Anaesthesia
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Five recent cohort studies have shown a frequency of awareness in paediatric anaesthesia of between 0.2% and 1.2%, but they were not individually large enough to identify risk factors. This study pooled raw data from these five studies to identify factors associated with awareness in children. The outcome of awareness was taken as the cases judged to be most likely awareness cases in each study. ⋯ A combined sample of 4486 anaesthetics revealed 33 cases of awareness. Unadjusted analysis demonstrated weak evidence that nitrous oxide used as an anaesthetic maintenance adjunct was associated with awareness (OR 2.04 (95% CI 0.97-4.33), p=0.06), and some evidence that use of a tracheal tube was associated with awareness (OR 2.78 (95% CI 1.11-6.94), p=0.03). Multivariable regression analysis revealed that nitrous oxide maintenance and use of a tracheal tube were independently associated with awareness (nitrous oxide, OR 2.4 (95% CI 1.08-5.32), p=0.03; tracheal tube, OR 3.0 (95% CI 1.20-7.56), p=0.02).
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Randomized Controlled Trial Comparative Study
The influence of propofol or desflurane on postoperative cognitive dysfunction in patients undergoing coronary artery bypass surgery.
We investigated the influence of either propofol or desflurane on the incidence of postoperative cognitive dysfunction in a randomised trial of 180 patients undergoing coronary artery bypass surgery. The primary outcome was incidence of postoperative cognitive dysfunction at 3 months, defined as ≥1 SD deterioration in two or more of 12 neurocognitive tests. ⋯ There was no difference in delirium (7/89 (7.9%) vs 12/91 (13.2%), respectively, length of hospital stay (median (IQR [range]) 7 (6-9 [4-15]) vs 6 (5-7 [5-16) days, respectively or other morbidities. Desflurane was associated with reduced early cognitive dysfunction.
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Randomized Controlled Trial Comparative Study
A comparison of pressure-controlled and volume-controlled ventilation for laparoscopic cholecystectomy.
The potential advantages of pressure-controlled over volume-controlled ventilation during laparoscopic surgery have yet to be proven. We randomly assigned 42 patients with BMI <30 kg.m(-2) scheduled for laparoscopic cholecystectomy to receive either pressure- or volume-controlled ventilation. ⋯ Gas exchange and haemodynamic stability were similar. We conclude that pressure-controlled ventilation is a safe alternative and offers some advantages to volume-controlled ventilation during laparoscopic cholecystectomy in non-obese patients.
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Comparative Study
A comparison of low vs conventional-dose heparin for minimal cardiopulmonary bypass in coronary artery bypass grafting surgery.
The biocompatibility of minimal extracorporeal circuits has improved; however, anticoagulation is still required. We compared standard high-dose anticoagulation with a low-dose heparin regimen in a retrospective study of patients who underwent coronary bypass surgery using minimal cardiopulmonary bypass. ⋯ There were no thromboembolic events in either group; however, patients in the low-dose group had lower 24-hour mean (SD) postoperative blood loss than the conventional group (545 (61) vs 680 (88) ml, p=0.001) and a reduced rate of transfusion of allogeneic blood (15% patients transfused vs 32%, p=0.01). An individually tailored low-dose heparin regimen for minimal cardiopulmonary bypass is safe and may be associated with reduced bleeding and lower transfusion requirements.
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The identification of the epidural space, insertion of an epidural catheter and lumbar puncture are advanced technical skills that can be challenging to teach to novice anaesthetists. The M43B Lumbar puncture simulator-II (Limbs & Things Ltd., Sussex Street, Bristol, UK) is a teaching aid designed for epidural and spinal insertion. The aim of this study was to determine if experienced anaesthetists thought this simulator may be a useful tool for training novice anaesthetists in these procedures. ⋯ The volunteers found threading of the epidural catheter difficult and rated it unlike a real patient (score 1.0 (0.2-2.0 [0-3])). During lumbar puncture, dural puncture scored 3.0 (3.0-4.0 [2-4]) and intrathecal injection scored 2.5 (1.0-3.0 [1-4]). However, the overall impression was that the simulator could be a useful tool for training of both epidurals (score 3.0 (3.0-4.0 [3-4])) and spinals (score 3.0 (3.0-3.5 [2-4])).