Summary

Background and objectives: Positive end-expiratory pressure may alter cardiac function and systemic haemodynamics. As transplanted livers may be sensitive to liver congestion, the aim of our study was to evaluate the effect of positive end-expiratory pressure on the cardiovascular system and in particular on central venous and iliac venous pressure in liver transplanted patients. Patients and methods: Seventy-two liver transplant patients were enrolled in this prospective, interventional study. On admission to our Intensive Care Unit all patients were ventilated in a biphasic positive airway pressure mode. Haemodynamic effects of three randomly set levels of end-expiratory pressures (0, 5 and 10 mbar) were studied in the immediate postoperative period in all patients. Mean arterial pressure, central venous pressure, pulmonary capillary wedge pressure, central iliac venous pressure and cardiac index were recorded and analysed at each of the three end-expiratory pressure levels. Results: The values of central- and wedge-pressure significantly increased with increased end-expiratory pressure. Central venous pressure increased by 24% and wedge pressure showed a 6% increase at 10 mbar in comparison to 0 mbar. The values for cardiac index and mean arterial pressure showed no statistically significant difference at 10 mbar as compared to 0 and 5 mbar. The mean pulmonary arterial and common iliac venous pressure were unaffected by different positive end-expiratory pressure levels. Conclusions: Short-term pressure controlled ventilation with end-expiratory pressure up to 10 mbar does not significantly impair systemic haemodynamics in liver-transplanted patients. Further studies are needed to determine whether these findings could be confirmed with higher pressure levels and/or over a longer period of ventilation time.

Anaesthesia is a medical specialty that is particularly concerned with the safety of the patient who is undergoing a surgical procedure. This is a prerequisite in order to provide quality of care, which is based on good clinical practice, on a sound organization, on an agreement on best practice and on adequate communication with other healthcare workers involved. Providing a safe environment for those working in healthcare is at least as important as other factors serving that objective. A working party on Safety and Quality in Anaesthesiological Practice in the Section and Board of Anaesthesiology of the European Union of Medical Specialists (EUMS/UEMS) has prepared guidelines that were amended and approved recently.

Summary

Background and objectives: A recent survey in the British Medical Journal reported the attitudes of orthopaedic surgeons towards the intraoperative death of a patient. Several replies to this article were from anaesthetists, who pointed out that other staff might be affected by ‘death on the table’. We designed a questionnaire survey to assess the attitudes of anaesthetists, concerning intraoperative death. Methods: Three hundred anonymized questionnaires were distributed to 12 anaesthetic departments throughout England. Results: Two hundred and fifty-one replies were received (84% response rate); 92% of respondents had experienced an intraoperative death, the majority of deaths being expected (60%) and non-preventable (77%), occurring mainly during emergency surgery (80%), particularly involving vascular surgery (41% of cases); 87% had administered another general anaesthetic in the following 24 h, most without their professional ability being compromised (77%). Conclusions: This survey shows that anaesthetists are highly likely to experience intraoperative death, the consequences of which can be extremely stressful. Although the majority of anaesthetists (71%) agreed that it was reasonable for medical staff not to take part in operations for 24 h after an intraoperative death, fewer (25%) thought the proposal practicable. Nevertheless, all departments should provide for the discontinuation of further operations, if the circumstances require it. Consideration should be given by all departments of anaesthesia towards the prevention of intraoperative death, and the management of its aftermath, including the provision of support for psychologically traumatized staff.

Summary

Background and objective: To evaluate the feasibility of an abbreviated focus assessed transthoracic echocardiographic protocol, consisting of four standardized acoustic views for cardiopulmonary screening and monitoring.

Methods: The protocol was applied in 210 patients in a 20-bed multidisciplinary intensive care unit in a university hospital. When inconclusive, an additional transoesophageal echocardiographic examination was performed. Diagnosis, indication, acoustic window, position and value were recorded. Significant pathology, load, dimensions and contractility were assessed.

Results: Two-hundred-and-thirty-three transthoracic and four transoesophageal echoes were performed. The protocol provided usable images of the heart in 97% of the patients, 58% subcostal, 80% apical and 69% parasternal. Images through one window were obtainable in 23%, through two windows in 41% and through three windows in 34%. In 227 patients (97.4%) the focus assessed echo protocol contributed positively. In 24.5% of cases the information was decisive, in 37.3% supplemental and in 35.6% supportive.

Conclusions: By means of an abbreviated, focus assessed transthoracic echo protocol it is feasible to visualize the haemodynamic determinants for assessment and optimization. One or more useful images are obtainable in 97% of critically ill patients.

Several studies have demonstrated that pre-operative fasting may be as short as 2 h for clear fluids and 6 h for solids with no adverse effect on volume or pH of gastric contents. Other studies suggest that many patients do not receive pre-operative prescribed medications. One hundred and fifty-three adults presenting for elective surgery (mean age 51 years) were studied to assess fasting practice. Fasting times far in excess of the recommended safe minimum were found. Mean length of fast for solids was 15 h 24 min (95% confidence intervals±49 min) and for fluids 12 h 30 min (95% confidence intervals±30 min). Of the 53 patients taking regular medications, 23 did not receive one or more drugs pre-operatively; most notably 45% of cardiac prescriptions were not administered. Despite strong evidence to support a change, actual practice continues to fall below accepted standards.

A review was undertaken of all 190 patients who were referred over 7 years, from 1991 to 1997 inclusive, for an epidural blood patch as a treatment for headache after dural puncture. The patterns of referral and symptoms, the distributions of age and gender and the effectiveness of the blood patch were examined. Most of the referrals (n=153) were after deliberate diagnostic dural puncture in neurology and neuroradiology, with a minority (n=28) used for anaesthesia and obstetrics, which were mostly inadvertent. Another nine cases were related to placement of an intrathecal catheter. The numbers of referrals per year reached a maximum in 1995 before falling again, a curious inverse relation to the number of invasive neuro-radiological diagnostic procedures. Most of the patients were between 30 and 50-years-old, with 25 younger than 30 and 14 older than 60. Women accounted for 70% of the referrals for headache, although the gender ratio amongst patients subjected to at risk procedures appeared closer to 50:50. Neckache accompanied the headache in 85% of cases, auditory problems were volunteered by three patients and one patient had diplopia for 6 weeks. Of the 190 patients who were referred, 186 received at least one patch, the symptoms in the remaining four being too mild or atypical to warrant blood patch treatment. This provided initial relief in all but two patients, one of whom received a further epidural blood patch with no effect. There was sustained relief of symptoms in 136 and a partial relapse in 38 patients, which resolved without needing any further blood patch. A second patch was provided for seven patients and a third for three patients, of whom two were cured. Of the patients who needed more than one blood patch, nine were after inadvertent dural puncture with a Tuohy needle and, of these patients, six were in labour. A total of 200 patches were provided in all for the 186 patients and all but three patients had a satisfactory outcome. Epidural blood patches are effective in treating headache after dural puncture, but less successful than is commonly believed, especially after inadvertent dural taps. A relapse after treatment does not always require a second patch. Specialities other than anaesthesia seemed reluctant to accept the benefits in both cost and comfort of using needles of improved design for dural puncture.

Background and objective: Clinical studies suggest that lidocaine may induce irreversible neurological damage after spinal application in human beings. The mechanisms underlying the possible cytotoxic action of lidocaine have only been suggested from animal studies. This study aimed to investigate if lidocaine exhibited cytotoxic action in a human model widely used for the study of neuronal apoptosis. This is important to know as it may help one to judge on possible neurotoxic risks imposed by the spinal application of lidocaine.

Methods: The concentration- and time-dependent effects of lidocaine on retinoic acid-differentiated human neuroblastoma SH-SY5Y cells were quantified by trypan blue staining, the release of lactate dehydrogenase, immunocytochemistry and flow cytometry.

Results: The local anaesthetic caused a significant increase in the number of cells staining positive for trypan blue, a significant increase of LDH release into the incubation medium, and a significant increase of 7AAD and annexin V binding. Lidocaine induced apoptosis already at 3 mm. At a concentration of 10 mmol 47% of the cells and at 30 mmol 98% of the cell population was necrotic. Both necrosis and apoptosis were time-dependent.

Conclusions: The results demonstrate that lidocaine exhibited neurotoxic effects in a human model established for the study of drug-induced neuronal apoptosis. The results were consistent with the neurotoxic clinical effects of lidocaine. These effects may be produced by more than a single mechanism.

A study of 56 patients was undertaken to determine whether there is a difference in the effect of the laryngeal mask airway and the endotracheal tube on the vocal tract after short-duration anaesthesia. All the patients were interviewed pre- and post-operatively.In 43 patients, it was possible to assess the larynx using videoendoscopy and videostrobolaryngoscopy both pre- and post-operatively. Selected acoustic characteristics were investigated in 51 patients pre- and 18–24 h post-operatively. Thirty-four patients that did not have anaesthesia were used as an age-matched control.

The interview showed, that patients in the LMA group complained less frequently of having post-operative complained less frequently of having post-operative demonstrated minor lesions of the vocal tract in six patients in the ETT group and in one patient in the LMA group. Of the 12 voice variables evaluated, there was no significant difference in any parameter between the two groups. Both groups had a higher fundamental frequency post-operatively.

Controversy persists over the efficacy of intercostal nerve block administered through a tunnelled extrapleural catheter. We have undertaken a randomized, prospective double-blind trial of two different local anaesthetic regimes to evaluate the effect of this technique on post-thoracotomy pain relief and pulmonary function. Sixty-eight patients were randomized to receive bupivacaine 0.25% (n=22), lignocaine 1% (n=21) or 0.9% NaCl (saline) (n=20) via an extrapleural catheter, inserted peroperatively. All patients underwent a standard posterolateral thoracotomy. Pain was assessed using a visual analogue pain score and by the requirement for opiate analgesia. Pulmonary function was measured using bedside spirometry. Pain scores were lower in the local anaesthetic groups at 24, 32 and 72 h compared with placebo (P< 0.05) and the total amount of opiate required was less than placebo for both lignocaine and bupivicaine (P< 0.05). Pulmonary function was better in the local anaesthetic groups throughout the post-operative period and was most pronounced at 24 h with a mean improvement of 30% for forced expiratory volume (FEV1), 24% for forced vital capacity (FVC) and 19% for peak expiratory flow rate (PEFR) compared with placebo. There was no significant difference between pain scores, opiate requirement or pulmonary function between lignocaine and bupivicaine. CT scanning demonstrated containment of the local anaesthetic in an extra-pleural tunnel. Extra-pleural infusion of local anaesthetics is a simple technique, with low risk of complications and provides effective pain relief as well as an improvement in post-operative pulmonary function. Lignocaine is equally as effective as bupivacaine and its use would result in some cost-saving.

Background and objective The purpose of this study was to investigate retrospectively what factors contribute to the development of the type of hyperlactatemia which may follow cardiopulmonary bypass despite well-maintained oxygen delivery and a normal perioperative course.

Methods The medical records of 124 patients undergoing elective cardiac surgery using cardiopulmonary bypass were reviewed. The patients were divided into a hyperlactatemia group (n = 34), where the serum lactate concentration was > 5.0 mmol L−1 perioperatively, and a normal lactatemia group (n=90), which comprised the remaining patients.

Results The duration of cardiopulmonary bypass in the hyperlactatemia group was significantly longer than for the normal lactatemia group. Significant differences of lactate concentrations between the groups, and significant elevations of serum lactate had been observed after the start of cardiopulmonary bypass. Oxygen extraction rates were significantly reduced during the period of cardiopulmonary bypass but, on the contrary, increased in the hyperlactatemia group after surgery. The area under the curve of mean arterial pressure consisted of 5-min interval plots during the initial period of cardiopulmonary bypass in the hyperlactatemia group. This was significantly smaller than for the normal lactatemia group. Weakly significant correlations between maximal lactate and duration of cardiopulmonary bypass, and especially the area under the curve, were observed.

Conclusions It is suggested that the pathophysiology observed is based on impairment of tissue oxygen utilization. The duration of cardiopulmonary bypass and especially the occurrence of hypotension at the start of the bypass period appears to be related to the development of lactic acidosis.

Summary

Background and objective: This prospective, randomized, double-blind study was conducted to evaluate the onset time and duration of sciatic nerve block produced with 0.5% levobupivacaine, 0.75% levobupivacaine and 0.75% ropivacaine.

Methods: Forty-five healthy patients undergoing hallux valgus repair were randomly allocated to receive sciatic nerve block with levobupivacaine 0.5% (n = 15), levobupivacaine 0.75% (n = 15) or ropivacaine 0.75% 20 mL (n = 15). A femoral nerve block was also performed with mepivacaine 2% 15 mL to cover pain related to the thigh tourniquet. A blinded observer recorded the onset time and duration of sciatic nerve block.

Results: The median (range) onset time was 5 (5–40) min with 0.75% levobupivacaine, 30 (5–60) min with 0.5% levobupivacaine and 20 (5–50) min with 0.75% ropivacaine (P = 0.02 and P = 0.12, respectively). Mean (25–75 percentiles) first request for pain medication occurred after 13 (11–14) h with 0.75% ropivacaine, 18 (15–19) h with 0.75% levobupivacaine and 16 (13–20) h with 0.5% levobupivacaine (P = 0.002 and P = 0.002, respectively). Rescue tramadol after surgery was required by three patients in the 0.75% levobupivacaine group, eight patients in the 0.5% levobupivacaine group and nine patients in the 0.75% ropivacaine group (P = 0.05).

Conclusions: We conclude that 0.75% levobupivacaine provides a shorter onset time than 0.5% levobupivacaine and a longer duration of postoperative analgesia than both 0.5% levobupivacaine and 0.75% ropivacaine with reduced need for rescue analgesia after surgery.

Summary

Introduction: We decided to investigate the pathogenesis of pulmonary ventilatory and radiographic abnormalities in patients after major vascular surgery. Patients and methods: Sixteen mechanically ventilated patients without heart failure were studied, within 3 h after major abdominal surgery. We measured extravascular lung water, intrathoracic, global end-diastolic and pulmonary blood volumes, 67Ga-transferrin pulmonary leak index and ventilatory and radiographic variables. The latter allowed computation of the lung injury score as a measure of lung injury. Results: The extravascular lung water was elevated (>7 mL kg−1) in 5 of 16 patients, while the pulmonary leak index was elevated in 11 patients and a supranormal extravascular lung water was associated with a high pulmonary leak index and higher extravascular lung water relative to intrathoracic blood volume or pulmonary blood volume. Patients were arbitrarily divided into those with a lung injury score >1 and ≤1, and only differed in the factors composing the score as well as in extravascular lung water divided by pulmonary blood volume. A lung injury score >1 was associated with a longer duration of mechanical ventilation. Conclusion: Our data suggest that mild, subclinical, pulmonary oedema is relatively common after major vascular surgery, mainly caused by increased pulmonary capillary permeability in the absence of overt heart failure. However, permeability oedema only partially contributes to postoperative lung injury score and need for mechanical ventilation, suggesting a major contribution by atelectasis.

Summary

Background and objective: Isoflurane has been shown experimentally to protect the myocardium against infarction but the clinical relevance of these findings is not yet well established. We therefore evaluated the effects of isoflurane administration before cardiopulmonary bypass (CPB) on postoperative cardiac troponin I (cTnI) release and clinical outcome in a large group of adult patients scheduled for cardiac surgery.

Methods: Three hundred and fifty-nine consecutive patients were included prospectively in an open observational study and divided into two groups according to whether or not isoflurane was administered before CPB. Postoperative cTnI release, in-hospital mortality, time to discharge from hospital, time to extubation and non-fatal postoperative cardiac events (number of internal cardioversions, need for inotropic support, ischaemic events, dysrhythmias and/or conduction abnormalities) were recorded.

Results: Two hundred and twenty-one (62%) patients did not receive isoflurane and 138 (38%) received isoflurane (1.3% [1.0–1.8%] minimum alveolar concentration over 22 [15–33] min). Postoperative cTnI release was not significantly different between the control and isoflurane groups (5.9 [1.0–336.8] vs. 6.0 [1.5–392.0] ng mL−1, P = 0.88). No significant differences were found in non-fatal cardiac events (63% vs. 57%, P = 0.22) and in-hospital mortality (1.8% vs. 1.4%, P = 0.79) between the control and isoflurane groups.

Conclusions: No significant effect was observed on postoperative cTnI release and in-hospital outcome when isoflurane was added to standardized intravenous anaesthesia before CPB in adult patients undergoing cardiac surgery.

In a double-blind randomized study, the incidence and severity of postoperative nausea and vomiting was investigated with a new formulation of etomidate (Etomidate-®Lipuro, B. Braun Melsungen AG, Germany) compared with propofol for induction of a balanced anaesthesia with isoflurane/fentanyl in air.

The incidence and intensity of nausea was examined by use of a visual analogue scale (VAS; 0–100 mm) at 1, 2, between 6 and 8, and 24 h postoperatively. One-hundred-and-sixty-four patients undergoing orthopedic procedures were studied. For etomidate vs. propofol, 14.6% vs. 14.2% male and 26.8% vs. 27.5% female patients were nauseated during the first two postoperative hours. The median rating for nausea remained below 5 mm at any time in both groups, i.e. the intensity of nausea was very low. The incidence of vomiting was higher in women receiving etomidate (26.8% vs. 10%).

We conclude that etomidate does not increase nausea during the early postoperative period.