British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of low-dose epidural with combined spinal-epidural analgesia for labour.
We have performed a randomized comparison of two low-dose epidural regimens for analgesia in labour, differing only in the manner in which initial analgesia was established. In the epidural (EPI) group, 484 women received a loading dose of 20 ml of 0.1% bupivacaine with fentanyl 2 micrograms ml-1. In the combined spinal-epidural (CSE) group, 524 women received a spinal injection of plain bupivacaine 2.5 mg with fentanyl 25 micrograms. ⋯ Other comparisons between groups revealed no differences. These findings may have been affected by an uneven distribution of multiparous women between the groups (25% in the EPI group and 34.2% in the CSE group; P = 0.002). However, subgroup analysis of primiparous and multiparous women did not alter the results.
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Randomized Controlled Trial Comparative Study Clinical Trial
Evaluation of pressure changes in a new design tracheal tube cuff, the Portex Soft Seal, during nitrous oxide anaesthesia.
We have measured pressure changes in a newly designed tracheal tube cuff, the Portex Soft Seal, during nitrous oxide anaesthesia compared with a Mallinckrodt Lo-Contour tube and a Portex Profile tube. The pressure increases in both control groups were significantly greater than those with the new design (P < 0.0001 in each case). The mean increase in pressure in the Mallinckrodt Lo-Contour tube cuff was 9.9 (SD 3.4) mm Hg compared with 10.3 (1.8) mm Hg in the Portex Profile tube cuff and 2.1 (1.5) mm Hg in the Portex Soft Seal tube cuff. We conclude that the Portex Soft Seal cuff prevented a significant increase in intracuff pressure during nitrous oxide anaesthesia.
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Randomized Controlled Trial Clinical Trial
Effect of omitting regular ACE inhibitor medication before cardiac surgery on haemodynamic variables and vasoactive drug requirements.
Adverse events during coronary artery bypass graft (CABG) surgery have been described in patients receiving angiotensin converting enzyme (ACE) inhibitors, including hypotension on induction of anaesthesia and an increase in vasoconstrictor requirements after cardiopulmonary bypass (CPB). Omitting regular ACE inhibitor medication before surgery may improve cardiovascular stability during anaesthesia. We evaluated prospectively the effect of omitting regular ACE inhibitor medication before CABG surgery on haemodynamic variables and use of vasoactive drugs. ⋯ However, these patients required more vasodilators to control hypertension after CPB and in the early postoperative period. There was no difference in hypotension on induction of anaesthesia or in the use of vasoconstrictors after CPB. We conclude that omitting ACE inhibitors before surgery did not have sufficient advantage to be recommended routinely.
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Randomized Controlled Trial Comparative Study Clinical Trial
High frequency jet ventilation and gas trapping.
We have compared three types of high frequency jet ventilation (HFJV) with conventional positive pressure ventilation in patients recovering from elective coronary artery bypass surgery. Twelve patients were allocated randomly to receive HFJV at ventilatory frequencies of 60, 100, 150 and 200 bpm from a standard jet ventilator at either the proximal or distal airway (HFJV.p and HFJV.d), or from a valveless high frequency jet ventilator acting as a pneumatic piston (VPP). Trapped gas volume (Vtr), cardiac index (CI) and right ventricular ejection fraction (RVEF) were measured. ⋯ The same three types of HFJV were compared using a lung model with variable values of compliance and resistance, to assess the impact of lung mechanics on gas trapping (Vtr, ml). Lung model compliance (C) was set at 50 or 25 ml cm H2O-1 and resistance (R) at 5 or 20 cm H2O litre-1 s, where values of 50 and 5, respectively, are normal. Vtr increased with ventilatory frequency for all types of jet ventilation (P < 0.05), varying with the type of jet ventilation used (P < 0.05).