British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Effects of fentanyl, alfentanil, remifentanil and sufentanil on loss of consciousness and bispectral index during propofol induction of anaesthesia.
The bispectral index (BIS) and a sedation score were used to determine and compare the effect of propofol in the presence of fentanyl, alfentanil, remifentanil and sufentanil. Seventy-five non-premedicated patients were assigned randomly into five groups (15 in each) to receive fentanyl, alfentanil, remifentanil, sufentanil or placebo. Opioids were administered using a target-con-trolled infusion device, to obtain the following predicted effect-site concentrations: fentanyl, 1.5 ng ml(-1); alfentanil, 100 ng ml(-1); remifentanil, 6 ng ml(-1); and sufentanil, 0.2 ng ml(-1). ⋯ The relationship between propofol effect-site concentration and BIS was preserved with or without opioids. In the presence of an opioid, LOC occurred at a lower effect-site concentration of propofol and at a higher BIS50 (i.e. the BIS value associated with 50% probability of LOC), compared with placebo. Although clinically the hypnotic effect of propofol is enhanced by analgesic concentrations of mu-agonist opioids, the BIS does not show this increased hypnotic effect.
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We present an unusual case of hypercapnia and surgical emphysema during transanal endoscopic microsurgery, which led to delayed post-operative ventilatory failure. The hypercapnia and surgical emphysema were secondary to rectal insufflation with carbon dioxide used to facilitate visualization and resection of a rectal tumour. Despite a return to wakefulness after surgery, the patient's level of consciousness deteriorated in the recovery area as a result of hypercapnia. ⋯ On close examination, surgical emphysema was identified in unusual areas, including the anterior abdominal wall, both loins, both groins and the left thigh. Reventilation was required until these unusual carbon dioxide stores had dissipated. We discuss the need for prolonged post-operative vigilance in patients with surgical emphysema secondary to carbon dioxide insufflation, and the risk of delayed ventilatory failure.
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Estimation of changes in cardiac output from the arterial blood pressure waveform in the upper limb.
We have developed a new pulse contour cardiac output (PulseCO) algorithm based on frequency analysis studies of the arterial system. PulseCO was compared with thermodilution cardiac output (TDCO) in 10 patients undergoing cardiac surgery. Results from one patient were unsuitable for analysis. ⋯ Least squares regression gave y = 0.71 x (r2 = 0.70) and the limits of agreement were from -21% to +25%. After phenylephrine had been given to five patients, PulseCO showed an increase in systemic vascular resistance consistent with the known pharmacological actions of the drug. The PulseCO algorithm was incorporated into a computer program that acquires arterial pressure data from an analogue-to-digital converter and displays beat-to-beat trend values.
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Randomized Controlled Trial Clinical Trial
Analgesic efficacy of tramadol 2 mg kg(-1) for paediatric day-case adenoidectomy.
We studied the analgesic efficacy of tramadol 2 mg kg(-1) for post-operative analgesia after day-case adenoidectomy in children aged 1-3 yr. Eighty children were allocated randomly to receive tramadol 2 mg kg(-1) i.v. or placebo immediately after induction of anaesthesia. Anaesthesia was induced with alfentanil 10 microg kg(-1) and propofol 4 mg kg(-1) followed by mivacurium 0.2 mg kg(-1) for tracheal intubation. ⋯ Forty-five per cent of children receiving tramadol did not require post-operative analgesia at all compared with 15% of children receiving placebo (P = 0.003). Recovery times and the incidence of adverse effects were similar in the two groups in the recovery room and at home. The requirement for rectal ibuprofen at home did not differ between groups.
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Randomized Controlled Trial Clinical Trial
Antinociceptive properties of neurosteroids IV: pilot study demonstrating the analgesic effects of alphadolone administered orally to humans.
Fourteen patients scheduled for orthopaedic knee reconstruction surgery were enrolled in a prospective, double-blind, randomized study in which they received alphadolone (25-500 mg, n = 9) or placebo (lactose, n = 5) given orally 1 h after operation. All the subjects received a standardized general anaesthetic and the same type of surgery followed by physiotherapy using a continuous passive movement machine. Morphine was administered intravenously after operation by patient-controlled analgesia. ⋯ The experiences of these side-effects were all rated as none, mild or moderate. Orally administered alphadolone caused statistically significant reductions in morphine use and simultaneous highly significant reductions in pain scores. We conclude that alphadolone is a useful analgesic in humans when given by the oral route.