Among patients who received venovenous extracorporeal membrane oxygenation (ECMO) for COVID-19, older age, male sex, and chronic lung disease have a moderate or high certainty of association with increased mortality, according to findings published in The Lancet Respiratory Medicine.
The systematic review and meta-analysis sought to summarize the association between precannulation prognostic factors (including patient factors, disease factors, and center factors) and the risk of in-hospital mortality in adult patients who received venovenous ECMO for acute respiratory failure secondary to COVID-19.
Investigators searched the MEDLINE and Embase databases from December 1, 2019, to April 14, 2022, for randomized controlled trials and observational studies published in English that included adult patients (aged ≥16 years) with COVID-19 confirmed by polymerase chain reaction, patients who required any configuration of ECMO for COVID-19-associated acute respiratory distress syndrome (ARDS), and the assessment of precannulation prognostic factors associated with in-hospital mortality.
The Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was used to assess overall certainty in pooled estimates. The primary outcome was in-hospital mortality. A total of 42 observational cohort studies with 17,449 patients were included. The studies were mostly from North America and Europe.
Of the patient factors, older age (5 studies; adjusted hazard ratio [aHR] 2.27 [95% CI, 1.63-3.16]; high certainty), was associated with increased mortality. Among 26 studies that included sex as a prognostic factor, male sex was probably associated with increased mortality (unadjusted odds ratio [uOR] 1.34 [95% CI, 1.20-1.49]; moderate certainty). Of 3 studies with lung disease as a prognostic factor, chronic lung disease was probably associated with increased mortality (aHR 1.55 [95% CI, 1.20-2.00]; moderate certainty).
Precannulation disease factors were included in 2 studies, which showed that increased driving pressure was associated with higher mortality (aHR 2.36 [95% CI, 1.40-3.97]; high certainty). Also, 8 studies that assessed symptom duration before cannulation as a prognostic factor showed that a greater symptom duration was probably associated with increased mortality (mean difference 1.51 days [95% CI, 0.36-2.65]; moderate certainty).
A total of 16 studies evaluated partial pressure of arterial carbon dioxide (PaCO2) as a prognostic factor and demonstrated that increased PaCO2 was probably associated with increased mortality (mean difference 4.04 mm Hg [95% CI, 1.64-6.44]; moderate certainty).
The duration of invasive mechanical ventilation before cannulation was assessed in 6 studies, which showed that longer ventilation duration was probably associated with increased mortality (uOR 1.94 [95% CI, 1.40-2.67]; moderate certainty). In addition, according to 2 studies that evaluated center volume, lower patient volume (or less experienced center) was probably associated with increased mortality (adjusted odds ratio 2.27 [95% CI, 1.28-4.05]; moderate certainty).
Study limitations included the use of prognostic factors of importance for patients who ultimately received ECMO, rather than for all patients potentially eligible for ECMO; the lack of appropriate adjustment for extrapulmonary organ failure in many included studies, which might have affected patient selection and outcomes; and variability in the quality of the prognostic modeling methodology used by the included studies.
“We advocate for the careful consideration of these prognostic factors as part of a risk stratification framework when evaluating a patient’s potential indication for venovenous ECMO for the treatment of COVID-19,” said the investigators.
Disclosure: Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
This article originally appeared on Pulmonology Advisor
Tran A, Fernando SM, Rochwerg B, et al. Prognostic factors associated with mortality among patients receiving venovenous extracorporeal membrane oxygenation for COVID-19: a systematic review and meta-analysis. Lancet Respir Med. Published online October 10, 2022. doi:10.1016/S2213-2600(22)00296-X