Adjusted calculation model of heparin management during cardiopulmonary bypass in obese patients: A randomised controlled trial

Update on antithrombotic therapy and body mass: a clinical consensus statement of the European Society of Cardiology Working Group on Cardiovascular Pharmacotherapy and the European Society of Cardiology Working Group on Thrombosis

Obesity and underweight are a growing health problem worldwide and a challenge for clinicians concerning antithrombotic therapy, due to the associated risks of thrombosis and/or bleeding. This clinical consensus statement updates a previous one published in 2018, by reviewing the most recent evidence on antithrombotic drugs based on body size categories according to the World Health Organization classification. The document focuses mostly on individuals at the extremes of body weight, i.e. underweight and moderate-to-morbid obesity, who require antithrombotic drugs, according to current guidelines, for the treatment or prevention of cardiovascular diseases or venous thromboembolism. Managing antithrombotic therapy or thromboprophylaxis in these individuals is challenging, due to profound changes in body composition, metabolism and organ function, and altered drug pharmacokinetics and pharmacodynamics, as well as weak or no evidence from clinical trials. The document also includes artificial intelligence simulations derived from in silico pharmacokinetic/pharmacodynamic models, which can mimic the pharmacokinetic changes and help identify optimal regimens of antithrombotic drugs for severely underweight or severely obese individuals. Further, bariatric surgery in morbidly obese subjects is frequently performed worldwide. Bariatric surgery causes specific and additional changes in metabolism and gastrointestinal anatomy, depending on the type of the procedure, which can also impact the pharmacokinetics of antithrombotic drugs and their management. Based on existing literature, the document provides consensus statements on optimizing antithrombotic drug management for underweight and all classes of obese patients, while highlighting the current gaps in knowledge in these complex clinical settings, which require personalized medicine and precision pharmacology.

EISOR Delivery: Regional experience with sharing equipe, equipment & expertise to increase cDCD donor pool in time of pandemic

Donation after circulatory death (DCD) programs are expanding in Europe, in the attempt to expand donors pool. Even in controlled DCD donors, however, a protracted warm ischemia time occurring in the perimortem period might damage organs, making these unsuitable for transplantation. Implementing a strategy of extracorporeal interval support for organ retrieval (EISOR), a regional reperfusion with normothermic, oxygenated blood provides a physiologic environment allowing extensive assessment of potential grafts, and potentially promotes recovery of native function. Here we report the results of a multi-center retrospective cohort study including 29 Maastricht Category III controlled DCD donors undergoing extracorporeal support in a regional DCD/EISOR Training Center, and in the network of referring In-Training Centers, under the liaison of the regional Transplant Coordination Center during COVID-19 pandemic, between March 2020 and November 2021. The study aims to understand whether a mobile, experienced EISOR team implementing a consistent technique and sharing its equipe, expertise and equipment in a regional network of hospitals, might be effective and efficient in implementing the regional DCD program activity even in a highly stressed healthcare system.

Increasing obesity is associated with lower postoperative bleeding in coronary bypass patients

OBJECTIVE

Despite inherent comorbidities, obese cardiac surgical patients paradoxically had shown lower morbidity and mortality, although the nature of this association is still unclear. Thus, the authors intended in this large registry-based study to investigate the impact of obesity on short- and long-term postoperative outcomes, focusing on bleeding and transfusion requirements.

DESIGN

Retrospective registry study.

SETTING

Three university hospitals.

PARTICIPANTS

A cohort of 12,330 prospectively compiled data from coronary bypass grafting patients undergoing surgery between 2007 to 2020 were retrieved from the Western Denmark Heart Registry.

INTERVENTIONS

The parameters were analyzed to assess the association between body mass index (BMI) and the selected outcome parameters.

MEASUREMENTS AND MAIN RESULTS

The crude data showed a clear statistically significant association in postoperative drainage from 637 (418-1108) mL in underweight patients with BMI <18.5 kg/m² to 427 (295-620) mL in severely obese patients with BMI ≥40 kg/m² (p < 0.0001, Kruskal-Wallis). Further, 50.0% of patients with BMI <18.5 received an average of 451 mL/m² in red blood cell transfusions, compared to 16.7% of patients with BMI >40 receiving 84 mL/m². The obese groups were less often submitted to reexploration due to bleeding, and fewer received perioperative hemostatics, inotropes, and vasoconstrictors. The crude data showed increasing 30-day and 6-month mortality with lower BMI, whereas the one-year mortality showed a V-shaped pattern, but BMI had no independent impact on mortality in logistic regression analysis.

CONCLUSION

Patients with high BMI may carry protection against postoperative bleeding after cardiac surgery, probably secondary to an inherent hypercoagulable state, whereas underweight patients carry a higher risk of bleeding and worse outcomes.

Intraoperative Monitoring of the Obese Patient Undergoing Surgery: A Narrative Review

With the increasing prevalence of obesity in the population, anaesthetists must confidently manage both the pathophysiological and technical challenges presented in bariatric and non-bariatric surgery. The intraoperative period represents an important opportunity to optimise and mitigate risk. However, there is little formal guidance on what intraoperative monitoring techniques should be used in this population. This narrative review collates the existing evidence for intraoperative monitoring devices in the obese patients. Although a number of non-invasive blood pressure monitors have been tested, an invasive arterial line remains the most reliable monitor if accurate, continuous monitoring is required. Goal-directed fluid therapy is recommended by clinical practice guidelines, but the methods tested to assess this had guarded applicability to the obese population. Transcutaneous carbon dioxide (CO₂) monitoring may offer additional benefit to standard capnography in this population. Individually titrated positive end expiratory pressure (PEEP) and recruitment manoeuvres improved intraoperative mechanics but yielded no benefit in the immediate postoperative period. Depth of anaesthesia monitoring appears to be beneficial in the perioperative period regarding recovery times and complications. Objective confirmation of reversal of neuromuscular blockade continues to be a central tenet of anaesthesia practice, particularly relevant to this group who have been characterised as an "at risk" extubation group. Where deep neuromuscular blockade is used, continuous neuromuscular blockade is suggested. Both obesity and the intraoperative context represent somewhat unstable search terms, as the clinical implications of the obesity phenotype are not uniform, and the type and urgency of surgery have significant impact on the intraoperative setting. This renders the generation of summary conclusions around what intraoperative monitoring techniques are suitable in this population highly challenging.

Identifying optimal heparin management during cardiopulmonary bypass in Chinese people: a retrospective observational comparative study

Traditionally heparin is adapted according to total body weight (TBW) to providing anticoagulation during cardiopulmonary bypass (CPB), but it may be inaccurate in some patients. The medical records of 100 adult patients who received CPB in Tongji Hospital of Tongji Medical College Huazhong University of Science and Technology over a 10-month period in 2017 were included in the retrospective study. An unfractionated heparin (UFH) bolus of 300 IU/kg TBW was injected before initiation of CPB followed by additional doses (50 to 100 IU/kg) to maintain a target activated coagulation time (ACT) of at least 480 s. We used TBW, ideal body weight (IBW), lean body weight (LBW), or body mass index (BMI) to establish and evaluate a linear model of ACT and the amount of heparin respectively. The linear fit effect of the model based on BMI on the original data is better than the others. As the instruments to measure heparin concentration is unavailable in most medical institutions in China. The new linear model based on BMI is helpful to estimate a more individualized heparin dosage in the heparinized phase and to provide useful reference to the amount of remaining heparin in the neutralization phase.