Predictors associated with mortality of veno-venous extracorporeal membrane oxygenation therapy

Prevalence and risk factors for in-hospital mortality of adult patients on veno-arterial extracorporeal membrane oxygenation for cardiogenic shock and cardiac arrest: A systematic review and meta-analysis

OBJECTIVES

To synthesize quantitative research findings on the prevalence and risk factors for in-hospital mortality of patients on veno-arterial extracorporeal membrane oxygenation (VA-ECMO).

METHODS

A comprehensive search was conducted for the period from May 2008 to December 2023 by searching the five electronic databases of PubMed, CINAHL, Web of Science, EMBASE, and Cochrane library. The quality of included studies was assessed using the Newcastle-Ottawa scale. The meta-analysis estimated the pooled odds ratio or standard mean difference and 95% confidence intervals.

RESULTS

A total of twenty-five studies with 10,409 patients were included in the analysis. The overall in-hospital mortality of patients on VA-ECMO was 56.7 %. In the subgroup analysis, in-hospital mortality of VA-ECMO for cardiogenic shock and cardiac arrest was 49.2 % and 75.2 %, respectively. The number of significant factors associated with an increased risk of in-hospital mortality in the pre-ECMO period (age, body weight, creatinine, chronic kidney disease, pH, and lactic acid) was greater than that in the intra- and post-ECMO periods. Renal replacement, bleeding, and lower limb ischemia were the most significant risk factors for in-hospital mortality in patients receiving VA-ECMO.

CONCLUSION

Early detection of the identified risk factors can contribute to reducing in-hospital mortality in patients on VA-ECMO. Intensive care unit nurses should provide timely and appropriate care before, during, and after VA-ECMO.

IMPLICATIONS FOR CLINICAL PRACTICE

Intensive care unit nurses should be knowledgeable about factors associated with the in-hospital mortality of patients on VA-ECMO to improve outcomes. The present findings may contribute to developing guidelines for reducing in-hospital mortality among patients considering ECMO.

External Validation of the PREdiction of Survival on Extracorporeal Membrane Oxygenation Therapy (PRESET) Score: A Single-Center Cohort Experience

Acute respiratory distress syndrome (ARDS) is a life-threatening condition affecting >10% of intensive care unit (ICU) patients worldwide with a mortality of up to 59% depending on severity. Extracorporeal membrane oxygenation (ECMO) is a potentially life-saving procedure in severe ARDS but is technically and financially challenging. In recent years, various scoring systems have been proposed to select patients most likely to benefit from ECMO, with the PREdiction of Survival on ECMO Therapy (PRESET) score being one of the most used. We collected data from 283 patients with ARDS of various etiology who underwent veno-venous (V-V) ECMO therapy at a German tertiary care ICU from January 2012 to December 2022. Median age in the cohort was 56 years, and 64.31% were males. The in-hospital mortality rate was 50.88% (n = 144). The median (25%; 75% quartile) severity scores were 38 (31; 49) for Simplified Acute Physiology Score (SAPS) II, 12 (10; 13) for Sequential Organ Failure Assessment (SOFA) and 7 (5; 8) for PRESET. Simplified Acute Physiology Score-II displayed the best prognostic value (area under the receiver operating characteristic [AUROC]: 0.665 [confidence interval (CI): 0.574-0.756; p = 0.046]). Prediction performance was weak in all analyzed scores despite good calibration. Simplified Acute Physiology Score-II had the best discrimination after adjustment of our original cohort. The use of scores explored in this study for patient selection for eligibility for V-V ECMO is not recommendable.

Association of RBC Transfusion Thresholds and Outcomes in Medical Patients With Acute Respiratory Failure Supported With Extracorporeal Membrane Oxygenation: A Single-Center Retrospective Cohort Study

BACKGROUND

The hemoglobin value to trigger RBC transfusion for patients receiving venovenous extracorporeal membrane oxygenation (ECMO) is controversial. Previous guidelines recommended transfusing to a normal hemoglobin level, but recent studies suggest that more RBC transfusions are associated with increased adverse outcomes.

RESEARCH QUESTION

Is implementation of different institutional RBC transfusion thresholds for patients receiving venovenous ECMO associated with changes in RBC use and patient outcomes?

STUDY DESIGN AND METHODS

This single-center retrospective study of patients receiving venovenous ECMO used segmented regression to test associations between implementation of institutional transfusion thresholds and trends in RBC use. Associations with secondary outcomes, including in-hospital survival, also were assessed.

RESULTS

The study included 229 patients: 91 in the no threshold cohort, 48 in the hemoglobin < 8 g/dL cohort, and 90 in the hemoglobin < 7 g/dL cohort. Despite a decrease in number of RBC units transfused per day of ECMO support after implementation of different thresholds (mean ± SD: 0.6 ± 1.0 in the no threshold cohort, 0.3 ± 0.8 in the hemoglobin < 8 g/dL cohort, and 0.3 ± 1.1 in the hemoglobin < 7 g/dL cohort; P < .001), segmented regression showed no association between implementation of transfusion thresholds and changes in trends in number of RBC units per day of ECMO. We observed an increased hazard of death in the no threshold cohort compared with the hemoglobin < 8 g/dL cohort (adjusted hazard ratio [aHR], 2.08; 95% CI, 1.12-3.88) and in the hemoglobin < 7 g/dL cohort compared with the hemoglobin < 8 g/dL cohort (aHR, 1.93; 95% CI, 1.02-3.62). No difference was found in the hazard of death between the no threshold and hemoglobin < 7 g/dL cohorts (aHR, 1.08; 95% CI, 0.69-1.69).

INTERPRETATION

We observed a decrease in number of RBC units per day of ECMO over time, but changes were not associated temporally with implementation of transfusion thresholds. A transfusion threshold of hemoglobin < 8 g/dL was associated with a lower hazard of death, but these findings are limited by study methodology. Further research is needed to investigate optimal RBC transfusion practices for patients supported with venovenous ECMO.

Prognostic factors in lung transplantation after extracorporeal membrane oxygenation bridging therapy: a systematic review and meta-analysis

Background

Extracorporeal membrane oxygenation (ECMO) has recently emerged as a critical support system for lung function in patients awaiting lung transplantation. This meta-analysis investigates the prognostic factors of lung transplantation following ECMO bridging therapy.

Methods

A comprehensive search was conducted in PubMed, Cochrane Library, Embase, CINAHL, Web of Science, Scopus, and ProQuest databases from inception to August 11, 2023. Included were cohort or case-control studies focusing on prognostic factors of lung transplantation with ECMO bridging therapy. Data extraction was performed independently, and study quality was assessed. A meta-analysis was carried out using RevMan 5.4 and Stata17.0 software to aggregate mortality rates and pertinent prognostic factors of ECMO as a bridge to lung transplantation.

Results

The search identified eight trials encompassing 1,086 participants. The prognosis of patients undergoing lung transplantation with ECMO bridging was significantly associated with several factors: prolonged ECMO support [odds ratio 1.07, 95% confidence interval (CI): 1.02-1.12, I2=77%], deterioration in liver and kidney function (odds ratio 3.62, 95% CI: 2.37-5.54, I2=0%), and complications during ECMO (odds ratio 2.24, 95% CI: 1.45-3.44, I2=5%).

Conclusions

Prolonged ECMO support, declining liver and kidney functions, and complications during ECMO are vital prognostic factors in lung transplantation following ECMO bridging therapy.

A Descriptive Analysis of Hybrid Cannulated Extracorporeal Life Support

BACKGROUND

Extracorporeal life support (ECLS) is pivotal for sustaining the function of failing hearts and lungs, and its utilization has risen. In cases where conventional cannulation strategies prove ineffective for providing adequate ECLS support, the implementation of an enhanced system with a third cannula may become necessary. Hybrid ECLS may be warranted in situations characterized by severe hypoxemia of the upper extremity, left ventricular congestion, and dilatation. Additionally, it may also be considered for patients requiring respiratory support or experiencing hemodynamic instability.

METHOD

All hybrid ECLS cases of adults at the University Hospital Zurich, Switzerland, between January 2007 and December 2019 with initial triple cannulation were included. Data were collected via a retrospective review of patient records and direct export of the clinical information system.

RESULTS

28 out of 903 ECLS cases were initially hybrid cannulated (3.1%). The median age was 57 (48.2 to 60.8) years, and the sex was equally distributed. The in-hospital mortality of hybrid ECLS was high (67.9%). In-hospital mortality rates differ depending on the indication (ARDS: 36.4%, refractory cardiogenic shock: 88.9%, cardiopulmonary resuscitation: 100%, post-cardiotomy: 100%, others: 75%). Survivors exhibited a lower SAPS II level compared with non-survivors (20.0 (12.0 to 65.0) vs. 55.0 (45.0 to 73.0)), and the allogenic transfusion of platelet concentrate was observed to be less frequent for survivors (0.0 (0.0) vs. 1.8 (2.5) units).

CONCLUSION

The in-hospital mortality rate for hybrid ECLS was high. Different indications showed varying mortality rates, with survivors having lower SAPS II scores and requiring fewer platelet concentrate transfusions. These findings highlight the complexities of hybrid ECLS outcomes in different clinical scenarios and underline the importance of rigorous patient selection.

Prolonged VV ECMO: Navigating the Unchartered Sea

How to cite this article: Kumar V. Prolonged VV ECMO: Navigating the Unchartered Sea. Indian J Crit Care Med 2023;27(11):779-781.