Marc Hein

Bypass during Liver Transplantation : Anachronism or Revival? Liver Transplantation Using a Combined Venovenous/Portal Venous Bypass—Experiences with 163 Liver Transplants in a Newly Established Liver Transplantation Program

Introduction. The venovenous/portal venous (VVP) bypass technique has generally become obsolete in liver transplantation (LT) today. We evaluated our experience with 163 consecutive LTs that used a VVP bypass. Patients and Methods. The liver transplant program was started in our center in 2010. LTs were performed using an extracorporal bypass device. Results. Mean operative time was 269 minutes and warm ischemic time 43 minutes. The median number of transfusion of packed cells and plasma was 7 and 14. There was no intraoperative death, and the 30-day mortality was 3%. Severe bypass-induced complications did not occur. Discussion. The introduction of a new LT program requires maximum safety measures for all of the parties involved. Both surgical and anaesthesiological management (reperfusion) can be controlled very reliably using a VVP bypass device. Particularly when using marginal grafts, this approach helps to minimise both surgical and anaesthesiological complications in terms of less volume overload, less use of vasopressive drugs, less myocardial injury, and better peripheral blood circulation. Conclusion. Based on our experiences while establishing a new liver transplantation program, we advocate the reappraisal of the extracorporeal VVP bypass.

Xenon or propofol anaesthesia for patients at cardiovascular risk in non-cardiac surgery

BACKGROUND The results of two European multi-centre trials on xenon anaesthesia led to the hypothesis that a xenon-based anaesthetic would keep left ventricular (LV) and circulatory function more stable than a propofol-based anaesthetic, in patients with coronary artery disease (CAD). METHODS In a prospective, randomized design, 40 patients of ASA classes III and IV with known CAD were anaesthetized for elective non-cardiac surgery with either xenon (n=20) or propofol (n=20), each combined with remifentanil. Target criteria were intraoperative LV function as evaluated by transoesophageal echocardiography (TOE: Tei index, circumferential fibre shortening), arterial pressure, and heart rate (HR). RESULTS Mean arterial pressure was decreased with propofol but was stable at pre-anaesthetic level with xenon (P<0.02) and HR was lower with xenon (P<0.01). The Tei index (also known as myocardial performance index) improved from 0.53 (0.14) to 0.45 (0.10) after 1 h with xenon and changed from 0.50 (0.14) to 0.55 (0.20) with propofol anaesthesia [means (SD); P=0.01 between the groups]. Deviation of circumferential fibre shortening from expected value after 1 h was -2 (14)% with xenon and -14 (18)% with propofol [means (SD); P=0.03]. There were no perioperative signs of acute myocardial ischaemia (TOE, ECG, and troponin T release). CONCLUSIONS Xenon anaesthesia provided a higher arterial pressure level than propofol, with no signs of cardiovascular compromise, in patients with CAD. Echocardiographic indices showed better LV function with xenon.

The Effect of Xenon Anesthesia on the Size of Experimental Myocardial Infarction

BACKGROUND:Volatile anesthetics protect the myocardium from ischemia reperfusion damage. Our hypothesis for this study was that xenon reduces the size of myocardial infarction similar in extent to the reduction associated with ischemic preconditioning. METHODS:Thirty-six pigs weighing 30–35 kg were anesthetized with thiopental and then randomized into four groups: control (myocardial ischemia only), ischemic preconditioning (five 5-min episodes of intermittent myocardial ischemia), xenon preconditioning (three 10-min exposures to xenon 70% followed by myocardial ischemia), and xenon anesthesia (xenon 70%, continued before and after myocardial ischemia). Myocardial ischemia was induced by placing a tourniquet around the left anterior descending coronary artery for 60 min followed by 2 h of reperfusion. Myocardial infarct size and the area at risk for myocardial infarction were measured by Evans Blue and triphenyl tetrazolium chloride staining, respectively. RESULTS:Mean (sd) myocardial infarct size was reduced from 64% ± 9% of the area at risk in the control group to 19% ± 12% with ischemic preconditioning (P < 0.001), and to 50% ± 9% with xenon anesthesia (P < 0.05 versus control, P < 0.001 versus ischemic preconditioning). Myocardial infarct size was not reduced with xenon preconditioning compared with the control group (59% ± 11%, P = 0.41). CONCLUSION:Myocardial infarct size was reduced by ischemic preconditioning but less so by xenon anesthesia. Brief, intermittent exposure to xenon before myocardial ischemia did not reduce myocardial infarct size.

Speckle Tracking Echocardiography Detects Uremic Cardiomyopathy Early and Predicts Cardiovascular Mortality in ESRD

Cardiovascular mortality is high in ESRD, partly driven by sudden cardiac death and recurrent heart failure due to uremic cardiomyopathy. We investigated whether speckle-tracking echocardiography is superior to routine echocardiography in early detection of uremic cardiomyopathy in animal models and whether it predicts cardiovascular mortality in patients undergoing dialysis. Using speckle-tracking echocardiography in two rat models of uremic cardiomyopathy soon (4-6 weeks) after induction of kidney disease, we observed that global radial and circumferential strain parameters decreased significantly in both models compared with controls, whereas standard echocardiographic readouts, including fractional shortening and cardiac output, remained unchanged. Furthermore, strain parameters showed better correlations with histologic hallmarks of uremic cardiomyopathy. We then assessed echocardiographic and clinical characteristics in 171 dialysis patients. During the 2.5-year follow-up period, ejection fraction and various strain parameters were significant risk factors for cardiovascular mortality (primary end point) in a multivariate Cox model (ejection fraction hazard ratio [HR], 0.97 [95% confidence interval (95% CI), 0.95 to 0.99; P=0.012]; peak global longitudinal strain HR, 1.17 [95% CI, 1.07 to 1.28; P<0.001]; peak systolic and late diastolic longitudinal strain rates HRs, 4.7 [95% CI, 1.23 to 17.64; P=0.023] and 0.25 [95% CI, 0.08 to 0.79; P=0.02], respectively). Multivariate Cox regression analysis revealed circumferential early diastolic strain rate, among others, as an independent risk factor for all-cause mortality (secondary end point; HR, 0.43; 95% CI, 0.25 to 0.74; P=0.002). Together, these data support speckle tracking as a postprocessing echocardiographic technique to detect uremic cardiomyopathy and predict cardiovascular mortality in ESRD.

Incidence of postoperative nausea and emetic episodes after xenon anaesthesia compared with propofol-based anaesthesia

BACKGROUND Xenon has been proved to be safe and efficacious for general anaesthesia in numerous trials. In addition, experimental studies demonstrate that xenon inhibits the 5-hydroxytryptamine type 3 (5-HT(3)) receptor. As 5-HT(3) receptor antagonists are known to decrease postoperative nausea and vomiting (PONV) to an extent comparable with a propofol-based total i.v. technique, we tested the hypothesis that general anaesthesia with xenon would result in a reduced incidence of PONV similar to that observed with propofol-based anaesthesia. METHODS After obtaining approval from the local ethics committee and written informed consent, 142 patients were randomized to receive xenon anaesthesia or propofol-based total i.v. anaesthesia (TIVA), both supplemented with remifentanil. The incidence of postoperative nausea and emetic episodes was recorded in the post-anaesthesia care unit and on the ward more than 24 h after anaesthesia. RESULTS A total of 142 patients were equally distributed between the xenon and TIVA groups. Anaesthesia was maintained with mean (sd) concentrations of either xenon 61 (2)% or propofol 100 (20) microg kg(-1) min(-1). Incidences of nausea and emetic episodes over the whole 24-h period were 66.2% and 35.2% in the xenon group and 26.8% and 16.9% in the TIVA group (P<0.001 and P<0.021). CONCLUSION Despite knowing the 5-HT(3) antagonistic properties of xenon, its use is associated with a higher incidence of nausea and emetic episodes compared with TIVA with propofol.

Neuroprotective properties of levosimendan in an in vitro model of traumatic brain injury

BackgroundWe investigated the neuroprotective properties of levosimendan, a novel inodilator, in an in vitro model of traumatic brain injury.MethodsOrganotypic hippocampal brain slices from mouse pups were subjected to a focal mechanical trauma. Slices were treated after the injury with three different concentrations of levosimendan (0.001, 0.01 and 0.1 μM) and compared to vehicle-treated slices. After 72 hrs, the trauma was quantified using propidium iodide to mark the injured cells.ResultsA significant dose-dependent reduction of both total and secondary tissue injury was observed in cells treated with either 0.01 or 0.1 μM levosimendan compared to vehicle-treated slices.ConclusionLevosimendan represents a promising new pharmacological tool for neuroprotection after brain injury and warrants further investigation in an in vivo model.

Anti-ischemic effects of inotropic agents in experimental right ventricular infarction.

Background: Right ventricular (RV) function is an important determinant of survival after myocardial infarction. The efficacy of reperfusion therapy might be increased by the cardioprotective action of inotropic agents, which are used for symptomatic therapy in situations with compromised hemodynamics. Therefore, we used a porcine model of RV ischemia and reperfusion (IR) injury to study the influence of milrinone, levosimendan and dobutamine on the extent and degree of myocardial injury.

Establishment of a porcine right ventricular infarction model for cardioprotective actions of xenon and isoflurane

Background: Right ventricular (RV) function is an important determinant of post‐operative outcome. Consequences of RV infarction might be limited by pre‐conditioning with volatile anesthetic drugs. Therefore, we used a porcine model of RV ischemia and reperfusion (IR) injury to study the influence of isoflurane and xenon on the extent and degree of myocardial injury.

The Effect of Xenon on Isoflurane Protection Against Experimental Myocardial Infarction

OBJECTIVES To investigate if the protective effects of xenon and isoflurane against myocardial ischemia-reperfusion damage would be additive. DESIGN A prospective, randomized laboratory investigation. SETTING An animal laboratory of a university hospital. PARTICIPANTS Thirty-six pigs (female German landrace). INTERVENTIONS In an open-chest preparation with thiopental anesthesia, the left anterior descending artery was occluded to produce ischemia for 60 minutes. One hour previously, ischemic preconditioning, isoflurane (0.55 minimum alveolar concentration [MAC]) alone, or isoflurane together with xenon (0.55 MAC each) were started in the respective groups. A fourth (control) group received no protective intervention. Myocardial ischemia was followed by 2 hours of reperfusion. MEASUREMENTS AND MAIN RESULTS Hearts were excised and stained (Evans Blue/TTC) to measure infarct size as related to the area at risk. Myocardial infarct size was reduced (means +/- standard deviation) from 64% +/- 9% of the area at risk in the control group to 19% +/- 12% with ischemic preconditioning to 46% +/- 12% with isoflurane and to 39% +/- 13% with isoflurane and xenon. All intervention groups were significantly different from the control (p < 0.05), and both anesthetic groups were significantly different from ischemic preconditioning (p < 0.05). CONCLUSION Combined isoflurane/xenon anesthesia reduced infarct size but not more than isoflurane alone. Ischemic preconditioning was more effective than the anesthetics.

Perioperatives Management der obstruktiven Schlafapnoe

There is lack of studies investigating procedures aiming at a decrease in perioperative mortality in patients with obstructive sleep apnoea (OSA). During anesthetic evaluation, identification of patients with OSA as well as using a risk score has been recommended by the American Society of Anesthesiology in order to identify the best perioperative strategy. Perioperative attention should be focused on a secure airway and the duration of monitoring that is necessary regarding severity of OSA, surgical stress and respiratory function. Postoperatively, residual neuromuscular blockade and a supine position have to be avoided. Continuous pulse oximetry should be used as long as patients remain at increased risk and should be applied until oxygen saturation remains above 90% with room air during sleep. Opioids should be excluded for pain management whenever possible, and CPAP or NIPPV should be administered as soon as feasible after surgery to patients who have been receiving it preoperatively.ZusammenfassungSystematische Untersuchungen zur perioperativen Letalitätsreduktion bei Patienten mit obstruktiver Schlafapnoe (OSA) stehen noch aus. Neben der Identifikation bisher unerkannter Schlafapnoepatienten im Rahmen der anästhesiologischen Aufklärung, empfiehlt eine Konsensuskonferenz der American Society of Anesthesiology die Verwendung eines Risikoscores, um die perioperative Versorgung zu planen. Perioperativ liegt besonderer Augenmerk auf der Atemwegssicherung, dem Ausschluss von Muskelrelaxansüberhängen, der Vermeidung flacher Rückenlagen sowie der Dauer der Monitorüberwachung. Hierbei sollten Patienten je nach OSA-Schwere, operativer Belastung und respiratorischer Funktion kontinuierlich mittels Pulsoxymetrie überwacht werden, solange die Patienten nicht selbstständig in der Lage sind, schlafend eine Sauerstoffsättigung über 90% zu halten. Postoperativ sollten suffiziente Analgesiekonzepte, möglichst unter Verzicht von Opioiden, und patienteneigene CPAP/NIPPV-Geräte genutzt werden.AbstractThere is lack of studies investigating procedures aiming at a decrease in perioperative mortality in patients with obstructive sleep apnoea (OSA). During anesthetic evaluation, identification of patients with OSA as well as using a risk score has been recommended by the American Society of Anesthesiology in order to identify the best perioperative strategy. Perioperative attention should be focused on a secure airway and the duration of monitoring that is necessary regarding severity of OSA, surgical stress and respiratory function. Postoperatively, residual neuromuscular blockade and a supine position have to be avoided. Continuous pulse oximetry should be used as long as patients remain at increased risk and should be applied until oxygen saturation remains above 90% with room air during sleep. Opioids should be excluded for pain management whenever possible, and CPAP or NIPPV should be administered as soon as feasible after surgery to patients who have been receiving it preoperatively.