European Pediatric Cardiac Anesthesia Fellowship Program: A First Proof of Concept

The Pediatric Cardiac Anesthesia (PCA) fellowship is a demanding training program in Europe and the United States. Successful completion of the program requires years of training in anesthesiology, a thorough understanding of cardiovascular anatomy and physiology, and extensive experience in the perioperative management of neonates and children with heart disease. In the context of the first candidate to successfully complete the PCA program in Europe, this article presents excerpts from the design and structure of the European PCA program. The PCA program is evaluated critically by both external and internal reviewers, and points are highlighted that could be included in the next version of the program.

Intraoperative Blood Pressure Management and Its Effects on Postoperative Delirium After Cardiac Surgery: A Single-Center Retrospective Cohort Study

OBJECTIVES

There is accumulating evidence that blood pressure management might be associated with end-organ dysfunction after cardiac surgery. This study aimed to investigate the impact of intraoperative hypotension (IOH) on adverse neurologic outcomes and mortality.

DESIGN

A single-center retrospective cohort study.

SETTING

The Heart and Diabetes Centre Bad Oeynhausen NRW, Ruhr-University Bochum.

PARTICIPANTS

This retrospective cohort study included 31,315 adult patients who underwent elective cardiac surgery at the authors' institution between January 2009 and December 2018.

INTERVENTIONS

All cardiac surgery procedures except assist device implantation, organ transplantation, and emergency surgery.

MEASUREMENTS AND MAIN RESULTS

Adverse neurologic outcomes were defined as postoperative delirium and stroke. IOH was defined as mean arterial pressure below 60 mmHg for >2 minutes. The frequency of IOH episodes and the cumulative IOH duration were recorded. The association between IOH and adverse neurologic outcomes was examined with unadjusted statistical analysis and multiple logistic regression analysis. Eight hundred forty-nine (2.9%) patients developed postoperative stroke, and 2,401 (7.7%) patients developed postoperative delirium. The frequency of IOH episodes was independently associated with postoperative delirium in the multiple logistic regression analysis (odds ratio 1.02, 95% CI 1.003-1.03, p < 0.001), whereas there was no association between it and stroke.

CONCLUSION

This large retrospective monocentric cohort study revealed that increased episodes of IOH were associated with the risk of developing postoperative delirium after cardiac surgery. This might have important clinical implications with respect to careful and precise hemodynamic monitoring and proactive treatment, especially in patients with increased risk for postoperative delirium.

Practical training concept for perfusionists at the heart and diabetes center Nordrhein-Westfalen

BACKGROUND

Increasing regulations and requirements of advisory bodies, in particular the Joint Federal Committee and the Medical Service of the health insurance funds, make it necessary to employ only demonstrably well-trained perfusionists. The minimum requirement for this staff is EBCP certification. Currently there is limited availability of such specialists on the German market. Therefore, the qualification of young people in this area is of central importance. The aim of this paper is to strengthen the training of perfusionists at our centre, to standardise the process and to provide the respective student with a "roadmap" to their internship.

MATERIAL & METHODS

The structure is based on a rough division of the 24 weeks of internship. This is described in detail in the following and is backed up with the learning objectives for the respective time periods.

RESULTS

At our centre, practical training has been standardized and clear responsibilities have been defined. Furthermore, as a centre of maximum care in the field of cardiac surgery, we can offer students the necessary number of perfusions in just six months to meet the requirements of the ECBP for practical training. According to this concept, 20 perfusionists have been successfully trained in the last 8 years. All of them have passed the exams and have been certified according to EBCP.

CONCLUSION

The aim of the practical semester is for the student to be in a position at the end of the semester to independently supervise simple cardiac surgery procedures with the aid of the Extra- Corporal Circulation (ECC) and to carry this out in accordance with the currently valid guidelines and directives (1-8) and the departmental procedural instructions based on them. Great emphasis is placed to the students becoming aware of their competence to act, knowing their limits and being able to assess when these limits have been reached and the involvement of experienced colleagues is necessary to ensure patient safety.

How Would We Treat Our Own Cystic Fibrosis With Lung Transplantation?

Lung transplantation is the only therapy for patients with end-stage lung disease. In advanced lung diseases such as cystic fibrosis (CF), life expectancy increases, and it is important to recognize extrapulmonary comorbidities. Cardiovascular involvement, including pulmonary hypertension, right-heart failure, and myocardial dysfunction, are manifest in the late stages of CF disease. Besides right-heart failure, left-heart dysfunction seems to be underestimated. Therefore, an optimal anesthesia and surgical management risk evaluation in this high-risk patient population is mandatory, especially concerning the perioperative use of mechanical circulatory support. The use of an index case of an older patient with the diagnosis of cystic fibrosis demonstrates the importance of early risk stratification and strategy planning in a multidisciplinary team approach to guarantee successful lung transplantation.

Midazolam for Post-Arrest Sedation in Pre-Hospital Emergency Care—a Multicenter Propensity Score Analysis

BACKGROUND

An out-of-hospital cardiac arrest (OHCA) with return of spontaneous circulation (ROSC) may need to be treated with airway management, emergency ventilation, invasive interventions, and post-arrest sedation. We investigated the influence of the use of midazolam for post-arrest sedation on achieving post-resuscitation care targets and the associated risk of hemodynamic complications.

METHODS

All emergency rescue missions of the Dresden, Gütersloh, and Lippe medical rescue services in the years 2019-2021 were reviewed to identify adult patients who had OHCA, unconsciousness, and sustained ROSC with spontaneous circulation until arrival at the hospital; the findings were supplemented with data from the German Resuscitation Registry. Patients who received midazolam (alone or in combination with other anesthetic agents) for post-arrest sedation were compared with those who did not. The endpoints were the regaining of a systolic blood pressure ≥ 100 mmHg, end-tidal pCO2 35-45 mmHg, and oxygen saturation (SpO2) 94-98%. A propensity score analysis was used to adjust for age, sex, and variables potentially affecting hemodynamic status or the targets for oxygenation and ventilation.

RESULTS

There were 2335 cases of OHCA among 391 305 emergency rescue missions. 571 patients had ROSC before arrival in the hospital (24.5%; female, 33.6%; age, 68 ± 14 years). Of the 395 among them (69.2%) who were treated with post-arrest sedation, 249 (63.0%) received midazolam. Patients who received midazolam reached the guideline-recommended targets for oxygenation, ventilation, and blood pressure more frequently than those who were not sedated: the respective odds ratios and 95% confidence intervals were 2.00 [1.20; 3.34], 1.57 [0.99; 2.48], and 1.41 [0.89; 2.21].

CONCLUSION

The pre-hospital administration of midazolam leads to more frequent pre-hospital attainment of the oxygenation and ventilation targets in post-resuscitation care, without any evidence of an elevated risk of hemodynamic complications.

PERSUADE Survey-PERioperative AnestheSia and Intensive Care Management of Left VentricUlar Assist DevicE Implantation in Europe and the United States

OBJECTIVE

To comprehensively assess relevant institutional variations in anesthesia and intensive care management during left ventricular assist device (LVAD) implantation.

DESIGN

The authors used a prospective data analysis.

SETTING

This was an online survey.

PARTICIPANTS

Participants were from LVAD centers in Europe and the US.

INTERVENTIONS

After investigating initial interest, 91 of 202 European and 93 of 195 US centers received a link to the survey targeting institutional organization and experience, perioperative hemodynamic monitoring, medical management, and postoperative intensive care aspects.

MEASUREMENTS AND MAIN RESULTS

The survey was completed by 73 (36.1%) European and 60 (30.8%) US centers. Although most LVAD implantations were performed in university hospitals (>5 years of experience), significant differences were observed in the composition of the preoperative multidisciplinary team and provision of intraoperative care. No significant differences in monitoring or induction agents were observed. Propofol was used more often for maintenance in Europe (p < 0.001). The choice for inotropes changed significantly from preoperatively (more levosimendan in Europe) to intraoperatively (more use of epinephrine in both Europe and the US). The use of quantitative methods for defining right ventricular (RV) function was reported more often from European centers than from US centers (p < 0.05). Temporary mechanical circulatory support for the treatment of RV failure was more often used in Europe. Nitric oxide appeared to play a major role only intraoperatively. There were no significant differences in early postoperative complications reported from European versus US centers.

CONCLUSIONS

Although the perioperative practice of care for patients undergoing LVAD implantation differs in several aspects between Europe and the US, there were no perceived differences in early postoperative complications.

Tranexamic Acid and the Risk of Delirium after Off-Pump Surgery

We investigated whether in patients undergoing off-pump coronary artery bypass grafting surgery a single bolus of 1 g tranexamic acid (TXA) impacts the risk of postoperative delirium using the propensity score matching approach. In 2,757 pairs, the risk of delirium was 4.2% (TXA group) and 5.0% (non-TXA group), with a relative risk in the TXA versus the non-TXA group of 0.83 (95% confidence interval: 0.65-1.07; p = 0.16). There was no significant interaction between TXA administration and renal function on the risk of delirium (p = 0.12). Data indicate that a single bolus of 1 g TXA does not increase the risk of delirium in patients undergoing off-pump surgery.

Peripheral cholinesterase activity is not correlated with postoperative delirium in urological surgery

The value of biomarkers, such as acetylcholinesterase and butyrylcholinesterase, for guiding perioperative patients suffering from postoperative delirium and/or (possibly related) postoperative cognitive dysfunction is unclear. Only recently have different biomarkers are being explored to assess postoperative delirium's occurrence and/or course. The aim of this work is to investigate whether acetylcholinesterase and butyrylcholinesterase can help detect increased risks of the development and course of postoperative delirium in urological patients undergoing surgery. In total, 45 urology patients were screened. During five perioperative time points (meaning preoperative and postoperative), acetylcholinesterase or butyrylcholinesterase concentrations from serum were correlated with three perioperative postoperative delirium and two perioperative postoperative cognitive dysfunction investigations. Results showed neither a significant decline of either acetylcholinesterase or butyrylcholinesterase concentration before and after surgery, nor a significant correlation with postoperative delirium. Furthermore, significant postoperative cognitive dysfunction could not be detected in this perioperative urological collective.

The Efficacy and Safety of a Low-Dose Tranexamic Acid Bolus-Only Protocol Compared with the Moderate-Dose Protocol in Valvular Heart Surgery

In 873 propensity score-matched pairs of patients undergoing valvular heart surgery, we compared a "moderate dose" of tranexamic acid (TXA) protocol (group 1; median TXA dose: 24 mg/kg body weight) with a 1.5-g "bolus-only" protocol (group 2; median TXA dose: 19 mg/kg body weight). The number of transfused patients was higher in group 2 than in group 1 (74.5 vs 66.0%, p < 0.001), as was the number of transfused red blood cell concentrates (p = 0.001). The risks of re-exploration and convulsive seizures were similar between groups (p > 0.50). Data indicate an impaired efficacy following the "bolus-only" protocol, without a significant safety improvement.

Implementation of the Kidney Disease Improving Global Outcomes guidelines for the prevention of acute kidney injury after cardiac surgery: An international cohort survey

BACKGROUND

Increasing evidence from randomised controlled trials supports the implementation of a six-measure care bundle proposed by the Kidney Disease Improving Global Outcomes (KDIGO) guidelines in patients at high risk for acute kidney injury (AKI) to reduce its incidence after cardiac surgery.

OBJECTIVE

To assess compliance with the KDIGO bundle in clinical practice.

DESIGN

Prospective observational multinational study.

SETTING

Six international tertiary care centres, from February 2021 to November 2021.

PATIENTS

Five hundred and thirty-seven consecutive patients undergoing cardiac surgery during a 1-month observational period.

INTERVENTIONS

All patients were assessed for the postoperative implementation of the following measures: avoidance of nephrotoxic medication and radiocontrast agents whenever possible, strict glycaemic control, close monitoring of renal function, optimisation of haemodynamic and volume status and functional monitoring of haemodynamic status.

MAIN OUTCOME MEASURES

The primary endpoint was the proportion of patients receiving fully compliant care. Secondary outcomes were occurrence of AKI and major adverse kidney event rate at day 30.

RESULTS

The full care bundle was applied to 0.4% of patients. There was avoidance of nephrotoxic drugs in 15.6%, radiocontrast agents in 95.3% and hyperglycaemia in 39.6%. Close monitoring of urine output and serum creatinine was achieved in 6.3%, 57.4% underwent optimisation of volume and haemodynamic status, and 43.9% received functional haemodynamic monitoring. 27.2% developed AKI within 72 h after surgery. The average number of implemented measures was 2.6 ± 1.0 and did not differ between AKI or non-AKI patients ( P  = 0.854).

CONCLUSION

Adherence with the KDIGO bundle was very low in cardiac surgery patients. Initiatives to improve guideline compliance might provide a strategy to mitigate the burden of AKI.

TRIAL REGISTRATION

www.drks.de DRKS00024204.

Patientinnen- und patientenbezogene Auswirkungen von prozessverantwortlicher Pflege

Background

Since January 2022, a primary nursing system called process-responsible nursing (PP) has substituted the standard room care system in an intensive care unit (ICU) at our institution. The process of the development and implementation of PP is already being evaluated in a separate study as an actual analysis prior to implementation, as well as after 6 and 12 months.

Aim

This pilot randomized controlled trial (RCT) aims to test the feasibility of an RCT. For this purpose, the duration of delirium, among other things, will be compared in the project ICU with the results of standard care in another ICU at the university hospital. As secondary aims, the incidence of delirium, anxiety, the satisfaction of relatives, and the effects of PP on nurses will be assessed.

Methods

It is planned to recruit about 400–500 patients over a period of one year. They will be allocated to PP or standard care. Delirium will be assessed using the Confusion Assessment Method for Intensive Care Units by specifically trained nurses three times a day. Anxiety in patients, the satisfaction of relatives, and the effects of PP on nurses will be evaluated using the numeric rating scale, a standardized questionnaire, and a focus group interview, respectively.

Expected results

The primary hypothesis is that compared to usual care PP reduces the duration of delirium by at least 8 h. Additional hypotheses are that PP reduces anxiety in patients and increases the satisfaction of relatives.

Current practices in medical nutrition therapy in the cardiac surgical critical care setting - an international multicenter observational study

BACKGROUND

Cardiac surgery patients with prolonged stay in the intensive care unit (ICU) are at high-risk for acquired malnutrition. Medical nutrition therapy practices in cardiac surgery patients are unknown. The objective of this study is to describe current nutrition practices in critically ill cardiac surgery patients worldwide.

METHODS

We conducted a prospective observational study in 13 international ICUs involving mechanically ventilated cardiac surgery patients with an ICU stay of at least 72 hours. Collected data included calorie and protein prescription, type and time to initiation of nutrition, and actual quantity of energy and protein delivered (maximum: 12 days).

RESULTS

Among 237 enrolled patients, enteral nutrition (EN) was started, on average, 45 hours after ICU admission (range 0-277 hours; site average 53 [range 10-79 hours]). EN was prescribed in 187 (79%) patients and combined EN and parenteral nutrition (PN) in 33 (14%). Overall, patients received 44.2% (0.0-117.2%) of prescribed calories and 39.7% (0.0-122.8%) of prescribed protein. At a site level, the average nutritional adequacy was 47.5% (30.5-78.6%) for calories and 43.6% (21.7-76.6%) for protein received from all nutritional sources.

CONCLUSION

Critically ill cardiac surgery patients with prolonged ICU stay experience significant delays in starting EN and receive low levels of calories and protein. There exists tremendous variability in site performance, whereas achieving optimal nutrition performance is doable.

VIDEO ABSTRACT

A video abstract (Video S1) is provided with the supplementary materials. This article is protected by copyright. All rights reserved.

Association between post-operative delirium and use of volatile anesthetics in the elderly: A real-world big data approach

STUDY OBJECTIVE

Early post-operative delirium is a common perioperative complication in the post anesthesia care unit. To date it is unknown if a specific anesthetic regime can affect the incidence of delirium after surgery. Our objective was to examine the effect of volatile anesthetics on post-operative delirium.

DESIGN

Single Center Observational Study.

SETTING

Post Anesthesia Care Units at a German tertiary medical center.

PATIENTS

30,075 patients receiving general anesthesia for surgery.

MEASUREMENTS

Delirium was assessed with the Nursing Delirium Screening Scale at the end of the recovery period. Subgroup-specific effects of volatile anesthetics on post-operative delirium were estimated using generalized-linear-model trees with inverse probability of treatment weighting. We further assessed the age-specific effect of volatiles using logistic regression models.

MAIN RESULTS

Out of 30,075 records, 956 patients (3.2%) developed delirium in the post anesthesia care unit. On average, patients who developed delirium were older than patients without delirium. We found volatile anesthetics to increase the risk (Odds exp. (B) for delirium in the elderly 1.8-fold compared to total intravenous anesthesia. Odds increases with unplanned surgery 3.0-fold. In the very old (87 years or older), the increase in delirium is 6.2-fold. This result was confirmed with internal validation and in a logistic regression model.

CONCLUSIONS

Our exploratory study indicates that early postoperative delirium is associated with the use of volatile anesthetics especially in the sub-cohort of patients aged 75 years and above. Further studies should include both volatile and intravenous anesthetics to find the ideal anesthetic in elderly patients.

Transfusions and early outcomes in anaemic patients undergoing off- or on-pump coronary artery bypass grafting

We retrospectively compared transfusion rates and early outcomes in 1621 consecutive patients with preoperative anaemia undergoing off-pump coronary artery bypass grafting (OPCAB) or on-pump coronary artery bypass grafting (ONCAB) surgery using a propensity score analysis with inverse probability of treatment weighting. Endpoints were transfusions, early morbidity, and mortality. Surgeries were performed by 45 dedicated OPCAB and/or ONCAB surgeons during the 10-year study period. Operative data did not differ significantly between study groups with the exception of a more frequent use of bilateral internal mammary artery revascularization approach in OPCAB patients than ONCAB patients. OPCAB was associated with fewer transfusions and lower risk for the need of postoperative renal replacement therapy, but higher risk of wound infections than ONCAB. Perioperative stroke risk and 30-day and 1-year mortality did not differ significantly between the groups. Our data in a 'real-world setting' indicate that in patients with preoperative anaemia both ONCAB and OPCAB are feasible surgical approaches regarding early morbidity and mortality.

Intraoperative Circulatory Support in Lung Transplantation: Current Trend and Its Evidence

Lung transplantation has a high risk of haemodynamic complications in a highly vulnerable patient population. The effects on the cardiovascular system of the various underlying end-stage lung diseases also contribute to this risk. Following a literature review and based on our own experience, this review article summarises the current trends and their evidence for intraoperative circulatory support in lung transplantation. Identifiable and partly modifiable risk factors are mentioned and corresponding strategies for treatment are discussed. The approach of first identifying risk factors and then developing an adjusted strategy is presented as the ERSAS (early risk stratification and strategy) concept. Typical haemodynamic complications discussed here include right ventricular failure, diastolic dysfunction caused by left ventricular deconditioning, and reperfusion injury to the transplanted lung. Pre- and intra-operatively detectable risk factors for the occurrence of haemodynamic complications are rare, and the therapeutic strategies applied differ considerably between centres. However, all the mentioned risk factors and treatment strategies can be integrated into clinical treatment algorithms and can influence patient outcome in terms of both mortality and morbidity.

Use of the CytoSorb® filter for elimination of residual therapeutic argatroban concentrations during heparinized cardiopulmonary bypass for heart transplantation

INTRODUCTION

No antidote or established extracorporeal elimination strategy is available for argatroban. Hemadsorption facilitates elimination of smaller drugs.

CASE REPORT

A 34-year-old patient underwent urgent heart transplantation. Because of a history of heparin-induced thrombocytopenia, preoperative anticoagulation was performed with argatroban. Despite ceasing of the continuous infusion of argatroban 2 h before surgery, concentration only declined from 0.60 μg/ml to 0.58 μg/ml before surgery, and the activated clotting time (ACT) value shortly was 223 s. Microvascular bleeding had been observed when starting surgery. A CytoSorb® absorption column was integrated into the system of the heparin-anticoagulated cardiopulmonary bypass (CPB) circuit and a flow of 400 mL/min provided during the 2 h of extracorporeal circulation. The argatroban concentration after weaning from CPB was 0.04 μg/ml and satisfying hemostasis had been achieved after protamine administration.

CONCLUSION

Data indicate that the CytoSorb® absorption column might be an effective tool for quick extracorporeal removal of therapeutic concentrations of argatroban.

Preoperative evaluation in thoracic surgery: limits of the patient's functional operability and consequence for perioperative anaesthesiologic management

PURPOSE OF REVIEW

Preoperative evaluation of older and more morbid patients in thoracic surgery is getting more advanced. In this context, early risk stratification has a crucial role for adequate informed decision-making, and thus for generating favourable effects of clinical outcome.

RECENT FINDINGS

Recent findings confirm that many risk factors impair mortality and morbidity beyond classical medical findings like results of lung function tests and values of the revised cardiac risk index. Especially results from holistic views on patients' functional status like frailty assessments are linked with long-term survival after lung resection.

SUMMARY

A comprehensive risk stratification by anaesthesiologists generates valuable guidance for the best strategy of clinical treatment. This includes preoperative, peri-operative and postoperative interventions, provided by interdisciplinary healthcare providers, resulting in an Early Risk Stratification and Strategy ('ERSAS') pathway.

Preoperative Risk Factors and Early Outcomes of Delirium in Valvular Open-Heart Surgery

BACKGROUND

 Compared with coronary artery bypass grafting surgery, data regarding postoperative delirium are scant in valvular open-heart surgery. Therefore, the goal of this retrospective study was to investigate the incidence, preoperative risk factors, and early outcomes of delirium in a large group of patients undergoing valvular open-heart surgery.

METHODS

 In 13,229 patients with isolated valvular or combined valvular and bypass surgery, the incidence of postoperative delirium was assessed until discharge. Independent risk factors of delirium were evaluated by multivariable logistic regression analysis. Moreover, we assessed the multivariable-adjusted risk of prolonged intensive care unit (ICU) stay (>48 hours) and in-hospital mortality in patients with delirium.

RESULTS

 Overall, the incidence of postoperative delirium was 8.4%. The incidence in patients experiencing a postoperative stroke or seizure was 23.1 and 29.7%, respectively. Twelve preoperative risk factors, mostly nonmodifiable, were independently associated with the risk of delirium, including advanced age, renal impairment, stroke, the need for emergency surgery, and severe preoperative anemia (hemoglobin < 9 g/dL). Postoperative delirium was associated with an adjusted odds ratio (OR) of prolonged ICU stay of 9.48 (95% confidence interval [CI]: 7.96-11.30). Adjusted in-hospital mortality was, however, significantly lower in patients with delirium versus patients without delirium (OR, 0.56; 95% CI: 0.38-0.83).

CONCLUSION

 In valvular open-heart surgery, postoperative delirium is a frequent neurological complication that is associated with other postoperative neurological complications and several, mostly nonmodifiable, preoperative risk factors. Although postoperative delirium was associated with a significantly increased risk of prolonged ICU stay, this did not translate into an increased short-term mortality.

Current practice of thoracic anaesthesia in Europe - a survey by the European Society of Anaesthesiology Part I - airway management and regional anaesthesia techniques

Background

The scientific working group for “Anaesthesia in thoracic surgery” of the German Society of Anaesthesiology and Intensive Care Medicine (DGAI) has performed an online survey to assess the current standards of care and structural properties of anaesthesia workstations in thoracic surgery.

Methods

All members of the European Society of Anaesthesiology (ESA) were invited to participate in the study.

Results

Thoracic anaesthesia was most commonly performed by specialists/board-certified anaesthetists and/or senior/attending physicians. Across Europe, the double lumen tube (DLT) was most commonly chosen as the primary device for lung separation (461/ 97.3%). Bronchial blockers were chosen less frequently (9/ 1.9%).

Throughout Europe, bronchoscopy was not consistently used to confirm correct double lumen tube positioning. Respondents from Eastern Europe (32/ 57.1%) frequently stated that there were not enough bronchoscopes available for every intrathoracic operation. A specific algorithm for difficult airway management in thoracic anaesthesia was available to only 18.6% (n = 88) of the respondents. Thoracic epidural analgesia (TEA) is the most commonly used form of regional analgesia for thoracic surgery in Europe. Ultrasonography was widely available 93,8% (n = 412) throughout Europe and was predominantly used for central line placement and lung diagnostics.

Conclusions

While certain „gold standards “are widely met, there are also aspects of care requiring substantial improvement in thoracic anaesthesia throughout Europe.

Our data suggest that algorithms and standard operating procedures for difficult airway management in thoracic anaesthesia need to be established. A European recommendation for the basic requirements of an anaesthesia workstation for thoracic anaesthesia is expedient and desirable, to improve structural quality and patient safety.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01480-w.

Evaluating live performance of machine learning based prediction models for different clinical risks: a study of live systems in different hospitals (Preprint)

Background

Machine learning algorithms are currently used in a wide array of clinical domains to produce models that can predict clinical risk events. Most models are developed and evaluated with retrospective data, very few are evaluated in a clinical workflow, and even fewer report performances in different hospitals. In this study, we provide detailed evaluations of clinical risk prediction models in live clinical workflows for three different use cases in three different hospitals.

Objective

The main objective of this study was to evaluate clinical risk prediction models in live clinical workflows and compare their performance in these setting with their performance when using retrospective data. We also aimed at generalizing the results by applying our investigation to three different use cases in three different hospitals.

Methods

We trained clinical risk prediction models for three use cases (ie, delirium, sepsis, and acute kidney injury) in three different hospitals with retrospective data. We used machine learning and, specifically, deep learning to train models that were based on the Transformer model. The models were trained using a calibration tool that is common for all hospitals and use cases. The models had a common design but were calibrated using each hospital’s specific data. The models were deployed in these three hospitals and used in daily clinical practice. The predictions made by these models were logged and correlated with the diagnosis at discharge. We compared their performance with evaluations on retrospective data and conducted cross-hospital evaluations.

Results

The performance of the prediction models with data from live clinical workflows was similar to the performance with retrospective data. The average value of the area under the receiver operating characteristic curve (AUROC) decreased slightly by 0.6 percentage points (from 94.8% to 94.2% at discharge). The cross-hospital evaluations exhibited severely reduced performance: the average AUROC decreased by 8 percentage points (from 94.2% to 86.3% at discharge), which indicates the importance of model calibration with data from the deployment hospital.

Conclusions

Calibrating the prediction model with data from different deployment hospitals led to good performance in live settings. The performance degradation in the cross-hospital evaluation identified limitations in developing a generic model for different hospitals. Designing a generic process for model development to generate specialized prediction models for each hospital guarantees model performance in different hospitals.

European Association of Cardiothoracic Anesthesiology and Intensive Care Pediatric Cardiac Anesthesia Fellowship Curriculum: First Edition

Pediatric cardiac anesthesia is a subspecialty of cardiac and pediatric anesthesiology dedicated to the perioperative care of patients with congenital heart disease. Members of the Congenital and Education Subcommittees of the European Association of Cardiothoracic Anaesthesiology and Intensive Care (EACTAIC) agreed on the necessity to develop an EACTAIC pediatric cardiac anesthesia fellowship curriculum. This manuscript represents a consensus on the composition and the design of the EACTAIC Pediatric Cardiac Anesthesia Fellowship program. This curriculum provides a basis for the training of future pediatric cardiac anesthesiologists by clearly defining the theoretical and practical requirements for fellows and host centers.

Artificial intelligence predicts delirium following cardiac surgery: A case study

Delirium is a highly relevant complication of surgical interventions. Current research indicates that despite increased awareness for delirium, it is often overlooked. We implemented an AI-based tool to monitor delirium in cardiac surgery patients in our specialist clinic. This appears to be a promising approach to improve detection of delirium, especially for underrecognized forms and in peripheral wards without intensive screening. We present a case in which the AI identified delirium, confirmed by our routine screening and specialist evaluation.

Impairment of Cognitive Function in Different Domains Early After Lung Transplantation

In this prospective observational pilot study patients with the diagnosis of end-stage lung disease and listed for lung transplantation underwent a cognitive function test battery before and after lung transplantation to investigate postoperative cognitive function in three domains (visual and verbal memory, executive functioning, concentration/speed of processing). Additionally we investigated intraoperative risk factors for postoperative cognitive dysfunction. In total, 24 patients were included in this pilot study. The incidence of postoperative cognitive dysfunction was 58.3%. In the cognitive dysfunction group, the domains executive functioning and concentration/attention were significantly impaired whereas memory was not affected. Patients with cognitive impairment had a significantly longer ICU stay. The strongest independent risk factor for the development of cognitive dysfunction was operation time. No influence of cerebral oxygen desaturations on cognitive dysfunction was found. This might have important implications for early psychological rehabilitation strategies in this high-risk patient collective.

Associations of preoperative stroke and tranexamic acid administration with convulsive seizures in valvular open-heart surgery

In cardiac surgery, use of the antifibrinolytic agent tranexamic acid (TXA) and acute perioperative stroke are both associated with convulsive seizures. We hypothesized that an older (preoperative) stroke increases the risk of TXA-associated seizures as well. To test this hypothesis, we retrospectively analyzed data from 16,110 patients who had undergone open-heart valvular surgery at our institution between 2009 and 2020. The dosing of TXA was moderate. Use of TXA and a history of stroke were both independently associated with convulsive seizure with an adjusted odds ratio (OR) of 2.40 (95%CI: 1.71-3.37) and 1.79 (95%CI: 1.27-2.54), respectively. Compared to patients without TXA administration, the adjusted OR of experiencing a seizure in TXA patients without a history of stroke was 2.44 (95%CI: 1.71-3.46) and in patients receiving TXA with a history of stroke 4.30 (95%CI: 2.65-6.99). However, there was no significant interaction between TXA use and preoperative stroke on convulsive seizures (P = 0.77). Compared to patients without seizure, for patients with seizure, the inverse probability-weighted ORs of in-hospital mortality and 30-day mortality were 3.58 (95%CI: 2.20-5.83) and 4.04 (95%CI: 2.34-6.98), respectively. We conclude that, in patients undergoing open-heart surgery, a history of stroke is independently associated with convulsive seizures but is not a contraindication for TXA use.

Moderate Dose of Tranexamic Acid and Complications after Valvular Heart Surgery

BACKGROUND

 In valvular open-heart surgery, data regarding the effect of a moderate dose of tranexamic acid (TXA) on clinical outcomes are limited.

METHODS

 Out of a cohort of 13,293 patients, we performed a propensity-score-matched analysis in 6,106 patients and assessed the risk of convulsive seizures (CS, primary endpoint), stroke, renal replacement therapy, and mortality (secondary endpoints). In the entire study cohort of 13,293 patients, we also assessed the multivariable-adjusted association of CS with postoperative outcomes.

RESULTS

 The risk of CS was significantly higher in the TXA group (2.4%; n = 72) than in the non-TXA group (1.0%; n = 32), with a relative risk ratio (RR) of 2.28 (95% confidence interval [CI]: 1.50-3.47; p < 0.001). The risk of CS was also higher in patients receiving TXA doses ≥25 mg/kg body weight (3.7%; n = 40) than in patients receiving <25 mg/kg body weight (1.6%; n = 32; p < 0.001). Perioperative secondary clinical endpoints and 1-year mortality did not differ significantly between study groups (p-value > 0.05). Compared with non-CS patients (n = 13,000), patients with nonhemorrhagic, nonembolic CS (n = 253) revealed higher multivariable-adjusted in-hospital risks of stroke (RR: 3.82 [95% CI: 2.44-5.60; p < 0.001]) and mortality (RR: 2.07 [95% CI: 1.23-3.48; p = 0.006]), and a higher 1-year mortality risk (RR: 1.85 [95% CI: 1.42-2.41; p < 0.001]).

CONCLUSION

 A moderate TXA dose was associated with a significantly higher risk of seizure, but not with other clinical complications such as stroke, renal replacement therapy, and mortality. However, in the small group of patients experiencing a seizure, the risks of stroke and short- and mid-term mortality were substantially higher than in patients not experiencing a seizure, indicating that the use of a low-dose TXA protocol (<25 mg/kg body weight) should be considered.

Perioperative management of patients with undergoing durable mechanical circulatory support

Durable mechanical circulatory support (MCS) devices revolutionized the treatment options for patients with end-stage heart failure (HF). Implantation of durable mechanical support has become an integral treatment modality in end-stage HF patients and it is associated with improved quality of life and survival. There is no doubt that this needs an interdisciplinary and interprofessional approach of cardiac surgeons, cardiologists, cardiac anesthesiologists, perfusionists, intensivists, psychologists, assist device coordinators as well as physiotherapists and intensive care. Implantation of durable MCS is a challenging procedure for the anesthesiologist due to the patient’s characteristics and comorbid diseases. It demands comprehensive training, high vigilance and quick response during the acute hemodynamic changes occurring during the surgery. Preoperative risk stratification is of major importance to guide perioperative medical treatment strategies. Most of these patients have several comorbidities and multiple medications. Therefore, to anticipate postoperative end-organ dysfunction such as cognitive dysfunction, pulmonary or renal failure, an interdisciplinary approach is necessary to optimize patient’s prior surgery. Transthoracic and transesophageal echocardiography (TTE and TEE), both play an invaluable role in diagnosing the cause and guiding the management in different unstable clinical situations. Especially prevention of postoperative right HF with subsequent necessity of temporary MCS is important as it is associated with higher mortality. The aim of this review is to provide an overview about the current concepts of perioperative management for durable MCS. A multimodal standard operating procedure supports early recovery after surgery and intensive care stay. Standardized perioperative care helps to ensure optimal medical treatment. This review focusses on several major skills of perioperative management of these high-risk surgical patients.

Implementation of strategies to prevent and treat postoperative delirium in the post-anesthesia caring unit : A German survey of current practice

Postoperative delirium is associated with worse outcome. The aim of this study was to understand present strategies for delirium screening and therapy in German Post-Anesthesia-Caring-Units (PACU). We designed a German-wide web-based questionnaire which was sent to 922 chairmen of anesthesiologic departments and to 726 anesthetists working in ambulatory surgery. The response rate was 30% for hospital anesthesiologists. 10% (95%-confidence interval: 8–12) of the anesthesiologists applied a standardised screening for delirium. Even though not on a regular basis, in 44% (41–47) of the hospitals, a recommended and validated screening was used, the Nursing Delirium Screening Scale (NuDesc) or the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU). If delirium was likely to occur, 46% (43–50) of the patients were examined using a delirium tool. 20% (17–23) of the patients were screened in intensive care units. For the treatment of delirium, alpha-2-agonists (83%, 80–85) were used most frequently for vegetative symptoms, benzodiazepines for anxiety in 71% (68–74), typical neuroleptics in 77% (71–82%) of patients with psychotic symptoms and in 20% (15–25) in patients with hypoactive delirium. 45% (39–51) of the respondents suggested no therapy for this entity. Monitoring of delirium is not established as a standard procedure in German PACUs. However, symptom-oriented therapy for postoperative delirium corresponds with current guidelines.

Tranexamic acid and convulsive seizures after off-pump coronary artery bypass surgery: the role of renal insufficiency

There is evidence that, in adult cardiac surgical patients undergoing on-pump procedures, tranexamic acid (TXA) dose-dependently increases the risk of convulsive seizure (CS). We aimed to investigate whether a single TXA bolus of 1 g influences the risk of CS in patients who were operated on without the use of cardiopulmonary bypass. In 2249 propensity-score-matched pairs who underwent off-pump coronary artery bypass grafting with or without TXA administration, the risk of CS was 0.5% and 0.3% in the TXA and non-TXA groups, respectively (P = 0.36). In the subgroups of patients with estimated glomerular filtration rates <30, 30-60 and >60 ml/min/1.73 m2, the risk of CS in the TXA group was 2.8%, 1.2% and 0.4%, respectively (P = 0.002), and in the non-TXA group 0.0%, 0.0% and 0.3%, respectively (P = 0.36). The risk of stroke, in-hospital mortality and 30-day mortality did not differ significantly between study groups (P-value >0.05). Our data indicate that in patients undergoing off-pump coronary artery bypass grafting, a single TXA bolus of 1 g generally does not increase the risk of CS. However, the presence and extent of renal insufficiency have a very significant impact on the incidence of CS even after single-dose TXA.

Comparing short-term outcome after implantation of the HeartWare® HVAD® and the Abbott® HeartMate 3®

AIMS

Centrifugal continuous flow pumps are currently the state of the art in left ventricular assist device therapy. This study was conducted to compare the results after implantation of the HVAD® and the HeartMate 3®.

METHODS AND RESULTS

We retrospectively analysed preoperative and post-operative patient data of all 106 patients, who received a HeartMate 3 (HM3) at our centre between 2014 and 2018. A total of 392 patients receiving a sintered HVAD® served as controls. Patient matching was performed for age, sex, Interagency Registry for Mechanically Assisted Circulatory Support level at the time of implant, perioperative right heart failure, and implantation strategy, that is, bridge to transplant or destination therapy, as well as preoperative renal function, that is, as indicated by serum creatinine levels. A total of 79 matched pairs could be identified. During a median follow-up of 15.3 months (range: 0-30 months), 23 (29.1%) and 19 (24.1%) patients died in the HVAD and HM3 groups, respectively, with a hazard ratio for mortality of 0.84 [95% confidence interval (CI): 0.46-1.54; P = 0.568]. Freedom from cerebrovascular events did not differ significantly between study groups, with a hazard ratio of 0.57 (95% CI: 0.23-1.45; P = 0.241). The risk of driveline infection was significantly lower in the HM3 (n = 33) than in the HVAD (n = 55) group (hazard ratio = 0.54; 95% CI: 0.35-0.84; P = 0.006). Eight HVAD, but no HM3, patients developed a pump thrombosis during follow-up (P = 0.148).

CONCLUSIONS

Performance of both currently used centrifugal left ventricular assist device systems is comparable in terms of short-term patient survival and freedom from cerebrovascular events. In our single-centre experience, HM3 patients less frequently develop driveline infections and no pump thrombosis, which requires further evaluation.

Tranexamic acid and convulsive seizures after isolated coronary artery bypass surgery: the role of cardiopulmonary bypass and renal function

In cardiac surgical patients, tranexamic acid (TXA) has been associated with an increased risk of convulsive seizure (CS). We aimed to investigate whether in patients undergoing isolated coronary artery bypass grafting (CABG) surgery the use of cardiopulmonary bypass (CPB) impacts the risk of CS. We studied 4198 propensity score matched patients. Patients who underwent CABG surgery without CPB, received a single bolus of 1 g TXA. Patients who underwent CABG with CPB, additionally received a TXA dose of 0.5 g in the CPB prime and an infusion of 0.2 g/h until the end of CPB. The risk of CS in the CPB group and the group without CPB was 0.7% and 0.6%, respectively (risk ratio 1.08, 95% confidence interval 0.51–2.30; P &gt; 0.99). Kidney function was significantly associated with the risk of CS (P = 0.005), the latter being highest in patients with glomerular filtration rates &lt;30 ml/min/1.73 m2 (2.2%) and lowest in those patients with values &gt;60 ml/min/1.73 m2 (0.4%). Our data in patients undergoing isolated CABG indicate no significant effect on CS risk by use of CPB when TXA doses of up to ∼2 g are given. However, caution regarding TXA administration is necessary in patients with renal impairment.

A case series on the value of tau and neurofilament protein levels to predict and detect delirium in cardiac surgery patients

BACKGROUND

Delirium following cardiac surgery is a relevant complication in the majority of elderly patients but its prediction is challenging. Cardiopulmonary bypass, essential for many interventions in cardiac surgery, is responsible for a severe inflammatory response leading to neuroinflammation and subsequent delirium. Neurofilament light protein (NfL) and tau protein (tau) are specific biomarkers to detect neuroaxonal injury as well as glial fibrillary acidic protein (GFAP), a marker of astrocytic activation.

METHODS

We thought to examine the perioperative course of these markers in a case series of each three cardiac surgery patients under off-pump cardiac arterial bypass without evolving delirium (OPCAB-NDEL), patients with a procedure under cardio-pulmonary bypass (CPB) without delirium (CPB-NDEL) and delirium after a CPB procedure (CPB-DEL). Delirium was diagnosed by the Confusion Assessment Method for the ICU and chart reviews.

RESULTS

We observed increased preoperative levels of tau in patients with later delirium, whereas values of NfL and GFAP did not differ. In the postoperative course, all biomarkers increased multi-fold. NfL levels sharply increased in patients with CPB reaching the highest levels in the CPB-DEL group.

CONCLUSION

Tau and NfL might be of benefit to identify patients in cardiac surgery at risk for delirium and to detect patients with the postoperative emergence of delirium.

Five-year experience using the Lung Allocation Score: the Munich Lung Transplant Group

OBJECTIVES

The Lung Allocation Score (LAS) was implemented in Germany on 10 December 2011 after demonstrating favourable outcomes in the USA since its introduction in 2005. There are only limited and short-term data on the effect of the LAS on lung transplantation programmes in Germany. The purpose of this study was to analyse our 5-year single-centre experience with the LAS within the influential area of the Eurotransplant Foundation (ET).

METHODS

After implementation of the LAS until December 2016, 294 patients underwent a single-lung transplantation or a bilateral sequential lung transplantation for end-stage lung disease at our centre. Patients were divided into 4 groups according to their primary diagnosis. The Kaplan-Meier analyses of survival probabilities were performed to compare types of transplant procedures, underlying diagnoses and the LASs at the time of transplantation. Waitlist characteristics, transplant procedures and up to 5-year post-transplant outcomes were analysed.

RESULTS

The proportion of lung transplants performed for interstitial lung disease increased over time from 27% in 2012 to 54% in 2016 (P = 0.056). At the same time, the proportion of patients with chronic obstructive pulmonary disease undergoing lung transplantation declined over the 5-year period, i.e. from 29% in 2011 to 19% in 2016 (P = 0.029). Overall waiting times of transplanted patients were approximately 200 days and did not markedly change over time. There was an increasing proportion of chronic obstructive pulmonary disease patients on the waitlist from 41% in 2011 to 51% in 2016 (P = 0.51). Outcomes were independent of the underlying disease entity or the LAS. Bilateral sequential lung transplantation was associated with a better long-term survival probability when compared with a single-lung transplantation (P < 0.001).

CONCLUSIONS

Our centre-specific 5-year experience confirms previous findings demonstrating that the LAS is a well-established tool for the selection of lung transplant candidates, respecting urgency and prognostic transplant benefit in a disease-specific manner. However, the LAS did not shorten overall waiting times in transplanted patients. Further long-term and multicentre data with respect to differential transplant centre activities have to be gathered for further evaluation.

Rescue TAVI for Aortic Regurgitation after Left Ventricular Assist Device Implantation Following Preoperative Impella® Support

A patient presented with a decompensated cardiomyopathy requiring invasive hemodynamic support with an Impella® heart pump. Extracorporeal life support (ECLS) became necessary during the further course and the patient was bridged to left ventricular assist device (LVAD) implantation. Postoperatively, the patient did not improve as expected due to new aortic regurgitation (AR) that was most likely caused by the previously placed Impella. A SAPIEN 3 transcatheter aortic valve was implanted as a bail-out strategy; an additional valve-in-valve rescue was required due to paravalvular regurgitation. This resulted in a restitution of valvular function and hemodynamic improvement. TAVI appears to be a valuable bail-out option for postoperative AR following LVAD implantation.

Remote ECLS-Implantation and Transport for Retrieval of Cardiogenic Shock Patients

OBJECTIVE

Extracorporeal life support (ECLS) emerges as a salvage option in therapy refractory cardiogenic shock but is limited to highly specialized tertiary care centers. Critically ill patients are often too unstable for conventional transport. Mobile ECLS programs for remote implantation and subsequent air or ground-based transport for patient retrieval could solve this dilemma and make full-spectrum advanced cardiac care available to patients in remote hospitals in whom shock otherwise might be fatal.

METHODS

From December 2012 to March 2016, 40 patients underwent venoarterial ECLS implantation in remote hospitals with subsequent transport to our center and were retrospectively analyzed. The mobile ECLS team was available 24/7, implantation was performed percutaneously bedside, and compact support systems designed for transport were used.

RESULTS

Twenty percent of the patients were female; the mean age was 55 ± 10 years, and the mean Interagency Registry for Mechanically Assisted Circulatory Support score was 1.3 ± 0.5. Patient retrieval was accomplished via ground-based (n = 29, 72.5%, mean distance = 27.9 ± 29.7 km [range, 5.6-107.1 km]) or air (n = 11, mean distance = 62.4 ± 27.2 km [range, 38.9-116.4 km]) transport. No ECLS-related complications occurred during transport. The ECLS system could be explanted in 65.0% (n = 26) of patients, and the 30-day survival rate was 52.5% (n = 21).

CONCLUSION

Remote ECLS implantation and interfacility transport on ECLS are feasible and effective. Interdisciplinary teams and full-spectrum cardiac care are essential to achieve optimal outcomes. Rapid-response ECLS networks have the potential to substantially increase the survival of cardiogenic shock patients.

Worldwide trends in heart and lung transplantation: Guarding the most precious gift ever

Transplantation is sadly a therapy to die for. The survival of a recipient with end-stage heart or lung disease requires the demise of a human being through brain death or cessation of circulation, with the noblest final act of offering one's organs to another. However, transplantation is constrained by severe hemodynamic, regulatory, inflammatory, and metabolic stresses in the donor, rendering the majority of offered organs unsuitable for transplantation. Coupled with our inability to acquire exact molecular and cellular information and missed opportunities for effectively modulating deteriorations of donors and allografts, anesthesia and critical care contributes to ongoing organ shortages. Progress is made with improving waiting lists by bridging patients for transplantation using mechanical support. However, this represents more complex recipients, higher risk transplant operations, and increased resource utilization. The advent of ex vivo perfusion allows implementing novel diagnostic and therapeutic strategies with real potential of reconditioning less ideal organs. This review advocates a paradigm change in critical care management of the potential donor for improving retrieval practices and for more intellectual involvement of our specialties in organ preservation, ex vivo evaluation and reconditioning, and the need for great advancement in our efficiency in converting unacceptable allografts to suitable donor organs.

Outcome of acute respiratory distress syndrome in university and non-university hospitals in Germany

Background

This study investigates differences in treatment and outcome of ventilated patients with acute respiratory distress syndrome (ARDS) between university and non-university hospitals in Germany.

Methods

This subanalysis of a prospective, observational cohort study was performed to identify independent risk factors for mortality by examining: baseline factors, ventilator settings (e.g., driving pressure), complications, and care settings—for example, case volume of ventilated patients, size/type of intensive care unit (ICU), and type of hospital (university/non-university hospital). To control for potentially confounding factors at ARDS onset and to verify differences in mortality, ARDS patients in university vs non-university hospitals were compared using additional multivariable analysis.

Results

Of the 7540 patients admitted to 95 ICUs from 18 university and 62 non-university hospitals in May 2004, 1028 received mechanical ventilation and 198 developed ARDS. Although the characteristics of ARDS patients were very similar, hospital mortality was considerably lower in university compared with non-university hospitals (39.3% vs 57.5%; p = 0.012). Treatment in non-university hospitals was independently associated with increased mortality (OR (95% CI): 2.89 (1.31–6.38); p = 0.008). This was confirmed by additional independent comparisons between the two patient groups when controlling for confounding factors at ARDS onset. Higher driving pressures (OR 1.10; 1 cmH₂O increments) were also independently associated with higher mortality. Compared with non-university hospitals, higher positive end-expiratory pressure (PEEP) (mean ± SD: 11.7 ± 4.7 vs 9.7 ± 3.7 cmH₂O; p = 0.005) and lower driving pressures (15.1 ± 4.4 vs 17.0 ± 5.0 cmH₂O; p = 0.02) were applied during therapeutic ventilation in university hospitals, and ventilation lasted twice as long (median (IQR): 16 (9–29) vs 8 (3–16) days; p < 0.001).

Conclusions

Mortality risk of ARDS patients was considerably higher in non-university compared with university hospitals. Differences in ventilatory care between hospitals might explain this finding and may at least partially imply regionalization of care and the export of ventilatory strategies to non-university hospitals.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1687-0) contains supplementary material, which is available to authorized users.