[The Role of the Anaesthesiologist in Liver Transplantation - Preoperative Evaluation]. / Die Rolle des Anästhesisten bei Lebertransplantationen ­ präoperative Evaluation.

Preoperative evaluation prior to listing for orthotopic liver transplantation (LT) requires a careful multidisciplinary approach with specialized teams including surgeons, hepatologists and anesthesiologists in order to improve short- and long-term clinical outcomes. Due to inadequate supply of donor organs and changing demographics, patients listed for LT have become older, sicker and share more comorbidities. As cardiovascular events are the leading cause for early mortality precise evaluation of risk factors is mandatory. This review focuses on the detection and management of coronary artery disease, cirrhotic cardiomyopathy, portopulmonary hypertension and hepatopulmonary syndrome in patients awaiting LT. Further insights are being given into scoring systems, patients with Acute-on-chronic-liver-failure (ACLF), frailty, NASH cirrhosis and into psychologic evaluation of patients with substance abuse.

Development of an Anticipatory Triage-Ranking Algorithm Using Dynamic Simulation of the Expected Time Course of Patients With Trauma: Modeling and Simulation Study.

BACKGROUND: In cases of terrorism, disasters, or mass casualty incidents, far-reaching life-and-death decisions about prioritizing patients are currently made using triage algorithms that focus solely on the patient's current health status rather than their prognosis, thus leaving a fatal gap of patients who are under- or overtriaged. OBJECTIVE: The aim of this proof-of-concept study is to demonstrate a novel approach for triage that no longer classifies patients into triage categories but ranks their urgency according to the anticipated survival time without intervention. Using this approach, we aim to improve the prioritization of casualties by respecting individual injury patterns and vital signs, survival likelihoods, and the availability of rescue resources. METHODS: We designed a mathematical model that allows dynamic simulation of the time course of a patient's vital parameters, depending on individual baseline vital signs and injury severity. The 2 variables were integrated using the well-established Revised Trauma Score (RTS) and the New Injury Severity Score (NISS). An artificial patient database of unique patients with trauma (N=82,277) was then generated and used for analysis of the time course modeling and triage classification. Comparative performance analysis of different triage algorithms was performed. In addition, we applied a sophisticated, state-of-the-art clustering method using the Gower distance to visualize patient cohorts at risk for mistriage. RESULTS: The proposed triage algorithm realistically modeled the time course of a patient's life, depending on injury severity and current vital parameters. Different casualties were ranked by their anticipated time course, reflecting their priority for treatment. Regarding the identification of patients at risk for mistriage, the model outperformed the Simple Triage And Rapid Treatment's triage algorithm but also exclusive stratification by the RTS or the NISS. Multidimensional analysis separated patients with similar patterns of injuries and vital parameters into clusters with different triage classifications. In this large-scale analysis, our algorithm confirmed the previously mentioned conclusions during simulation and descriptive analysis and underlined the significance of this novel approach to triage. CONCLUSIONS: The findings of this study suggest the feasibility and relevance of our model, which is unique in terms of its ranking system, prognosis outline, and time course anticipation. The proposed triage-ranking algorithm could offer an innovative triage method with a wide range of applications in prehospital, disaster, and emergency medicine, as well as simulation and research.

Effects of awake caudal anesthesia on mean arterial blood pressure in very low birthweight infants.

BACKGROUND: Intraoperative blood pressure is a relevant variable for postoperative outcome in infants undergoing surgical procedures. It is therefore important to know whether the type of anesthesia has an impact on intraoperative blood pressure management in very low birth weight infants. Here, we retrospectively analyzed intraoperative blood pressure in very low birthweight infants receiving either awake caudal anesthesia without sedation, or caudal block in combination with general anesthesia, both for open inguinal hernia repair. METHODS: Ethical approval was provided by the University of Tuebingen Ethical Committee on 05/29/2018 with the project number 403/2018BO2. Patient records of infants admitted by the neonatologist (median age at birth 31.1 ± 3.5 weeks, median weight at birth 1240 ± 521 g) which were scheduled for inguinal hernia repair were retrospectively evaluated for the course of mean arterial blood pressure and perioperative interventions to stabilize blood pressure. A total of 42 patients were included, 16 patients (11 boys, 5 girls) received awake caudal anesthesia, 26 patients (22 boys, 4 girls) a combination of general anesthesia and caudal block. RESULTS: Approximately 3% of the measured mean arterial blood pressure values in the caudal anesthesia group were below a critical margin of 35 mmHg, in contrast to 47% in the combined anesthesia group (p < 0.001). Patients in the latter group showed a significantly larger drop of mean arterial blood pressure below 35 mmHg (4.7 ± 2.7 mmHg vs. 1.9 ± 1.6 mmHg; p < 0.005) and a significantly longer time of mean arterial blood pressure below 35 mmHg (25.6 ± 26.0 min vs. 0.9 ± 2.3 min; p < 0.001), although they received more volume and vasopressor boluses for stabilization (27 ± 14.8 ml vs. 10 ± 4.1 ml; p < 0.01 and 0.15 ± 0.06 ml vs. 0 ml of cafedrine/theoadrenaline; p < 0.001). CONCLUSIONS: The study indicates that the use of caudal block as stand alone procedure for inguinal hernia repair in very low birthweight infants might be advantageous in preventing critical blood pressure drops compared to a combination of caudal block with general anesthesia.

Allopregnanolone Enhances GABAergic Inhibition in Spinal Motor Networks.

The neurosteroid allopregnanolone (ALLO) causes unconsciousness by allosteric modulation of γ-aminobutyric acid type A (GABAA) receptors, but its actions on the spinal motor networks are unknown. We are therefore testing the hypothesis that ALLO attenuates the action potential firing of spinal interneurons and motoneurons predominantly via enhancing tonic, but not synaptic GABAergic inhibition. We used video microscopy to assess motoneuron-evoked muscle activity in organotypic slice cultures prepared from the spinal cord and muscle tissue. Furthermore, we monitored GABAA receptor-mediated currents by performing whole-cell voltage-clamp recordings. We found that ALLO (100 nM) reduced the action potential firing of spinal interneurons by 27% and that of α-motoneurons by 33%. The inhibitory effects of the combination of propofol (1 µM) and ALLO on motoneuron-induced muscle contractions were additive. Moreover, ALLO evoked a tonic, GABAA receptor-mediated current (amplitude: 41 pA), without increasing phasic GABAergic transmission. Since we previously showed that at a clinically relevant concentration of 1 µM propofol enhanced phasic, but not tonic GABAergic inhibition, we conclude that ALLO and propofol target distinct subpopulations of GABAA receptors. These findings provide first evidence that the combined application of ALLO and propofol may help to reduce intraoperative movements and undesired side effects that are frequently observed under total intravenous anesthesia.

Automated closed-loop management of body temperature using forced-air blankets: preliminary feasibility study in a porcine model.

BACKGROUND: Management of a patient's body temperature is an important aspect of care that should be addressed by targeted temperature management (TTM). Often, non-invasive methods like forced-air blankets are used. Especially in the operating room this management may be a subsidiary and repetitive task requiring constant observation of the patient's body temperature and adaption using the limited set of available settings. Thus, automation of TTM is a feasible target to improve patient outcome and reduce caregiver workload. METHODS: A Philips IntelliVue MP 50 patient monitor with an arterial PiCCO catheter system was used to measure patient blood temperature. Thermal management was performed with a 3M Bair Hugger 755 warming unit with forced air blankets. The warming unit was extended by a computer interface to allow for remote and automated control. A proposed closed-loop algorithm reads the measured temperature and performs automated control of the 3M Bair Hugger. Evaluation was performed in an experimental intensive care setting for animal studies. Two fully automated trials are compared with two manual and two uncontrolled trials in the same study setting using six female pigs for prolonged observation times of up to 90 hours in each trial. RESULTS: The developed system and proposed algorithm allow more precise temperature management by keeping a set target temperature within a range of ± 0.5 °C in 88% of the observation time and within a range of ± 1.0 °C at all times. The proposed algorithm yielded better performance than did manual control or uncontrolled trials. It was able to adapt to individual patient needs as it is more dynamic than look-up table approaches with fixed settings for various temperatures. CONCLUSIONS: Closed-loop TTM using non-invasive forced-air warming blankets was successfully tested in a porcine study with the proposed hardware interface and control algorithm. This automation can be beneficial for patient outcome and can reduce caregiver workload and patient risk in clinical settings. As temperature readings are most often available, existing devices like the 3M Bair Hugger can easily be expanded. However, even if clinical application is feasible, open questions regarding approval and certification of such automated systems within the current legal situation still need to be answered.

Selecting living donors for uterus transplantation: lessons learned from two transplantations resulting in menstrual functionality and another attempt, aborted after organ retrieval.

PURPOSE: To contribute to establishing donor selection criteria based on our experience with two successful living-donor human uterus transplantations (UTx) and an aborted attempt. METHODS: This interventional study included three patients with uterine agenesis, aged 23, 34, and 23 years, scheduled for UTx, and their uterus-donating mothers, aged 46, 61, and 46 years, respectively. Interventions included preoperative investigations, donor surgery, back-table preparation, and recipient surgery. Preoperative imaging, surgical data, histopathology, menstrual pattern, and uterine blood flow were the main outcome measures. RESULTS: In the first case (46-year-old mother/23-year-old daughter), donor/recipient surgery took 12.12/5.95 h. Regular spontaneous menstruations started 6-week post-transplantation, continuing at 24-28-day intervals throughout the 6-month observation period. Repeated follow-up cervical biopsies showed no signs of rejection. In the second case (61-year-old donor), surgery lasted 13.10 h; attempts to flush the retrieved uterus failed due to extreme resistance of the left uterine artery (UA) and inability to perfuse the right UA. Transplantation was aborted to avoid graft vessel thrombosis or insufficient blood flow during potential pregnancy. Histopathology revealed intimal fibrosis and initial sclerosis (right UA), extensive intimal fibrosis (parametric arterial segments), and subtotal arterial stenosis (myometrial vascular network). In the third case (46-year-old mother/23-year-old daughter), donor/recipient surgery took 9.05/4.52 h. Menstruations started 6-week post-transplantation. Repeated cervical biopsies showed no signs of rejection during the initial 12-week follow-up period. CONCLUSIONS: Meticulous preoperative evaluation of potential living uterus donors is essential. This may include selective contrast-enhanced UA angiograms and limitation of donor age, at least in donors with risk factors for atherosclerosis. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03048396.

2D Echocardiographic Evaluation of Right Ventricular Function Correlates With 3D Volumetric Models in Cardiac Surgery Patients.

OBJECTIVES: The early diagnosis and treatment of right ventricular (RV) dysfunction are of critical importance in cardiac surgery patients and impact clinical outcome. Two-dimensional (2D) transesophageal echocardiography (TEE) can be used to evaluate RV function using surrogate parameters due to complex RV geometry. The aim of this study was to evaluate whether the commonly used visual evaluation of RV function and size using 2D TEE correlated with the calculated three-dimensional (3D) volumetric models of RV function. DESIGN AND SETTING: Retrospective study, single center, University Hospital. PARTICIPANTS AND INTERVENTION: Seventy complete datasets were studied consisting of 2D 4-chamber view loops (2-3 beats) and the corresponding 4-chamber view 3D full-volume loop of the right ventricle. RV function and RV size of the 2D loops then were assessed retrospectively purely qualitatively individually by 4 clinician echocardiographers certified in perioperative TEE. Corresponding 3D volumetric models calculating RV ejection fraction and RV end-diastolic volumes then were established and compared with the 2D assessments. MEASUREMENTS AND MAIN RESULTS: 2D assessment of RV function correlated with 3D volumetric calculations (Spearman's rho -0.5; p<0.0001). No correlation could be established between 2D estimates of RV size and actual 3D volumetric end-diastolic volumes (Spearman's rho 0.15; p = 0.25). CONCLUSION: The 2D assessment of right ventricular function based on visual estimation as frequently used in clinical practice appeared to be a reliable method of RV functional evaluation. However, 2D assessment of RV size seemed unreliable and should be used with caution.

[The Influence of Anesthesia On Perioperative Outcome in Children - Institutional and Individual Factors]. / Anästhesie und Outcome: Einfluss bei Kindern.

The perioperative care of children is challenging for health care providers. Since anesthetists cannot affect the nature of the disease and have hardly an impact on the decision for surgery we summarized in this review individual and institutional factors for improving perioperative outcome by anesthetists. Individual factors include the level of education and the professional experience of the anesthetist as well as an anesthetic management that is focused on the maintenance of an adequate cerebral perfusion. Besides individual factors this review emphasizes the importance of institutional factors as measures to reduce anxiety and insecurity of the parents which result in less distress and coping of the children in the postanesthesia care unit as well as less need for pain medication, less emergence delirium and less sleep disorders. A behaviorally oriented preoperative preparation of parents and children also affects the postoperative course of the pediatric patients positively as well as institutional concepts for the reduction of perioperative medication errors and adverse drug events. We believe that perspectively pediatric surgery will be increasingly performed in high volume hospitals which are able to guarantee beneficial institutional structures as well as a high educational level and high professional experience of the employed anesthetists.

Contributors to individual quality of life after liver transplantation.

BACKGROUND: With increasing improvements of patient survival after liver transplantation, the focus on outcome measures shifts from survival rate to quality of life. Individual quality of life is crucial to rehabilitate patients after transplantation. Therefore, it is important to identify specific issues that contribute to high individual quality of life. In contrast to the Short form 36 Health Survey (SF-36), the Schedule for the Evaluation of Individual aspects of Quality of Life-direct weighting (SEIQoL-DW) allows patients to name the areas of life, which are important to them. DESIGN: In a semi-structured interview style, 71 patients following liver transplant were asked to complete the SEIQoL-DW and the SF-36 in a cross-sectional design. RESULTS: We found five quality of life areas that were chosen by more than half of the patients: family, friends, sports, partnership and profession/occupation. Health was only mentioned by 45% of all patients. Individual quality of life did not differ from healthy population. In the SF-36, patients showed normal mental health parameters but reduced physical components. A strong correlation between SEIQoL-DW-Index and the mental component summary of the SF-36 was observed. CONCLUSION: In addition to the widely used standardized SF-36, the individual measure SEIQoL-DW shows new aspects concerning the areas of quality of life, which are personally important to the participants. Less than half of our patients mentioned health and the five most nominated areas are not related to health. By focusing on health, the importance of health-related factors is overrated, and the impact of non-medical effects is underrepresented.

Caudal Block versus Wound Infiltration for Inguinal Procedures in Young Children: A Randomized Clinical Study.

INTRODUCTION: Inguinal procedures in children are frequent and typically performed in an outpatient setting. We aimed to analyze whether there is a difference in postoperative pain scores and setup time (start of anesthesia management to incision time) when comparing caudal block (CB) with local wound infiltration. MATERIALS AND METHODS: We enrolled pediatric outpatients scheduled for inguinal procedures. Patients were randomized to receive either preincision CBs or end-of-procedure local wound infiltration. Postoperative pain scores until 24 hours postoperatively and setup time were analyzed. RESULTS: Fifty-two patients were included in the study. Thirty patients received a CB, and 22 patients received local infiltration (LI). There was no significant difference in postoperative pain scores. Setup time was significantly higher in the CB group: median 22.5 minutes IQR (16-46 minutes) compared with 17 minutes in the LI group IQR (10-35 minutes), p-value of 0.0026. CONCLUSION: Both CB and LI result in good postoperative pain control after inguinal procedures in pediatric outpatients. Since LI is less time consuming and has lower risks for complications, we recommend this technique for inguinal procedures in pediatric outpatients. Our findings will need to be confirmed in larger cohorts, but we believe the evidence generated with this study has the potential to positively influence patient care, operating room efficiency, and costs.

Recovery of residual curarization after red blood cell transfusion.

BACKGROUND: The muscle-relaxing effects of succinylcholine are terminated via hydrolysis by plasma cholinesterase. There are multiple genetic variants of this enzyme and clinical circumstances that might influence the activity of plasma cholinesterase and eventually lead to prolonged neuromuscular blockade following succinylcholine application. CASE REPORT: Here, we report a parturient woman with atonic bleeding who suffered significant blood loss (hemoglobin 6.0 g•dL-¹). For surgical curettage, general anesthesia was performed by using short-acting succinylcholine. By the end of the 105-minute procedure, the patient's trachea was extubated. After extubation she showed signs of the prolonged neuromuscular blocking action of succinylcholine. At this time, the patient received an AB0-compatible red blood cell transfusion and recovered instantly from neuromuscular blockade. The plasma cholinesterase (3.200 U•L-¹) was below the normal range (4.900-12.000 U•L-¹). Patient's blood DNA analysis revealed heterozygously the genetic K variant of plasma cholinesterase. After red blood cell transfusion, serum potassium was elevated (5.7 mmol•L-¹; 4.4 mmol•L-¹ prior to transfusion). CONCLUSIONS: Pregnancy, blood loss and genetic variation contributed to impairment of plasma cholinesterase. Due to high-speed red blood cell transfusion, hemolytic release of erythrocyte cholinesterase might have terminated the neuromuscular blocking succinylcholine effect.

Hemodynamic Instability during Surgery for Pheochromocytoma: A Retrospective Cohort Analysis.

BACKGROUND: Perioperative hemodynamic instability is one of the most common adverse events in patients undergoing adrenalectomy for pheochromocytoma. The aim of this study was to analyze the impact of perioperative severe hemodynamic instability. METHODS: We present a retrospective, single-center analysis in a major tertiary hospital of all consecutive patients undergoing elective adrenalectomy from 2005 to 2019 for pheochromocytoma. Severe perioperative hypertension and hypotension were evaluated, defined as changes in blood pressure larger than 30% of the preoperative patient-specific mean arterial pressure (MAP). RESULTS: Unilateral adrenalectomy was performed in 67 patients. Intraoperative episodes of hemodynamic instability occurred in 97% of all patients (n = 65), severe hypertension occurred in 24 patients (36%), and severe hypotensive episodes occurred in 62 patients (93%). Patients with more than five severe hypotensive episodes (n = 29) received higher preoperative alpha-adrenergic blockades (phenoxybenzamine 51 ± 50 mg d-1 vs. 29 ± 27 mg d-1; p = 0.023) and had a longer mean ICU stay (39.6 ± 41.5 h vs. 20.6 ± 19.1 h, p = 0.015). CONCLUSION: Intraoperative hypotensive, rather than hypertensive, episodes occurred during adrenalectomy. The occurrence of more than five hypotensive episodes correlated well with a significantly longer hospital stay and ICU time.

Impact of soman and acetylcholine on the effects of propofol in cultured cortical networks.

Patients intoxicated with organophosphorous compounds may need general anaesthesia to enable mechanical ventilation or for control of epileptiform seizures. It is well known that cholinergic overstimulation attenuates the efficacy of general anaesthetics to reduce spontaneous network activity in the cortex. However, it is not clear how propofol, the most frequently used intravenous anaesthetic today, is affected. Here, we investigated the effects of cholinergic overstimulation induced by soman and acetylcholine on the ability of propofol to depress spontaneous action potential activity in organotypic cortical slices measured by extracellular voltage recordings. Cholinergic overstimulation by co-application of soman and acetylcholine (10 µM each) did not reduce the relative inhibition of propofol (1.0 µM; mean normalized action potential firing rate 0.49 ± 0.06 of control condition, p < 0.001, Wilcoxon signed rank test) but clearly reduced its efficacy. Co-application of atropine (10 nM) did not improve the efficacy. Propofol preserved its relative inhibitory potential but did not produce a degree of neuronal depression which can be expected to assure hypnosis in humans. Since a combination with atropine did not improve its efficacy, an increase in dosage will probably be necessary when propofol is used in victims suffering from organophosphorous intoxication.

Comparison of safety and periprocedural complications of transfemoral aortic valve replacement under local anaesthesia: minimalist versus complete Heart Team.

AIMS: The aim of the study was to evaluate peri-interventional complications and in-hospital complications in different team settings when performing transfemoral aortic valve replacement (TAVR) under local anaesthesia. METHODS AND RESULTS: We performed TAVR under local anaesthesia with a minimalist Heart Team consisting of two interventional cardiologists, an echocardiographer and two cardiac catheterisation laboratory nurses. In August 2015, new guidelines for TAVR were issued by the National Federal Joint Committee. In accordance with these guidelines, we began to perform TAVR using a complete Heart Team, consisting of two interventional cardiologists, an echocardiographer, a cardiac surgeon, an anaesthesiologist, a cardiovascular perfusionist, two cardiac catheterisation laboratory nurses, a surgical nurse and an anaesthetist nurse. In this study, we retrospectively analysed periprocedural and in-hospital outcomes. Two hundred and ninety-two (55.1%) patients were treated by the minimalist Heart Team, whereas 238 (44.9%) were treated by the complete Heart Team. There were no significant differences in periprocedural (1.4% vs. 1.3%, p=1.0) and in-hospital mortality (4.8% vs. 5.0%, p=0.9) as well as in conversion to open heart (0.3% vs. 0.8%, p=0.59) or immediate vascular surgery (0.3% vs. 2.1%, p=0.1) for minimalist versus complete Heart Team, respectively. CONCLUSIONS: TAVR under local anaesthesia can be safely performed by a minimalist Heart Team. We did not observe any differences in fatal periprocedural complications and mortality when compared with those of a complete Heart Team.