British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Clonidine decreases postoperative oxygen consumption in patients recovering from general anaesthesia.
Twenty ASA I patients, undergoing thyroid surgery were allocated randomly to receive at the end of surgery either an isotonic saline solution or clonidine 2 micrograms kg-1 i.v. administered over 20 min. Oxygen consumption (VO2) and carbon dioxide production (VCO2) were measured during recovery in patients breathing spontaneously with a head canopy system. ⋯ The effect of clonidine was associated with a reduction in shivering. Sedative and analgesic properties of clonidine may also contribute to the reduction in metabolic demand during recovery from anaesthesia.
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Randomized Controlled Trial Comparative Study Clinical Trial
Systemic fentanyl enhances the spread of spinal analgesia produced by lignocaine.
Seventy-one patients undergoing transurethral prostatectomy under spinal anaesthesia were allocated randomly to one of four groups; fentanyl-naloxone (F-Nal), fentanyl-normal saline (F-NS), normal saline-naloxone (NS-Nal), and normal saline-normal saline (NS-NS) group. Twenty minutes after subarachnoid injection of hyperbaric lignocaine 100 mg, we tested the level of spinal analgesia (pinprick sensation) and administered i.v. either fentanyl 100 micrograms (F-Nal and F-NS groups) or normal saline 2 ml (NS-Nal and NS-NS groups). Ten minutes later, we assessed the new levels of analgesia and administered i.v. either naloxone 0.4 mg (F-Nal and NS-Nal groups) or normal saline 1 ml (F-NS and NS-NS groups). ⋯ Forty minutes after spinal block, the decrease in analgesia in the F-Nal group (3.97 cm) differed significantly from that in the other groups (P less than 0.01). Systemic fentanyl enhanced the spread of analgesia. This enhancement was antagonized by naloxone.
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Comparative Study
Effectiveness of preoxygenation in morbidly obese patients.
The time taken for the oxygen saturation (SpO2) to decrease to 90% after preoxygenation was studied in six morbidly obese patients and six matched controls of normal weight. During apnoea the obese patients maintained Spo2 greater than 90% for 196 (SD 80) s (range 55-208 s), compared with 595 (SD 142) s (range 430-825 s) in the control group (P less than 0.001). One patient in the obese group had desaturation before the onset of complete relaxation and tracheal intubation, without complications. Bedside lung function tests were not significantly different between groups and cannot be used as a predictor of the effectiveness of preoxygenation.
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Case Reports
Repair of traumatic transection of the thoracic aorta: esmolol for intraoperative control of arterial pressure.
We report the intraoperative use of esmolol for control of arterial pressure during repair of a traumatic transection of the descending thoracic aorta. A mean infusion rate of esmolol 50.5 micrograms kg-1 min-1 resulted in a decrease in mean arterial pressure to 63 mm Hg and heart rate to 99 beat min-1 and was associated with excellent surgical conditions. The infusion rate of esmolol was titrated easily against mean arterial pressure, which increased rapidly on discontinuing its infusion. Control of arterial pressure with esmolol was comparable to that achieved with sodium nitroprusside, but without the reflex tachycardia or decrease in Pao2 associated with the latter agent.