British journal of anaesthesia
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A new design of tracheal tube cuff was compared with two types of high-volume, low-pressure (HVLP) cuffed tracheal tube for leakage of fluid from the subglottic space into the trachea. Spontaneous and positive-pressure ventilation were simulated using a mechanical lung, an intubated model trachea and a ventilator. Excised human tracheas were intubated and leakage past the cuff assessed. ⋯ The new design completely prevented leakage in the model during all modes of ventilation, during tracheal suctioning, and with tube movement. The new cuff also prevented leakage in the excised human tracheas. Tracheal wall distention and tracheal wall pressures were similar for all cuffs tested.
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Randomized Controlled Trial Comparative Study Clinical Trial
Effects of premedication on dose requirements for propofol: comparison of clonidine and hydroxyzine.
The influence of a single dose of clonidine (5 micrograms kg-1) or hydroxyzine (1 mg kg-1) on intraoperative propofol requirements was determined in 28 male patients (ASA I) undergoing elective orthopaedic surgery. Patients were randomly allocated to receive either clonidine or hydroxyzine orally 2 h before induction of anaesthesia. After a loading dose of propofol (2.5 mg kg-1), mivacurium (0.2 mg kg-1) and alfentanil (15 micrograms kg-1), anaesthesia was maintained with a standardized propofol infusion supplemented with nitrous oxide (66%) in oxygen. ⋯ The clonidine group demonstrated a 14.5% decrease in total propofol requirements (P < 0.05) and a 52.2% reduction in additional propofol boluses (P < 0.02) in comparison with the hydroxyzine group. intraoperative heart rate and mean arterial pressure were significantly lower in the clonidine group but no patients needed treatment with ephedrine for hypotension or bradycardia. Recovery of psychomotor function and discharge from the recovery room were not delayed in the clonidine group. This study indicates that 5 micrograms kg-1 clonidine given as premedication in ASA I patients reduces intraoperative propofol requirements in comparison with 1 mg kg-1 hydroxyzine without inducing adverse effects on recovery or haemodynamic stability.
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Randomized Controlled Trial Clinical Trial
Granisetron in the prevention of nausea and vomiting after middle-ear surgery: a dose-ranging study.
This study was undertaken to determine the minimum effective dose of granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, for the prevention of postoperative nausea and vomiting (PONV) after middle-ear surgery. In a randomized, double-blind, placebo-controlled trial, 120 women (ASA I) received placebo (saline) or granisetron at three different doses (20 micrograms kg-1, 40 micrograms kg-1, 100 micrograms kg-1) i.v. immediately before the induction of anaesthesia (n = 30 for each group). ⋯ A complete response, defined as no PONV and no need for another rescue antiemetic during 0-3 h after anaesthesia, occurred in 40%, 43%, 83% and 87% of patients who had received placebo, granisetron 20 micrograms kg-1, granisetron 40 micrograms kg-1 or granisetron 100 micrograms kg-1, respectively; the corresponding incidence during 3-21 h after anaesthesia was 47%, 47%, 87% and 87% (P < 0.05; overall Fisher's exact probability test). Granisetron 40 micrograms kg-1 appears to be the minimum effective dose for preventing PONV in women undergoing middle-ear surgery.
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Randomized Controlled Trial Clinical Trial
Tropisetron reduces vomiting after tonsillectomy in children.
Nausea and vomiting are common after adenotonsillectomy. Tropisetron is a new, long-acting serotonin antagonist that is an effective antiemetic in adults. Its effect on postoperative nausea and vomiting in children is unknown. ⋯ Children received metoclopramide 0.15 mg kg-1 as a rescue antiemetic. We found that tropisetron reduced the overall incidence of emetic episodes after surgery (29% compared with 65% in control group; P = 0.019) and the incidence of severe vomiting (0% compared with 52% in control group; P < 0.001). We conclude that tropisetron is an effective antiemetic for children undergoing tonsillectomy.
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Randomized Controlled Trial Clinical Trial
Haemodynamic responses to extubation after cardiac surgery with and without continued sedation.
We studied the haemodynamic response to cessation of mechanical ventilation and removal of the tracheal tube in 84 patients after coronary artery bypass grafting. Patients were sedated on the ICU with propofol 1-3 mg kg-1 h-1, and randomly allocated to extubation while awake or while still sedated. Systolic and diastolic blood pressures and heart rate increased significantly faster in the awake group as mechanical ventilation was stopped; systolic blood pressure 6.1 (3.0) vs 0.7 (1.8) mm Hg min-1, diastolic blood pressure 2.1 (1.6) vs 0.2 (0.9) mm Hg min-1, heart rate 2.1 (1.7) vs 0.2 (0.5) beats min-2; P < 0.01 in each case. ⋯ No patient in the sedated group had any new ischaemic ECG changes. Significant new ST segment changes did not occur in the sedated group but were present in five patients in the awake group (P = 0.013), one of whom suffered a perioperative myocardial infarction. Removal of the tracheal tube while patients are still sedated after coronary artery bypass grafting is safe, and reduces the incidences of haemodynamic disturbance and myocardial ischaemia during extubation.