British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Propofol attenuates formation of lipid peroxides in tourniquet-induced ischaemia-reperfusion injury.
We studied 20 adult ASA I patients undergoing elective peripheral surgery allocated randomly to one of two groups. In the propofol group (n = 9) anaesthesia was induced with propofol and fentanyl followed by continuous infusion of propofol. In the control group (n = 11), after induction of anaesthesia with thiopentone and fentanyl, anaesthesia was maintained with isoflurane. ⋯ In the propofol group this was significant only at 30 min (1.85 (0.03) vs 1.74 (0.04) mumol litre-1). TBARS concentrations of reperfused muscle tissue were significantly higher than pre-reperfusion concentrations in the control group (70.30(10.06) vs 52.13 (5.73) nmol/g wet tissue). We conclude that propofol attenuated ischaemia-reperfusion-induced lipid peroxidation in the therapeutic doses used in anaesthesia.
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We have studied dose requirements, recovery times and pharmacokinetics of rocuronium in 32 intensive care patients. After an initial dose of 50 mg, rocuronium was administered as maintenance doses of 25 mg whenever two responses to train-of-four (TOF) stimulation reappeared (bolus group; n = 27) or by continuous infusion to maintain one response in the TOF (infusion group; n = 5). Median requirements for rocuronium were 27.4 (range 14.5-68.3) mg h-1 and 43.7 (30.9-50.3) mg h-1 in patients in the bolus and infusion groups, respectively. ⋯ The plasma concentration profile (n = 12) was described adequately by a two-compartment model. Mean plasma clearance (Cl), steady-state distribution volume (Vss), mean residence time (MRT) and elimination half-life (T1/2 beta) were 3.16 (SD 1.15) ml kg-1 min-1, 769 (334) ml kg-1, 262 (120) min and 337 (163) min, respectively. Recovery times, Vss, MRT, and T1/2 beta differed from previously published data obtained after rocuronium infusion of moderate duration in surgical patients.
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We describe an obstetric patient who developed incapacitating headache after inadvertent dural tap and was treated with repeated blood patching. She subsequently developed severe lumbar back pain which, after exclusion of suspected extradural abscess, was treated successfully with simple analgesics and physiotherapy. Two possible explanations are offered to account for her symptoms. We compare this case with others in the literature.
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We have studied in 12 patients the effect of desflurane in nitrous oxide on the electroencephalogram (EEG) and the early cortical auditory evoked response (AER). After induction with desflurane, patients' lungs were ventilated to maintain three different end-expiratory concentrations of desflurane (1.5, 3 and 6%) during four consecutive 10-min periods before surgery. As the end-expiratory concentration of desflurane was increased, Pa and Nb (AER) amplitudes decreased and their latencies increased, and spontaneous EEG showed an increase in amplitude and a slowing of frequency. ⋯ From regression slopes, mean percentage changes of each variable were calculated for a 1 MAC change in desflurane concentration, Pa amplitude showed the largest change (mean 49% (95% confidence interval 40-56%) decrease for a 1 MAC increase). This was greater than that of F95 for a similar confidence interval, indicating better resolution. This study confirms that the early cortical AER is affected by desflurane in a similar manner to that of other anaesthetic agents and as such remains the most promising EEG derived measure of depth of anaesthesia.