Anaesthesia
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Randomized Controlled Trial Clinical Trial
Evaluation of a needle-free injection system for local anaesthesia prior to venous cannulation.
We evaluated a single-use, disposable, carbon-dioxide-powered, needleless injector (J-Tip, National Medical Products Inc., CA, USA), which is claimed to deliver a virtually painless, subcutaneous injection. Seventy-two patients undergoing various types of surgery had a large-bore intravenous cannula inserted prior to induction of general anaesthesia. Three minutes beforehand, a subcutaneous injection of 0.3 ml of 1% plain lidocaine was administered. ⋯ Pain scores were recorded on injection of the lidocaine and on insertion of the cannula. There was significantly less pain on injection with the needleless injector than with the 25 G needle (p < 0.001) but, surprisingly, there was more pain on cannulation (p < 0. 001). We conclude that the device certainly delivers a less painful subcutaneous injection than a 25 G needle, but perhaps provides less effective skin anaesthesia for venous cannulation at sites where the subcutaneous space is small; its use might be better suited to areas where the subcutaneous space is deeper.
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Randomized Controlled Trial Clinical Trial
Airway obstruction with cricoid pressure.
Cricoid pressure may cause airway obstruction. We investigated whether this is related to the force applied and to the technique of application. We recorded expired tidal volumes and inflation pressures during ventilation via a face-mask and oral airway in 52 female patients who were anaesthetised and about to undergo elective surgery. ⋯ An expired tidal volume of < 200 ml was taken to indicate airway obstruction. Airway obstruction did not occur without cricoid pressure, but did occur in one patient (2%) with cricoid pressure at 30 N, in 29 patients (56%) with 30 N applied in an upward and backward direction and in 18 (35%) patients with cricoid pressure at 44 N. Cricoid pressure applied with a force of 44 N can cause airway obstruction but if cricoid pressure is applied with a force of 30 N, airway obstruction occurs less frequently (p = 0.0001) unless the force is applied in an upward and backward direction.
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Randomized Controlled Trial Comparative Study Clinical Trial
Bispectral index monitoring: comparison of two types of electrode.
Bis-monitoring is a new method of monitoring anaesthetic depth. Bis-monitoring is easy to perform, but the Bis-monitor and the original, disposable electrodes are expensive. The aim of this study was to determine whether the original Zipprep electrodes could be replaced by the much cheaper electrocardiogram electrodes. ⋯ The impedance in the electrocardiogram electrodes was higher than in the Zipprep electrodes, but this did not affect the bispectral index. No other problems with either type of electrode were detected. It is concluded that Zipprep electrodes can be replaced by electrocardiogram electrodes in normal clinical practice.
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Randomized Controlled Trial Clinical Trial
Pretreatment with ketorolac and venous occlusion to reduce pain on injection of propofol.
We performed a randomised, double-blind, prospective trial to discover whether intravenous ketorolac 10 mg made up to 2 ml with saline, with or without venous occlusion for 2 min, reduces the pain on injection of propofol. In 90 patients, pain scores were obtained during injection of propofol following pretreatment of the vein with saline, ketorolac or ketorolac with venous occlusion. ⋯ There was no difference in venous sequelae at 7 days postoperatively between the groups. Our results suggest that pain on injection of propofol may be related to release of local kininogens and that nonsteroidal anti-inflammatory drugs may have a role in reducing that pain.
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Randomized Controlled Trial Clinical Trial
Effect of clonidine premedication on haemodynamic responses to fibreoptic bronchoscopy.
The usual haemodynamic response to fibreoptic bronchoscopy is an increase in heart rate and blood pressure. We therefore compared, in a prospective, randomised, double-blind study, the effect of two doses of oral clonidine premedication (150 microg or 300 microg) with placebo (control group) on the haemodynamic alterations in 62 patients who underwent elective fibreoptic bronchoscopy. Significant increases in blood pressure and heart rate were observed during fibreoptic bronchoscopy only in the control group. ⋯ Compared with the control group, time to awakening was significantly longer only in patients premedicated with 300 microg clonidine. In conclusion, premedication with 150 microg oral clonidine attenuates haemodynamic responses to fibreoptic bronchoscopy, without causing excessive haemodynamic depression and sedation. These data encourage the administration of clonidine as premedication in patients undergoing fibreoptic bronchoscopy, particularly in those with, or at risk for, coronary artery disease.