British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Effect of dexamethasone on postoperative emesis and pain.
In this double-blind, randomized, placebo-controlled study, we have evaluated the effect of preoperative administration of dexamethasone on postoperative vomiting and pain in 60 women undergoing general anaesthesia for major gynaecological surgery. Dexamethasone 10 mg (group D) or saline (group S) was administered i.v. in a double-blind manner during induction of anaesthesia. ⋯ Six patients in group D and 19 in group S experienced vomiting at least once within the 24-h postoperative period; dexamethasone was effective in reducing the overall incidence of vomiting from 63.3% to 20.0% (P < 0.01). Other variables were similar between the groups, and the influence of dexamethasone on postoperative pain was minimal.
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Comparative Study
Analysis of the EEG bispectrum, auditory evoked potentials and the EEG power spectrum during repeated transitions from consciousness to unconsciousness.
We have compared the auditory evoked potential (AEP) index (a numerical index derived from the AEP), 95% spectral edge frequency (SEF), median frequency (MF) and the bispectral index (BIS) during alternating periods of consciousness and unconsciousness produced by target-controlled infusions of propofol. We studied 12 patients undergoing hip or knee replacement under spinal anaesthesia. During periods of consciousness and unconsciousness, respective mean values for the four measurements were: AEP index, 60.8 (SD 13.7) and 37.6 (6.5); BIS, 85.1 (8.2) and 66.8 (10.5); SEF, 24.2 (2.2) and 18.7 (2.1); and MF, 10.9 (3.3) and 8.8 (2.0). ⋯ There was no recorded value for MF that was 100% specific for unconsciousness. Of the four measurements, only AEP index demonstrated a significant difference (P < 0.05) between all mean values 1 min before recovery of consciousness and all mean values 1 min after recovery of consciousness. Our findings suggest that of the four electrophysiological variables, AEP index was best at distinguishing the transition from unconsciousness to consciousness.
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We describe the successful use of methadone in the restoration of sedation and provision of analgesia in two morphine-tolerant, paediatric patients who had suffered significant thermal injuries and were undergoing mechanical ventilation. Both patients had exhibited escalating requirements for sedative drugs while undergoing ventilation yet remained inadequately sedated. ⋯ Hyperalgesia and morphine tolerance appear to be associated; it is proposed that methadone acts primarily, under these circumstances, by re-establishing the analgesic state. Such use of methadone in the morphine-tolerant patient also afforded a concomitant sedative-sparing effect.
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We have studied prospectively the clinical course and serum concentrations of thromboxane B2 (TxB2) and leukotriene B4 (LTB4) in patients developing adult respiratory distress syndrome (ARDS) after oesophagectomy. The clinical course was assessed according to a validated ARDS score, and intra- and postoperative measurements of TxB2 and LTB4 in pre- and post-pulmonary blood were performed in 18 patients undergoing oesophagectomy for oesophageal carcinoma and 11 control patients undergoing thoracotomy and pulmonary resection. Six of 18 patients undergoing oesophagectomy, but no control patient, developed ARDS. ⋯ Only patients with ARDS had a significant postoperative increase in post-pulmonary, but not pre-pulmonary, TxB2 concentrations (P < 0.05 vs patients without ARDS). This study provides evidence that TxA2, originating from the lungs, was associated with the development of ARDS after oesophageal resection. In view of the high incidence of ARDS after oesophagectomy (10-30%), prophylactic treatment of patients undergoing oesophageal resection with clinically applicable thromboxane synthetase inhibitors may be warranted.