British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Pre-emptive analgesia: comparison of preoperative with postoperative caudal block on postoperative pain in children.
We have compared in 25 children the effect of preoperative with postoperative caudal block on pain after circumcision in a double-blind, randomized study. After induction of anaesthesia, patients were allocated randomly to receive a caudal block either before (n = 14) or immediately after (n = 11) surgery. Postoperative pain was rated on a paediatric pain scale. ⋯ Using the Mann-Whitney U test (significance < or = 0.05) there was no significant difference in cumulative postoperative analgesic requirements within the first 48 h and in times to first analgesic administration between the groups. Cumulative pain score, assessed every 30 min for the first 8 h after operation, was significantly lower for those patients who received caudal anaesthesia after operation. Thus we could not demonstrate any advantage in performing caudal block before compared with after surgery.
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Randomized Controlled Trial Comparative Study Clinical Trial
Spinal anaesthesia for caesarean section: comparison of infusions of phenylephrine and ephedrine.
Maternal cardiovascular changes and neonatal acid-base status were assessed in 29 healthy women undergoing elective lower segment Caesarean section under spinal anaesthesia. The patients were allocated randomly to one of three groups to receive an i.v. infusion of one of the following: ephedrine 1 mg min-1 (group E1: n = 10), ephedrine 2 mg min-1 (group E2: n = 9), or phenylephrine 10 micrograms min-1 (group P: n = 10). Invasive arterial pressure was monitored continuously and if hypotension occurred (defined as a 20% decrease from baseline, taken after i.v. preload administration), bolus doses of either ephedrine (6 mg in groups E1 and E2) or phenylephrine (20 micrograms in group P) were given. ⋯ The total time that the patients remained hypotensive was greatest in group P (P < 0.005), less in group E1 and least in group E2. Neonatal Apgar scores and acid-base profiles were similar in all three groups. In this study, an infusion of phenylephrine 10 micrograms min-1 with bolus doses of 20 micrograms was shown to be significantly less effective in maintaining systolic arterial pressure within 20% limits of baseline compared with an infusion of ephedrine 1 or 2 mg min-1 with bolus doses of 6 mg.
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Preoperative fasting was introduced to reduce the risk and severity of aspiration pneumonitis. Adequate time (6h) must still be allowed before operation for solid foods to be emptied from the stomach. However, the overwhelming weight of evidence supports the practice of reducing the duration of the preoperative fluid fast for elective paediatric surgical patients [3, 15]. ⋯ Potential benefits of reduced thirst, better perioperative experience, improved compliance and reduced hypoglycaemia may be seen. Patients at risk of GOR and aspiration pneumonitis, including those presenting for emergency surgery, must receive special consideration. As aspiration pneumonitis is so rare, careful reporting of complications potentially related to a reduced fasting period is necessary.
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We have studied the haemodynamic effects of subarachnoid block in elderly patients. Thirty patients were undergoing elective transurethral surgery and 18 non-elective orthopaedic surgery, predominantly fractured neck of femur. Systolic arterial pressure (SAP) was measured by automated oscillotonometry, central venous pressure (CVP) by manometer and cardiac index (CI), stroke index (SI) and heart rate (HR) by transthoracic electrical bioimpedance. ⋯ CVP, SI and HR were all restored to baseline values, however, SVRI was decreased further (P < 0.05). Fourteen patients required additional treatment with metaraminol which restored SVRI to baseline values. Patients with systolic hypertension were more likely to require treatment with metaraminol (P = 0.04).
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Randomized Controlled Trial Comparative Study Clinical Trial
Effects of midazolam and diazepam as premedication on heart rate variability in surgical patients.
We have examined the effects of midazolam 0.06 mg kg-1 i.m. and diazepam 0.2 mg kg-1 orally as premedication on the spectral components of heart rate (HR) variability in 24 elderly patients aged 65-87 yr and 24 young patients aged 18-35 yr undergoing elective surgery. The low-frequency/high-frequency (LF/HF) ratio of HR variability increased after arrival in the operating room in elderly patients who received no premedication, but not in young patients. ⋯ However, diazepam increased the low-frequency component and the total power of HR variability in both young and elderly patients. We conclude that cardiac sympathetic nerve activity increased after arrival in the operating room in the elderly, that midazolam or diazepam reduced this increase and that diazepam caused an increase in the total power of HR variability that has not been observed for other agents.