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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Randomized Controlled Trial Clinical Trial
Reduced haemostatic factor transfusion using heparinase-modified thrombelastography during cardiopulmonary bypass.
We set out to determine if the heparinase-modified thrombelastogram using anticoagulated blood from patients during cardiac surgery could guide treatment with haemostatic components. In 60 patients a simple algorithm predicted a possible 60-80% decrease in the use of haemostatic components. ⋯ Ten patients in the clinical group received a total of 16 units of fresh frozen plasma and nine platelet concentrates compared with five patients transfused with five units of fresh frozen plasma and one platelet concentrate in the algorithm group. Twelve-hour chest tube losses [algorithm group 470 (295-820) ml, clinically managed group 390 (240-820) ml (median, quartile values)] were not different between groups despite the threefold reduction in the use of haemostatic products, showing that intra-operative monitoring of coagulation in the anticoagulated patient can be used to guide treatment.
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Comparative Study Clinical Trial Controlled Clinical Trial
Choice of opioid for initiation of combined spinal epidural analgesia in labour--fentanyl or diamorphine.
Sixty-two women requesting regional analgesia in labour were allocated to receive a 1.5 ml intrathecal injection as part of a combined spinal-epidural (CSE) analgesic technique. This contained either bupivacaine 2.5 mg plus fentanyl 25 microg (group F) or bupivacaine 2.5 mg plus diamorphine 250 microg (group D). Times of analgesic onset and offset were recorded, motor and proprioceptive assessments made and side-effects noted. ⋯ Maternal hypotension, pruritus, proprioceptive loss, nausea and fetal bradycardia were rare and not severe, and their incidences did not differ between groups. No respiratory depression was observed after CSE. This use of diamorphine was not associated with increased side-effects compared with fentanyl/bupivacaine, and it has a longer duration of action.
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Transoesophageal echocardiography (TOE) has gained widespread acceptance among cardiac anaesthetists as a tool to facilitate peri-operative decision-making. This observational study analyses the impact of TOE and its inter-observer variability on intra-operative patient management during cardiac and major vascular surgery. From June 1996 to December 1998, standardized reports were obtained from 11 anaesthetists in 1891 adult cardiac and vascular surgery patients undergoing routine biplane or multiplane TOE. ⋯ There was no significant difference in the case mix between observers. TOE had an important impact on intraoperative patient management. Inter-observer variability was significant for several variables but not for the frequency of additional surgical procedures.
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Nitric oxide synthase requires tetrahydrobiopterin for its activity. In animal models of sepsis, changes in circulating tetrahydrobiopterin concentrations precede increases in nitrate. We measured plasma tetrahydrobiopterin and nitrate concentrations on three consecutive days in 10 patients with septic shock and 10 critically ill control patients. ⋯ In patients with septic shock, both tetrahydrobiopterin and total nitrate concentrations were higher than those in critically ill controls but were increased mainly in patients with renal failure. In summary, tetrahydrobiopterin concentration increases during septic shock, in line with increases in nitrate concentration. However, as for nitrate, concentrations