Complications of Peripheral Cannulation Site in Obese Patients on Adult Extracorporeal Membrane Oxygenation

Impact of Body Mass Index on Stroke in Extracorporeal Cardiopulmonary Resuscitation: Data from the Extracorporeal Life Support Organization Registry

Objective: We aimed to characterize the impact of body mass index (BMI) on stroke in patients receiving extracorporeal cardiopulmonary resuscitation (ECPR). Methods: We queried the Extracorporeal Life Support Organization registry for patients receiving ECPR (2020-2024). Patients were categorized into five BMI groups: underweight (<18.5 kg/m2), normal weight (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), class 1 obesity (30-34.9 kg/m2), and class 2 obesity or above (≥35 kg/m2). A generalized additive model (GAM) analysis was used to identify the BMI range with the greatest stroke risk. Multivariable regression was used to compare odds of stroke between standard BMI groups and normal weight. Propensity score matching was used to compare stroke and mortality between normal weight and the BMI group with the highest predicted stroke risk. Results: Of 6390 patients (median age = 57.5, 68.6% male), 470 (7.4%) had a stroke during ECMO support (4.5% ischemic; 3.4% hemorrhagic). A total of 9.6% (n = 131) of class 1 obesity patients experienced stroke compared with 6.6% (n = 111) of normal weight, 6.9% (n = 79) of class 2 obesity or above, 6.9% (n = 143) of overweight, and 5.4% (n = 6) of underweight patients (p = 0.01). The GAM analysis showed a highest predicted stroke risk for class 1 obesity patients (n = 1366), which was confirmed by multivariable regression (adjusted odds ratio (aOR) = 1.63, 95%CI = 1.01-2.62, p = 0.045). After propensity matching (n = 357 each), class 1 obesity was associated with ischemic (aOR = 2.01, 95%CI = 1.02-4.08, p = 0.047) but not hemorrhagic stroke. Odds of hospital mortality were higher in both class 1 and 2 obesity patients compared with normal weight. Conclusions: Class 1 obesity was associated with increased odds of ischemic but not hemorrhagic stroke compared with normal weight patients.

Obesity Is Associated With Increased Mortality in Patients Undergoing Venoarterial Extracorporeal Membrane Oxygenation

OBJECTIVES

To determine the relationship between all-cause hospital mortality and morbidity in patients treated with venoarterial extracorporeal membrane oxygenation (ECMO) and to assess whether this relationship is mediated via body mass index (BMI).

DESIGN

Using the Extracorporeal Life Support Organization (ELSO) registry, venoarterial ECMO runs from 2015 to 2021 were retrospectively analyzed. Patient demographics, ECMO indications, and complications for survivors and decedents were univariately compared. Logistic regression with fractional polynomials was used to estimate the relationship between BMI and both mortality and complications in venoarterial ECMO patients.

SETTING

Contributing centers to the ELSO ECMO registry.

PATIENTS

Patients that underwent venoarterial ECMO at an ELSO contributing ECMO center.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Twenty-two thousand eight hundred twenty-five venoarterial ECMO runs met inclusion criteria for analysis. The mean BMI for survivors was 28.4 ± 6.5 vs. 29.5 ± 6.9 kg/m 2 for decedents. BMI was significantly associated with mortality ( p < 0.001), with the proportion of patients dying increasing with increasing BMI: 47% of underweight patients died, increasing to 50% for the normal range, to 53%, 56%, 58%, and 65% for preobese, class 1, class 2, and class 3 obese patients, respectively. Relative to a BMI of 25, a BMI of 35 had an odds ratio (OR) of death of 1.15 (1.09-1.18), and a BMI of 45 an OR of 1.46 (1.25-1.57). BMI was significantly associated with increased mechanical and renal complications, but decreased pulmonary complications.

CONCLUSIONS

In patients undergoing venoarterial ECMO, increasing BMI was associated with increasing all-cause mortality and mechanical and renal complications.

Does obesity matter in patients receiving venoarterial extracorporeal membrane oxygenation? The U-shaped relationship between body mass index and mortality after extracorporeal cardiopulmonary resuscitation

BACKGROUND

The impact of obesity on the prognosis of patients receiving venoarterial extracorporeal membrane oxygenation remains unclear. This study examines the association between body mass index and in-hospital mortality among patients on venoarterial extracorporeal membrane oxygenation support.

METHODS

This retrospective study enrolled adult patients who received venoarterial extracorporeal membrane oxygenation support, which included extracorporeal cardiopulmonary resuscitation, at National Taiwan University Hospital between 2010 and 2021. Patients were classified as follows: underweight (body mass index <18.5), normal weight (18.5≤ body mass index <24), overweight (24≤ body mass index <27), class I obesity (27≤ body mass index <30), class II obesity (30≤ body mass index <35), and class III obesity (body mass index ≥35). Multivariable Cox regression with spline models was employed.

RESULTS

The study included 1,329 patients; of these, 670 underwent extracorporeal cardiopulmonary resuscitation, and the overall mortality rate was 61.6%. Multivariable Cox regression revealed that class III obesity was significantly associated with higher mortality (hazard ratio 2.11, 95% confidence interval 1.48-3.02, P = .001), particularly in the extracorporeal cardiopulmonary resuscitation subgroup (hazard ratio 2.71, 95% confidence interval 1.71-4.29, P < .001). No significant association was observed in the non-extracorporeal cardiopulmonary resuscitation subgroup (hazard ratio 1.29, 95% confidence interval 0.70-2.36, P = .415). Although underweight patients initially exhibited higher mortality (hazard ratio 1.77, 95% confidence interval 1.12-2.80, P = .015), this effect was attenuated after adjusting the confounders (hazard ratio 1.46, 95% confidence interval 0.91-2.35, P = .119). Kaplan-Meier analysis indicated that class III obesity was associated with the highest in-hospital mortality, followed by the underweight group (log-rank P = .009).

CONCLUSION

Obesity increased mortality in patients who underwent venoarterial extracorporeal membrane oxygenation, but this was primarily due to a nonlinear U-shaped distribution between body mass index and in-hospital mortality observed in patients receiving extracorporeal cardiopulmonary resuscitation. Further studies are needed to clarify the causal factors underlying these associations.

Prediction and prevention of post-procedural bleedings in patients with cirrhosis

Although post-procedural bleedings are infrequent in patients with cirrhosis, they are associated with significant morbidity and mortality. Therefore, predicting and preventing such bleedings is important. Established predictors of post-procedural bleeding include high-bleeding risk procedure, severe cirrhosis and high body mass index; prognostic value of anemia, acute kidney injury and bacterial infection is more uncertain. While prothrombin time and international normalized ratio do not predict post-procedural bleeding, some evidence suggests that platelet count, whole blood thrombin generation assay and viscoelastic tests may be helpful in this context. Prevention of postprocedural bleeding involves careful management of antithrombotic drugs during the periprocedural period. Patients with cirrhosis present unique challenges due to altered pharmacokinetics and pharmacodynamics of antithrombotic drugs, but there is a lack of dedicated studies specifically focused on this patient population. Guidelines for periprocedural management of antithrombotic drugs developed for patients without liver disease are thus applied to those with cirrhosis. Some technical aspects may decrease the risk of post-procedural bleeding, namely ultrasoundguidance, opting for transjugular route rather than percutaneous route, and the level of expertise of the operator. The effectiveness of platelet transfusions or thrombopoietin-receptor agonists remains uncertain. Transfusion of fresh-frozen plasma, of fibrinogen, and administration of tranexamic acid are not recommended for reducing post-procedural bleeding in patients with cirrhosis. In conclusion, prediction of post-procedural requires a global approach taking into account the patients characteristics, the risk of the procedure, and the platelet count. There is little data to support prophylactic correction of hemostasis, and dedicated studies are needed.

Anticoagulation and associated complications in veno-arterial extracorporeal membrane oxygenation in adult patients: A systematic review and meta-analysis

Objective

To describe the incidence of bleeding and thrombotic complications in VA-ECMO according to anticoagulation strategy.

Design

This systematic review and meta-analysis included randomised controlled trials (RCTs) and observational studies reporting bleeding and thrombotic complications in VA-ECMO. The incidence of primary outcomes according to anticoagulation drug and monitoring test was described.

Data sources

CENTRAL, MEDLINE, Embase and CINAHL (2010-January 2024).

Review methods

Data was extracted using Covidence. A meta-analysis of proportions was performed using STATA MP v18.1 metaprop.

Results

We included 159 studies with 21,942 patients. No studies were at low risk of bias. The incidence of major bleeding or thrombotic events was similar among heparin-, bivalirudin- and anticoagulation-free cohorts. The pooled incidence of major bleeding and thrombotic complications were 40% (95%CI 36-44, I2 = 97.12) and 17% (95%CI 14-19, I 2  = 92.60%), respectively. The most common bleeding site was thoracic. The most common ischaemic complication was limb ischaemia. The incidences of major bleeding or thrombotic events, intracranial haemorrhage and ischaemic stroke were similar among all monitoring tests. Mechanical unloading was associated with a high incidence of major bleeding events (60%, 95%CI 43-77, I2 = 93.32), and ischaemic strokes (13%, 95%CI 7-19, I2 = 81.80).

Conclusions

Available literature assessing the association between anticoagulation strategies in VA-ECMO, and bleeding and thrombosis is of limited quality. We identified a substantially higher incidence of major bleeding events than a previous meta-analysis. Limited numbers of patients anticoagulated with alternatives to heparin were reported. Patients with additional mechanical LV unloading represent a cohort at particular risk of bleeding and thrombotic complications.

Prone position in obese patients with acute respiratory distress syndrome after cardio-thoracic surgery

OBJECTIVES

Prone positioning (PP) has benefits in patients with acute respiratory distress syndrome. The objective of this study was to compare the effects and complications of PP in obese versus non-obese patients with moderate-to-severe acute respiratory distress syndrome after cardiothoracic surgery.

METHODS

We retrospectively analysed a database established in 2014-2021 in an intensive care unit. The primary end point was the change in PaO2/FiO2 induced by PP. Secondary end points included pressure ulcers, mediastinitis and intensive care unit mortality. The groups with versus without obesity (body mass index >30 kg/m2) were compared, and a mixed linear model was built to identify factors associated with the PaO2/FiO2 change.

RESULTS

81 patients with acute respiratory distress syndrome (36 with vs 45 without obesity) and 189 PP sessions were included. PP duration was 17.2 ± 4.5 h in obese and 18.0 ± 3.8 h in non-obese patients (P = 0.23). Mean number of sessions was 2.6 ± 1.4 in obese and 2.1 ± 1.3 in non-obese patients (P = 0.10). Median PaO2/FiO2 increase after the 1st PP session was 75.0% [14.5-123.0] and 72% [15.5-130.5] in the groups with versus without obesity (P = 0.67). Stage 3/4 pressure ulcers were more common in the obese group (44.4% vs 22.2%; P = 0.03) and occurred chiefly on the face. No significant differences between the obese and non-obese groups were found for mediastinitis (16.7% vs 8.9%, P = 0.33) or intensive care unit mortality (22% vs 20%, P = 0.81).

CONCLUSIONS

Improvement of oxygenation was not statistically different between patients with versus without obesity. Pressure ulcers were more common in the obese group, whereas mediastinitis was not. No patient experienced wound dehiscence.

Effects of Concomitant Intra-Aortic Balloon Pump Usage and Different Cannulation Techniques on Venoarterial Extracorporeal Membrane Oxygenation Support in Terms of Organ Perfusion

INTRODUCTION

Various cannulation strategies for venoarterial extracorporeal membrane oxygenation (V-A ECMO) support are currently in use according to the clinical urgency and experience of the rescuing team. Although central V-A ECMO is considered more effective than a peripheral approach, the superiority of one cannulation configuration instead of another remains a controversial subject. This study mainly aims to compare the contribution of V-A ECMO circulatory support modalities to patients' improvement according to various cannulation site strategies and additional usage of intra-aortic balloon pump (IABP).

METHODS

The study design involved the categorization of all patients into two groups: isolated V-A ECMO support and V-A ECMO plus IABP support. Secondly, we divided the patients into four groups considering V-A ECMO cannulation sites, such as central (aorto-atrial), axillo-femoral, femoro-femoral, and jugulo-femoral. We analyzed the parameters regarding the outcome for each group.

RESULTS

When comparing cannulation sites in relation to laboratory parameters for assessing organ perfusion, no statistically significant differences were observed among the groups. We found no statistically significant result within the groups affecting organ perfusion. The complication rates were higher in patients with concomitant IABP support, but the difference was not statistically significant likewise.

CONCLUSION

V-A ECMO provides effective perfusion, no matter which cannulation site is preferred during the decision-making process, and the utilization of IABP support has no additional contribution to the outcomes. We believe that the most suitable strategy should be a tailor-made decision according to the clinical status of patients, the pathology, urgency, and cost-effectiveness.

VV-ECMO in critical COVID-19 obese patients: a cohort study

BACKGROUND

Obesity causes significant difficulties in successful extracorporeal membrane oxygenation (ECMO) support and may interfere with patient outcomes. During the COVID-19 pandemic, we experienced an increased number of obese patients supported with ECMO in our intensive care unit due to severe illness in this population.

METHODS

We designed a single-center retrospective study to identify prognostic factors for 180-day survival in obese critical COVID-19 patients receiving venovenous ECMO (VV-ECMO). We included adult critical COVID-19 patients on VV-ECMO, who were obese and overweight (according to the World Health Organization) and admitted to a tertiary hospital's intensive care unit from April 1, 2020, to May 31, 2022. Univariate logistic regression analysis was performed to assess differences in 180-day mortality.

RESULTS

Forty-one patients were included. The median age was 55 (IQR 45-60) years, and 70.7% of the patients were male. The median body mass index (BMI) was 36 (IQR 31-42.5) kg/m2; 39% of patients had a BMI ≥ 40 kg/m2. The participants had 3 (IQR 1.5-4) days of mechanical ventilation prior to ECMO, and 63.4% were weaned from VV-ECMO support after a median of 19 (IQR 10-34) days. The median ICU length of stay was 31.9 (IQR 17.5-44.5) days. The duration of mechanical ventilation was 30 (IQR 19-49.5) days. The 180-day mortality rate was 41.5%. Univariate logistic regression analysis revealed that a higher BMI was associated with greater 180-day survival (OR 1.157 [1.038-1.291], p = 0.009). Younger age, female sex, less invasive ventilation time before ECMO, and fewer complications at the time of ECMO cannulation were associated with greater 180-day survival [OR 0.858 (0.774-0.953), p 0.004; OR 0.074 (0.008-0.650), p 0.019; OR 0.612 (0.401-0.933), p 0.022; OR 0.13 (0.03-0.740), p 0.022), respectively].

CONCLUSION

In this retrospective cohort of critical COVID-19 obese adult patients supported by VV-ECMO, a higher BMI, younger age, and female sex were associated with greater 180-day survival. A shorter invasive ventilation time before ECMO and fewer complications at ECMO cannulation were also associated with increased survival.

Should Obesity Be an Exclusion Criterion for Extracorporeal Membrane Oxygenation Support? A Scoping Review

Obesity is often considered a contraindication to extracorporeal membrane oxygenation (ECMO) candidacy due to technical challenges with vascular access, higher cardiac output requirements, and known associations between obesity and overall increased morbidity and mortality due to chronic health conditions. However, a growing body of literature suggests that ECMO may be as safe and efficacious in both obese and nonobese patients. This scoping review provides a synthesis of the available literature on the outcomes of obese patients supported with (1) venovenous (VV)-ECMO in acute respiratory distress syndrome (ARDS) not due to coronavirus disease 2019 (COVID-19), (2) VV-ECMO in ARDS due to COVID-19, (3) venoarterial (VA)-ECMO for all indications, and (4) studies combining data of patients supported with VA- and VV-ECMO. A librarian-assisted search was performed using 4 primary electronic medical databases (PubMed, Web of Science, Excerpta Medica database [Embase], and Cochrane Library) from January 2003 to March 2023. Articles that reported outcomes of obese patients requiring ECMO support were included. Two reviewers independently screened titles, abstracts, and full text of articles to determine eligibility. Data extraction was performed using customized fields established a priori within a systematic review software system. A total of 354 publications were imported for screening on titles and abstracts, and 30 studies were selected for full-text review. A total of 26 publications met the inclusion criteria: 7 on VV-ECMO support in non-COVID-19 ARDS patients, 6 on ECMO in COVID-19 ARDS patients, 8 in patients supported with VA-ECMO, and 5 combining both VA- and VV-ECMO data. Although the included studies are limited to retrospective analyses and display a heterogeneity in definitions of obesity and comparison groups, the currently available literature suggests that outcomes and complications of ECMO therapy are equivalent in obese patients as compared to nonobese patients. Hence, obesity as measured by body mass index alone should not be considered an exclusion criterion in the decision to initiate ECMO.

Impact of obesity on outcomes of extracorporeal membrane oxygenation support: a systematic review and meta-analysis

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is used when standard methods of standard treatment methods are not successful. Obese patients present unique challenges during ECMO due to large body size hindering sufficient flows, difficulties with patient positioning and anatomical landmark identification, and restricted radiology scans. This meta-analysis aims to investigate the impact of obesity on the outcomes of patients undergoing ECMO.

METHODS

Databases (PubMed, Embase, and Scopus databases) were searched to identify relevant studies published until July 2023. Data were reported as odds ratios (OR) with 95% confidence interval (CI), and the descriptive data were reported as standard difference of means (SDM) by a random effects model.

RESULTS

A literature search identified 345 studies. Of them, 18 studies met the inclusion criteria. The findings from the meta-analysis revealed no significant association between obesity and survival outcomes after ECMO (odds ratio (OR): 0.91, 95% confidence interval (CI): 0.70-1.17, p: 0.46). Moreover, no comparative significant differences were found between obese and non-obese individuals on the duration of ECMO procedure (standardized mean difference (SMD): 0.07, -0.03-0.17), length of hospital stay (-0.03, -0.19 to 0.12), and duration of ventilation support (-0.10, -0.44 to 0.24).

CONCLUSION

The meta-analysis findings suggest no significant impact of obesity on the survival outcomes after the ECMO procedure. There was no significant impact of obesity on the duration of ECMO procedures, length of hospital stay, and duration of ventilation support.

Obesity and Extracorporeal Membrane Oxygenation (ECMO): Analysis of Outcomes

Traditionally, patients with obesity have been deemed ineligible for extracorporeal life support (ELS) therapies such as extracorporeal membrane oxygenation (ECMO), given the association of obesity with chronic health conditions that contribute to increased morbidity and mortality. Nevertheless, a growing body of literature suggests the feasibility, efficacy, and safety of ECMO in the obese population. This review provides an in-depth analysis of the current literature assessing the effects of obesity on outcomes among patients supported with ECMO (venovenous [VV] ECMO in noncoronavirus disease 2019 and coronavirus disease 2019 acute respiratory distress syndrome, venoarterial [VA] ECMO, and combined VV and VA ECMO), offer a possible explanation of the current findings on the basis of the obesity paradox phenomenon, provides a framework for future studies addressing the use of ELS therapies in the obese patient population, and provides guidance from the literature for many of the challenges related to initiating, maintaining, and weaning ELS therapy in patients with obesity.

Association between body mass index and clinical outcomes in patients with out-of-hospital cardiac arrest undergoing extracorporeal cardiopulmonary resuscitation: A multicenter observational study

Background

We examined the association between body mass index (BMI) and outcomes in patients with out-of-hospital cardiac arrest (OHCA) undergoing extracorporeal cardiopulmonary resuscitation (ECPR).

Methods

We retrospectively analyzed the database of an observational multicenter cohort in Japan. Adult patients with OHCA of cardiac etiology who received ECPR between 2013 and 2018 were categorized as follows: underweight, BMI < 18.5; normal weight, BMI = 18.5-24.9; overweight, BMI = 25-29.9; and obese, BMI ≥ 30 kg/m2. The primary outcome was in-hospital mortality; secondary outcomes were unfavorable neurological outcomes at discharge (cerebral performance category ≥ 3) and ECPR-related complications. BMI's association with outcomes was assessed using a logistic regression model adjusted for age, sex, comorbidities, witness/bystander CPR, initial rhythm, prehospital return of spontaneous circulation, and low-flow time.

Results

In total, 1,044 patients were analyzed. Their median age was 61 (IQR, 49-69) years; the median BMI was 24.2 (21.5-26.9) kg/m2. The overall rates of in-hospital mortality, unfavorable neurological outcome, and ECPR-related complications were 62.2%, 79.9%, and 31.7%, respectively. In multivariate analysis, the overweight and obese groups had higher in-hospital mortality odds than the normal BMI group (odds ratio [95%CI], 1.37 [1.02-1.85], p = 0.035; and 2.09 [1.31-3.39], p < 0.001, respectively). The odds ratio for unfavorable neurological outcomes increased more in the obese than in the normal BMI group (3.17 [1.69-6.49], p < 0.001). ECPR-related complications were not significantly different among groups.

Conclusions

In OHCA patients undergoing ECPR, a BMI ≥ 25 kg/m2 was associated with increased in-hospital mortality, and a BMI ≥ 30 kg/m2 was also associated with a worse neurological outcome.

Procedural-Related Bleeding in Hospitalized Patients With Liver Disease (PROC-BLeeD): An International, Prospective, Multicenter Observational Study

BACKGROUND & AIMS

Hospitalized patients with cirrhosis frequently undergo multiple procedures. The risk of procedural-related bleeding remains unclear, and management is not standardized. We conducted an international, prospective, multicenter study of hospitalized patients with cirrhosis undergoing nonsurgical procedures to establish the incidence of procedural-related bleeding and to identify bleeding risk factors.

METHODS

Hospitalized patients were prospectively enrolled and monitored until surgery, transplantation, death, or 28 days from admission. The study enrolled 1187 patients undergoing 3006 nonsurgical procedures from 20 centers.

RESULTS

A total of 93 procedural-related bleeding events were identified. Bleeding was reported in 6.9% of patient admissions and in 3.0% of the procedures. Major bleeding was reported in 2.3% of patient admissions and in 0.9% of the procedures. Patients with bleeding were more likely to have nonalcoholic steatohepatitis (43.9% vs 30%) and higher body mass index (BMI; 31.2 vs 29.5). Patients with bleeding had a higher Model for End-Stage Liver Disease score at admission (24.5 vs 18.5). A multivariable analysis controlling for center variation found that high-risk procedures (odds ratio [OR], 4.64; 95% confidence interval [CI], 2.44-8.84), Model for End-Stage Liver Disease score (OR, 2.37; 95% CI, 1.46-3.86), and higher BMI (OR, 1.40; 95% CI, 1.10-1.80) independently predicted bleeding. Preprocedure international normalized ratio, platelet level, and antithrombotic use were not predictive of bleeding. Bleeding prophylaxis was used more routinely in patients with bleeding (19.4% vs 7.4%). Patients with bleeding had a significantly higher 28-day risk of death (hazard ratio, 6.91; 95% CI, 4.22-11.31).

CONCLUSIONS

Procedural-related bleeding occurs rarely in hospitalized patients with cirrhosis. Patients with elevated BMI and decompensated liver disease who undergo high-risk procedures may be at risk to bleed. Bleeding is not associated with conventional hemostasis tests, preprocedure prophylaxis, or recent antithrombotic therapy.

The Relation Between Obesity and Mortality in Postcardiotomy Venoarterial Membrane Oxygenation

BACKGROUND

Obesity is an important health problem in cardiac surgery and among patients requiring postcardiotomy venoarterial extracorporeal membrane oxygenation (V-A ECMO). Still, whether these patients are at risk for unfavorable outcomes after postcardiotomy V-A ECMO remains unclear. The current study evaluated the association between body mass index (BMI) and in-hospital outcomes in this setting.

METHODS

The Post-cardiotomy Extracorporeal Life Support (PELS-1) study is an international, multicenter study. Patients requiring postcardiotomy V-A ECMO in 36 centers from 16 countries between 2000 and 2020 were included. Patients were divided in 6 BMI categories (underweight, normal weight, overweight, class I, class II, and class III obesity) according to international recommendations. Primary outcome was in-hospital mortality, and secondary outcomes included major adverse events. Mixed logistic regression models were applied to evaluate associations between BMI and mortality.

RESULTS

The study cohort included 2046 patients (median age, 65 years; 838 women [41.0%]). In-hospital mortality was 60.3%, without statistically significant differences among BMI classes for in-hospital mortality (P = .225) or major adverse events (P = .126). The crude association between BMI and in-hospital mortality was not statistically significant after adjustment for comorbidities and intraoperative variables (class I: odds ratio [OR], 1.21; 95% CI, 0.88-1.65; class II: OR, 1.45; 95% CI, 0.86-2.45; class III: OR, 1.43; 95% CI, 0.62-3.33), which was confirmed in multiple sensitivity analyses.

CONCLUSIONS

BMI is not associated to in-hospital outcomes after adjustment for confounders in patients undergoing postcardiotomy V-A ECMO. Therefore, BMI itself should not be incorporated in the risk stratification for postcardiotomy V-A ECMO.

Impact of BMI on outcomes in respiratory ECMO: an ELSO registry study

PURPOSE

The impact of body mass index (BMI) on outcomes in respiratory failure necessitating extracorporeal membrane oxygenation (ECMO) has been poorly described. We aimed to assess: (i) whether adults with class II obesity or more (BMI ≥ 35 kg/m²) have worse outcomes than lean counterparts, (ii) the form of the relationship between BMI and outcomes, (iii) whether a cutoff marking futility can be identified.

METHODS

A retrospective analysis of the Extracorporeal Life Support Organization (ELSO) Registry from 1/1/2010 to 31/12/2020 was conducted. Impact of BMI ≥ 35 kg/m² was assessed with propensity-score (PS) matching, inverse propensity-score weighted (IPSW) and multivariable models (MV), adjusting for a priori identified confounders. Primary outcome was in-hospital mortality. The form of the relationship between BMI and outcomes was studied with generalized additive models. Outcomes across World Health Organisation (WHO)-defined BMI categories were compared.

RESULTS

Among 18,529 patients, BMI ≥ 35 kg/m² was consistently associated with reduced in-hospital mortality [PS-matched: OR: 0.878(95%CI 0.798-0.966), p = 0.008; IPSW: OR: 0.899(95%CI 0.827-0.979), p = 0.014; MV: OR: 0.900(95%CI 0.834-0.971), p = 0.007] and shorter hospital length of stays. In patients with BMI ≥ 35 kg/m², cardiovascular (17.3% versus 15.3%), renal (37% versus 30%) and device-related complications (25.7% versus 20.6%) increased, whereas pulmonary complications decreased (7.6% versus 9.3%). These findings were independent of confounders throughout PS-matched, IPSW and MV models. The relationship between BMI and outcomes was non-linear and no cutoff for futility was identified.

CONCLUSION

Patients with obesity class II or more treated with ECMO for respiratory failure have lower mortality risk and shorter stays, despite increased cardiovascular, device-related, and renal complications. No upper limit of BMI indicating futility of ECMO treatment could be identified. BMI as single parameter should not be a contra-indication for respiratory ECMO.