Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Serum glutathione S-transferase concentrations and creatinine clearance after sevoflurane anaesthesia.
The effects of sevoflurane and isoflurane on serum glutathione S-transferase concentrations and creatinine clearance were compared in 50 ASA I-III patients aged over 18 years undergoing body surface surgery of 1-3 h predicted duration. Patients randomly received sevoflurane (n = 24) or isoflurane (n = 26) in nitrous oxide and oxygen (FIO2 = 0.4) via a nonrebreathing system. ⋯ Patients received significantly less (p < 0.05) sevoflurane (1.0 MAC-h) than isoflurane (1.5 MAC-h). Using serum glutathione S-transferase concentrations and creatinine clearance as markers of hepatic and renal function respectively, no statistically significant differences were identified between the groups.
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Randomized Controlled Trial Clinical Trial
Effect of the size of a tracheal tube and the efficacy of the use of the laryngeal mask for fibrescope-aided tracheal intubation.
We randomly allocated 60 patients with normal airways into three groups to compare the ease of fibrescope-aided tracheal intubation using 8.0-mm internal diameter (group F8) and 6.0-mm (group F6) reinforced tracheal tubes and to evaluate the efficacy of the laryngeal mask as an aid for fibreoptic tracheal intubation (group L). In group F8 tracheal intubation was optimal in 2 of 20 patients and in two patients in whom intubation over the fibrescope was difficult the attempts resulted in inadvertent oesophageal intubation. ⋯ In both groups F6 and L tracheal intubation was completed within less than about 1 min. We conclude that conventional fibrescope-aided tracheal intubation with a 6.0-mm tracheal tube is easier than with an 8.0-mm tube and that the laryngeal mask facilitates fibrescope-aided tracheal intubation.
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Randomized Controlled Trial Clinical Trial
The effect of a heat and moisture exchanger on humidity in a low-flow anaesthesia system.
The heat and humidity in a low-flow breathing system was measured in order to study the inherent humidifying properties of the system at low fresh gas flows (< 1 and 21.min-1) and whether a heat and moisture exchanger could compensate for the loss of heat and humidification occurring at higher fresh gas flows (51.min-1) in these systems. Sixty patients were randomly divided into three groups (< 1, 2 and 51.min-1 fresh gas flows) with a heat and moisture exchanger and three groups without a heat and moisture exchanger in the breathing system. ⋯ Three more measurements were performed at 10, 30 and 60 min after control. At low fresh gas flows the humidifying properties of the low-flow breathing system are adequate (i.e. provide an absolute humidity > 20 mg.l-1) but at a fresh gas flow of 51.min-1 there is a need for a heat and moisture exchanger for adequate humidification of the inspired gas.
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Clinical Trial Controlled Clinical Trial
Accuracy of pulse oximetry in patients with low systemic vascular resistance.
In order to assess the accuracy of pulse oximeters in patients with septic shock, we compared 80 paired readings of oxygen saturations taken from pulse oximeters and oxygen saturations obtained from co-oximetry in patients receiving intensive therapy with indwelling pulmonary artery flotation catheters. Comparison between groups with low or normal systemic vascular resistance indices showed a small (1.4%) but significant (p < 0.001) underreading of the saturation from the pulse oximeter in the presence of a low systemic vascular resistance. With normal or high systemic vascular resistance pulse oximeter readings correlated well with co-oximetry. We hypothesise that the main cause of this underreading is because the pulse oximeter is sensing pulsatile venous flow due to the opening of arteriovenous channels in the skin in septic states.