British journal of anaesthesia
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Randomized Controlled Trial Multicenter Study Clinical Trial
A new tracheal tube for difficult intubation.
We have compared a new Portex tracheal tube with the Oxford tube in performing simulated grade 3 difficult intubations. The Portex tube was modified so that the bevel faced backwards, as in the Oxford tube. A gum elastic introducer was used with both tubes. ⋯ Over the course of the study, intubation time decreased progressively (P < 0.001). This provides new evidence of the need for trainees to practise the art of intubation when the cords are not visible. Our estimate of the learning "half-life" was 15 intubations; we conclude that 30 simulated grade 3 intubations would be a reasonable objective for trainees before handling high-risk cases.
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Comparative Study
Pharmacokinetics and pharmacodynamics of cisatracurium in patients with end-stage liver disease undergoing liver transplantation.
We determined the pharmacokinetics and pharmacodynamics of cisatracurium, one of the 10 isomers of atracurium, in 14 patients with end-stage liver disease undergoing liver transplantation and in 11 control patients with normal hepatic and renal function undergoing elective surgery. Blood samples were collected for 8 h after i.v. bolus administration of cisatracurium 0.1 mg kg-1 (2 x ED95). Plasma concentrations of cisatracurium and its metabolites were determined using an HPLC method with fluorescence detection. ⋯ The recovery index (25-75% recovery) was also similar in both groups: 15.4 (4.2) min in liver transplant patients and 12.8 (1.9) min in control patients (ns). After cisatracurium, peak laudanosine concentrations were 16 (5) and 21 (5) ng ml-1 in liver transplant and control patients, respectively. In summary, minor differences in the pharmacokinetics and pharmacodynamics of cisatracurium in liver transplant and control patients were not associated with any clinically significant differences in recovery profiles after a single dose of cisatracurium.
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Randomized Controlled Trial Comparative Study Clinical Trial
Hydroxyethylstarch compared with modified gelatin as volume preload before spinal anaesthesia for Caesarean section.
We studied 90 patients undergoing elective Caesarean section under spinal anaesthesia who received lactated Ringer's solution 1000 ml with up to 1000 ml of modified gelatin, lactated Ringer's solution 1000 ml with up to 1000 ml of 6% hydroxyethylstarch or only up to 1000 ml of 6% hydroxyethylstarch. Lumbar puncture was performed as soon as 500 ml of the colloid were infused. ⋯ In both groups receiving the 2000 ml preload, packed cell volume (PCV) values decreased by more than 20%, which may be of concern in patients already presenting with mild anaemia. In patients who received the colloid without the crystalloid, PCV values decreased by 14% but the risk of severe hypotension was comparable with the crystalloid-gelatin combination.
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We discontinued temporarily an infusion of propofol for surgical reasons in 20 patients undergoing incontinence surgery. The patients, who had not received neuromuscular blockers, were allowed to regain consciousness to a level enabling them to cough on command, open their eyes, and identify and verbally confirm a randomly assigned digit shown on paper. Thereafter, 5-14 min after discontinuation of the propofol infusion, anaesthesia was reinstituted. ⋯ Only 35% of patients were able to recall one or more of the stimuli presented during wakefulness or were even able to recall having been "awake", and there were very few differences in memory on the day after surgery compared with 1 h after anaesthesia. In comparison with corresponding stimuli given before anaesthesia, memory of material learned during wakefulness was significantly impaired (P < 0.0001). Thus patients temporarily capable of cognitive action during propofol anaesthesia may have no subsequent explicit recall of intraoperative events.