A contemporary analysis of the volume-outcome relationship for extracorporeal membrane oxygenation in the United States

Association of Interhospital Transfer With Outcomes of Extracorporeal Membrane Oxygenation: A Contemporary Analysis

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has emerged as a life-sustaining measure for individuals with end-stage cardiopulmonary derangements. An estimated one-third of patients must be transferred to a specialized center to receive this intervention. Therefore, the present study sought to characterize the impact of interhospital transfer (IHT) status on outcomes following ECMO.

METHODS

The 2016-2020 National Inpatient Sample was queried to identify all adult (≥18 years) hospitalizations for ECMO. Patients were stratified based on transfer status from another acute care hospital. Multivariable regression models were developed to assess the association between transfer status and outcomes of interest. Patient and operative factors associated with IHT were identified using regression.

RESULTS

Of an estimated 61,180 hospitalizations entailing ECMO, 21,410 (35.0%) were transfers. Annual transfer volume doubled over the study period, from 2915 to 5945 (nptrend < .001). The predicted morality risk of non-transfers decreased between 2016 and 2020 but remained similar in transferred patients. Following adjustment, transfer was associated with increased odds of in-hospital mortality, complications, duration of stay, and hospitalization costs. Patients experiencing transfer were less likely to be of black race and private insurance status.

CONCLUSION

Despite increasing transfer volume and utilization of ECMO, IHT was associated with significant mortality and hospital complication risks. Further work to reduce adverse outcomes, resource burden, and socioeconomic differences within IHT may improve accessibility to this life-saving modality.

Defining the Cross-Volume Effect of Extracorporeal Life Support on Outcomes of Cardiogenic Shock

BACKGROUND

Cardiogenic shock (CS) remains a leading cause of mortality despite advancements in mechanical circulatory support and other management strategies. In particular, venoarterial extracorporeal membrane oxygenation (ECMO) requires expertise in cardiac surgery, cardiology, and critical care. The benefits of such expertise may extend beyond patients undergoing ECMO.

METHODS

Hospitalizations in adults (aged ≥18 years) with a primary diagnosis of CS who were not undergoing ECMO, cardiac operations, durable left ventricular assist device therapy, or heart transplantation were abstracted from the 2016-2020 Nationwide Readmissions Database. Multivariable regression models were developed to assess the association of cardiac surgical and ECMO institutional caseload with clinical and financial outcomes.

RESULTS

Of an estimated 70,339 patients with CS identified for study, 33,643 (47.8%) were treated at a high-volume hospital for ECMO (HVH-ECMO). HVH-ECMO was associated with decreased odds of in-hospital mortality (adjusted odds ratio [aOR], 0.85; 95% CI, 0.75-0.95), respiratory complications (aOR, 0.86; 95% CI, 0.79-0.94), and nonhome discharge (aOR, 0.86; 95% CI, 0.79-0.94). However, HVH-ECMO was associated with a longer length of stay by 1.7 days (95% CI, 1.3-2.1) and higher inpatient costs by $9170 (95% CI, $6,490-$12,060). Although ECMO volume was inversely associated with the predicted risk of in-hospital mortality, institutional volume of cardiac operations was not significantly associated with mortality.

CONCLUSIONS

Our findings suggest improved outcomes for patients with CS who were treated at an HVH-ECMO. Multidisciplinary care pathways, including those among surgery, cardiology, and critical care, may influence CS management. Further studies are needed to characterize long-term outcomes of regionalization and ensure equitable access for all populations.

Association of severe obesity with risk of conversion to open in laparoscopic cholecystectomy for acute cholecystitis

Background

Obesity is a known risk factor for cholecystitis and is associated with technical complications during laparoscopic procedures. The present study seeks to assess the association between obesity class and conversion to open (CTO) during laparoscopic cholecystectomy (LC).

Methods

Adult acute cholecystitis patients with obesity undergoing non-elective LC were identified in the 2017-2020 Nationwide Readmissions Database. Patients were stratified by obesity class; class 1 (Body Mass Index [BMI] = 30.0-34.9), class 2 (BMI = 35.0-39.9), and class 3 (BMI ≥ 40.0). Multivariable regression models were developed to assess factors associated with CTO and its association with perioperative complications and resource utilization.

Results

Of 89,476 patients undergoing LC, 40.6 % had BMI ≥ 40.0. Before adjustment, class 3 obesity was associated with increased rates of CTO compared to class 1-2 (4.6 vs 3.8 %; p < 0.001). Following adjustment, class 3 remained associated with an increased likelihood of CTO (Adjusted Odds Ratio [AOR] 1.45, 95 % Confidence Interval [CI] 1.31-1.61; ref.: class 1-2). Patients undergoing CTO had increased risk of blood transfusion (AOR 3.27, 95 % CI 2.54-4.22) and respiratory complications (AOR 1.36, 95 % CI 1.01-1.85). Finally, CTO was associated with incremental increases in hospitalization costs (β + $719, 95 % CI 538-899) and length of stay (LOS; β +2.20 days, 95 % CI 2.05-2.34).

Conclusions

Class 3 obesity is a significant risk factor for CTO. Moreover, CTO is associated with increased hospitalization costs and LOS. As the prevalence of obesity grows, improved understanding of operative risk by approach is required to optimize clinical outcomes. Our findings are relevant to shared decision-making and informed consent.

Machine learning based predictive modeling of readmissions following extracorporeal membrane oxygenation hospitalizations

Background

Despite increasing utilization and survival benefit over the last decade, extracorporeal membrane oxygenation (ECMO) remains resource-intensive with significant complications and rehospitalization risk. We thus utilized machine learning (ML) to develop prediction models for 90-day nonelective readmission following ECMO.

Methods

All adult patients receiving ECMO who survived index hospitalization were tabulated from the 2016-2020 Nationwide Readmissions Database. Extreme Gradient Boosting (XGBoost) models were developed to identify features associated with readmission following ECMO. Area under the receiver operating characteristic (AUROC), mean Average Precision (mAP), and the Brier score were calculated to estimate model performance relative to logistic regression (LR). Shapley Additive Explanation summary (SHAP) plots evaluated the relative impact of each factor on the model. An additional sensitivity analysis solely included patient comorbidities and indication for ECMO as potential model covariates.

Results

Of ∼22,947 patients, 4495 (19.6 %) were readmitted nonelectively within 90 days. The XGBoost model exhibited superior discrimination (AUROC 0.64 vs 0.49), classification accuracy (mAP 0.30 vs 0.20) and calibration (Brier score 0.154 vs 0.165, all P < 0.001) in predicting readmission compared to LR. SHAP plots identified duration of index hospitalization, undergoing heart/lung transplantation, and Medicare insurance to be associated with increased odds of readmission. Upon sub-analysis, XGBoost demonstrated superior disclination compared to LR (AUROC 0.61 vs 0.60, P < 0.05). Chronic liver disease and frailty were linked with increased odds of nonelective readmission.

Conclusions

ML outperformed LR in predicting readmission following ECMO. Future work is needed to identify other factors linked with readmission and further optimize post-ECMO care among this cohort.

Adjunctive Therapies in Acute Respiratory Distress Syndrome

Despite significant advances in understanding acute respiratory distress syndrome (ARDS), mortality rates remain high. The appropriate use of adjunctive therapies can improve outcomes, particularly for patients with moderate to severe hypoxia. In this review, the authors discuss the evidence basis behind prone positioning, recruitment maneuvers, neuromuscular blocking agents, corticosteroids, pulmonary vasodilators, and extracorporeal membrane oxygenation and considerations for their use in individual patients and specific clinical scenarios. Because the heterogeneity of ARDS poses challenges in finding universally effective treatments, an individualized approach and continued research efforts are crucial for optimizing the utilization of adjunctive therapies and improving patient outcomes.

Cardiac Extracorporeal Membrane Oxygenation in Community Cardiac Surgery Program: Are the Results Comparable?

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) outcomes in small centers are commonly considered less favorable than in large-volume centers. New ECMO protocols and procedures were established in our regional community hospital system as part of a cardiogenic shock initiative. This retrospective study aims to evaluate the outcomes of veno-arterial extracorporeal membrane oxygenation (VA ECMO) and extracorporeal cardiopulmonary resuscitation (ECPR) in a community hospital system with cardiac surgery capability and assess whether protocol optimization and cannulation standards result in comparable outcomes to larger centers whether the outcomes of this new ECMO program at the community hospital setting were comparable to the United States averages.

METHODS

Our regional system comprises five hospitals with 1500 beds covering southwestern New Jersey, with only one of these hospitals having cardiac surgery and ECMO capability. In May 2021, the new ECMO program was initiated. Patients were screened by a multidisciplinary call, cannulated by our ECMO team, and subsequently treated by the designated team. We reviewed our cardiac ECMO outcomes over two years, from May 2021 to April 2023, in patients who required ECMO due to cardiogenic shock or as a part of extracorporeal cardiopulmonary resuscitation (ECPR).

RESULTS

A total of 60 patients underwent cardiac ECMO, and all were VA ECMO, including 18 (30%) patients who required ECPR for cardiac arrest. The overall survival rate for our cardiac ECMO program turned out to be 48% (29/60), with 50% (22/42) in VA ECMO excluding ECPR and 39% (7/18) in the ECPR group. The hospital survival rate for the VA ECMO and ECPR groups was 36% (15/42) and 28% (5/18), respectively. The ELSO-reported national average for hospital survival is 48% for VA ECMO and 30% for ECPR. Considering these benchmarks, the hospital survival rate of our program did not significantly lag behind the national average.

CONCLUSIONS

With protocol, cannulation standards, and ECMO management optimized, the VA ECMO results of a community hospital system with cardiac surgery capability were not inferior to those of larger centers.

Extracorporeal Carbon Dioxide Removal to Avoid Invasive Ventilation During Exacerbations of Chronic Obstructive Pulmonary Disease: VENT-AVOID Trial - A Randomized Clinical Trial

Rationale: It is unclear whether extracorporeal CO2 removal (ECCO2R) can reduce the rate of intubation or the total time on invasive mechanical ventilation (IMV) in adults experiencing an exacerbation of chronic obstructive pulmonary disease (COPD). Objectives: To determine whether ECCO2R increases the number of ventilator-free days within the first 5 days postrandomization (VFD-5) in exacerbation of COPD in patients who are either failing noninvasive ventilation (NIV) or who are failing to wean from IMV. Methods: This randomized clinical trial was conducted in 41 U.S. institutions (2018-2022) (ClinicalTrials.gov ID: NCT03255057). Subjects were randomized to receive either standard care with venovenous ECCO2R (NIV stratum: n = 26; IMV stratum: n = 32) or standard care alone (NIV stratum: n = 22; IMV stratum: n = 33). Measurements and Main Results: The trial was stopped early because of slow enrollment and enrolled 113 subjects of the planned sample size of 180. There was no significant difference in the median VFD-5 between the arms controlled by strata (P = 0.36). In the NIV stratum, the median VFD-5 for both arms was 5 days (median shift = 0.0; 95% confidence interval [CI]: 0.0-0.0). In the IMV stratum, the median VFD-5 in the standard care and ECCO2R arms were 0.25 and 2 days, respectively; median shift = 0.00 (95% confidence interval: 0.00-1.25). In the NIV stratum, all-cause in-hospital mortality was significantly higher in the ECCO2R arm (22% vs. 0%, P = 0.02) with no difference in the IMV stratum (17% vs. 15%, P = 0.73). Conclusions: In subjects with exacerbation of COPD, the use of ECCO2R compared with standard care did not improve VFD-5. Clinical trial registered with www.clinicaltrials.gov (NCT03255057).

An Update on Management of Adult Patients with Acute Respiratory Distress Syndrome: An Official American Thoracic Society Clinical Practice Guideline

Background: This document updates previously published Clinical Practice Guidelines for the management of patients with acute respiratory distress syndrome (ARDS), incorporating new evidence addressing the use of corticosteroids, venovenous extracorporeal membrane oxygenation, neuromuscular blocking agents, and positive end-expiratory pressure (PEEP). Methods: We summarized evidence addressing four "PICO questions" (patient, intervention, comparison, and outcome). A multidisciplinary panel with expertise in ARDS used the Grading of Recommendations, Assessment, Development, and Evaluation framework to develop clinical recommendations. Results: We suggest the use of: 1) corticosteroids for patients with ARDS (conditional recommendation, moderate certainty of evidence), 2) venovenous extracorporeal membrane oxygenation in selected patients with severe ARDS (conditional recommendation, low certainty of evidence), 3) neuromuscular blockers in patients with early severe ARDS (conditional recommendation, low certainty of evidence), and 4) higher PEEP without lung recruitment maneuvers as opposed to lower PEEP in patients with moderate to severe ARDS (conditional recommendation, low to moderate certainty), and 5) we recommend against using prolonged lung recruitment maneuvers in patients with moderate to severe ARDS (strong recommendation, moderate certainty). Conclusions: We provide updated evidence-based recommendations for the management of ARDS. Individual patient and illness characteristics should be factored into clinical decision making and implementation of these recommendations while additional evidence is generated from much-needed clinical trials.