Summary

Background and objective: To study the effect of age and other risk factors on: (a) the incidence and outcome of cardiopulmonary resuscitation and (b) any decision to institute a ‘Do Not Attempt Resuscitation’ order following cardiac surgery.

Methods: Prospective audit of cardiac arrest calls following 6550 consecutive open-heart surgery cases and retrospective audit of all cardiac surgical deaths not preceded by cardiac arrest calls.

Results: One-hundred-and-seventy-four patients (2.7%) had audited cardiac arrests of whom 70 (40%) survived to discharge. Elderly patients (≥70 yr old) had higher incidence of cardiac arrest (3.8% vs. 2%, P < 0.001). Survival to discharge following cardiopulmonary resuscitation was lower in the elderly patients, 33% vs. 48%, the difference approaching statistical significance (P = 0.06). Cardiopulmonary resuscitation was withheld in 46% of elderly vs. 40% of younger deaths (P = 0.40) which represented 3.1% of elderly vs. 1.2% younger patients (P < 0.001). Similar proportions of elderly (62%) and younger (67%) patients had failure of ≥3 organ systems on institution of the ‘Do Not Resuscitate’ order (P = 0.70).

Conclusion: ‘Do Not Resuscitate’ orders appeared twice as frequently in elderly patients (≥70 yr). However, the proportions of deaths without cardiopulmonary resuscitation and the organ failure scores between age groups were similar suggesting that severity of illness was more important than age in determining resuscitation status.

Diabetes mellitus is the most common metabolic disease and its incidence is increasing. New classifications have been recently proposed based upon a better knowledge of pathogenesis, mechanisms of glucose transport and insulin resistance. The perioperative care of diabetic patients is less dependent on blood-glucose control, which needs to be exceptionally tight, and is usually easily obtained thanks to pharmacological improvements, human insulins and analogues, technical progress with blood-glucose monitoring at the bedside and infusion with constant flow rates. More important is the influence of end-organ pathology, often clinically silent, which must be carefully assessed during the preoperative evaluation. The organ impairments concern especially the heart, but also all those organs that were modified by abnormal glycosylated proteins. The pre-existing pathology has many consequences on anaesthesia management; the anaesthetic technique depends essentially on their existence. A better long-term control of diabetes both for Type 1 and Type 2 by insulins, and the new oral anti-diabetic drugs reduce the incidence of the end-organ pathology and the risk linked to organ failures in the perioperative period.

Dimenhydrinate is an inexpensive antihistaminic drug, that is frequently used as an anti-emetic during anaesthesia. The popularity of the drug is contrasted by the lack of modern studies concerning its efficacy in reducing the incidence of post-operative nausea and vomiting. Thus, dimenhydrinate was compared with placebo in this prospective, randomized, double-blind study. One hundred and thirty-three female in-patients were studied. They were stratified according to the type of surgery (laparoscopic cholecystectomy, thyroid resection or knee arthroscopy) to ensure an homogenous distribution in both groups. General anaesthesia was induced with etomidate, fentanyl, vecuronium and maintained with enflurane in N2O/O2. Neuromuscular block was reversed with pyridostigmine/atropine. Patients in the dimenhydrinate group (n=67) received 62 mg dimenhydrinate intravenously after induction of anaesthesia. Placebo patients (n=66) received saline. Administration of dimenhydrinate (and placebo) was repeated three times during the 48-h study to mitigate the short half-life of the drug. Post-operative analgesia and anti-emetic rescue medication was standardized. Episodes of vomiting, retching and the need for additional anti-emetics were recorded. Nausea was assessed using a 10-cm visual analogue scale. Post-operative nausea and vomiting was rated as ‘none’, ‘mild’, ‘moderate’ and ‘severe’ using a fixed scoring algorithm. There were no differences between the two groups with regard to biometric data, type of surgery and distribution of risk factors for developing post-operative nausea and vomiting. In the dimenhydrinate group, more patients remained completely free from post-operative nausea and vomiting compared with placebo (dimenhydrinate: 38.8%; placebo:15.1%; P=0.004). The incidence of severe post-operative nausea and vomiting was also reduced from 39.4% to 14.9%. No relevant side effects were observed. Intra-operative dimenhydrinate, followed by three further administrations after surgery, reduces the incidence and the severity of post-operative nausea and vomiting without side effects. However, there still remained an unacceptable high number of patients who were not prevented completely from experiencing post-operative nausea and vomiting.

Background and objective: Computers offer the potential for the assessment of children who have difficulties in communication and cannot describe pain using conventional approaches. Such approaches must be reliable and valid. As a preliminary step towards this goal, the validity and reliability of a computer-assisted pain assessment for children (MacInterview) was assessed using children with no known disabilities who had undergone surgery.

Methods: MacInterview uses body outlines and a range of different pain representations with scaling for size and intensity, and associated emotion. Following piloting with non-clinic children, the experience of acute postoperative pain was assessed for 30 children undergoing adenotonsillectomy or tonsillectomy the day following surgery using the MacInterview and three existing standardized assessment measures. Each child self-reported their current experience of postoperative pain on two occasions 30 min apart, and retrospectively on pain the previous evening in the immediate postoperative period.

Results: Analyses indicated good performance of MacInterview, showing positive correlations between 0.65 and 0.88 with standardized pain-intensity measures, and test-retest reliability was 0.9. Face validity was high, and children enjoyed the procedure.

Conclusions: The procedure shows promise and is likely to merit further development for children showing difficulties in communication.

Amide local anaesthetics inhibit platelet function. We hypothesized that residual anaesthetic in the epidural space could decrease efficacy of an epidural blood patch in preventing postdural puncture headache. Levobupivacaine has recently been approved for epidural anaesthesia. Its effects on coagulation have not previously been studied. The aim of this study was to determine the effects of levobupivacaine on clotting using thromboelastography. Ten ASA Class I volunteers were studied. Venous blood samples were analysed using a Haemoscope 2000D TEG analyser. Whole blood, a 50% saline control and two levobupivacaine solutions (2.5 mg mL−1 and 2.5 μg mL−1 in blood) were compared. The former reproduces that produced in the epidural space by blood (20 mL for an epidural blood patch) and levobupivacaine 0.5% (20 mL). The latter approximates plasma concentrations following epidural injection of levobupivacaine 0.5% (20 mL). P < 0.05 was considered significant. Maximum amplitude (MA), a measure of clot strength, is decreased by levobupivacaine 2.5 mg mL−1. Levobupivacaine 2.5 mg mL−1 decreases clot strength and may reduce efficacy of a prophylactic epidural blood patch.

The effects of intravenous and epidural clonidine, 4 μg kg−1, combined with epidural morphine, 40 μg kg−1, on the neuro-endocrine and immune stress responses to thoracic surgery are reported. A control group received only epidural morphine. Anaesthesia was induced and maintained with propofol. Catecholamines, vasopressin, cortisol, β-endorphin concentrations and leucocyte counts were measured before drug administration, immediately after intubation of the trachea, after thoracotomy and at the end of surgery. Catecholamines did not change in any of the groups. The other stress hormones increased during surgery, the pattern being similar in the three groups. Total leucocyte and neutrophil counts were increased in all groups at the end of surgery, but the increase was least in the epidural clonidine group. The number of lymphocytes was reduced at the end of surgery in the epidural and intravenous group, compared with the control group in which the number of lymphocytes did not change. The effects are more pronounced with epidural than with intravenous administration. We conclude that clonidine can modulate the immune stress response to thoracic surgery.

The anti-emetic effects of ondansetron and droperidol were evaluated in 134 ASA Grade I and II female patients, scheduled for laparoscopic cholecystectomy and minor gynaecological laparoscopic surgery, who were randomly assigned to receive ondansetron 4 mg or droperidol 75 μg kg−1 intravenously immediately after induction of anaesthesia. The patients were assessed 1, 6, 12 and 24 h after surgery for intensity of nausea and number of vomiting episodes. In the case of the patients undergoing laparoscopy, vomiting episodes occurred in a similar proportion in patients treated with ondansetron or droperidol, with the probability of the Type I error of 0.05 and the Type error II of 0.1. Although there was no difference between the two groups in emetic episodes following all laparoÍscopic procedures and gynaecological laparoscopic surgery, there was a significant difference between these parameters after laparoscopic cholecystectomy. The patients treated with ondansetron experienced a lower intensity of nausea (P=0.04) after laparoscopic cholecystectomy, less frequent severe nausea (P=0.02) and episodes of vomiting (P=0.04) when compared with those in the droperidol group. We conclude, that despite the result the droperidol prophylaxis appears to be an effective alternative to ondansetron in all patients undergoing laparoscopy, the ondansetron prophylaxis is superior to droperidol in patients undergoing laparoscopic cholecystectomy.

Summary

Background and objective: Articaine is an amide local anaesthetic widely used in dentistry. Human ether-a-go-go-related gene (HERG) potassium channels constitute potential targets involved in cardiotoxic side-effects of various pharmacological agents including amide local anaesthetics. The aim of this study was to determine the sensitivity of HERG channels to the inhibitory action of articaine and to further evaluate the effect of the mutations Y652A and F656A in the putative drug-binding region of HERG on the sensitivity for articaine. Methods: We examined the inhibition of wild-type and mutant HERG channels, transiently expressed in Chinese hamster ovary cells by articaine. Whole cell patch-clamp recordings were performed at room temperature. Results: Inhibition of HERG wild-type and HERG Y652A channels by articaine was concentration dependent and reversible. The concentration-response data were described by Hill functions (wild type: IC50 = 224 ± 6 μmol L−1, Hill coefficient h = 1.17 ± 0.03, n = 23; Y652A: IC50 = 360 ± 48 μmol L−1, h = 0.93 ± 0.08, n = 26). The mutation Y5652A decreased the sensitivity by factor 1.6. The mutation F656A decreased inhibition of inward tail currents by 300 μmol L−1 articaine in 100 mmol extracellular K+ 3-fold. Conclusions: Our results indicate that the local anaesthetic articaine does not inhibit HERG channels at clinically relevant concentrations. Articaine may therefore constitute a safer alternative for local and regional anaesthesia. The aromatic amino acid F656 rather than Y652 in the S6 region might play a role in interaction of the drug with the channel.

The delivery of an hypoxic gas mixture to a patient during general anaesthesia is a rare event due to contemporary standards of monitoring, equipment design and alarm features. An incident is described where a split occurred in a rubber seal round the top of a flowmeter control tube. This resulted in a downstream oxygen leak and the delivery of an hypoxic gas mixture to the patient. The bobbin on the oxygen flowmeter did not accurately reflect the amount of oxygen being delivered. A paramagnetic oxygen analyser and a fuel cell oxygen electrode indicated that the inspired oxygen concentration was lower than intended. The anaesthetic machine was exchanged, and the operation continued uneventfully. The faulty anaesthetic machine subsequently passed a formal pressure test by the hospital engineers and also close examination of the flowmeter control valves. The importance of monitoring equipment and the interpretation of the information that they provide is emphasized.

In order to compare the neuromuscular effects following rocuronium 0.6 mg kg−1 and atracurium 0.5 mg kg−1 30 children aged from 18 to 67 months were studied under the same anaesthetic conditions. After induction of anaesthesia with etomidate and fentanyl, neuromuscular blockade was monitored by recording the electromyographic response of the adductor pollicis muscle to a supramaximal train-of-four (TOF) stimulation of the ulnar nerve at 2 Hz for 2 s at 20-s intervals. Intubation was performed when more than 90% muscle relaxation was achieved, thereafter anaesthesia was maintained with 70% nitrous oxide in oxygen and isoflurane 0.5% end-tidal. Mean onset of action was significantly faster following rocuronium (86±44.9 s) (mean±SD) compared with atracurium (126.3±61.0 s). Clinical duration with rocuronium was 22.8±5.31 min and thus significantly shorter than that of atracurium, which was 31.5±6.01 min. A statistically significant difference between rocuronium and atracurium also had been found for recovery of T1 to 50%, 75% and 90% as well as for the time taken to a TOF ratio of 70%. The recovery index for rocuronium and atracurium was not significantly different with 9.2±3.43 min and 10.9±2.65 min, respectively. Thus, rocuronium may be more advantageous than atracurium for short-lasting surgical procedures in young children.

Summary

Background and objective: The purpose of the present study was to determine the pharmacokinetics of the μ-agonist opioid pirinitramide (piritramide) after prolonged administration.

Methods: Nine patients requiring intensive care therapy and artificial ventilation for several days received piritramide with a median infusion rate of 5 mg h−1 (range 4.8–10 mg h−1) for a median period of 69.9 h (range 49–89 h) for analgesia and sedation. After the end of the infusion, frequent arterial blood samples were withdrawn for 96 h and assayed for piritramide using a gas chromatographic method. Standard compartmental models were fitted to the individual concentration–time courses to characterize the elimination of piritramide after prolonged administration.

Results: The concentration–time course after the end of the infusion was adequately described with a three-compartment model in eight patients and a two-compartment model in one patient (standard two-stage geometric mean and 16–84% quantile: volumes of distribution V1 = 47.9 (26.8–85.8) L, V2 = 402 (241–672) L, V3 = 332 (124–885) L; clearances Cl1 = 66.5 (53.2–83.0)L h−1, Cl2 = 215 (125–369)L h−1, Cl3 = 18.4 (9.2–36.8) L h−1). Both the steady-state volume of distribution (782 L) and the terminal elimination half-life (17.4 h) were larger than predicted from single bolus pharmacokinetic studies (412.5 L and 10.4 h, respectively), the context-sensitive half-time after more than 72 h of administration was 32% shorter than predicted (285 vs. 420 min).

Conclusions: Despite increasing terminal elimination half-life and volume of distribution at steady state (increasing drug load for a given plasma concentration), the context-sensitive half-time of piritramide after3 days of administration is lower than predicted from bolus kinetics, making the drug a suitable candidate for intensive care unit analgesia.

Summary

Background and objective: The Eschmann multiple-use introducer is widely used in the management of difficult intubations. Transillumination of the neck is less commonly used. We conducted a randomized crossover study comparing the Trachlight® lightwand and Eschmann multiple-use introducer in simulated difficult intubation. Methods: Sixty-four healthy patients were studied using a standard anaesthetic and full muscle relaxation assessed by train of four. A Macintosh laryngoscope was then inserted and then lowered to simulate a Grade 3 view. Tracheal placement was attempted with both Trachlight® lightwand and Eschmann multiple-use introducer in a randomized order. Anaesthetists placing the devices had extensive experience with the Eschmann multiple-use introducer, but only 15 previous uses of the Trachlight®. Success rates and time for tracheal placement were recorded. Results: The Eschmann multiple-use introducer and Trachlight® were successfully placed in 96.8% and 93.7%, respectively (n.s.). Mean (SD) time to intubation for Eschmann multiple-use introducer and Trachlight® were 15(6) and *21(13), respectively (*P < 0.001). Conclusion: The Trachlight® is a potentially useful alternative to the Eschmann multiple-use introducer in difficult intubation.

The Section and Board of Anaesthesiology of the European Union of Medical Specialists aims (EUMS/UEMS) at harmonization of training of anaesthesiologists and at improvement of patient care throughout Europe. Pain medicine is considered to be an area of expertise in anaesthesiology although exclusivity is not claimed. The Section and Board has approved both a core syllabus for pain medicine to be part of the specialist training in anaesthesiology and an additional qualification in pain medicine following the completion of a 5 yr basic specialty training in anaesthesiology. These proposals were prepared by the Working Party on Pain Medicine of the Section and Board. It considers a multidisciplinary approach to pain to contribute to quality in care and has taken the initiative to set up a Multidisciplinary Joint Committee on Pain Medicine within the EUMS/UEMS, for which these guidelines define the area of expertise of anaesthesiology.