Showing papers in "European Journal of Anaesthesiology in 2002"

Allergic reactions occurring during anaesthesia

Abstract: Anaphylactic reactions to anaesthetic and associated agents used during the perioperative period have been reported with increasing frequency in most developed countries. Any drug administered in the perioperative period can potentially produce life-threatening immune-mediated anaphylaxis. Most published reports on the incidence of anaphylaxis come from France, Australia, the UK and New Zealand. These reflect an active policy of systematic clinical and/or laboratory investigation of suspected immune-mediated reactions. The estimated incidence of anaphylaxis ranges from 1:10,000 to 1:20,000. Muscle relaxants (69.1%) and latex (12.1%) were the most frequently involved drugs according to the most recent French epidemiological survey. Clinical symptoms do not afford an easy distinction between immune-mediated anaphylactic reactions and anaphylactoid reactions resulting from direct non-specific histamine release. Moreover, when restricted to a single clinical symptom, anaphylaxis can easily be misdiagnosed. Pre- and postoperative investigation must be performed to confirm the nature of the reaction, the responsibility of the suspected drugs and to provide precise recommendations for future anaesthetic procedures. These include plasma histamine, tryptase and specific IgE concentration determination at the time of the reaction and at skin tests 6 weeks later. In addition, since no specific treatment has been shown reliably to prevent the occurrence of anaphylaxis, allergy assessment must be performed in all high-risk patients. Treatment of anaphylaxis is aimed at interrupting contact with the responsible antigen, inhibiting mediator production and release, and modulating the effects of released mediators. It must be initiated as quickly as possible and relies on widely accepted principles. Finally, the need for proper epidemiological studies and the relative complexity of allergy investigation should be underscored. They represent an incentive for further development of allergo-anaesthesiology clinical networks to provide expert advice for anaesthetists and allergologists.

Voltage-dependent block of neuronal and skeletal muscle sodium channels by thymol and menthol.

Abstract: SummaryBackground and objective:Thymol is a naturally occurring phenol derivative used in anaesthetic practice as a stabilizer and preservative of halothane, usually at a concentration of 0.01%. Although analgesic effects have long been described for thymol and its structural homologue menthol, a mo

Predictors of successful neuraxial block: a prospective study.

Abstract: Background and objective: The epidural and subarachnoid spaces should be identified at the first attempt, since multiple punctures increase the risk of postdural puncture headache, epidural haematoma and neural trauma. The study aimed to describe the predictors of successful neuraxial blocks at the first attempt.Methods: After institutional Review Board approval, 1481 patients undergoing spinal or epidural anaesthesia were prospectively enrolled. For each block we recorded: gender, age, height, weight, body habitus, anatomical landmarks (palpability of the spinous processes), spinal anatomy, patient positioning, premedication, needle type and gauge, approach, spinal level of the block, and the provider’s level of experience. Retrieval of cerebrospinal fluid or loss of resistance to saline or air identified the subarachnoid and epidural spaces, respectively. The outcome variable was the first attempt success or failure (whether or not the needle was correctly located with one skin puncture and produced adequate surgical anaesthesia). Backward stepwise logistic regression tested its association with the other variables.Results: The first-attempt rate of success was 61.51%. Independent predictors (Odds ratio, 95% confidence limits) were the quality of anatomical landmarks (1.92 (1.57; 2.35)), the provider’s level of experience (1.24 (1.15; 1.33)) and the adequacy of patient positioning (3.84 (2.84; 5.19)).Conclusions: The successful location of the subarachnoid or the epidural space at the first attempt is influenced by the quality of patients’ anatomical landmarks, the adequacy of patient positioning and the provider’s level of experience.

Magnesium infusion reduces perioperative pain.

Abstract: Background and objective Magnesium has antinociceptive effects in animal and human models of pain. These effects are primarily based on the regulation of calcium influx into the cell. The aim of this study was to determine whether perioperative infusion of magnesium would reduce postoperative pain and anxiety. Methods Twenty-four patients, undergoing elective hysterectomy, received a bolus of 30 mg kg(-1) magnesium sulphate or the same volume of isotonic sodium chloride solution intravenously before the start of surgery and 0.5 g h(-1) infusion for the next 20 h. Intraoperative and postoperative analgesia were achieved with fentanyl and morphine respectively. Patients were evaluated pre- and postoperatively for anxiety. Results Fentanyl consumption and total morphine requirements were significantly decreased in the magnesium group compared to the control group. Postoperative anxiety scores and sedation were similar between groups. Conclusions Continuous magnesium infusion, including the pre-, intra-, and postoperative periods reduces analgesic requirements. These results demonstrate that magnesium can be an adjuvant for perioperative analgesic management.

Postoperative pain management in orthopaedic patients: no differences in pain score, but improved stress control by epidural anaesthesia

Abstract: Background and objective: To investigate the interactions of postoperative pain and endocrine stress response, three groups of 21 patients each with total knee arthroplasty were compared in a randomized, prospective design. For postoperative pain management, a three-in-one block, an epidural catheter analgesia or an intravenous patient-controlled analgesia was used. Methods: After standardized balanced anaesthesia, the pain intensity was measured by a visual analogue scale (VAS). For detection of epinephrine, norepinephrine, antidiuretic hormone, adrenocorticotropic hormone and cortisol in the plasma, blood samples were taken at six time points before and up to 180 min after the start of pain therapy. In addition, systolic arterial pressure, heart rate, partial arterial oxygen saturation, nausea, vomiting and satisfaction of the patients were recorded. Results: Within 15 min after the start of pain therapy, VAS in all groups was similarly reduced from >40 mm to a range <10 mm (P < 0.001). Initially, all endocrine stress variables exceeded the normal range. Epidural anaesthesia led to a significant decrease of epinephrine and norepinephrine concentrations, while an increase was observed in the group with patient-controlled analgesia, and the decrease in patients with the three-in-one block was less than in patients receiving epidural anaesthesia (P = 0.001). Differences in antidiuretic hormone, adrenocorticotropic hormone and cortisol were less pronounced. Systolic arterial pressure decreased significantly in all groups, particularly in patients with epidural anaesthesia. Partial arterial oxygen saturation and the incidence of nausea and vomiting were comparable. All patients were satisfied with the methods used. Conclusions: All methods of pain management led to sufficient analgesia, but they were not accompanied by an adequate reduction in endocrine stress response. Thus, postoperative pain is only a secondary stressor and sufficient analgesia with subjective well-being does not prove a stress-free state. With regard to the reduction of sympathoadrenergic stress response, epidural anaesthesia is superior to the three-in-one block and patient-controlled analgesia. Epidural anaesthesia is recommended particularly for high-risk patients with hypertension, coronary heart disease and diabetes mellitus. In these patients, the reduction of a 'hidden' endocrine stress response in addition to prevention of pain is of special interest.

The effects of fenoldopam on renal function in patients undergoing elective aortic surgery

Abstract: BACKGROUND AND OBJECTIVE Postoperative renal impairment is a recognized complication of infrarenal aortic cross-clamping. Our hypothesis was that the renal vasodilating and natriuretic effects of fenoldopam mesylate, a selective dopamine (DA1) agonist, would preserve renal function in patients undergoing elective infrarenal aortic cross-clamping. METHODS A prospective, randomized, double blind controlled clinical trial was performed. Twenty-eight ASA II-III patients undergoing elective aortic surgery requiring infrarenal aortic cross-clamping were studied. According to random allocation, patients received either fenoldopam (0.1 microg kg(-1) min(-1)) or placebo intravenously prior to surgical skin incision until release of the aortic clamp. Plasma creatinine, creatinine clearance, urinary output, fractional excretion of sodium, and free water clearance were measured: (a) prior to admission to hospital; (b) during the period from insertion of the urinary catheter until application of the aortic cross-clamp; (c) during the period of aortic cross-clamping; (d) 0-4 h, and (e) 4-8 h after release of the clamp and on days 1, 2, 3, and 5 postoperatively. RESULTS Fenoldopam (0.1 microg kg(-1)min(-1)) administration was not associated with haemodynamic instability. On application of the aortic cross-clamp creatinine clearance decreased significantly in the placebo (83 +/- 20 to 42 +/- 29 mL min(-1) (mean +/- SD)) (P < 0.01) but not in the fenoldopam group, and this decrease persisted for at least 8 h after release of the cross-clamp (83 +/- 20 to 54 +/- 33 mL min(-1) (mean +/- SD)) (P < 0.05). Plasma creatinine concentration increased significantly from baseline on the first postoperative day in the placebo group (87 +/- 12 to 103 +/- 28 micromolL(-1) (mean +/- SD)) (P < 0.01) but not in the fenoldopam group. CONCLUSIONS These findings are consistent with the hypothesis that fenoldopam possesses a renoprotective effect during and after infrarenal aortic cross-clamping.

Laudanosine, an atracurium and cisatracurium metabolite

Abstract: Laudanosine is a metabolite of the neuromuscular-blocking drugs atracurium and cisatracurium with potentially toxic systemic effects. It crosses the blood-brain barrier and may cause excitement and seizure activity. Its interest in recent years has increased because of the recognized interaction with gamma-aminobutyric acid, opioid and nicotinic acetylcholine receptors. It has been shown to produce analgesia in animals. In the cardiovascular system, high plasma concentrations produce hypotension and bradycardia. In hepatic failure, its elimination half-life is prolonged but only moderate accumulation occurs in adults, whereas in infants and children plasma concentration are greater. In patients undergoing liver transplantation, laudanosine concentrations are increased during preanhepatic, anhepatic and postanhepatic stages. Patients with renal failure have higher plasma concentrations and a longer mean elimination half-life. In pregnancy, laudanosine crosses the placental barrier. The mean transplacental transfer is 14% of maternal blood concentrations. Except for prolonged administration of atracurium in intensive care units, laudanosine accumulation and related toxicity seem unlikely to be achieved in clinical practice. When cisatracurium is used, plasma concentrations of laudanosine are lower. Further studies are needed, especially around the interactions with gamma-aminobutyric acid, opioid and nicotinic acetylcholine receptors.

Perioperative risk factors in elective pneumonectomy: the impact of excess fluid balance.

Abstract: Background and objective This study was performed to identify risk factors for complications and in-hospital mortality associated with pneumonectomy. Methods The influence of fluid balance during anaesthesia was evaluated, taking into account the patient's age, gender and body mass index, smoking habits, history of pulmonary or cardiac disorders, the site of pneumonectomy and duration of anaesthesia. One-hundred-and-seven patients undergoing elective pneumonectomy were included in the study. Results A total of 31 patients (29%) suffered from one or more postoperative complications, seven (22.4%) of these had severe dysrhythmias, six (19.6%) had pulmonary complications and three (9.3%) had cardiovascular complications. The overall mortality rate was 10.3%. Conclusions Based on logistic regression analysis, our data indicate the following risk factors for postoperative complications: positive fluid balance exceeding 4000 mL during anaesthesia (pulmonary complications and mortality), body mass index 25 kg m(-2) (severe dysrhythmias), or history of chronic heart disease (pulmonary complications). Thirteen patients (12.4%) suffered from a fluid balance > 4000 mL during anaesthesia. Regression analysis indicated that fluid balance exceeding 4000 mL was associated with a higher risk of postoperative complications than blood loss exceeding 1000 mL and to be the strongest risk factor for postoperative pulmonary complications and in-hospital mortality. Further trials estimating the effect of restrictive fluid regimens and the use of vasopressors for blood pressure control during anaesthesia must be carried out.

Sedation assessment in critically ill patients with bispectral index.

Abstract: Background and objective: Clinical sedation assessment becomes insufficient in deeply sedated patients. Bispectral index as a processed electroencephalogram parameter provides a continuous and observer-independent value reported to change with sedation. The aim of this prospective observational study was to determine the reliability and possible confounding factors of the bispectral index to assess sedation in surgical intensive care patients. Methods: Following major surgery, bispectral index, body temperature and electromyographic activity of 44 ventilated patients were recorded. Sedation levels were assessed with Ramsay sedation score. Results: Although bispectral index correlated with Ramsay sedation score (-0.64; P < 0.01) we found that in deeply sedated patients temperature instability and electromyographic activity increased bispectral index. Bispectral index correlated significantly with electromyographic activity (0.80; P < 0.01) and with an increase of body temperature (0.55; P < 0.01) not only in all patients but also in clinically deeply sedated patients (0.57; P < 0.01 and 0.46; P < 0.05). Conclusions: Only under certain conditions, such as low muscular activity and body temperature stability, may the bispectral index be a useful addition to clinical scoring in the sedation assessment of critically ill patients.

Impact of the reduction of anaesthesia turnover time on operating room efficiency.

Abstract: SummaryBackground and objective:We investigated whether an increase in anaesthesia staffing to permit induction of anaesthesia before the previous case had ended ('overlapping') would increase overall efficiency in the operating room. Hitherto, the average duration of operating sessions was too long

Preload and haemodynamic assessment during liver transplantation: a comparison between the pulmonary artery catheter and transpulmonary indicator dilution techniques.

Abstract: Background and objective: Liver transplantation is characterized by several changes in intravascular blood volume due to vasodilatation based on neurohumoral mediators, intraoperative bleeding and anaesthesia technique effects. Today, with the transpulmonary indicator dilution technique, cardiac index (CIart) can be evaluated and preload assessed in terms of the intrathoracic blood volume index (ITBVI). The aim was to analyse in patients undergoing liver transplantation two preload variables, pulmonary artery occlusion pressure (PAOP) and ITBVI with respect to cardiac index (CIpa) and stroke volume index (SVIpa), the correlation between ITBVI and PAOP, and secondary the relationship between the changes (A) of ITBVI and PAOP and the changes of CIpa and SVIpa, and the relationships between ΔITBVI and ΔPAOP. The reproducibility and precision of all Clart and CIpa measurements were also evaluated. Methods: A prospective study was performed in 60 patients monitored with a pulmonary artery catheter and with the PiCCO® system. The variables were evaluated with a linear regression model. Results: Linear regression analysis between ITBVI-Clpa and ITBVI-SVIpa were r 2 = 0.47 (P < 0.0001) and r 2 = 0.55 (P < 0.0001) respectively, while PAOP poorly correlated to CIpa (r 2 = 0.02), SVIpa (r 2 = 0.015) and ITBVI (r 2 = 0.002). Only changes in ITBVI were correlated with changes in CIpa (Δ 1 , r 2 = 0.37; Δ 2 , r 2 = 0.32), and SVIpa (Δ 1 , r 2 = 0.60; Δ 2 , r 2 = 0.47). The mean bias between CIart and CIpa was 0.13 L min -1 m -2 (2 SD = 1.04L min -1 m -2 ) (r 2 = 0.86, P < 0.0001). Conclusions: In comparison with PAOP, ITBVI seems a more reliable indicator of cardiac preload in patients undergoing liver transplantation.

Central neuraxial blocks and anticoagulation: a review of current trends.

Abstract: Summary Patients receiving anticoagulants offer a challenge to anaesthesiologists. The issue of spinal haematoma following central neuraxial block in such patients is a contentious issue. Although rare, with an estimated incidence of <1:150 000 for epidural blocks and 1:220 000 for spinal anaesthetics in patients with normal coagulation status, this is an emergency situation with a potentially grave prognosis. The review presents cases of spinal haematomata that have occurred in the last 5 years, both spontaneously and after central neuraxial blockade. Of the 60 cases reported in the literature, 33% occurred following central neuraxial block and, of these, 55% were associated with concomitant use of anticoagulants. The pharmacology of the newer and older anticoagulants is also described. The variety of risk factors and diverse recommendations that have been described in these patients are reviewed.

Prophylactic intravenous bolus ephedrine for elective Caesarean section under spinal anaesthesia.

Abstract: BACKGROUND AND OBJECTIVE To evaluate the efficacy and optimal dose of prophylactic intravenous ephedrine for the prevention of maternal hypotension associated with spinal anaesthesia for Caesarean section. METHODS After patients had received an intravenous preload of 0.5 L of lactated Ringer's solution, spinal anaesthesia was administered in the sitting position with hyperbaric bupivacaine 2.5 mL 0.5% combined with 25 microg fentanyl. A total of 68 patients were randomized to receive a simultaneous 2 mL bolus intravenously of either 0.9% saline (Group C, n = 20), ephedrine 6 mg (Group E-6, n = 24), or ephedrine 12 mg (Group E-12, n = 22). Further rescue boluses of ephedrine 6 mg were given if systolic arterial pressure fell to below 90 mmHg, greater than 30% below baseline, or if symptoms suggestive of hypotension were reported. RESULTS There was a significantly higher incidence of hypotension in Group C (60% patients) compared to Group E-12 (27%), but not in Group E-6 (50%). The 95% Confidence Interval for the difference in proportions between Groups C and E-12 was 6-60%, P < 0.05. Fewer rescue boluses of ephedrine were required in Group E-12 compared with Group C (1.8 +/- 1.2 vs. 3.3 +/- 2.1, P < 0.05). There were no significant differences in the incidence of maternal nausea or vomiting, or of neonatal acidaemia between groups. CONCLUSION A prophylactic bolus of ephedrine 12 mg intravenously given at the time of intrathecal block, plus rescue boluses, leads to a lower incidence of hypotension following spinal anaesthesia for elective Caesarean section compared to intravenous rescue boluses alone.

Bilateral paravertebral somatic nerve block for ventral hernia repair.

Abstract: Background and objective: Unilateral paravertebral nerve blockade has been reported to produce excellent afferent nerve block, reduce the incidence of postoperative nausea and vomiting, and reduce hospital stay following inguinal hernia repair. The aim was to compare the use of bilateral paravertebral blocks to regular general anaesthesia for ventral hernia repair. Methods: Sixty patients were prospectively allocated to receive either bilateral paravertebral nerve blockade (midazolam for block; supplemented with light intraoperative sedation if needed) or general anaesthesia for ventral hernia repair. The end-points of the study were length of hospital stay, postoperative analgesia (visual analogue scale, supplemental opioid requirement) and incidence of postoperative nausea and vomiting. Results: The duration of hospital stay was observed to be shorter in patients handled with bilateral paravertebral nerve blockade (2.3 [SD 1.3] days) compared with patients receiving general anaesthesia (4.1 (3.0) days). Paravertebral analgesia resulted in both lower visual analogue scores and a significantly reduced need for supplemental opioid administration during the first 48 h postoperatively compared with general anaesthesia (P < 0.001). The rate of postoperative nausea and vomiting in the paravertebral nerve blockade group was only 3.3%, while 26.7% of patients in the general anaesthesia group suffered from postoperative nausea and vomiting (P < 0.05). Paravertebral nerve blockade was associated with good patient acceptance in 90% of patients. Conclusions: Bilateral paravertebral blockade combined with light intravenous sedation was superior to general anaesthesia for ventral hernia repair. Paravertebral blockade was associated with shorter hospital stay, improved analgesia and less postoperative nausea and vomiting. It is suggested that this technique deserves more widespread use in patients undergoing ventral hernia repair.

Lidocaine-induced cell death in a human model of neuronal apoptosis

Abstract: 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.

Postoperative residual curarization with cisatracurium and rocuronium infusions

Abstract: SummaryBackground and objective:Monitoring of neuromuscular blockade still often relies on clinical judgement. Moreover, there are substantial national differences in the use of agents to 'reverse' their effects. We investigated the recovery characteristics and incidence of postoperative residual cu

Does ibuprofen increase perioperative blood loss during hip arthroplasty

Abstract: Background and objective: To determine whether prior exposure of non-steroidal anti-inflammatory drugs increases perioperative blood loss associated with major orthopaedic surgery.Methods: Fifty patients scheduled for total hip replacement were allocated to two groups (double blind, randomized manner). All patients were pretreated for 2 weeks before surgery: Group 1 with placebo drug, Group 2 with ibuprofen. All patients were injected intrathecally with bupivacaine 20 mg plus morphine 0.1 mg, in a total volume of 4 mL, to provide surgical anaesthesia.Results: The presence of severe adverse effects caused eight patients in the ibuprofen group and six in the placebo group to terminate their participation in the trial. The perioperative blood loss increased by 45% in the ibuprofen group compared with placebo. The total (±SD) blood loss in the ibuprofen group was 1161 (±472) mL versus 796 (±337) mL in the placebo group.Conclusions: Pretreatment with ibuprofen before elective total hip surgery increases the perioperative blood loss significantly. Early discontinuation of non-selective non-steroidal anti-inflammatory drugs is advised.

Long QT syndrome and anaesthesia

Abstract: The long QT syndrome is a disorder of myocardial electrical conduction that leaves the heart vulnerable to the ventricular tachydysrhythmia torsade de pointes. Clinically, this results in syncope or sudden death. The long QT syndrome may be congenital, if caused by abnormal myocardial potassium or sodium ion channels, or acquired, if due to drugs, electrolyte abnormalities or metabolic conditions. Triggers for the development of torsade de pointes include both anaesthesia and surgery. Some anaesthetic agents prolong the QT interval. The condition is reviewed and suggestions are made for the anaesthetic management of affected patients.

Anaesthesia for elective liver resection: some points should be revisited.

Abstract: Improvement in surgical techniques, technology and perioperative assessment has dramatically simplified the anaesthetic care for elective liver resection. Patients with a non-tumorous healthy liver should only need the usual preoperative assessment. Patients with pre-existing parenchymal liver disease should be specifically assessed for gas exchange impairment, alcoholic or nutritional-associated cardiomyopathy, infection, cirrhosis decompensation, acute alcoholic hepatitis, and kidney impairment. The type of anaesthetic management does not influence the intra- and postoperative courses. Intermittent clamping of the portal vascular triad is better tolerated than prolonged continuous periods of ischaemia--especially in patients with abnormal liver parenchyma. Intraoperative antibiotic prophylaxis must be administered to prevent translocation of intestinal enterobacteria to the systemic circulation in patients with both healthy and diseased livers. Blood-salvage techniques have limited indications in liver resection. Systematic invasive haemodynamic monitoring is no longer warranted. An arterial cannula should only be considered in procedures of long duration and in selected situations likely to cause anticipated circulatory impairment: total liver vascular occlusion, repeat surgery, combined organ resection, and surgery conducted on tumours >10 cm in size or in connection with the vena cava. In a recent large series of liver resections, 60% of patients did not need a blood transfusion, only 2% of transfused patients received >10 units of blood and cirrhosis was not predictive of increased intraoperative bleeding. Postoperative ascites, which always develops at the expense of circulating fluid, is a frequent occurrence in patients with healthy or diseased livers. Intra- and postoperative fluid limitation does not prevent postoperative ascites. Volume expansion, diuretics and vasopressor therapy should be initiated early to prevent kidney failure.

Monitoring intravascular volumes for postoperative volume therapy.

Abstract: Background and objective: The feasibility of monitoring measured intravascular volumes and the cardiac filling pressures were compared to reflect the optimal volume status of postoperative patients. Methods: In a prospective clinical study, 14 hypovolaemic adult patients were included after cardiac surgery. All patients received 1000 mL hydroxyethyl starch after meeting the authors’ criteria for hypovolaemia. Pressures were measured by use of a pulmonary artery catheter and volumes were determined by double-indicator dilution technique. Results: Stroke volume index (SVI), central venous pressure (CVP), pulmonary artery occlusion pressure (PAOP), intrathoracic blood volume index (ITBVI) and total circulating blood volume (TBVI circ ) increased significantly after volume loading (30.7 ± 9.8 to 41.7 ± 9.6 mL m −2 , 4.9 ± 1.7 to 9.1 ± 2.3 mmHg, 6.6 ± 1.3 to 10.6 ± 1.9 mmHg, 858 ± 255 to 965 ± 163 mL m −2 , and 1806 ± 502 to 2110 ± 537 mL m −2 , respectively). During the subsequent 1 h steady-state period, CVP and PAOP decreased significantly (9.1 ± 2.2 to 7.4 ± 2.2 mmHg and 10.6 ± 1.9 to 9.2 ± 2.0 mmHg, respectively), whereas SVI and intravascular volumes remained unchanged. The changes of CVP and PAOP did not correlate with changes in stroke volume during volume loading ( r 2 = 0.06 and 0.03, respectively) and during steady-state ( r 2 = 0.17 and 0.00 respectively). On the other hand, a significant correlation was found between changes of the intrathoracic blood volume and changes in stroke volume during the volume loading ( r 2 = 0.67) and also during the steady-state phase ( r 2 = 0.83). Conclusions: Intrathoracic blood volume reflects more accurately the preload dependency of cardiac output in postoperative patients than left/right-sided cardiac filling pressures.

Effect of VIMA with sevoflurane versus TIVA with propofol or midazolam-sufentanil on the cytokine response during CABG surgery.

Abstract: Background and objective Cardiac surgery with cardiopulmonary bypass triggers an inflammatory response involving pro-inflammatory cytokines such as tumour necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6) and interleukin 8 (IL-8). We investigated whether different anaesthetic techniques alter the pro-inflammatory cytokine response to cardiac surgery. Methods Thirty patients scheduled for elective coronary artery bypass grafting (CABG) surgery were randomized into three groups of 10 patients. They received either volatile inhalation induction and maintenance (Group 1) or total intravenous anaesthesia with propofol and a minimal dose sufentanil (Group 2) or a moderate dose midazolam-sufentanil (Group 3). The effect of the different anaesthetic techniques on plasma levels of TNF-alpha, IL-6 and IL-8 were examined during and after anaesthesia. Results Concentrations of TNF-alpha, and IL-8 were comparable in the three groups throughout all measurements. Before the start of cardiopulmonary bypass, IL-6 was significantly higher in Group 1 than in Group 2 (P = 0.009) or Group 3 (P = 0.030), but there were no differences between groups after cardiopulmonary bypass or postoperatively. In the three groups there was a positive correlation between aortic clamping time and serum concentrations of IL-6 (r = 0.54) and IL-8 (r = 0.62). Length of stay in intensive care was correlated with high levels of TNF-alpha (r = 0.78). Conclusions Albeit there is difference between the volatile induction and maintenance of the anaesthesia method and the total intravenous anaesthesia technique on the pro-inflammatory cytokine response to surgical stimulation before starting of cardiopulmonary bypass, neither technique can modify the pro-inflammatory cytokine response to ischaemia-reperfusion or extracorporeal circulation.

Neurological complications following central neuraxial blocks: are there predictive factors?

Abstract: Severe complications such as spinal epidural haematoma and an array of adverse neurological events leading to temporary or permanent disability have been ascribed to central neuraxial blocks. Infections (meningitis, abscesses), chemical injuries and very rarely cerebral ischaemia or haemorrhage, or both, have also been ascribed directly or indirectly to spinal and/or epidural anaesthesia. Some case reports, and very few retrospective studies, have focused their attention on the fact that central nerve blocks can cause, albeit rarely, permanent damage to the spinal cord or nerve roots, or both. The cause of this damage in many cases remains unclear. The attention of investigators and practitioners is focused both on understanding the causative mechanisms of such accidents and in identifying 'alarm events' that can arise during the administration of a central block, if any. We reviewed the international literature for the neurological complications of central neuraxial blocks to identify some events that, if they occurred during the block procedure, could be perceived as dangerous.

Aetiology of convulsions due to stellate ganglion block: a review and report of two cases.

Abstract: Stellate ganglion block is a selective sympathetic block that affects the ipsilateral head, neck, upper extremity and upper part of the thorax. Convulsions are a recognized complication of intra-arterial injection during stellate ganglion block. As central nervous system toxicity depends ultimately on the concentration of the local anaesthetics presented to the brain, the likely causative factors are discussed as well as the types of toxic symptoms and their onset times. The paper considers the aetiological factors of such convulsions resulting from stellate ganglion block in two patients.

Sex differences in cortisol response to noxious stress

Abstract: Objectives Evidence has accumulated that men and women show different responses to noxious stimuli, with women exhibiting greater sensitivity to pain than men. Data concerning sex differences in cortisol response patterns have revealed inconsistent results so far. The purpose of the present study was to examine sex differences in subjective pain and cortisol response to a noxious stressor. Methods Seventy-six subjects (39 male and 37 female) were investigated by a modification of the cold pressor test that consisted of intermittent immersion of the hand into ice water (plunge test, PT). The PT was conducted twice, in consecutive trials, to guarantee a sufficient exposure to the noxious stressor for eliciting cortisol responses. In each trial, tolerance time and pain ratings visual analog scale (VAS) were assessed. Seven saliva samples (c1-c7) were collected to determine cortisol levels at baseline (c1-c2), directly before (c3) and 20 minutes after noxious stress (c4), and during recovery period (c5-c7). Results We found no significant sex differences in tolerance time in trial 1, but highly significant differences in tolerance time in trial 2, with higher tolerance times in men. No significant sex differences were found for the VAS ratings of pain intensity and unpleasantness in the 2 trials. In contrast, a significantly larger cortisol increase in men was observed compared with women. Analysis of covariance revealed that this result could not be attributed to sex differences in cortisol level at baseline and in tolerance time. Discussion The present study demonstrates that men show a larger cortisol response to a noxious stressor than women that is not attributable to sex differences in subjective pain. The conclusion of a causal relation between larger cortisol responses and higher pain tolerance thresholds in men is tempting but yet speculative.

Succinylcholine improves the time of performance of a tracheal intubation in prehospital critical care medicine

Abstract: BACKGROUND AND OBJECTIVE The study aimed to evaluate and improve airway management in the prehospital setting, i.e. physicians working on board ambulances. A quality control programme focusing on anaesthesia was instituted to improve the time taken to perform endotracheal intubation. METHODS All consecutive patients requiring tracheal intubation were prospectively analysed before (first period) and after the training programme focusing on anaesthetic protocols for tracheal intubation (second period). The number of attempts at laryngoscopy, the time taken to achieve tracheal intubation, the difficulties encountered and the related complications of the anaesthetic technique were recorded. At the end of the first period, the results were reported to the whole staff of the unit and the anaesthesia protocols were then modified by introducing succinylcholine into the induction sequence, as part of a training programme. RESULTS Two-hundred-and-eighty patients were evaluated (97 in the first period, 183 in the second). All patients were successfully intubated in both periods. The percentage of difficult intubations (as assessed by the physician) was lower in the second period (20 versus 35%, respectively; P < 0.01). The success rate at the first attempt was significantly higher (74% [68-80] 95% CI versus 55% [45-65] 95% CI, P < 0.01) and the duration of intubation was significantly shorter in the second period than in the first (1.4 +/- 3.2 vs. 4.1 +/- 6.7 min, respectively; P < 0.001). The incidence of complications (hypoxaemia, laryngospasm, bronchospasm) was lower in the second period (15 versus 31%, P < 0.01). CONCLUSIONS The time to perform tracheal intubation can be improved by the introduction of succinylcholine into the prehospital anaesthetic protocol. Rapid sequence induction should be taught as a way of improving tracheal intubation in the prehospital setting.

Operating room management and strategies in Switzerland: results of a survey.

Abstract: Background and objective: Operating room management structures and interrelationships both within the operating suite and with other departments in the hospital can be very complex. Several different professional and support groups are represented that often have infrastructures of their own that may compete or conflict with the management hierarchy in the operating room. Today, there is often little actual management of the operating suite as an entity. We surveyed current operating room management in Switzerland.Methods: A questionnaire was sent to the chief anaesthesiologists of all public hospitals in Switzerland. It asked for information about the structure, organization and management of operating rooms as well as respondents’ opinions and expectations about management. Derived from both the literature and the results of the survey, a ‘stages of excellence’ model of best practice was developed.Results: The overall response rate was 70%. Most anaesthesiologists were unsatisfied with current management policies and structures in their operating rooms. Of the hospitals questioned, 40% did not have an information system at all for the operating rooms. The remaining 60% had an information system that allowed rough scheduling in 71%, but only a few had more sophisticated systems that enabled dynamic scheduling (19%), user-defined conflict checking (5%), administration of a subsequent patient transfer station (postanaesthesia care units, intensive medical care, intensive care units) (10%) or other more advanced uses. All hospitals questioned offered some type of ambulatory surgery in a ‘hospital-integrated’ manner (i.e. use of the same operating room for both in- and outpatient surgery), but none had implemented a more efficient system where outpatient surgery was performed in separate facilities.Conclusions: Current management of the operating room in Switzerland is far from best-practice standards.

Bacterial contamination of propofol: the effects of temperature and lidocaine.

Abstract: Background and objective The intravenous anaesthetic propofol may become contaminated once the ampoules have been opened. The effect of lidocaine and cooling was tested on the bacterial contamination of propofol. Methods The study was performed in two parts. In Part 1,1920 aliquots of propofol alone, and of a propofollidocaine mixture, were drawn into sterile syringes and stored at room temperature (24-26 degrees C) or in the refrigerator (12-14 degrees C). In Part 2, 1200 aliquots from opened ampoules of propofol alone, or as a propofol-lidocaine mixture, were stored at room temperature or in the refrigerator. Samples were aerobically cultured at 0, 1, 2, 4, 8 and 12 h. Results In Part 1, diphtheroid bacillus was isolated from one aliquot (0.06%). In Part 2, there was bacterial growth in both groups; the number of contaminated ampoules increased with time and it was 20-26% at 12 h. Diphtheroid bacilli and coagulase-negative staphylococci were the most frequent micro-organisms. Conclusions When propofol is stored in opened ampoules, the bacterial contamination rate is high. Adding lidocaine, or storing opened ampoules at 12-14 degrees C, does not affect the contamination rate, except during the first few hours. It is advisable to draw propofol aseptically into a syringe in an amount that can be used during one procedure.

Comparison of effects of remifentanil, alfentanil and fentanyl on cardiovascular responses to tracheal intubation in morbidly obese patients.

Abstract: BACKGROUND AND OBJECTIVE The effects of remifentanil, alfentanil and fentanyl were compared on cardiovascular responses to laryngoscopy and endotracheal intubation in morbidly obese patients. METHODS Eighty morbidly obese ASA I-II patients were included in the study. Patients were randomly divided into four groups to receive either 1 microgkg(-1) fentanyl (Group F), 10 microgkg(-1) alfentanil (A), 1 microgkg(-1) followed by an infusion of 0.5 pg kg min(-1) remifentanil (R) or saline (P). The patients corrected weight was used to calculate the drug doses. Body mass indices (range) were: 54.3 +/- 7.37 (49-78.4), 55.67 +/- 7.44 (48.5-78.4), 53.17 +/- 5.36 (48.1-63.2), and 56.3 +/- 6.09 (46.6-67.7) kg m(-2), in Groups F, R, A and P respectively. Systolic, diastolic and mean arterial pressures and heart rate were measured non-invasively at three time points, which were 2 min before induction, 2 min after induction and 2 min after endotracheal intubation. RESULTS After induction of anaesthesia, arterial pressures decreased significantly in all groups, but the decrease was more pronounced in Groups A and R. After induction, heart rate decreased significantly in all groups except in Group P. After intubation, haemodynamic responses were similar in the remifentanil, fentanyl and alfentanil groups and were within normal limits. In Group P, arterial pressures and heart rates were significantly higher. CONCLUSIONS Alfentanil, fentanyl and remifentanil in the doses described had similar effects in controlling the haemodynamic response to tracheal intubation in ASA I-II morbidly obese patients.

Cost-reduction analysis of propofol versus sevoflurane: maintenance of anaesthesia for gynaecological surgery using the bispectral index

Abstract: Background and objective The study was designed to compare the costs of propofol versus sevoflurane for the maintenance of the hypnotic component of anaesthesia during general anaesthesia, guided by the bispectral index, for gynaecological laparoscopic surgery. Methods Forty ASA Grade I-II female patients scheduled for gynaecological laparoscopy were randomly allocated to two groups. All patients received a continuous infusion of remifentanil (0.25 microg kg(-1) min(-1)) for 2 min. Then anaesthesia was induced with propofol 1% at 300 mL h(-1) until loss of consciousness. To guide the bispectral index between 40 and 60, Group 1 patients received propofol 10 mg kg(-1) h(-1) initially, which was increased or decreased by 2 mg kg(-1) h(-1) steps; Group 2 patients received sevoflurane, initially set at 2 vol.% and adjusted with steps of 0.2-0.4%. The time and quality of anaesthesia and recovery were assessed in two postoperative standardized interviews. Results Patient characteristics, the propofol induction dose, the bispectral index and the haemodynamic profiles during induction of anaesthesia, and its duration, were similar between the groups. In Group 1, 7.55 +/- 1.75 mg kg(-1) h(-1) propofol and in Group 2, 0.20 +/- 0.09 mL kg(-1) h(-1) liquid sevoflurane were used for maintenance. The cost for maintenance, including wasted drugs, was higher when using propofol (Euro 25.14 +/- 10.69) than sevoflurane (Euro 12.80 +/- 2.67). Postoperatively, recovery profiles tended to be better with propofol; however, the day after discharge no differences were found. Conclusions When applying the bispectral index to guide the administration of hypnotic anaesthetic drugs, propofol-based maintenance of anaesthesia was associated with the highest cost. A trend towards a better recovery profile was obtained with propofol. However, on the day after discharge, no differences in quality were observed.