British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Effect of i.v. low-dose adrenaline and phenylephrine infusions on plasma concentrations of bupivacaine after lumbar extradural anaesthesia in elderly patients.
Thirty patients undergoing primary total hip replacement under lumbar extradural anaesthesia with 0.75% bupivacaine 25 ml were allocated randomly to receive either low-dose adrenaline or phenylephrine infusions i.v. throughout surgery. Haemodynamic measurements and arterial blood samples were obtained before the extradural injection and at 10, 20, 30, 40, 50, 60 and 90 min thereafter. ⋯ Cardiac output was significantly greater in patients receiving adrenaline infusions (P less than 0.01). It is postulated that the smaller circulating concentrations of bupivacaine observed in patients receiving adrenaline were caused by increased cardiac output and a greater volume of distribution than in patients receiving phenylephrine.
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Randomized Controlled Trial Clinical Trial
P6 acupuncture and postoperative vomiting after tonsillectomy in children.
We have studied the effect of P6 acupuncture on postoperative vomiting in 45 children undergoing tonsillectomy. After induction of anaesthesia and before the start of surgery, 50% of the patients received P6 acupuncture (in the middle of the ventral surface of the wrist) for 5 min. There was no difference in the incidence of vomiting between the acupuncture (39%) and non-acupuncture (36%) groups. We conclude that, when administered after induction of anaesthesia, P6 acupuncture is ineffective in reducing vomiting after tonsillectomy in children.
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Comparative Study
Comparison of contemporaneous and retrospective assessment of postoperative pain using the visual analogue scale.
We have assessed postoperative pain in 50 patients who had undergone total abdominal hysterectomy, using repeated contemporaneous and single retrospective visual analogue scores. There were significant correlations between the median, mean and greatest contemporaneous scores, and the single retrospective scores, but there was a wide scatter of results among and within individual patients. We conclude that the wide variability between the two methods of assessment suggests that the two techniques should not be used interchangeably.
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We have studied the effects of an extradural block using bupivacaine with adrenaline 90-100 micrograms on blood flow in the maternal uterine and placental arcuate arteries and the fetal umbilical, renal and middle cerebral arteries, using a colour Doppler technique in eight healthy parturients undergoing elective Caesarean section. Fetal myocardial function was investigated simultaneously by M-mode echocardiography. ⋯ There were no significant differences in maternal or fetal blood velocity waveforms, and no significant changes were found in any of the fetal myocardial measurements relative to control values. These observations suggest that extradural anaesthesia using bupivacaine with adrenaline does not have an adverse effect on vascular resistance in the uteroplacental or fetal circulations or on fetal myocardial function in normal pregnancy when bupivacaine-adrenaline is administered fractionally and maternal hypotension is prevented by rapid crystalloid volume loading.