Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Leg elevation and wrapping in the prevention of hypotension following spinal anaesthesia for elective caesarean section.
Ninety-seven parturients undergoing elective Caesarean section were allocated randomly to have their legs elevated to approximately 30 degrees on pillows or elevated and wrapped with elasticated Esmarch bandages or neither (controls) following spinal anaesthesia. All patients received intravenous crystalloid (20 ml.kg-1 over 20 min) prior to spinal injection and were placed in the left lateral tilt position. Significant hypotension was treated with intravenous ephedrine in 5 mg bolus doses. ⋯ There was no significant difference in the time of onset of hypotension between the groups. For those patients requiring ephedrine, there was no significant difference in mean dose requirements between the groups. The use of leg compression immediately postspinal provides a simple means of reducing the accompanying hypotension and should be used more widely.
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Comparative Study
The measurement of right ventricular ejection fraction by thermodilution. A comparison of values obtained using differing injectate ports.
Thermodilution measurements of cardiac output and right ventricular ejection fraction were obtained using a rapid response pulmonary artery catheter. Values were compared when injectate was administered via either a cannula within the right internal jugular vein or the dedicated right atrial port of the pulmonary artery catheter. Mean (SD) bias for cardiac output and right ventricular ejection fraction measurements were 0.08 (0.32) l.min-1 and 2.6 (6.6)% respectively. We therefore conclude that both injectate techniques will provide similar values for cardiac output but dissimilar values for right ventricular ejection fraction measurement.
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A constant pressure differential valve for the control of tracheal tube cuff pressure was tested under clinical conditions. Fifty-one patients underwent controlled ventilation and 20 patients were allowed to breathe spontaneously. Nitrous oxide 66% with oxygen 33% and halothane were used via a circle system. ⋯ Fifty-two control patients had the same incidence of sore throat (40%) and hoarseness (30%) at 24 h. With spontaneous ventilation, fresh gas flows of 5-15 l.min-1 maintained the cuff pressure above 10 cmH2O. We conclude that this valve prevents excessive tracheal cuff pressure while maintaining the airway seal.