Tonna, Joseph E.

Background The prognostic significance of an adverse acid–base milieu despite venoarterial extracorporeal membrane oxygenation support in patients with cardiogenic shock remains poorly defined. We examined metabolic and respiratory disturbances in the ELSO (Extracorporeal Life Support Organization) Registry among patients who received venoarterial extracorporeal membrane oxygenation support for refractory cardiogenic shock. Methods Arterial blood gas acid–base values at 24 hours following venoarterial extracorporeal membrane oxygenation initiation were analyzed, with patients classified by pH, arterial partial pressure of carbon dioxide, and bicarbonate. Multivariable logistic regression and exploratory machine learning analyses were used to assess predictors of in‐hospital mortality. Results Among 15 144 adult patients, 74.6% (10 860) had neither respiratory nor metabolic acidosis, 13.1% (1909) had isolated respiratory acidosis, 11.6% (1684) had isolated metabolic acidosis, and 0.7% (100) had combined acidosis. In‐hospital mortality occurred in 7719 (51.0%) patients and increased incrementally across patients with lower pH (adjusted odds ratio [OR], 2.03 with each 0.1‐unit decrease in pH, using 7.4 as a reference point [95% CI, 1.82–2.26]), bicarbonate (adjusted OR, 1.93 per each 5‐mEq/L <24 mEq/L [95% CI, 1.76–2.12]) or base excess (adjusted OR, 1.90 per each 5‐mEq/L <0 mEq/L [95% CI, 1.75–2.07]) (all P <0.01). Mortality varied significantly, being highest for the low‐pH metabolic acidosis cluster (adjusted OR, 1.90 [95% CI, 1.70–2.12], P <0.01). Conclusions Survival decreased progressively with worse acidemia or metabolic acidosis despite 24 hours of hemodynamic support with venoarterial extracorporeal membrane oxygenation among patients with cardiogenic shock. Our findings emphasize the prognostic significance of metabolic parameters as potentially modifiable risk factors and underscore the need for early recognition and interventions to mitigate severe metabolic derangements.

Abstract Perioperative low cardiac output syndrome (LCOS) remains a significant complication in adult cardiac surgery, contributing to substantial morbidity, prolonged intensive care, and increased mortality. Its incidence is expected to rise further due to the evolving complexity of referred surgical patients, often characterised by advanced age, multiple comorbidities, challenging anatomy, and impaired haemodynamics. Despite advances in pharmacological and perioperative care, outcomes for high-risk patients have not shown significant improvement, prompting interest in temporary mechanical circulatory support (tMCS) as a proactive strategy. This Expert Consensus Document from the European Association for Cardio-Thoracic Surgery (EACTS) presents the first dedicated guidance on the pre-emptive use of tMCS in high-risk adult cardiac surgical patients. Developed by a multidisciplinary task force, it emphasises structured risk stratification, early initiation, and individualised device management informed by interdisciplinary Heart Team discussions. The document proposes clinical pathways for patient selection, defines criteria for tMCS initiation, and provides practical algorithms for various scenarios, including advanced heart failure, cardiogenic shock, and post-cardiotomy LCOS. It reviews the current evidence on available tMCS devices, such as intra-aortic balloon pumps, microaxial flow pumps, veno-arterial extracorporeal life support and hybrid strategies, and addresses perioperative care, intensive care unit protocols, ethical considerations, as well as informed consent and support withdrawal. Despite promising results, substantial knowledge gaps remain, including long-term outcome data, device selection criteria, and cost-effectiveness analyses. This consensus aims to support clinical decision-making, standardise practice, and stimulate research to improve outcomes in a growing population of high-risk surgical patients.

OBJECTIVES: To investigate whether severe hyperoxia predisposes to end-organ complications and whether these complications contribute to in-hospital mortality among cardiogenic shock (CS) patients supported in venoarterial extracorporeal membrane oxygenation (VA-ECMO). DESIGN: Adult patients with CS from the Extracorporeal Life Support Organization Registry between 2010 and 2023 were categorized into normoxia (Pao 2 60–150 mm Hg), mild hyperoxia (Pao 2 151–300 mm Hg), and severe hyperoxia (Pao 2 > 300 mm Hg) based on their Pao 2 at 24 hours. The primary outcome was in-hospital mortality. End-organ complications were analyzed using multivariate logistic regression models, and causal mediation analysis was performed to estimate the direct and indirect effects of hyperoxia on mortality. SETTING: Multicenter, multinational prospective cohort study. PATIENTS: Adults with CS supported on VA-ECMO. INTERVENTIONS: Partial pressure of oxygen at 24 hours after VA-ECMO cannulation. MEASUREMENTS/MAIN RESULTS: A total of 10,541 patients were included (normoxia: 48.4%, mild hyperoxia: 30.0%, severe hyperoxia: 21.5%). There was higher in-hospital mortality in patients with severe hyperoxia (71.7%, adjusted OR [aOR]: 2.17; 95% CI, 1.19–2.50) and mild hyperoxia (63.8%, aOR: 1.34; 95% CI, 1.19–1.50) compared normoxia (52.7%; referent group). Severe hyperoxia was associated with more end-organ complications, which incrementally predicted higher mortality (aOR: 1.42; 95% CI, 1.25–1.61). Mediation analysis demonstrated that hyperoxia primary exerted a direct effect on mortality (86%), with contributions from neurologic (3.1%), hepatic (3.9%), renal (3.5%), and bleeding (2.3%) complications. CONCLUSIONS: Severe hyperoxia in patients with CS receiving VA-ECMO is associated with increased mortality and more end-organ complications. However, most of the effect of severe hyperoxia on mortality occurs via direct effects, independent of end-organ complications. These findings highlight the potential direct toxicity of hyperoxia and underscore the need for strategies to optimize oxygen delivery in this critically ill population.

Background Venoarterial extracorporeal membrane oxygenation (ECMO) provides full hemodynamic support for patients with cardiogenic shock, but optimal timing of ECMO initiation remains uncertain. We sought to determine whether earlier initiation of ECMO is associated with improved survival in cardiogenic shock. Methods and Results We analyzed adult patients with cardiogenic shock who received venoarterial ECMO from the international Extracorporeal Life Support Organization (ELSO) registry from 2009 to 2019, excluding those cannulated following an operation. Multivariable logistic regression evaluated the association between time from admission to ECMO initiation and in‐hospital death. Among 8619 patients (median, 56.7 [range, 44.8–65.6] years; 33.5% women), the median duration from admission to ECMO initiation was 14 (5–32) hours. Patients who had ECMO initiated within 24 hours (n=5882 [68.2%]) differed from those who had ECMO initiated after 24 hours, with younger age, more preceding cardiac arrest, and worse acidosis. After multivariable adjustment, patients with ECMO initiated >24 hours after admission had higher risk of in‐hospital death (adjusted odds ratio, 1.20 [95% CI, 1.06–1.36]; P =0.004). Each 12‐hour increase in the time from admission to ECMO initiation was incrementally associated with higher adjusted in‐hospital mortality rate (adjusted odds ratio, 1.06 [95% CI, 1.03–1.10]; P <0.001). The association between longer time to ECMO and worse outcomes appeared stronger in patients with lower shock severity. Conclusions Longer delays from admission to ECMO initiation were associated with higher a mortality rate in a large‐scale, international registry. Our analysis supports optimization of door‐to‐support time and the avoidance of inappropriately delayed ECMO initiation.

Introduction: Venoarterial extracorporeal membrane oxygenation (VA ECMO) provides full hemodynamic support for cardiogenic shock (CS), but optimal timing of ECMO initiation remains uncertain. Hypothesis: We hypothesized that earlier initiation of ECMO would be associated with improved survival in CS patients. Methods: We analyzed adult patients with CS who received VA ECMO from the Extracorporeal Life Support Organization (ELSO) Registry from 2009 - 2019, excluding those cannulated following an operation. Multivariable logistic regression evaluated the association between time from admission to ECMO initiation and in-hospital mortality. Results: Among 8619 patients (median 56.7 years; 33.5% females), the duration from admission to ECMO initiation was 14 (5, 32) hours. Patients who had ECMO initiated within 24 hours (n = 5882 [68.2%]) differed from those who had ECMO initiated after 24 hours, with younger age, more preceding cardiac arrest, and worse acidosis. After adjustment, patients with ECMO initiated more than 24 hours after admission had higher risk of adjusted in-hospital mortality (adjusted OR 1.20, 95% CI 1.06-1.36, p = 0.004) (Figure 1). Each 12-hour increase in the time from admission to ECMO initiation was incrementally associated with higher adjusted in-hospital mortality (adjusted OR 1.06, 95% CI 1.03-1.10, p < 0.001). The association between longer time to ECMO and worse outcomes appeared stronger in patients with lower shock severity. Among patients who were cannulated within 24 hours, those cannulated during the same day shift had lower mortality than those who were admitted at night and cannulated the following day (adjusted OR adjusted OR 0.81, 95% CI 0.66-0.99, p = 0.04). Conclusions: Longer delays from admission to ECMO initiation were associated with higher mortality in a large-scale, international registry. Our analysis supports optimization of door-to-support time and the avoidance of inappropriately delayed ECMO initiation.

Background: Exposure to hyperoxia, a high arterial partial pressure of oxygen (PaO2), may be associated with worse outcomes in patients receiving extracorporeal membrane oxygenator (ECMO) support. We examined hyperoxia in the Extracorporeal Life Support Organization Registry among patients receiving venoarterial ECMO for cardiogenic shock. Methods: We included Extracorporeal Life Support Organization Registry patients from 2010 to 2020 who received venoarterial ECMO for cardiogenic shock, excluding extracorporeal CPR. Patients were grouped based on PaO2 after 24 hours of ECMO: normoxia (PaO2 60–150 mmHg), mild hyperoxia (PaO2 151–300 mmHg), and severe hyperoxia (PaO2 >300 mmHg). In-hospital mortality was evaluated using multivariable logistic regression. Results: Among 9959 patients, 3005 (30.2%) patients had mild hyperoxia and 1972 (19.8%) had severe hyperoxia. In-hospital mortality increased across groups: normoxia, 47.8%; mild hyperoxia, 55.6% (adjusted odds ratio, 1.37 [95% CI, 1.23–1.53]; P <0.001); severe hyperoxia, 65.4% (adjusted odds ratio, 2.20 [95% CI, 1.92–2.52]; P <0.001). A higher PaO2 was incrementally associated with increased in-hospital mortality (adjusted odds ratio, 1.14 per 50 mmHg higher [95% CI, 1.12–1.16]; P <0.001). Patients with a higher PaO2 had increased in-hospital mortality in each subgroup and when stratified by ventilator settings, airway pressures, acid-base status, and other clinical variables. In the random forest model, PaO2 was the second strongest predictor of in-hospital mortality, after older age. Conclusions: Exposure to hyperoxia during venoarterial ECMO support for cardiogenic shock is strongly associated with increased in-hospital mortality, independent from hemodynamic and ventilatory status. Until clinical trial data are available, we suggest targeting a normal PaO2 and avoiding hyperoxia in CS patients receiving venoarterial ECMO.

Abstract Aims Shock severity predicts mortality in patients with cardiogenic shock (CS). We evaluated the association between pre-cannulation Society for Cardiovascular Angiography and Intervention (SCAI) shock classification and mortality among patients receiving venoarterial (VA) extracorporeal membrane oxygenation (ECMO) support for CS. Methods and results We included Extracorporeal Life Support Organization (ELSO) Registry patients from 2010 to 2020 who received VA ECMO for CS. SCAI shock stage was assigned based on hemodynamic support requirements prior to ECMO initiation. In-hospital mortality was analyzed using multivariable logistic regression. We included 12 106 unique VA ECMO patient runs with a median age of 57.9 (interquartile range: 46.8, 66.1) years and 31.8% were females; 3472 (28.7%) were post-cardiotomy. The distribution of SCAI shock stages at ECMO initiation was: B, 821 (6.8%); C, 7518 (62.1%); D, 2973 (24.6%); and E, 794 (6.6%). During the index hospitalization, 6681 (55.2%) patients died. In-hospital mortality increased incrementally with SCAI shock stage (adjusted OR: 1.24 per SCAI shock stage, 95% CI: 1.17–1.32, P &lt; 0.001): B, 47.5%; C, 52.8%; D, 60.8%; E, 65.1%. A higher SCAI shock stage was associated with increased in-hospital mortality in key subgroups, although the SCAI shock classification was only predictive of mortality in non-surgical (medical) CS and not in post-cardiotomy CS. Conclusion The severity of shock prior to cannulation is a strong predictor of in-hospital mortality in patients receiving VA ECMO for CS. Using the pre-cannulation SCAI shock classification as a risk stratification tool can help clinicians refine prognostication for ECMO recipients and guide future investigations to improve outcomes.