British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Heat retention using passive systems during anaesthesia: comparison of two plastic wraps, one with reflective properties.
Hypothermia during prolonged surgery may be prevented by active and passive warming methods. We have compared randomly two types of occlusive body wraps in groups of 20 patients. One wrap had additional reflective properties which, by reducing radiative in addition to convective and evaporative heat loss, was expected to improve heat conservation. ⋯ Skin and core body temperatures increased and core temperature exceeded 37 degrees C in 40% of patients in both groups. This continuous increase in temperature was unexpected and the observed heat gain may have been stimulated endogenously by the type of surgery rather than that supplied externally. Overall, mean hourly heat gain was similar in both groups: 71 (SD 28) kJ h-1 in the reflective group and 67 (33) kJ h-1 in the other group.
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Randomized Controlled Trial Clinical Trial
Prevention of hypothermia by cutaneous warming with new electric blankets during abdominal surgery.
We have evaluated the efficacy of new electric warming blankets, which meet the requirements of the international standard for perioperative electrical and thermal safety, in preventing intraoperative hypothermia. We studied 18 patients undergoing abdominal surgery, allocated to one of two groups: in the control group, there was no prevention of intraoperative hypothermia (n = 8) and in the electric blanket group, two electric blankets covered the legs and upper body (n = 10). ⋯ Five patients shivered in the control group compared with one in the electric blanket group (P < 0.05). We conclude that cutaneous warming with electric blankets was an effective means of preventing intraoperative hypothermia during prolonged abdominal surgery.
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Randomized Controlled Trial Comparative Study Clinical Trial
Skin vasomotor reflex induced by laryngoscopy: comparison of the McCoy and Macintosh blades.
We studied 22 female patients (ASA I or II) to investigate if laryngoscopy and intubation induced the skin vasomotor reflex (SVmR), and to compare the effects of the McCoy and Macintosh blades on the SVmR. Anaesthesia was induced with fentanyl, midazolam, vecuronium and nitrous oxide. In 11 patients, the vocal cords were seen for 3 s with the McCoy blade. ⋯ In the other 11 patients, the first and second laryngoscopies, respectively, were performed with the Macintosh and McCoy blades. Laryngoscopy alone and intubation with laryngoscopy significantly reduced skin blood flow in the ring finger of all patients (P < 0.01), indicating that both procedures provoked the SVmR. The magnitude of the SVmR and haemodynamic changes did not differ significantly between the two groups.
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Comparative Study
Comparison of the accuracy of the lithium dilution technique with the thermodilution technique for measurement of cardiac output.
A new indicator dilution technique for measurement of cardiac output is described. Lithium chloride is injected via a central venous catheter and its dilution curve measured in arterial blood using a lithium-selective electrode. We assessed the lithium dilution cardiac output measurement (LiDCO) and a conventional thermodilution cardiac output measurement (ThDCO) by comparing the results of both with cardiac output determined by electromagnetic flowmetry (EMCO) under controlled laboratory conditions in 10 swine. ⋯ The correlation coefficient between LiDCO and EMCO (0.95) was higher than that between ThDCO and EMCO (0.87). The precision value of LiDCO (0.04) was significantly less (i.e. better) than that of ThDCO (0.09). The results of this study indicated that LiDCO was more reliable compared with conventional ThDCO.
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A new prototype of the laryngeal mask airway (LMA), the intubating laryngeal mask airway (ILMA), was used to facilitate tracheal intubation in 100 fasted patients presenting for elective surgery. Alignment of the ILMA with the larynx was assessed fibreoptically before intubation without the investigator performing the intubation being aware of the view score. ⋯ Of the seven intubation failures, five occurred in the first 20 patients. Conventional connection to the breathing system and ventilation of the lungs of the patients were possible throughout the intubation procedure.