In pregnant women with acute respiratory distress syndrome, extracorporeal life support can be effective and safe for both the mother and fetus, according to a meta-analysis of 332 articles published in the April issue of the Journal of Thoracic and Cardiovascular Surgery (2016;151:1154-60).
Dr. Sarah A. Moore and her coauthors at the University of New Mexico, Albuquerque, reported that their literature search yielded a total of 45 patients treated with extracorporeal life support (ECLS) or extracorporeal membrane oxygenation (ECMO). The reports were published from 1991-2015.
Dr. Moore and her colleagues also reported on the first successful use of ECLS in a pregnant patient at their own institution with life-threatening hantavirus cardiopulmonary syndrome.
The researchers extrapolated from the literature were case reports and small case series. In the 45-patient study cohort, the survival rate was 77.8% after ECLS for mothers and 65.1% for the fetuses. The average gestational age was 26.5 weeks, ranging from 28 to 43 weeks, and the patients were on ECLS for an average of 12.2 days, with a range of one to 57 days.
The most common reason for ECLS in this cohort was severe H1N1 influenza, otherwise known as swine flu, complicated with acute respiratory distress syndrome (ARDS). The largest series, from France, involved 11 pregnant women treated with ECMO for severe ARDS secondary to severe H1N1 influenza (PLoS One. 2010;5:e13112). Unlike other reports, the New Mexico meta-analysis did not include postpartum patients.
The mitigating case for the study was a previously healthy 25-year-old pregnant woman who was in respiratory failure with hantavirus cardiopulmonary syndrome (HCPS) when she arrived at University of New Mexico Health Sciences Center. Despite mechanical ventilation, the patient remained severely hypoxic and developed worsening hypertension. “The patient was placed on venoarterial ECMO for 72 hours, recovered without complications, and delivered a healthy infant,” Dr. Moore and her colleagues said. “The mother and son remain asymptomatic 6 years later.”
Dr. Moore and her colleagues said strategies used in the nonpregnant population with ARDS might not be appropriate in pregnant mothers for two reasons: permissive hypercapnia may harm the fetus; and prone positioning can be difficult for women in late-term pregnancy. Also, corticosteroids for H1N1 influenza have been controversial.
That doesn’t mean ECLS in pregnant women is not without its complications; the most common was major bleeding, reported in seven of the reviewed articles. Other complications included hemolysis, cannula dislodgement, uterine compression causing ineffective flow rate that improved after emergency cesarean section, and nosocomial infections, including urinary tract and line-related infections.
The study also took a closer look at the use of ECMO in pregnant women during the 2009 H1N1 pandemic; 8 of 33 pregnant women placed on ECMO died, compared with two maternal deaths among the 12 pregnant women placed on ECLS for other reasons.
Dr. Moore and her coauthors acknowledged several limitations of their study, namely the likelihood of selection bias, “given that centers are less inclined to publish their bad outcomes.” Other limits the researchers noted are: the small cohort obviated a proper statistical analysis; there was no control group; and the survival rate in pregnant women with ARDS who do not have ECLS is unknown. Dr. Moore and her coauthors had no relationships to disclose.