. There were no major complications relating to the technique and we conclude that extrapleural paravertebral block is a simple and effective method for post-thoracotomy analgesia in young infants.