Anaesthesia
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Randomized Controlled Trial Comparative Study
A comparison of the pelvic angle applied using lateral table tilt or a pelvic wedge at elective caesarean section.
Lateral table tilt or a pelvic wedge are commonly used to reduce inferior vena cava compression during obstetric anaesthesia in the supine position. Direct measurement of pelvic angle allows individual assessment of the effectiveness of these manoeuvres in achieving a tilted position. We observed routine practice during caesarean section after random allocation to one or other of these methods. ⋯ There was a significant difference between table angle and pelvic angle in the women with table tilt (p = 0.0003), but no significant difference in pelvic angle between the table tilt and wedge groups. Measurement of table angle does not represent pelvic position adequately in the majority of women. However, this study showed that lateral table tilt and a pelvic wedge were equally effective in producing tilt of the pelvis.
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Randomized Controlled Trial
Changes in the photoplethysmogram with tracheal intubation and remifentanil concentration.
Autonomic sympathetic activation, for instance following noxious stimuli, decreases the size and flattens the shape of the photoplethysmographic peripheral pulse waveform. We report a simple measure of the waveform shape, the ratio of mean-to-peak wave amplitude, for measuring nociception level during general anaesthesia. Fifty participants, anaesthetised with propofol and remifentanil, were randomly allocated to one of three different remifentanil effect-site concentrations (1, 3 and 5 ng.ml(-1) ). ⋯ The mean (SD) ratios following intubation at remifentanil effect-site concentrations of 1 ng.ml(-1) , 3 ng.ml(-1) and 5 ng.ml(-1) , were 0.49 (0.03), 0.48 (0.03) and 0.45 (0.04), respectively. Remifentanil therefore suppressed changes in the mean-to-peak ratio caused by tracheal intubation (p = 0.006). The ratio of the mean-to-peak plethysmographic amplitude may represent a simple measure of the balance of autonomic sympathetic and parasympathetic activity under general anaesthesia, and its performance following intubation was significantly different from peak amplitude (p = 0.046).
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Randomized Controlled Trial Comparative Study
A randomised crossover trial comparing a single-use polyvinyl chloride laryngeal mask airway with a single-use silicone laryngeal mask airway.
We compared insertion rates of single-use polyvinyl chloride laryngeal mask airways (LMAs) vs single-use silicone LMAs in 72 anaesthetised patients. Both airways were produced by Flexicare Medical. Laryngeal mask airway insertion was successful on the first attempt in 68/72 (94%) polyvinyl chloride LMAs vs 64/72 (89%) silicone LMAs (p = 0.39). ⋯ Laryngeal mask airway position, as assessed using a fibrescope, was not different (p = 0.077). The median (IQR [range]) leak pressure was 16 (12-20 [6-30]) cmH(2) O for the polyvinyl LMA and 18 (13-22 [6-30]) cmH(2) O or the silicone LMA (p = 0.037). In conclusion, we did not find any important differences between polyvinyl chloride and silicone laryngeal mask airways.
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Randomized Controlled Trial Comparative Study
A randomised comparison of two intranasal dexmedetomidine doses for premedication in children.
We compared sedation levels in children following administration of intranasal dexmedetomidine. One hundred and sixteen children aged between 1 and 8 years were enrolled in this prospective, randomised trial. Children were assigned to receive either intranasal dexmedetomidine 1 μg.kg(-1) (Group 1) or 2 μg.kg(-1) (Group 2). ⋯ Both doses produced a similar level of satisfactory sedation in children aged 1-4 years, whereas 2 μg.kg(-1) resulted in a higher proportion of satisfactory sedation in children aged 5-8 years. There were no adverse haemodynamic effects. We conclude that intranasal dexmedetomidine in a premedication dose of 2 μg.kg(-1) resulted in excellent sedation in children.
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Randomized Controlled Trial Comparative Study
A comparison of intra-operative blood loss and acid-base balance between vasopressor and inotrope strategy during living donor liver transplantation: a randomised, controlled study.
Administration of vasopressors or inotropes during liver transplant surgery is almost universal, as this procedure is often accompanied by massive haemorrhage, acid-base imbalance, and cardiovascular instability. However, the actual agents that should be used and the choice between a vasopressor and an inotrope strategy are not clear from existing published evidence. In this prospective, randomised, controlled and single-blinded study, we compared the effects of a vasopressor strategy on intra-operative blood loss and acid-base status with those of an inotrope strategy during living donor liver transplantation. ⋯ Patients in the phenylephrine group had lower lactate levels in the late pre-anhepatic and the early anhepatic phase and needed less bicarbonate administration than those in the dopamine/dobutamine group (median (IQR [range]) 40 (0-100 [0-160]) mEq vs 70 (40-163 [0-260]) mEq, respectively, p=0.018). Postoperative clinical outcomes and laboratory-measured hepatic and renal function did not differ between the groups. Increased vascular resistance and reduction of portal blood flow by intra-operative phenylephrine infusion is assumed to decrease the amount of intra-operative bleeding and thereby ameliorate the progression of lactic acidosis during liver transplant surgery.