British journal of anaesthesia
-
Randomized Controlled Trial Comparative Study Clinical Trial
Augmentation of the neuromuscular blocking effects of cisatracurium during desflurane, sevoflurane, isoflurane or total i.v. anaesthesia.
We have evaluated the enhancement of cisatracurium-induced neuromuscular block by potent inhalation anaesthetic agents, by constructing dose-effect curves for cisatracurium in 84 patients during anaesthesia with 1.5 MAC (70% nitrous oxide) desflurane, sevoflurane, isoflurane or total i.v. anaesthesia (TIVA). Acceleromyography (TOF-Guard) and train-of-four (TOF) stimulation of the ulnar nerve were used (2 Hz every 12 s). Cisatracurium was administered in increments of 15 micrograms kg-1 until depression of T1/T0 > 95% was reached. ⋯ These were significantly lower than the values for TIVA (21 (4) and 51 (13) micrograms kg-1) (P < 0.01 in each case). After equi-effective dosing, times to T1/T0 = 25% were similar in all groups (19 (7), 19 (5), 20 (5) vs 16 (4) min). Recovery index25-75% and time to a TOF ration of 0.70 were prolonged significantly by desflurane and sevoflurane compared with TIVA (18 (5), 19 (8) vs 12 (4) min and 43 (11), 44 (10) vs 35 (5) min, respectively), whereas the difference was not significant for isoflurane (14 (6) and 41 (7) min).
-
Comparative Study Clinical Trial Controlled Clinical Trial
Bispectral index: comparison of two montages.
We have compared fronto-central and bifrontal montages using a new EEG monitor, the Aspect A-1000. The monitor uses bispectral analysis to derive an index of anaesthetic depth, the bispectral index (BIS). We compared reliability, impedance and BIS for each montage. ⋯ However, BIS values derived from each montage were found to differ in an unpredictable manner. The bifrontal montage is easy to apply and reliable but it is not comparable with a fronto-central montage. We conclude that the BIS may be useful for following trends in anaesthetic depth in individual cases but it is less helpful when making comparison between patients or as a single value.
-
Clinical Trial Controlled Clinical Trial
Laryngoscopy and fibreoptic intubation in acromegalic patients.
Acromegaly is recognized as a cause of difficulty in airway management and tracheal intubation. We evaluated prospectively the conditions for laryngoscopy and fibreoptic intubation in 15 acromegalic patients. Each patient served as his or her own control. ⋯ The larynx could not be seen with both techniques in one patient, and the trachea was intubated blindly with the help of an introducer. Our results showed that fibreoptic intubation may prove difficult or fail in acromegalic patients. Difficulties in seeing the vocal cords with a fibrescope were present most often in patients who also had probable intubation difficulties with a rigid laryngoscope.
-
Thrombelastography (TEG) correlates with postoperative chest drain output in patients undergoing cardiopulmonary bypass (CPB). In vitro incubation with heparinase allows TEG monitoring during CPB, despite heparin anticoagulation. Hypothermia impairs coagulation, but these effects cannot be assessed by standard coagulation tests performed at 37 degrees C. ⋯ Maximum amplitude (MA), reflecting absolute clot strength, was not affected at temperatures of 33-37 degrees C. These findings indicate a decrease in the speed of clot formation, but not absolute deterioration in clot quality. Furthermore, heparinase-modified TEG indicated that there were nine cases in which heparin effects persisted after heparin reversal with protamine, providing a rational guide to protamine therapy.