Showing papers in "BJA: British Journal of Anaesthesia in 2002"

Effectiveness of acute postoperative pain management: I. Evidence from published data

Abstract: Background This review examines the evidence from published data concerning the incidence of moderate-severe and of severe pain after major surgery, with three analgesic techniques; intramuscular (i.m.) analgesia, patient controlled analgesia (PCA), and epidural analgesia. Methods A MEDLINE search of the literature was conducted for publications concerned with the management of postoperative pain. Over 800 original papers and reviews were identified. Of these 212 papers fulfilled the inclusion criteria but only 165 provided usable data on pain intensity and pain relief. Pooled data on pain scores obtained from these studies, which represent the experience of a total of nearly 20 000 patients, form the basis of this review. Results Different pain measurement tools provided comparable data. When considering a mixture of three analgesic techniques, the overall mean (95% Cl) incidence of moderate-severe pain and of severe pain was 29.7 (26.4–33.0)% and 10.9 (8.4–13.4)%, respectively. The overall mean (95% Cl) incidence of poor pain relief and of fair-to-poor pain relief was 3.5 (2.4–4.6)% and 19.4 (16.4–22.3)%, respectively. For i.m. analgesia the incidence of moderate-severe pain was 67.2 (58.1–76.2)% and that of severe pain was 29.1 (18.8–39.4)%. For PCA, the incidence of moderate-severe pain was 35.8 (31.4–40.2)% and that of severe pain was 10.4 (8.0–12.8)%. For epidural analgesia the incidence of moderate-severe pain was 20.9 (17.8–24.0)% and that of severe pain was 7.8 (6.1–9.5)%. The incidence of premature catheter dislodgement was 5.7 (4.0–7.4)%. Over the period 1973–1999 there has been a highly significant (P Conclusions These results suggest that the UK Audit Commission (1997) proposed standards of care might be unachievable using current analgesic techniques. The data may be useful in setting standards of care for Acute Pain Services.

Volatile anaesthetics may be the main cause of early but not delayed postoperative vomiting: a randomized controlled trial of factorial design

Abstract: Background Despite intensive research, the main causes of postoperative nausea and vomiting (PONV) remain unclear. We sought to quantify the relative importance of operative, anaesthetic and patient-specific risk factors to the development of PONV. Methods We conducted a randomized controlled trial of 1180 children and adults at high risk for PONV scheduled for elective surgery. Using a five-way factorial design, we randomly assigned subjects by gender who were undergoing specific operative procedures, to receive various combinations of anaesthetics, opioids, and prophylactic antiemetics. Results Of the 1180 patients, 355 (30.1% 95% CI (27.5–32.7%)) had at least one episode of postoperative vomiting (PV) within 24 h post-anaesthesia. In the early postoperative period (0–2 h), the leading risk factor for vomiting was the use of volatile anaesthetics, with similar odds ratios (OR (95% CI)) being found for isoflurane (19.8 (7.7–51.2)), enflurane (16.1 (6.2–41.8)) and sevoflurane (14.5 (5.6–37.4)). A dose–response relationship was present for the use of volatile anaesthetics. In contrast, no dose response existed for propofol anaesthesia. In the delayed postoperative period (2–24 h), the main predictors were being a child (5.7 (3.0–10.9)), PONV in the early period (3.4 (2.4–4.7)) and the use of postoperative opioids (2.5 (1.7–3.7)). The influence of the antiemetics was considerably smaller and did not interact with anaesthetic or surgical variables. Conclusion Volatile anaesthetics were the leading cause of early postoperative vomiting. The pro-emetic effect was larger than other risk factors. In patients at high risk for PONV, it would therefore make better sense to avoid inhalational anaesthesia rather than simply to add an antiemetic, which may still be needed to prevent or treat delayed vomiting.

Pathophysiology and clinical implications of perioperative fluid excess

Abstract: The practice of perioperative fluid therapy is variable, ranging from ‘high volume’ to ‘dry’ regimen. A review of the data on the effect of ‘high volume’ perioperative fluid therapy suggests that the resulting overhydration may have deleterious effects on cardiac and pulmonary function, and on recovery of gastrointestinal motility (postoperative ileus), tissue oxygenation, wound healing and coagulation. These observations call for randomized studies of the effects of ‘high’ vs ‘low’ volume replacement therapy on postoperative morbidity, in order to establish evidence-based guidelines for perioperative fluid management. Perioperative fluid replacement has been, and still is, the focus of much debate. This debate has primarily focused on the various types of fluid components available for replacement therapy, and not on the actual amount of fluid administered.

Comparative effect of paracetamol, NSAIDs or their combination in postoperative pain management: a qualitative review

Abstract: Background Quantitative reviews of postoperative pain management have demonstrated that the number of patients needed to treat for one patient to achieve at least 50% pain relief (NNT) is 2.7 for ibuprofen (400 mg) and 4.6 for paracetamol (1000 mg), both compared with placebo. However, direct comparisons between paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs) have not been extensively reviewed. The aims of this review are (i) to compare the analgesic and adverse effects of paracetamol with those of other NSAIDs in postoperative pain, (ii) to compare the effects of combined paracetamol and NSAID with those of either drug alone, and (iii) to discuss whether the adverse effects of NSAIDs in short-term use are justified by their analgesic effects, compared with paracetamol. Methods Medline (1966 to January 2001) and the Cochrane Library (January 2001) were used to perform a systematic, qualitative review of postoperative pain studies comparing paracetamol (minimum 1000 mg) with NSAID in a double-blind, randomized manner. A quantitative review was not performed as too many studies of high scientific standard (27 out of 41 valid studies, including all major surgery studies) would have been excluded. Results NSAIDs were clearly more effective in dental surgery, whereas the efficacy of NSAIDs and paracetamol seemed without substantial differences in major and orthopaedic surgery, although firm conclusions could not be made because the number of studies was limited. The addition of an NSAID to paracetamol may confer additional analgesic efficacy compared with paracetamol alone, and the limited data available also suggest that paracetamol may enhance analgesia when added to an NSAID, compared with NSAIDs alone. Conclusions Paracetamol is a viable alternative to the NSAIDs, especially because of the low incidence of adverse effects, and should be the preferred choice in high-risk patients. It may be appropriate to combine paracetamol with NSAIDs, but future studies are required, especially after major surgery, with specific focus on a potential increase in side-effects from their combined use.

Randomized controlled trial to investigate influence of the fluid challenge on duration of hospital stay and perioperative morbidity in patients with hip fractures

Abstract: Background A prospective, randomized controlled trial comparing conventional intraoperative fluid management with two differing methods of invasive haemodynamic monitoring to optimize intraoperative fluid therapy, in patients undergoing proximal femoral fracture repair under general anaesthesia. Methods Ninety patients randomized to three groups; conventional intraoperative fluid management (Gp CON, n=29), and two groups receiving additional repeated colloid fluid challenges guided by central venous pressure (Gp CVP, n=31) or oesophageal Doppler ultrasonography (Gp DOP, n=30). Primary outcome measures were time to medical fitness to discharge, hospital stay and postoperative morbidity. Results The fluid challenge resulted in significantly greater perioperative changes in central venous pressure between Gp CVP and Gp CON (mean 5 (95% confidence interval 3–7) mm Hg) (P Conclusions Invasive intraoperative haemodynamic monitoring with fluid challenges during repair of femoral fracture under general anaesthetic shortens time to being medically fit for discharge.

Comparison of predictive models for postoperative nausea and vomiting

Abstract: Background. In order to identify patients who would benefit from prophylactic amtiemetics, six predictive models have been described for the risk assessment of postoperative nausea and vomiting (PONV). This study compared the validity and practicability of these models in patients undergoing general anaesthesia. Methods. Data were analysed from 1566 patients who underwent balanced anaesthesia without prophylactic antiemetic treatment for various types of surgery. A systematic literature search identified six predictive models for PONV. These models were compared with respect to validity (discriminating power and calibration characteristics) and practicability. Discriminating power was measured by the area under the receiver operating characteristic curve (AUC) and calibration was assessed by weighted linear regression analysis between predicted and actual incidences of PONV. Practicability was assessed according to the number of factors to be considered for the model (the fewer factors the better), and whether the score could be used in combination with a previously applied cost-effective concept. Results. The incidence of PONV was 600/1566 (38.1%). The discriminating power (AUC) obtained by the models (named according to the first author) using the risk classes from the recommended prophylactic concept were as follows: Apfel, 0.68; Koivuranta, 0.66; Sinclair, 0.66; Palazzo, 0.63; Gan, 0.61; Scholz, 0.61. For four models, the following calibration curves (expressed as the slope and the offset) were plotted: Apfel, y=0.82x+0.01, r 2 =0.995; Koivuranta, y=1.13x‐0.10, r 2 =0.999; Sinclair, y=0.49x+0.29, r 2 =0.789; Palazzo, y=0.30x+0.30, r 2 =0.763. The numbers of parameters to be considered were as follows: Apfel, 4; Koivuranta, 5; Palazzo, 5; Scholz, 9; Sinclair, 12; Gan, 14. Conclusion. The simplified risk scores provided better discrimination and calibration properties compared with the more complex risk scores. Therefore, simplified risk scores can be recommended for antiemetic strategies in clinical practice as well as for group comparisons in randomized controlled antiemetic trials.

The role of non‐technical skills in anaesthesia: a review of current literature

Abstract: level Solving problems by reasoning Uses mental resources to create mental model of problem and to work out solution from ®rst principles Supervisor level Supervisory control Allocates attention and mental resources Resource management level Resource management Uses available resources, information, equipment and personnel to manage perioperative care of patient Fletcher et al.

Postoperative sore throat after ambulatory surgery

Abstract: Background Sore throat is a common complication of anaesthesia that affects patient satisfaction after surgery. Methods We studied 5264 ambulatory surgical patients prospectively to determine the patient, anaesthetic, and surgical factors associated with sore throat. Results In 5264 patients, 12.1% reported a sore throat. Patients with tracheal tube had the greatest incidence, 45.4%, followed by patients with laryngeal mask airway, 17.5%, while patients with a facemask had a lower incidence of sore throat, 3.3%. Female patients had more sore throats than male patients (13.4 vs 9.1%). Airway management had the strongest influence on the incidence of sore throat. Sore throat in ambulatory surgical patients was associated with female sex, younger patients, use of succinylcholine, and gynaecological surgery. Conclusion Airway management, female sex, younger patients, surgery for gynaecological procedure, and succinylcholine predicts postoperative sore throat. Increased awareness of the predictive factors can help to avoid this combination and improve patient satisfaction.

Depth of sedation in children undergoing computed tomography: validity and reliability of the University of Michigan Sedation Scale (UMSS)

Abstract: Background. Safe care of sedated children requires ongoing assessment of the depth of sedation to permit early recognition of progression to over-sedation. This study evaluated the validity and reliability of the University of Michigan Sedation Scale (UMSS) as a measure of sedation during procedures. The UMSS is a simple observational tool that assesses the level of alertness on a five-point scale ranging from 1 (wide awake) to 5 (unarousable with deep stimulation). Methods. Thirty-two children aged 4 months to 5 yr (mean 1.5 yr), sedated for computed tomography (CT), were studied prospectively. The CT nurse assessed sedation using the UMSS before sedative administration and every 10 min thereafter. The child was videotaped during each assessment, and segments were edited and their order was randomized. Four nurses blinded to sedative administration viewed the segments and scored sedation using the UMSS. One of these nurses also scored sedation using a visual analogue scale (VAS) and another using the Observer’s Assessment of Alertness/Sedation Scale (OAAS). To examine the test‐retest reliability, 75 randomly selected video segments were viewed and scored on a second occasion. Results. Changes in scores from baseline to discharge supported construct validity (P<0.0001). Criterion validity was demonstrated by significant correlations between the UMSS and the VAS and OAAS. There was good interobserver agreement between blinded observers’ scores for each level of sedation and at discharge, and between blinded observers and the CT nurse for scores of 0 and 1 (lighter levels of sedation), but less agreement for scores 2 and 3 (deeper sedation) and discharge scores. Test‐retest reliability was supported by agreement in the observers’ UMSS scores. Conclusion. The UMSS is a simple, valid and reliable tool that facilitates rapid and frequent assessment and documentation of depth of sedation in children.

Ultrasound-guided infraclavicular brachial plexus block.

Abstract: Background Peripheral nerve blocks are almost always performed as blind procedures. The purpose of this study was to test the feasibility of seeing individual nerves of the brachial plexus and directing the block needle to these nerves with real time imaging. Methods Using ultrasound guidance, infraclavicular brachial plexus block was performed in 126 patients. Important aspects of this standardized technique included (i) imaging the axillary artery and the three cords of the brachial plexus posterior to the pectoralis minor muscle, (ii) marking the position of the ultrasound probe before introducing a Tuohy needle, (iii) maintaining the image of the entire length of the needle at all times during its advancement, (iv) depositing local anaesthetic around each of the three cords and (v) placing a catheter anterior to the posterior cord when indicated. Results In 114 (90.4%) patients, an excellent block permitted surgery without a need for any supplemental anaesthetic or conversion to general anaesthesia. In nine (7.2%) patients local or perineural administration of local anaesthetic, and in three (2.4%) conversion to general anaesthesia, was required. Mean times to administer the block, onset of block and complete block were 10.0 (sd 4.4), 3.0 (1.3) and 6.7 (3.2) min, respectively. Mean lidocaine dose was 695 (107) mg. In one patient, vascular puncture occurred. In 53 (42.6%) patients, an indwelling catheter was placed, but only three required repeat injections, which successfully prolonged the block. Conclusion The use of ultrasound appears to permit accurate deposition of the local anaesthetic perineurally, and has the potential to improve the success and decrease the complications of infraclavicular brachial plexus block.

Mechanisms of (local) anaesthetics on voltage-gated sodium and other ion channels

Abstract: Local anaesthetics have been used clinically for well over a century, but the molecular mechanisms by which they alter specific functions of the peripheral nerve system remained unclear for a long time. Investigations during the last few decades presented evidence implicating the sodium (Na + ) channel protein as a target for specific, clinically important, local anaesthetic effects on mammalian neurones. In this review I will present the state of knowledge of the action of local anaesthetics at the molecular level, with an emphasis on Na + channels. After a brief survey of the history of concepts of local anaesthetic actions, the structure of the Na + channel will be described with regard to its function in order to understand the recent findings that have followed the description of the amino acid sequence of the Na + channel protein. 46 At clinically relevant concentrations local anaesthetics can also affect potassium (K + ) and calcium (Ca 2+ ) channels, which might help explain some of their side-effects. General anaesthetics also interact with these targets (ion channels), but differences in selectivity compared with local anaesthetics have been reported. Current findings indicate that local anaesthetics also act on intracellular mechanisms, which raises the question of whether these might explain toxicity and other side-effects.

Pharmacokinetics of dexmedetomidine infusions for sedation of postoperative patients requiring intensive care

Abstract: Background The pharmacokinetics of the alpha-2 adrenoceptor agonist dexmedetomidine were studied in 10 patients requiring postoperative sedation and mechanical ventilation in the intensive care unit (ICU), and compared with previous volunteer data. Methods On arrival in the ICU, sedation with dexmedetomidine was commenced with a loading dose of 2.5 μg kg−1 h−1 over 10 min followed by a maintenance infusion of 0.7 μg kg−1 h−1 into a central vein. Blood samples for measurement of plasma dexmedetomidine concentrations were taken during and after sedative infusions at predetermined intervals. Pharmacokinetic variables were estimated using non-compartmental methods. In addition, non-linear mixed effects modelling was used to obtain variable estimates not readily attainable from non-compartmental methods. Respiratory and haemodynamic data were recorded to enable correlation of any adverse events with the calculated pharmacokinetic profile. Results The harmonic mean distribution half-life of dexmedetomidine was 8.6 min and the harmonic mean terminal half-life was 3.14 h. Steady-state volume of distribution averaged 173 litres, clearance averaged 48.3 litres h−1, and the mean residence time averaged 3.86 h. Conclusions Mean dexmedetomidine pharmacokinetic variables seen in postoperative, intensive care patients were similar to those previously found in volunteers, with the exception of the steady-state volume of distribution. A small loading dose provided effective sedation with no adverse events.

Pharmacogenetics of codeine metabolism in an urban population of children and its implications for analgesic reliability

Abstract: Background. Codeine analgesia is wholly or mostly due to its metabolism to morphine by the cytochrome P450 enzyme CYP2D6, which shows significant genetic variation in activity. The aims of this study were to investigate genotype, phenotype and morphine production from codeine in children undergoing adenotonsillectomy, and to compare analgesia from codeine or morphine combined with diclofenac. Methods. Ninety-six children received either codeine 1.5 mg kg ‐1 or morphine 0.15 mg kg ‐1 in a randomized, double-blind design. Genetic analysis was performed and plasma morphine concentrations at 1 h were determined. Postoperative analgesia and side-effects were recorded. Results. Forty-seven per cent of children had genotypes associated with reduced enzyme activity. Mean (SD) morphine concentrations were significantly lower (P<0.001) after codeine [4.5 (0.3) ng ml ‐1 ] than after morphine [24.7 (1.5) ng ml ‐1 ], and morphine and its metabolites were not detected in 36% of children given codeine. There was a significant relationship between phenotype and plasma morphine (P=0.02). More children required rescue analgesia after codeine at both 2 (P<0.05) and 4 h after administration (P<0.01). Fifty-six per cent of children vomited after morphine and 29% after codeine (P<0.01). Neither phenotype nor morphine concentration was correlated with either pain score or the need for rescue analgesia (r=‐0.21, 95% confidence interval ‐0.4, ‐0.01). Conclusions. Reduced ability for codeine metabolism may be more common than previously reported. Plasma morphine concentration 1 h after codeine is very low, and related to phenotype. Codeine analgesia is less reliable than morphine, but was not well correlated with either phenotype or plasma morphine in this study. Br J Anaesth 2002; 89: 839‐45

Patient-controlled epidural analgesia versus continuous infusion for labour analgesia: a meta-analysis

Abstract: Background Patient-controlled epidural analgesia (PCEA) is a relatively new method of maintaining labour analgesia. There have been many studies performed that have compared the efficacy of PCEA with continuous epidural infusion (CEI). The purpose of this systematic review is to compare the efficacy and safety of PCEA and CEI. Methods All randomized controlled trials that compared PCEA, without background infusion, with CEI were sought from the literature. These were rated for quality using a validated, fivepoint scale. The primary outcome was the number of patients who received anaesthetic interventions. Secondary outcomes included the dose of local anaesthetic, incidence of motor block, quality of analgesia, obstetric and safety outcomes. Where feasible, the data were combined using meta-analytical techniques. For dichotomous data, the risk difference (RD) and 95% confidence intervals (CI) were calculated. For continuous data, the weighted mean differences (WMD) were calculated. The differences were statistically significant when the 95% CI excluded 0. Results Nine studies comprised of 640 patients were found. There were fewer anaesthetic interventions in the PCEA group (RD, 27%; 95% CI, 18–36%; P Conclusion Patients who receive PCEA are less likely to require anaesthetic interventions, require lower doses of local anaesthetic and have less motor block than those who receive CEI. Future research should be directed at determining differences in maternal satisfaction and obstetric outcome.

Rectal and parenteral paracetamol, and paracetamol in combination with NSAIDs, for postoperative analgesia

Abstract: Background We have reviewed the analgesic efficacies of rectal and parenteral paracetamol and tested the evidence for a possible additive analgesic effect of the combination of paracetamol with a non-steroidal anti-inflammatory drug (NSAID) in postoperative pain. Methods Randomized controlled trials were evaluated. Outcome measures were pain scores and demand for supplementary analgesia. Results Eight studies compared rectal paracetamol with placebo. One study of single-dose administration of rectal paracetamol 40–60 mg kg−1 and three studies of repeat dosing with 14–20 mg kg−1 showed significant analgesic efficacy, while studies of a single dose of 10–20 mg kg−1 were negative. Ten studies compared parenteral paracetamol with placebo and eight studies showed improved pain relief with paracetamol. Of the nine studies comparing paracetamol with a combination of paracetamol and an NSAID, six studies showed improved pain relief for the combination while only two of the six studies comparing an NSAID with a combination of an NSAID and paracetamol showed improved pain relief for the combination. Conclusions Considering the few studies available, evidence was found of a clinically relevant analgesic effect of rectal and parenteral paracetamol. Concurrent use of paracetamol and an NSAID was superior to paracetamol alone but no evidence was found of superior analgesic effect of the combination compared with the NSAID alone.

Stress in UK intensive care unit doctors

Abstract: Background Doctors have long been considered at risk of occupational stress. Methods A postal survey of all members of the Intensive Care Society using validated instruments. Results Eight-five per cent of members returned questionnaires and 70% were eligible for the study. Twenty-nine per cent were suffering General Health Questionnaire-12 (GHQ-12) identified distress and 12% Symptom Checklist-Depression (SCL-D) defined depression. There were no significant age or sex differences between staff suffering distress or depression and those who did not. Dissatisfaction with career correlated highly with both distress and depression (P Conclusions Nearly one in three ICU doctors appeared distressed (GHQ), and one in 10 depressed (SCL-D); this is no greater than that reported in other specialities. Perceived stressors reveal some key areas of concern for the employer and the specialty.

Continuous and intermittent cardiac output measurement: pulmonary artery catheter versus aortic transpulmonary technique

Abstract: Background Cardiac output (CO) can be measured intermittently by bolus thermodilution methods in the pulmonary artery (COpa) or in the aorta (COart). A continuous thermodilution method (CCO) and a method for continuous estimation using the arterial pulse wave (PCCO) are also available. Methods We compared two methods of intermittent CO measurements in patients during liver transplantation: COpa, regarded as the current clinical standard, and an aortic transpulmonary thermodilution technique (COart) performed with the PiCCO system. We also compared CCO and PCCO. Measurements were made in 62 patients at three stages: after the induction of anaesthesia, after caval clamping phase, and at the end of surgery. We used Bland–Altman and correlation analysis. Results We found close agreement between the techniques. Mean bias between COart and COpa and PCCO and CCO was 0.15 (2 sd of differences between methods=1.74) litre min −1 and –0.03 (1.75) litre min −1 , respectively. Mean bias between CCO and COpa and PCCO and COpa was 0.02 (1.48) litre min −1 and 0.04 (1.69) litre min −1 , respectively. Conclusions Measurement with the aortic transpulmonary thermodilution technique gives continuous and intermittent values that agree with the pulmonary thermodilution method.

Maternal deaths from anaesthesia. An extract from Why Mothers Die 1997–1999, the Confidential Enquiries into Maternal Deaths in the United Kingdom

Abstract: This article is reprinted from Why Mothers Die 1997–1999, the fifth report of the Confidential Enquiries into Maternal Deaths in the United Kingdom. RCOG Press, 2001; 134–49. Reproduced with permission from the Editorial Board.

Double‐blind, placebo‐controlled analgesic study of ibuprofen or rofecoxib in combination with paracetamol for tonsillectomy in children

Abstract: Background The analgesics used for paediatric tonsillectomy may be associated with side-effects such as sedation, respiratory depression and vomiting (opioids) or increased bleeding [non-steroidal anti-inflammatory drugs (NSAIDs)]. In our institution, we employ a combination of paracetamol, NSAID and opioid, although there is no published evidence of analgesic benefit from adding NSAIDs to paracetamol in children. Methods This randomized, double-blinded clinical study examined the analgesic effectiveness of combining paracetamol (20 mg kg−1) with rofecoxib (0.625 mg kg−1), ibuprofen (5 mg kg−1) or placebo as premedication for (adeno)tonsillectomy (n=98) in children aged 3–15 yr. Intravenous fentanyl 1–2 μg kg−1 was given intraoperatively. Regular oral paracetamol (15 mg kg−1, 4 hourly) was given after operation and could be supplemented on request from the child with oral ibuprofen 5 mg kg−1 or oral codeine 1 mg kg−1. The primary outcome variable was need for early supplementary analgesia (within 2 h after surgery). Results The addition of ibuprofen to paracetamol reduced the need for early analgesia from 72% to 38% of children (difference 34%; 95% confidence interval 4–64%). The addition of rofecoxib to paracetamol did not significantly alter the need for early analgesia (68 vs 72%). Pain scores were higher in those children who required early analgesia. There were no differences between the groups in operative blood loss or complications, total 24-h analgesic consumption, pain scores at 4 and 8 h, vomiting or antiemetic use. Conclusion This study provides evidence to support the combination of ibuprofen (but not rofecoxib) with paracetamol for perioperative analgesia in children.

Parkinson’s disease and anaesthesia

Abstract: Parkinson's disease is an increasingly common disease of elderly patients who present a particular anaesthetic challenge. This review explores the epidemiology, aetiology, pathogenesis, and pathophysiology of the condition, particularly the possible role of genetic factors. The clinical features are described in detail and recent advances in medical management are highlighted. Controversies surrounding the use of the newer drugs and possible advances in neurosurgical interventions are discussed. Particular anaesthetic problems in patients with Parkinson's disease are respiratory, cardiovascular, and neurological. Potential drug interactions are described and recommendations are made about suitable anaesthetic techniques.

Ketorolac, diclofenac, and ketoprofen are equally safe for pain relief after major surgery.

Abstract: Background Ketorolac is approved for the relief of postoperative pain but concerns have been raised over a possible risk of serious adverse effects and death. Two regulatory reviews in Europe on the safety of ketorolac found the data were inconclusive and lacked comparison with other non-steroidal anti-inflammatory drugs. The aim of this study was to compare the risk of serious adverse effects with ketorolac vs diclofenac or ketoprofen in adult patients after elective major surgery. Methods This prospective, randomized multicentre trial evaluated the risks of death, increased surgical site bleeding, gastrointestinal bleeding, acute renal failure, and allergic reactions, with ketorolac vs diclofenac or ketoprofen administered according to their approved parenteral and oral dose and duration of treatment. Patients were followed for 30 days after surgery. Results A total of 11 245 patients completed the trial at 49 European hospitals. Of these, 5634 patients received ketorolac and 5611 patients received one of the comparators. 155 patients (1.38%) had a serious adverse outcome, with 19 deaths (0.17%), 117 patients with surgical site bleeding (1.04%), 12 patients with allergic reactions (0.12%), 10 patients with acute renal failure (0.09%), and four patients with gastrointestinal bleeding (0.04%). There were no differences between ketorolac and ketoprofen or diclofenac. Postoperative anticoagulants increased the risk of surgical site bleeding equally with ketorolac (odds ratio=2.65, 95% CI=1.51–4.67) and the comparators (odds ratio=3.58, 95% CI=1.93–6.70). Other risk factors for serious adverse outcomes were age, ASA score, and some types of surgery (plastic/ear, nose and throat, gynaecology, and urology). Conclusions We conclude that ketorolac is as safe as ketoprofen and diclofenac for the treatment of pain after major surgery.

Randomized crossover comparison of the ProSeal with the classic laryngeal mask airway in unparalysed anaesthetized patients

Abstract: Background. The ProSeal is a wire-reinforced laryngeal mask airway with an additional drain tube that leads to the distal tip of the laryngeal cuff. The design should improve the seal with the larynx. Methods. The ProSeal and classic laryngeal mask airways were compared in 180 patients in a randomized crossover study. Patients were anaesthetized without neuromuscular blocking drugs. Results. The ProSeal took more time and more attempts to insert successfully than the classic laryngeal mask airway. Insertion was successful on the first attempt in 81% of cases with the ProSeal and 90% with the classic laryngeal mask airway. The ProSeal required more air to achieve an intracuff pressure of 60 cm H2O (6 ml more for size 4 and 12 ml more for size 5). Laryngeal seal pressure was better with the ProSeal than the classic laryngeal mask airway. Median seal pressure was 29 cm H2O with the ProSeal and 18 cm H2O with the classic laryngeal mask airway. Laryngeal seal pressure was greater than 20 cm H2O in 87% of patients with the ProSeal and 41% with the classic laryngeal mask airway. Laryngeal seal pressure was greater than 40 cm H2O in 21% of patients with the ProSeal and in none of the patients with the classic laryngeal mask. Once placed, the ProSeal remained a stable and effective airway. Gastric tube insertion through the drain tube was attempted in 147 cases and was successful in 135 (92%). Conclusion. The ProSeal is more difficult to insert than the classic laryngeal mask airway but allows positive pressure ventilation more reliably than the classic laryngeal mask airway. Br J Anaesth 2002; 88: 527‐33

In vivo effect of haemodilution with saline on coagulation: a randomized controlled trial†‡

Abstract: Background Previous studies have shown that 10–30% haemodilution with crystalloid may induce a hypercoagulable state demonstrable by using the Thrombelastograph® (TEG). While most are in vitro studies, the few in vivo studies are limited by confounding surgical or ‘environmental' factors. We conducted this randomized controlled study to evaluate the coagulation changes associated with in vivo haemodilution. Methods Twenty patients undergoing major hepatobiliary surgery were randomly allocated to one of two study groups. Group H (n=10) had 30% blood volume withdrawn over 30 min and replaced with saline. Group C (n=10) did not have any blood withdrawn. Blood samples were taken in both groups at 10, 20 and 30 min. Native TEG, complete blood count, coagulation profile, fibrinogen, antithrombin III, protein C and thrombin–antithrombin complex concentrations were measured. Results Compared with Group C, Group H patients had significantly greater shortening of r-time at 30 min (–30% vs +36%), greater shortening of k-time at all time points (–36% vs +17% at 10 min; –37% vs +44% at 20 min; –45% vs +49% at 30 min), and greater widening of α at 30 min (+71% vs +4%). The decrease in antithrombin III and other natural procoagulants and anticoagulants closely followed that of haematocrit, with the exception of thrombin–antithrombin complex. Conclusion In vivo haemodilution of up to 30% with saline can induce a hypercoagulable state. The mechanism remains unclear as disproportionate dilution of natural anticoagulants was not detected. Thrombin–antithrombin complex concentration remained stable despite haemodilution in Group H, which may suggest increased thrombin generation.

Neuroprotective and neurotoxic properties of the ‘inert’ gas, xenon

Abstract: Background. Antagonists of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors have been shown not only to have neuroprotective effects but also to exhibit neurotoxic properties. In this study, we used c-Fos, a protein product of an immediate early gene, as a marker of neuronal injury to compare the neuroprotective effects of xenon and the neurotoxic properties of xenon, nitrous oxide, and ketamine, three anaesthetics with NMDA receptor antagonist properties. Methods. We used an in vivo rat model of brain injury in which N-methyl-DL-aspartic acid (NMA) is injected subcutaneously (s.c.) and c-Fos expression in the arcuate nucleus is used as a measure of injury. To examine the neurotoxic potential of each of the three anaesthetics with NMDA receptor antagonist properties, c-Fos expression in the posterior cingulate and retrosplenial (PC/RS) cortices was measured. Results. Xenon dose-dependently suppressed NMA-induced c-Fos expression in the arcuate nucleus with an IC50 of 47 (2)% atm. At the highest concentration tested (75% atm) NMAinduced neuronal injury was decreased by as much as that observed with the prototypical NMDA antagonist MK801 (0.5 mg kg ‐1 s.c.). Both nitrous oxide and ketamine dose-dependently increased c-Fos expression in PC/RS cortices; in contrast, xenon produced no significant effect. If the dopamine receptor antagonist haloperidol was given before either nitrous oxide or ketamine, their neurotoxic effects were eliminated. Conclusions. Uniquely amongst anaesthetics with known NMDA receptor antagonist action, xenon exhibits neuroprotective properties without co-existing neurotoxicity. The reason why ketamine and nitrous oxide, but not xenon, produce neurotoxicity may involve their actions on dopaminergic pathways. Br J Anaesth 2002; 89: 739‐46

Effects of high inspired oxygen fraction during elective Caesarean section under spinal anaesthesia on maternal and fetal oxygenation and lipid peroxidation

Abstract: Background. Oxygen supplementation is given routinely to parturients undergoing Caesarean section under regional anaesthesia. While the aim is to improve fetal oxygenation, inspiring a high oxygen fraction (FIO2 ) can also increase free radical activity and lipid peroxidation in both the mother and baby. In this prospective, randomized, double-blind study, we investigated the effect of high inspired oxygen fraction (FIO2 ) on maternal and fetal oxygenation and oxygen free radical activity in parturients having Caesarean section under spinal anaesthesia. Methods. Forty-four healthy parturients were randomized to breathe either 21% (air group) or 60% oxygen (oxygen group) intraoperatively via a ventimask. Maternal arterial blood was collected at 5-min intervals from baseline until delivery, and umbilical arterial and venous blood was collected at delivery. We measured blood gases and the products of lipid peroxidation (8-isoprostane, malondialdehyde (MDA), hydroperoxide (OHP)) and purine metabolites. Results. At delivery, the oxygen group had greater maternal arterial PO2 [mean 30.0 (SD 6.3) vs 14.2 (1.9) kPa; mean difference 15.8 kPa, 95% confidence interval 12.9‐18.7 kPa, P<0.001] and greater umbilical venous PO2 [4.8 (1.0) vs 4.0 (1.4) kPa; mean difference 0.8 kPa, 95% confidence interval 0.0‐1.5 kPa, P=0.04] compared with the air group. Maternal and umbilical plasma concentrations of lipid peroxides (8-isoprostane, MDA, OHP) were greater in the oxygen group than in the air group (P<0.05). Conclusions. We conclude that breathing high FIO2 modestly increased fetal oxygenation but caused a concomitant increase in oxygen free radical activity in both mother and fetus. Br J Anaesth 2002; 88: 18‐23

How reliable is length-based determination of body weight and tracheal tube size in the paediatric age group? The Broselow tape reconsidered

Abstract: Background The Broselow tape was designed to estimate body weight and tracheal tube size on the basis of the body length of emergency paediatric patients. The tape was validated previously in US populations. We assessed its accuracy in a sample of European children by reviewing paediatric anaesthetic charts at the Triemli City Hospital for 1999. Methods Age, body length and body weight measured before surgery as well as the size of the tracheal tube used were recorded. The body weight was estimated on the basis of body length using the Broselow tape and was compared with the measured weight. Tracheal tube size selections using the Broselow tape and an age-based formula were compared with the size of the tube used. Results A good correlation was found between the Broselow weight and the measured weight (r2=0.88). Bland–Altman analysis revealed a mean bias of –0.52 kg for the entire study population. For children ≤20 kg the mean bias was –0.05 kg, and for children >20 kg was –1.05 kg. The Broselow weight was found to be within a 10% error of the measured weight in 65% of children. Tracheal tube selection by the Broselow tape method was adequate in 55% but underestimated the actual tube size in 39%. The age-based formula matched the actual tracheal tube size in 41% of children but overestimated it in 57%. Conclusions The Broselow tape is an accurate means to assess body weight from length in smaller children; in older children it underestimated body weight. Endotracheal tube size selection by the Broselow tape appears to match the size of the tube used better than the age-based formula. The results in a European sample of children are comparable to the US data.

Optimizing fluid therapy in mechanically ventilated patients after cardiac surgery by on‐line monitoring of left ventricular stroke volume variations. Comparison with aortic systolic pressure variations

Abstract: Background Mechanical ventilation causes changes in left ventricular preload leading to distinct variations in left ventricular stroke volume and systolic arterial pressure. Retrospective off-line quantification of systolic arterial pressure variations (SPV) has been validated as a sensitive method of predicting left ventricular response to volume administration. We report the real-time measurement of left ventricular stroke volume variations (SVV) by continuous arterial pulse contour analysis and compare it with off-line measurements of SPV in patients after cardiac surgery. Methods SVV and SPV were determined before and after volume loading with colloids in 20 mechanically ventilated patients. Results SVV and SPV decreased significantly after volume loading and were correlated (r=0.89; P Conclusions Monitoring of SVV enables real-time prediction and monitoring of the left ventricular response to preload enhancement in patients after cardiac surgery and is helpful for guiding volume therapy.

Heat stroke: implications for critical care and anaesthesia

Abstract: Heat-related illnesses, such as heat stroke, are relatively uncommon in temperate climates. Much of the clinical experience comes from Saudi Arabia (where there is an annual pilgrimage to Mecca) and the military. Case reports and review articles are not commonly seen in anaesthesiarelated journals. The intention of this article is to review the available literature on heat stroke and to discuss its relationship with other hyperthermic syndromes, such as malignant hyperthermia.