Summary

Background and objective: To produce up-to-date clinical practice guidelines on the prevention of venous thromboembolism in surgery and obstetrics. Methods: A Steering Committee defined the scope of the topic, the questions to be answered, and the assessment criteria. Eight multidisciplinary working groups (total of 70 experts) performed a critical appraisal of the literature in the following disciplines: pharmacology of antithrombotic agents, orthopaedics; general surgery (gastrointestinal (GI) and varicose vein surgery); urology; gynaecology and obstetrics; thoracic, cardiac and vascular surgery; surgery of the head, neck and spine; and surgery of burns patients. The resultant reports and guidelines were submitted for comment and completion of the Appraisal of Guidelines Research & Evaluation questionnaire to a total of 150 peer reviewers, before producing definite guidelines. Results: The report answers the following questions for each type of surgery: (i) What is the venous thromboembolism incidence according to clinical and/or paraclinical criteria in the absence of prophylaxis? (with stratification of venous thromboembolism risk into low, moderate and high categories); (ii) What is the efficacy and safety of the prophylactic measures used? (iii) When should prophylaxis be introduced and how long should it last? (iv) Does ambulatory surgery affect efficacy and safety of prophylaxis? Conclusions: Apart from answering the above questions, the guidelines provide a summary table for each discipline. This table stratifies types of surgery into the three risk categories, specifies the recommended prophylaxis for venous thromboembolism (pharmacological and/or mechanical) and grades each recommendation. In addition, whenever appropriate, the recommended prophylaxis is adjusted to low- and high-risk patients.

Summary

Background and objective: The enzyme haeme oxygenase-1 is highly inducible by oxidative agents. Its product carbon monoxide is thought to exert anti-inflammatory properties. We recently showed, that critically ill patients produce higher amounts of carbon monoxide compared to healthy controls. In the present study we compare endogenous carbon monoxide production with the severity of illness of intensive care unit patients. Methods: Exhaled carbon monoxide concentration was measured in 95 mechanically ventilated, critically ill patients (mean age ± SD, 59.5 ± 15.7) on a carbon monoxide monitor. Measurements were taken every hour for 24 h in each patient. Data were analysed using Mann–Whitney rank sum test. Correlation analysis was performed with the Spearman's rank order correlation. Results: Carbon monoxide production correlated weakly with the multiple organ dysfunction score (R = 0.27; P = 0.009). Patients suffering from cardiac disease (median 22.5, interquartile range 16.2–27.4 μL kg−1 h−1 vs. median 18.2, interquartile range 14.2–21.8 μL kg−1 h−1, P = 0.008) and critically ill patients undergoing dialysis (median 25.0, interquartile range 21.4–30.2 μL kg−1 h−1, vs. median 19.4, interquartile range 14.7–23.3 μL kg−1 h−1, P = 0.004) produced significantly higher amounts of carbon monoxide compared to critically ill controls. Conclusion: The findings suggest that endogenous carbon monoxide production might reflect the severity of acute organ dysfunction.

Summary

Background and objective: Inhalation anaesthetics given only during post-ischaemic reperfusion have some protective effect against reperfusion injury in the heart. Adenosine triphosphate-regulated mitochondrial potassium channels have been shown to be an important mediator of cardioprotection. Thus, we investigated whether 5-hydroxydecanoate, a putative mitochondrial potassium channel blocker, prevents the cardioprotective effect of volatile anaesthetics. Methods: Forty rats were randomly allocated to four groups of equal size: control group, 5-hydroxydecanoate group, 5-hydroxydecanoate + sevoflurane group and 5-hydroxydecanoate + isoflurane group. Seven minutes after the start of perfusion, normal saline (control group) or 5-hydroxydecanoate (the other groups) was administered. Ten minutes after the start of perfusion, the heart was rendered globally ischaemic for 10 min. One minute before the end of the ischaemic period, 2.7% sevoflurane or 1.4% isoflurane were administered in the 5-hydroxydecanoate + sevoflurane or 5-hydroxydecanoate + isoflurane groups respectively. The heart was reperfused for 10 min. Results: Adenosine triphosphate content at the end of reperfusion in the 5-hydroxydecanoate + sevoflurane group was significantly lower (P < 0.05) than those in the control and the 5-hydroxydecanoate + isoflurane groups (19.9 ± 8.7, 28.1 ± 3.4 and 30.4 ± 2.3 μmol g−1, respectively). In addition, the combination of inhalation anaesthetics and 5-hydroxydecanoate decreased the ratios of recovered hearts from ischaemia (5-hydroxydecanoate + sevoflurane group: 40%, 5-hydroxydecanoate + isoflurane group 50%). Conclusion: 5-hydroxydecanoate alone caused no significant changes in haemodynamics and myocardial metabolism. However, the combination of 5-hydroxydecanoate and volatile anaesthetics impaired the recovery from ischaemia. Although animal data cannot be extrapolated to human beings, we suggest that more attention be paid to patients on sulphonylurea drugs, which inhibit potassium channels, when they are anaesthetized with volatile anaesthetics.

Summary

Background and objective: We conducted this study in order to evaluate the potential myotoxic effects of ropivacaine after single injection in rats and the time-course of the possible damage. Methods: One hundred and twenty-eight male Wistar rats were allocated to four different groups. The first three groups received intramuscular injections with ropivacaine 0.75%, ropivacaine 0.5% and normal saline, respectively, into the right tibialis anterior muscle. The fourth group received needle puncture without injection. Eight rats from each group were sacrificed 2, 4, 7 and 30 days after injection. Samples were blindly examined under light microscope for evidence of myotoxicity, scored as 0 = no damage to 3 = myonecrosis and statistically analysed. Samples obtained 7 days after injection were also examined under transmission electron microscope. Results: Ropivacaine 0.75% and ropivacaine 0.5% caused extensive destruction to muscles fibres, compared to saline or needle on days 2, 4 and 7. Statistically significant differences were found in muscle damage by drug injections among all groups except for saline vs. needle groups. Thirty days after injections all sample appearances had returned to normal. Conclusions: Ropivacaine after single intramuscular injection caused reversible muscle damage in a dose-dependent manner.

Summary

Background and objective: Gabapentin has been suggested to decrease acute postoperative pain. We evaluated the effect of gabapentin on pain after abdominal hysterectomy. Methods: Sixty patients scheduled for abdominal hysterectomy were randomized to receive orally gabapentin 400 mg 6 hourly or placebo. Treatment started 18 h preoperatively and continued for 5 postoperative days. Pain (visual analogue score) and consumption of morphine for 48 h and of oral paracetamol/codeine were recorded after 2, 4, 8, 24 and 48 h and on days 3–5 postoperatively. After 1 month, patients were interviewed by phone for pain, and analgesic intake after hospital discharge. Results: Morphine consumption (mean ± SD) was 35 ± 15.7 mg in the control and 28 ± 12.1 mg in the gabapentin group (P = 0.21). Median number (range) of paracetamol 500 mg/codeine 30 mg tablets taken during days 3–5 was 1.0 (0–6) in the control and 2.0 (0–9) in the gabapentin group (P = 0.35). The visual analogue scores at rest and after cough did not differ between the two groups (F = 0.92, df = 1, P = 0.34 and F = 0.56, df = 1, P = 0.46, respectively). One month after surgery, 22/27 (81%) of the control group and 9/25 (36%) of the gabapentin group reported pain in the surgical area (χ2 = 11.15, P = 0.002), while 11/27 (41%) of controls and 7/25 (28%) of gabapentin patients consumed analgesics for pain (χ2 = 0.93, P = 0.39). The intensity of pain was decreased in the gabapentin group (χ2 = 12.6, P = 0.003). Conclusions: Gabapentin has no effect on immediate pain after abdominal hysterectomy but decreases pain 1 month postoperatively.

Summary

Background and objective: Quality of acute pain management is far from being satisfactory. These deficits are not caused by the complexity of the medical problem but by difficulties in organization and hospital structures, sand procedures. Continuous quality improvement is a recommended tool to overcome such difficulties and to increase quality in the long run. This study reports the implementation of benchmarking-based continuous quality improvement to improve postoperative pain management at a university hospital. Methods: A specialised pain nurse interviewed patients of three surgical departments on the first day after surgery, and continuously assessed process and outcome quality parameters. A multidisciplinary team of anaesthetists, surgeons, nurses and pharmacists implemented a regular procedure of data analysing and internal benchmarking. Results and suggested improvements were fed back to the healthcare teams. Results: From 1998 to 2002, 6756 patients were assessed. Average pain on ambulation and maximal pain were 3.7 ± 2.4 and 5.0 ± 2.5 (mean ± SD) on a 11-point numeric rating scale. Pain intensity at rest was 1.9 ± 1.8. Over time, pain intensity on ambulation decreased (P = 0.022) whereas maximal pain and pain at rest remained unchanged. There was an increase in the number of patients who received non-opioid analgesia (P < 0.001). Conclusions: A continuous quality improvement process could be established and is now successfully used in clinical routine. Cornerstones of this project were frequent assessments of process and outcome parameters, regular benchmarking and implementation of feedback mechanisms. Changes in organization of medical management and multidisciplinary teamwork seem to be more important than medical or technical aspects.

Summary

Background and objective: This placebo-controlled study was performed to evaluate the efficacy of dexmedetomidine compared with meperidine and placebo in preventing postanaesthetic shivering. Methods: We studied 120 patients (ASA I–II) scheduled for elective abdominal or orthopaedic surgery of about 1–3 h duration. Forty patients in each group randomly received 1 μg kg−1 of dexmedetomidine, 0.5 mg kg−1 of meperidine or saline 0.9% as placebo, intravenously (i.v.). Mean arterial pressure, heart rate, oxygen saturation and central body temperature were measured. Extubation, awakening and orientation times, shivering, pain, recovery and sedation scores were recorded. Results: Postanaesthetic shivering was seen in 22 patients in the placebo group, four patients in the meperidine group and six patients in the dexmedetomidine group. Sedation scores were significantly higher in the dexmedetomidine group compared with meperidine and placebo groups. Both dexmedetomidine and meperidine caused a significantly prolonged extubation and awakening time compared with placebo. Also, dexmedetomidine caused a significantly prolonged orientation time compared with other two groups. Conclusion: Intraoperative intravenously administration of dexmedetomidine 1 μg kg−1 reduces postanaesthetic shivering as does meperidine 0.5 mg kg−1 in patients after major surgery.

Summary

Background and objective: Patients have the right to be informed about the expected benefits and risks of medical and surgical procedures. Ideally this information should be scientifically based and presented to the patient in time. In morbidly obese patient undergoing general anaesthesia, postoperative pulmonary complications are an important cause of postoperative morbidity and mortality. A 46-yr-old female with a body mass index of 89.8 kg m−2 was scheduled to undergo radical abdominal surgery for cervix carcinoma. In order to inform her accurately on the risk of developing postoperative pulmonary complications, we undertook to answer the following question: What is the risk to develop postoperative pulmonary complications in a morbidly obese patient about to undergo abdominal surgery under general anaesthesia? Methods: A Medline search was conducted from 1966 to 2004 with respect to postoperative pulmonary complications in abdominal surgery of morbidly obese patients. Altogether, 213 articles were found, of which seven were selected. Additionally, seven cross-references and or related articles were used. Results: For obese patients who undergo abdominal surgery under general anaesthesia, the likelihood to develop atelectasis is 10.4 ± 4.8% (P < 0.001) with a correlation coefficient of 0.28–0.34 (P < 0.05). The likelihood to develop atelectasis and pneumonia taken together is 29.3% with an adjusted odds ratio of 2.82 (95% confidence interval 1.66–4.78; P = 0.0001). Conclusion: Considering the positive correlation coefficient and the high body mass index of this patient she has a risk of at least 29.3% to develop pneumonia and/or atelectasis, which should affect the anaesthetic strategy in this patient.

Summary

Background and objective: Recently published guidelines for checking anaesthetic equipment do not contain specific advice on how to check the correct functioning of the capnograph before inducing anaesthesia. Methods: We undertook a postal survey of UK consultant (physician) anaesthetists to establish what methods for checking the capnograph are currently in use. Two hundred and two questionnaires were sent to consultants in different hospitals and 163 returned, a response rate of 81%. Results: 52.1% consultants of check the capnograph themselves. Of these, 55.3% use their own expired breath to confirm a response to carbon dioxide. Other methods used by consultant anaesthetists to check capnograph function include the machine self-test (16.5%), visual checks of the capnograph and sampling tubing (10.3%), and sampling of patient expired carbon dioxide (7.1%). Conclusion: The most common method for testing capnograph function among consultant anaesthetists and their assistants in the UK is the direct measurement of exhaled breath.

Summary

Background and objectives: The potential for increased drug administration errors during the transition to the International Colour Coding syringe labelling system has been highlighted. The purpose of this study was to assess the potential effects before their introduction into our department. Methods: Thirty-one anaesthetists, 19 with no previous practical experience of the new labelling system (Group 1), and 12 with previous experience (Group 2), volunteered to induce general anaesthesia for a standardized simulated patient in a designated theatre. They were presented with a scenario designed to suggest the need for a rapid sequence induction and provided with drug syringes labelled with the International Colour Coding system. All drug administrations were recorded. Active error was defined as the injection of the wrong drug. Latent error was defined as the selection of a syringe in error but stopping short of administering the drug. Results: In Group 1 a total of 107 drug injections were recorded of which 1 (0.9%) was an active error and 16 (15%) involved latent errors. Eleven anaesthetists (58%) performed at least one latent error. Group 2 had an error rate of 3%, a 6.9 (1.3–26.7) fold reduction in the rate of error (P = 0.023). Conclusions: Although only one drug was given in active error, latent errors occurred in 15% of drug administrations. The only factor conferring protection against error was prior experience of the new labelling system. The period of transition to the International Colour Coding syringe labelling system represents a time of increased risk of drug administration error.

Summary

Background and objective: We conducted a study investigating the effectiveness of four face mask designs in the bag-mask ventilation of a special manikin adapted to simulate a difficult airway. Methods: Forty-eight anaesthetists volunteered to bag-mask ventilate the manikin for 3 min with four different face masks. The primary outcome of the study was to calculate mean percentage leak from the face masks over 3 min. Anaesthetists were also asked to rate the face masks using a visual analogue score. Results: The single-use scented intersurgical face mask had the lowest mean leak (20%). This was significantly lower than the mean leak from the single-use, cushioned 7000 series Air Safety Ltd. face mask (24%) and the reusable silicone Laerdal face mask (27%) but not significantly lower than the mean leak from the reusable anatomical intersurgical face mask (23%). Conclusions: There was a large variation in both performance and satisfaction between anaesthetists with each design. This highlights the importance of having a variety of face masks available for emergency use.