British journal of anaesthesia
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Setting an appropriate positive end-expiratory pressure (PEEP) value is determined by respiratory mechanics, gas exchange and oxygen transport. As these variables may be optimal at different PEEP values, a unique PEEP value may not exist which satisfies both the demands of minimizing mechanical stress and optimizing oxygen transport. In 15 surfactant-deficient piglets, PEEP was increased progressively. ⋯ In the lavage model, the lower inflection point of the PV curve may reflect opening pressure rather than the pressure required to keep the recruited lung open. Recruitment takes place together with a change in the elastic properties of the already open parts of the lung. No single PEEP level is optimal for both oxygen transport and reduction of mechanical stress.
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
Rapacuronium for modified rapid sequence induction in elective caesarean section: neuromuscular blocking effects and safety compared with succinylcholine, and placental transfer.
We have compared rapacuronium 2.5 mg kg-1 (n = 20) with succinylcholine 1.5 mg kg-1 (n = 22) in a multicentre, blinded, randomized study in full-term parturients undergoing elective Caesarean section under general anaesthesia. Thiopental 5 mg kg-1 was given i.v. followed by the neuromuscular blocking agent. Sixty seconds later intubation was performed. ⋯ At delivery (17.7 (3.2) min), mean maternal plasma concentrations of rapacuronium were 9041.4 (1259.1) ng ml-1 and 506.4 (24.9) ng ml-1 for Org 9488 (the main metabolite). Corresponding values for umbilical venous plasma were 808.0 (92.1) ng ml-1 and 59.1 (6.5) ng ml-1, and for umbilical arterial plasma, 361.4 (56.4) ng ml-1 and 29.7 (4.6) ng ml-1, respectively. Umbilical venous to maternal venous ratios for rapacuronium and Org 9488 were 8.8% (1.3)% and 10.2 (1.7)%, respectively.
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Randomized Controlled Trial Clinical Trial
Interscalene brachial plexus anaesthesia with 0.5%, 0.75% or 1% ropivacaine: a double-blind comparison with 2% mepivacaine.
We have compared interscalene brachial plexus block performed with ropivacaine or mepivacaine in 60 healthy patients undergoing elective shoulder surgery. Patients were allocated randomly to receive interscalene brachial plexus anaesthesia with 20 ml of 0.5% ropivacaine (n = 15), 0.75% ropivacaine (n = 15), 1% ropivacaine (n = 15) or 2% mepivacaine (n = 15). Readiness for surgery (loss of pinprick sensation from C4 to C7 and inability to elevate the limb from the bed) was achieved sooner with 1% ropivacaine (mean 10 (SD 5) min) than with 0.5% ropivacaine (22 (7) min) (P < 0.001) or 2% mepivacaine (18 (9) min) (P < 0.02). Postoperative analgesia was similar with the three ropivacaine concentrations (11.5 (5) h, 10.7 (2) h and 10 (2.4) h with 0.5%, 0.75% and 1% concentrations, respectively) and nearly two-fold longer compared with 2% mepivacaine (5.1 (2.7) h) (P < 0.001).
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Randomized Controlled Trial Comparative Study Clinical Trial
Combined spinal-epidural analgesia in labour: comparison of two doses of intrathecal bupivacaine with fentanyl.
We have compared intrathecal bupivacaine 1.25 mg and fentanyl 25 micrograms (group A) with bupivacaine 2.5 mg and fentanyl 25 micrograms (group B), for combined spinal-epidural analgesia in 49 labouring parturients in a prospective, randomized, double-blind study. Onset and quality of analgesia were similar in both groups, with median visual analogue scale pain scores of 0 achieved in 5-10 min. Median duration of analgesia was longer in group B (median 120 (range 90-120) min) compared with group A (75 (75-105) min) (P = 0.013). ⋯ Patient-midwife satisfaction scores and other side effects were similar. We conclude that intrathecal bupivacaine 1.25 mg with fentanyl 25 micrograms provided analgesia of similar onset and quality compared with bupivacaine 2.5 mg and fentanyl 25 micrograms. Although the duration of analgesia was shorter, the incidences of motor block and hypotension were less with the smaller dose.
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Randomized Controlled Trial Clinical Trial
Effect of oral and i.v. tenoxicam in postoperative pain after total knee replacement.
We have evaluated the effect of oral and i.v. tenoxicam on postoperative pain after unilateral total knee replacement in a double-blind, randomized, controlled study. Tenoxicam was administered to two groups of patients, either before (40 mg orally) or after (40 mg i.v.) surgery, then at 24 h after surgery (40 mg i.v.) and at the end of each day for 8 days (20 mg orally). A third group were given placebo at all times. ⋯ There was no significant reduction in the requirement for PCA morphine for the duration of the study in either of the treatment groups, or for co-dydramol in the first 2 days, but tenoxicam significantly reduced the need for co-dydramol over the remaining 7 days. There were no significant differences in mobility between groups. There was a high incidence of adverse events reported, with a similar number in each of the three groups.