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Use of extracorporeal membrane oxygenation (ECMO) was associated with a modestly increased risk of new mental health diagnoses in patients treated for critical illness in an intensive care unit (ICU), a retrospective cohort study in Canada showed.

Among adult survivors who received ECMO, incidence of a new mental health diagnosis was 22.1 per 100 person-years compared with 14.5 per 100 person-years in ICU survivors who did not receive ECMO, reported Shannon M. Fernando, MD, MSc, of the University of Ottawa in Ontario, Canada, and colleagues in .

After propensity weighting, use of ECMO for critical illness was significantly associated with an increased risk of new mental health diagnoses (HR 1.24, 95% CI 1.01-1.52), primarily depression, anxiety, and trauma-related disorders.

"The use of ECMO has grown worldwide, particularly in the context of the COVID-19 pandemic, where ECMO has been used for refractory respiratory failure in cases of severe COVID-19," the researchers wrote.

"Given the severity of illness found among patients receiving ECMO, its invasive nature, as well as the prolonged duration of therapy and recovery that is often required among those who survive ... survivors after ECMO may be at even greater risk of downstream mental health morbidity than other survivors of critical illness," they added.

Overall, ECMO outcomes in the context of the pandemic have varied, ranging from "reasonable" to "exceptional."

Of the secondary mental health outcomes assessed by Fernando and team, ECMO and non-ECMO survivors had comparable rates per 100 person-years for substance misuse (1.6 vs 1.4; HR 0.86, 95% CI 0.48-1.53) and deliberate self-harm (0.4 vs 0.3; HR 0.68, 95% CI 0.21-2.23).

Furthermore, "there were fewer than five total cases of death by suicide in the entire cohort," the group noted.

"As care providers, we can tell our patients that it's common to struggle with your mental health after an ICU admission," said co-author Peter Tanuseputro, MD, also of the University of Ottawa, in a statement. "ICU survivors need to realize that they often face months or years of recovery, and families and healthcare providers need to support them."

In an , Marieke Zegers, PhD, of Radboud University Medical Center in Nijmegen, the Netherlands, and colleagues noted that the study design only makes it "possible to hypothesize about the causal factors between ECMO and new mental health problems," reiterating the biological mechanisms proposed by the study authors, including potentially increased susceptibility "to hypoxemia, shock, and reduced oxygen delivery that can predispose neurons to apoptosis and higher risk for neurological complications such as ischemic stroke or delirium."

The editorialists also pointed out that only pre-existing mental health diagnosis (HR 2.39, 95% CI 1.78-3.20) and an outpatient psychiatry visit during the year prior to ICU admission (HR 1.82, 95% CI 1.25-2.65) were significantly associated with an increased risk of a new mental health diagnosis.

"This finding corroborates results of previous studies that showed was the most important prognostic factor for mental health outcomes after ICU care, and even," they wrote. "This suggests that ECMO treatment might be an extra trigger for mental problems in patients who already are vulnerable to mental health conditions."

That "almost half of the study population, including patients who received ECMO and those who did not, had at least one primary care or psychiatry visit for mental health in the preceding 5 years ... raises the question of whether the primary outcome truly reflected new mental health problems," Zegers and team added, noting that the primary finding persisted after exclusion of patients with prior mental health diagnoses in a sensitivity analysis.

"We really need more research and investment in the area of post-critical illness," said Fernando. "Patients will need help long after they leave the ICU."

For this study, Fernando and colleagues followed 4,462 adults who were admitted to the ICU and survived to hospital discharge from April 2010 through March 2020. Of these survivors, 642 had received ECMO (mean age 50.7 years, 40.7% women) and were followed for a median of 730 days; they were matched to 3,820 ICU survivors who did not receive ECMO (mean age 51.0 years, 40.0% women), who were followed for a median 1,390 days.

The groups were matched for characteristics including age, sex, mental health history, critical illness severity, and hospital length of stay.

Of the 642 ECMO survivors, 37% were diagnosed with a new mental health condition.

The primary outcome was comprised of a composite of mood disorders, anxiety disorders, post-traumatic stress disorder, schizophrenia, other psychotic disorders, other mental health disorders, and social problems. The group also looked at eight secondary outcomes, including incidence of substance misuse, deliberate self-harm, death by suicide, and individual components of the composite primary outcome.

Fernando and colleagues acknowledged that their study was observational, and therefore cannot confirm a causal relationship between ECMO and downstream mental health effects.

The team is now gearing up to test a virtual treatment program for post-ICU syndrome, a collection of physical, mental, and emotional symptoms that persist after an ICU admission.

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