Anaesthesia
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Randomized Controlled Trial Clinical Trial
The haemodynamic effects of propofol in combination with ephedrine.
Forty ASA1 patients presenting for minor gynaecological surgery were randomly allocated into four study groups to compare the haemodynamic effects of adding different doses of ephedrine to an induction dose of propofol. Heart rate, oxygen saturation and non-invasive arterial blood pressure were monitored before and for 5 min after induction. In those patients who received propofol alone, there was a significant decrease in both systolic (p < 0.001) and diastolic (p = 0.003) blood pressure. ⋯ The addition of ephedrine 10 mg was insufficient to prevent hypotension. There was no significant effect on either heart rate or oxygen saturation in any group. We conclude that ephedrine may be safely employed to reduce the degree of hypotension during induction with propofol in this patient group.
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Randomized Controlled Trial Comparative Study Clinical Trial
Acid aspiration prophylaxis for emergency Caesarean section.
Over a 3.5 year period, 384 patients requiring emergency Caesarean section under general anaesthesia received at random one of six acid aspiration prophylaxis regimens as soon as the decision was made for surgery. In the first phase of the study, sodium citrate administered orally 0.3 M, 30 ml (group C, n = 120) was compared with metoclopramide 10 mg administered intravenously and sodium citrate (group MC, n = 65). In the second phase, all patients received sodium citrate, and either intravenous administration of ranitidine 50 mg (group RC, n = 50), omeprazole 40 mg (group OC, n = 50), ranitidine 50 mg with metoclopramide 10 mg (group RMC, n = 50) or omeprazole 40 mg with metoclopramide 10 mg (group OMC, n = 49). ⋯ The proportion of patients with pH < 3.5 and volume > 25 ml in the C and MC groups (43/185) was greater than that in the OC, RC, OMC and RMC groups (18/199, p < 0.001). Ranitidine and omeprazole administered intravenously were equally effective adjuncts to sodium citrate in reducing gastric acidity for emergency Caesarean section. Compared with sodium citrate alone, the addition of either ranitidine, omeprazole or metoclopramide alone did not reduce gastric volume while small reductions in gastric volume were seen with the addition of metoclopramide and either ranitidine or omeprazole.
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Randomized Controlled Trial Comparative Study Clinical Trial
Patient-controlled alfentanil. Target-controlled infusion for postoperative analgesia.
We have compared the opioid effects of a patient-demand, target-controlled infusion of alfentanil (n = 10), with patient-controlled bolus administration of morphine (n = 10) following major spinal surgery in Chinese patients aged from 11 to 67 years. The same general anaesthesia regimen was used in all patients. One group of patients were given intra-operative morphine analgesia followed by postoperative intravenous morphine patient-controlled analgesia, while the other group received an intra-operative target-controlled infusion of alfentanil. ⋯ There was a significantly (p < 0.001) lower respiratory rate in the alfentanil group compared with patients receiving morphine at, clinically assessed, equianalgesia. The predicted plasma alfentanil concentrations increased rapidly from about 30 ng.ml-1 during the first 4 h to around 100 ng.ml-1 at the end of the 24-h study period. The precision of the target-controlled infusion system was 75.4% and the mean prediction error (bias) 58.1%, suggesting an underestimation of the measured alfentanil concentrations by the alfentanil infusion system in these Chinese patients.
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Randomized Controlled Trial Comparative Study Clinical Trial
Topical ibuprofen for skin analgesia prior to venepuncture.
The analgesic effect of topical ibuprofen was investigated in ten volunteers. There were no significant differences in visual analogue scale pain scores for pinprick after 15 and 60 min of application of ibuprofen, placebo and EMLA cream. Comparison of visual analogue scale scores for venous cannulation after similar durations of ibuprofen and EMLA creams found significantly (p < 0.014) lower scores for EMLA at 60 min. We do not consider ibuprofen cream to be clinically useful for venous cannulation.
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In order to improve arterial oxygenation and venous admixture during one lung ventilation, the effect of selective infusion of prostaglandin E1 into the pulmonary artery of the ventilated lung was investigated in 12 adult patients undergoing thoracotomy. Patients' bronchi were intubated with a Mallinckrodt bronchial tube and ventilated with 66% oxygen in air. Cardiopulmonary factors such as systemic and pulmonary arterial pressures, pulmonary vascular resistance, blood gas analyses, cardiac output and airway pressure were measured before and during one-lung ventilation; venous admixture (Qs/Qt) was calculated. ⋯ The plasma endothelin-1 concentration reached a plateau between the end of one lung ventilation (before closing the thorax) and 6 h postoperatively. This correlated inversely with the pre-operative forced expiratory volume in one second (r = -0.68, p < 0.005), declining to normal values 72 h after operation. The selective infusion of PGE1 into the pulmonary artery of the ventilated lung corrected pulmonary vasoconstriction and improved both arterial oxygenation and venous admixture during one lung ventilation for thoracotomy.