British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Pharmacological vasodilatation improves efficiency of rewarming from hypothermic cardiopulmonary bypass.
An afterdrop in core temperature after hypothermic cardiopulmonary bypass (CPB) is related to inadequate peripheral rewarming. We proposed that pharmacological vasodilatation during rewarming on bypass would improve peripheral rewarming and reduce the degree of afterdrop. Fifty-nine of 120 patients were randomized to receive a sodium nitroprusside (SNP) infusion during the rewarming stage of hypothermic CPB. ⋯ Patients receiving SNP had a warmer mean peripheral temperature (MPT) (32.9 degrees C vs 32.4 degrees C; P = 0.05) on termination of CPB. Postoperative core temperature fell less in the SNP group (35.6 degrees C vs 35.2 degrees C; P = 0.01) as did MPT (31.8 degrees C vs 31.2 degrees C; P = 0.004). SNP-induced vasodilatation during rewarming from hypothermic CPB improves peripheral rewarming, reduces the degree of postoperative core and peripheral hypothermia and reduces time to extubation.
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Meta Analysis
Meta-analysis of the efficacy of extradural clonidine to relieve postoperative pain: an impossible task.
Clonidine, an alpha2 adrenoceptor agonist, has anti-hypertensive and anti-nociceptive effects. It is commonly used in association with local anaesthetics and opioids to enhance the quality and duration of extradural analgesia in the postoperative period, and to decrease the incidence of side effects. As a sole analgesic, it has seldom been used to relieve postoperative pain. ⋯ The data from these studies were difficult to interpret because of the tremendous variation in variables, especially dose of clonidine, level of extradural injection, time of administration, type of anaesthesia, type of surgery, and reference and rescue drugs. The simultaneous extradural use of local anaesthetics and opioids further hindered data interpretation, and precluded any meta-analysis. Proposals for a standard study design are made to help comparison between studies involving extradural clonidine and postoperative pain.
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Randomized Controlled Trial Clinical Trial
I.v. clonidine prevents post-extradural shivering.
We have studied the efficacy of i.v. clonidine to prevent shivering in 100 healthy patients who received extradural block for knee arthroscopy. Patients were randomly allocated to two groups. Just before extradural anaesthesia (0 min = baseline), group I (n = 50) received i.v. clonidine 1 microgram kg-1, group II (n = 50) received a saline bolus. ⋯ Patients with severe shivering were seen only in group II. There were no significant differences between the groups during the study period in SAP, HR, SpO2, cutaneous temperature or level of sedation. We conclude that preventive use of i.v. clonidine 1 microgram kg-1 provides a significant reduction in the incidence of post-extradural shivering without clinically relevant adverse side effects.
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We studied the size 4 laryngeal mask airway (LMA) to test the hypothesis that oropharyngeal leak pressure and fibreoptic position improves with increasing cuff volume. After LMA insertion, 50 anaesthetized adult patients had the cuff inflated in 5-ml increments to 40 ml. ⋯ Gastric insufflation was detected more frequently when the cuff volume exceeded 20 ml. We conclude that inflation of the size 4 LMA to the maximum recommended volume provides suboptimal conditions and that this value should be reduced from 30 to 20 ml.