The aim of the present multiple cross-over study was to compare the effects of biphasic positive airway pressure (BIPAP) ventilation with synchronized intermittent mandatory ventilation combined with pressure support ventilation (S-IMV/PSV) in sedated and awake patients after coronary artery bypass grafting (CABG) surgery. Twenty-four patients with no evidence of preoperative respiratory dysfunction and an uncomplicated intraoperative course were investigated. The patients were randomly assigned to one of two groups starting with either BIPAP or S-IMV/PSV mode. Haemodynamic measurements and blood gas analyses were performed during sedation with 2.0 mg kg−1 h−1 propofol in the primary mode, after switching to the alternative ventilatory mode, and in the primary mode again. The same sequence of measurements was repeated in awake patients who had reached extubation criteria. In awake patients, PSV was performed instead of S-IMV. Statistical analysis of data was performed using non-parametric tests. Inspiratory peak pressure increased significantly during S-IMV/PSV in sedated patients in both groups. Other ventilatory parameters did not differ significantly between BIPAP and S-IMV/PSV in both groups. Similarly, haemodynamic parameters and blood-gas analyses did not vary with the ventilatory mode. Our results demonstrate that BIPAP ventilation has comparable effects on haemodynamics and pulmonary gas exchange compared with S-IMV/PSV and PSV when used for short-term ventilatory support in patients after cardiac surgery.

Droperidol and dimenhydrinate are inexpensive anti-emetic drugs. Droperidol, especially, has been studied extensively, but there are no studies on the combination of both drugs for prevention of post-operative nausea and vomiting. One hundred and forty male hospitalized patients undergoing nasal surgery were randomized to receive one of four anti-emetic regimes: placebo, dimenhydrinate (1 mg kg−1), droperidol (15 μg kg−1), or the combination of both drugs (droperidol 15 μg kg−1+dimenhydrinate 1 mg kg−1) administered after induction of anaesthesia. Patients in the dimenhydrinate-group and the combination-group received a second dose of dimenhydrinate 6 h after the first administration to mitigate the short half-life of the drug. For general anaesthesia a standardized technique, including benzodiazepine premedication, propofol, desflurane in N2O/O2, vecuronium, and a continuous infusion of remifentanil, was used. Post-operative analgesia and anti-emetic rescue medication were standardized. Episodes of vomiting, retching, nausea, and the need for additional anti-emetics were recorded for 24 h. The main endpoint of this study was the number of patients who were completely free of post-operative nausea and vomiting (Fisher's Exact Test) Furthermore, the severity of post-operative nausea and vomiting was analysed using a standardized scoring algorithm. The incidence of patients completely free of post-operative nausea and vomiting was 62.9% in the placebo-group, 77.1% in the dimenhydrinate-group (P =0.21), and 82.9% in the droperidol-group (P =0.07). This increased to 94.3% in the combination-group (P =0.0015). In all three treatment groups the severity of post-operative nausea and vomiting was reduced significantly compared with placebo treatment (P =0.0003). The incidence of side effects was similar in the four groups. Dimenhydrinate was ineffective in reducing the incidence of post-operative nausea and vomiting and droperidol only reduced the severity of post-operative nausea and vomiting. However, the combination of both drugs significantly reduces the incidence of post-operative nausea and vomiting when compared with placebo treatment.

Summary

Background and objective: We evaluated the effect of two different preload solutions: (i) Ringer's lactate (compound sodium lactate intravenous infusion BP) and (ii) 0.9% sodium chloride solution on the neonatal acid–base status of the newborn infants. The two standard regimens were compared to detect a possible difference. Methods: A 2 L crystalloid fluid bolus was administered immediately before spinal anaesthesia for elective Caesarean section in two groups of 20 healthy parturients, while rigorously maintaining maternal normotension. Results: No significant differences in the Apgar scores at 1 and 5 min, or infant well-being were demonstrated in either of the two groups. The data show that umbilical artery PCO2 is lower in the Ringer's lactate group and that pH is insignificantly higher by 0.03. Conclusions: The choice of Ringer's lactate or saline for fluid preload does not have any effect on neonatal well-being.

Environmental monitoring of anaesthetic gases was carried out in theatre areas in eight hospitals as well as in Delivery suites, radiology, radiotherapy and Dental suites. High staff exposures occurred in nontheatre areas although exposures in theatres were generally satisfactory. Environmental control measures are required where staff exposures exceed legal standards.

Iatrogenic pneumocephalus is an uncommon complication observed after using the ‘loss-of-resistance’ technique with an air filled syringe. We report and review two cases of pneumocephalus: one subarachnoid and the other epidural.

Background and objective In a randomized, placebo-controlled, double-blind trial, we compared the efficacy of dolasetron and metoclopramide in preventing postoperative nausea and vomiting in women undergoing hysterectomy.

Methods Patients were allocated randomly to one of three groups: group A (n =50) received 50 mg dolasetron orally, group B (n =50) received 20 mg metoclopramide intravenously and placebo orally, group C (n =50) received placebo orally. If patients complained of retching or vomiting, or if patients demanded an antiemetic, 1.25 mg droperidol was administrated intravenously. To quantify postoperative nausea and vomiting the following score was used: 0 =no nausea, 1 =nausea, 2 =retching, 3 =single vomiting, 4 =multiple vomiting. The Raatz test was used to analyse postoperative nausea and vomiting (PONV) scores.

Results Dolasetron reduced the postoperative nausea and vomiting score significantly (P <0.02 vs. metoclopramide; P <0.0001 vs. placebo). Metoclopramide also reduced the postoperative nausea and vomiting score (P <0.02 vs. placebo). Fisher's exact test showed a significant reduction of vomiting in the dolasetron group compared with metoclo-pramide-treated patients (P <0.007) and placebo-treated patients (P <0.000006) and a significantly lower rate of nausea in comparison to the placebo group (P <0.009). There were no significant differences between the metoclopramide and the placebo groups (in Fisher's exact test). The use of postoperative droperidol per patient was significantly lower in the dolasetron group (P <0.04 vs. metoclopramide; P <0.0001 vs. placebo) than in the metoclopramide (P <0.02 vs. placebo) and in the placebo groups.

Conclusions Oral dolasetron is more effective than either metoclopramide given intravenously or placebo for preventing vomiting after hysterectomy. It also was significantly superior to either metoclopramide or placebo concerning the PONV score and the need for droperidol rescue.

The aim of specific monitoring in neuroanaesthesia is to detect, as quickly as possible, intraoperative ischaemic insults so that the brain and the spinal cord may be protected from harmful and frequently inevitable events due to the type of surgery, patient positioning, haemodynamic changes or any intercurrent event. New monitors are being introduced into the operating theatre, but only a few are considered to be an absolute standard of care in neurosurgery, e.g. facial nerve monitoring for surgery of acoustic neuromas and recording of evoked potentials during repair of scoliosis. In the past decade, new monitoring devices have moved from the experimental stage to the operating theatre and although most are still in a phase of technological development and/or definition of their field of applicability they are being used as guides for clinical practice in those instances where cerebral well-being might be impaired. The metabolic consequences of hyperventilation, pharmacological electroencephalogram burst suppression, hypothermia, etc. can now be assessed in the operating theatre. Non-invasive monitoring is being rapidly integrated into our daily work because of its lack of secondary effects. Nevertheless, each new development is regarded as an addition rather than as a substitute for existing equipment. The perfect combination of monitors to provide essential information during an individual surgical procedure to influence a better patient outcome, is still uncertain and needs extensive clinical research.

Summary

Background and objectives: Increasing numbers of patients taking herbal medicine products are presenting for anaesthesia and surgery. Anaesthetists need to consider the perioperative implications of herbal medicines and should, therefore, have some knowledge of this subject. Methods: A postal questionnaire survey was sent to a random 5% of practising members of the Association of Anaesthetists of Great Britain and Ireland residing in the UK, to identify attitudes, practice and knowledge regarding herbal medicines. Results: From 341 questionnaires there were 221 replies, a 65% response rate. Ninety per cent stated that they seldom or never asked patients about herbal medicine usage, yet 65% felt that there could be potentially harmful effects of herbal medicines in the perioperative period. There was a very poor level of knowledge with respect to the current management of 10 well-known herbal medicines. However, 75% agreed that information about perioperative usage of herbal medicines is important, and 77% felt that herbal medicines should be in the undergraduate medical curriculum. Reading was the usual source of herbal medicine product information. Most (82%) felt their knowledge of herbal medicine products and the implications in patient care were inadequate. Conclusions: This sample of anaesthetists require education on herbal medicines. Suggestions for remedial action are given.

Summary

Closed circuit anaesthesia was described decades ago but did not achieve wide popularity among anaesthesiologists mainly because reliable control of inspiratory gas concentrations was not possible. Recent innovations including fast gas analysers, electronically controlled dosage systems and algorithms for feedback control have made possible the development of sophisticated closed circuit ventilators designed for routine clinical practice. The main advantages comprise economic use of medical gases and volatile anaesthetics, reduction of anaesthetic gas loss into the atmosphere, improved airway acclimatization as well as estimations of oxygen consumption. This article reviews historical aspects, recent developments as well as advantages and limitations of closed system anaesthesia.

Summary

Background: Leucocytes are a pivotal component of the inflammatory cascade that results in tissue injury in a large group of disorders. Free radical production and endothelial activation promote leucocyte–endothelium interactions via endothelial expression of vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1) which augment these processes, particularly in the setting of reperfusion injury. Propofol has antioxidant properties which may attenuate the increased expression of these molecules that is observed. Methods: Cultured human umbilical vein endothelial cells were exposed to 20 h of hypoxia, then returned to normoxic conditions. Cells were treated with saline, Diprivan® 5 μg mL−1 or propofol 5 μg mL−1, for 4 h after reoxygenation and were examined for ICAM-1 and VCAM-1 expression. Results: Hypoxia did not increase the expression of ICAM-1/VCAM-1. ICAM-1 expression peaked 12 h after reoxygenation (21.75(0.6) vs. 9.6(1.3), P = 0.02). Propofol, but not Diprivan®, prevented this increase (8.2(2.9) vs. 21.75(0.6), P = 0.009). VCAM-1 expression peaked 24 h after reoxygenation (9.8(0.9) vs. 6.6(0.6), P = 0.03). Propofol and Diprivan® prevented this increase, with no difference between the two treatments observed (4.3(0.3) and 6.4(0.5) vs. 9.8(0.9), P = 0.001, 0.02, respectively). Conclusion: These effects are likely to be attributable to the antioxidant properties of propofol, and suggest that propofol may have a protective role in disorders where free radical mediated injury promotes leucocyte–endothelium adhesive interactions.

In 1892 Osler described ‘rapid loss of flesh’ in prolonged sepsis. Thereafter, for years, limb weakness was attributed to cachectic myopathy, and difficulty weaning from mechanical ventilation was attributed to diaphragmatic fatigue. In 1961 Mertens described ‘coma-polyneuropathies’, and in 1971 Henderson and colleagues described polyneuropathy in patients with burns. In 1984 Bolton and colleagues, in a series of reports, defined the clinical, electrophysiological and morphological features of septic encephalopathy and critical illness polyneuropathy. Evidence suggested that polyneuropathy was due to the ‘toxic’ effects of sepsis. Polyneuropathy was a common cause of difficulty in weaning when lung and cardiac cause had been excluded. Since 1984, cases of critical illness polyneuropathy have been reported from several countries. Moreover, a number of investigators reported instances of critical illness myopathy. Comprehensive studies by Latronico and colleagues indicated that polyneuropathy and myopathy often occurred together in the same patient. With successful treatment of sepsis, improvement often occurred in encephalopathy, polyneuropathy and myopathy, except in very severe cases.