British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of ondansetron and prochlorperazine for the prevention of nausea and vomiting after adenotonsillectomy.
This study has compared the incidences of nausea, vomiting and headache after ondansetron 0.06 mg kg-1 i.v., prochlorperazine 0.2 mg kg-1 i.m. and prochlorperazine 0.1 mg kg-1 i.v. given during induction of general anaesthesia to 282 patients undergoing adenotonsillectomy. The cardiovascular effects of the drugs were similar. ⋯ Nausea and vomiting in the same patient was reduced from 29% to 2% by i.v. ondansetron (P < 0.0005) and to 3% by i.m. prochlorperazine (P < 0.0005), and appeared to be less severe in these groups. Headache was most frequent after i.v. ondansetron (35%: P < 0.05), but occurred with similar frequency after i.m. prochlorperazine (32%) and i.v. prochlorperazine (29%).
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of the pharmacodynamics and pharmacokinetics of an infusion of cis-atracurium (51W89) or atracurium in critically ill patients undergoing mechanical ventilation in an intensive therapy unit.
We have studied 12 critically ill, sedated patients who required a neuromuscular blocking drug to assist mechanical ventilation in an intensive care unit. Patients were randomized to receive an infusion of cis-atracurium 0.18 mg kg-1 h-1 (group 1, n = 6) or atracurium 0.6 mg kg-1 h-1 (group 2, n = 6) preceded, if necessary, by a bolus dose of 2 x ED95 of the same drug (cis-atracurium 0.1 mg kg-1 or atracurium 0.5 mg kg-1). Neuromuscular block was monitored using an accelerograph and the infusion rate adjusted regularly so that it was possible to detect the first response to train-of-four (TOF) stimulation of the ulnar nerve at the wrist. ⋯ Using the NONMEM program, a single compartment pharmacokinetic model was fitted to the plasma concentrations of cis-atracurium and the cis-cis, cis-trans and trans-trans isomers of atracurium. The mean population pharmacokinetic values for cis-atracurium were: volume of distribution (V) = 21,900 (SEM 416) ml; clearance (Cl) = 549 (79) ml min-1; half-life (T1/2) = 27.6 (3.6) min; and for the three groups of atracurium isomers were: cis-cis, V = 15,100 (720) ml, Cl = 449 (42) ml min-1, T1/2 = 23.4 (1.2) min; cis-trans, V = 18,000 (667) ml, Cl = 1070 (43) ml min-1, T1/2 = 11.7 (0.1); trans-trans, V = 13,100 (1280) ml, Cl = 1560 (55) ml min-1, T1/2 = 5.8 (0.4) min. Plasma laudanosine concentrations were lower in the cis-atracurium (peak value 1.3 micrograms ml-1) than in the atracurium (maximum 4.4 micrograms ml-1) group.
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Clinical Trial Controlled Clinical Trial
Radial artery tonometry: moderately accurate but unpredictable technique of continuous non-invasive arterial pressure measurement.
Radial artery tonometry provides continuous measurement of non-invasive arterial pressure (CNAP) by a sensor positioned above the radial artery. An inflatable upper arm cuff enables intermittent oscillometric calibration. CNAP was compared with invasive radial artery pressure recordings from the opposite wrist in 22 high-risk surgical patients with an inter-arm oscillometric mean arterial pressure difference < or = 10 mm Hg. ⋯ Individual accuracy of oscillometry was good or acceptable in all 22 patients. The trend in CNAP changes (difference between consecutive measurements) was sufficiently accurate during induction of anaesthesia, as only 47 (7.6%), 14 (2.3%) and 27 (4.4%) of 616 systolic, diastolic and mean CNAP values differed by more than 10 mm Hg of invasive pressure trends. We conclude that: intermittent oscillometry provides accurate arterial pressure monitoring; CNAP measurements offer a reliable trend indicator of pressure changes during induction of anaesthesia and may be considered an alternative to invasive pressure measurements, should arterial cannulation be difficult in an awake patient; and accuracy of absolute CNAP values is only moderate and unpredictable, thus radial artery tonometry should not replace invasive monitoring in high-risk patients during major surgical procedures.
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Clinical Trial Controlled Clinical Trial
Laryngeal mask airway performance: effect of cuff deflation during anaesthesia.
We studied the effect of deflating the laryngeal mask airway (LMA) cuff in situ on recorded respiratory tidal ventilation in 30 spontaneously breathing anaesthetized patients. Another 26 patients were studied in whom the LMA cuff was undisturbed. ⋯ Complete cuff deflation, however, resulted in a 17% decrease in mean tidal ventilation (P < 0.05), with two patients (6%) demonstrating a substantial leak around the cuff and airway obstruction. The practice of complete cuff deflation during the recovery period from anaesthesia cannot be recommended.