788: Can we achieve low tidal volume ventilation in pregnant women with acute respiratory distress syndrome?

Abstract

Lung protective low-tidal volume ventilation (LTVV) has been shown to decrease mortality in Acute Respiratory Distress Syndrome (ARDS). ARDS occurs more frequently in pregnancy, yet changes in respiratory physiology during pregnancy and concern for fetal-acid base status may interfere with LTVV strategy. This study assessed use of LTVV in pregnancy and identified maternal and fetal outcomes of mechanically ventilated pregnant patients with ARDS. This is a retrospective cohort study of women with ARDS who were mechanically ventilated for greater than 24 hours between January 2012 and February 2017 at a tertiary care center. ARDS was defined clinically, and LTVV was defined as weighted daily average tidal volume ≤8 mL/kg of ideal body weight. Pregnant patients (N=23) had 128 days of ventilation, and non-pregnant patients (N=681) had 3,174 days. Demographic, pregnancy and fetal outcome data were collected on pregnant patients. Compliance with LTVV was stratified by trimester, and groups compared with chi-squared analysis. We had no maternal deaths and extracorporeal membrane oxygenation (ECMO) was used in 8.7% of patients (N=2). Causes of ARDS included sepsis, pneumonia, and asthma exacerbation. Obstetric complications occurred frequently, with 21.7% (N=5) experiencing preeclampsia, and 50.0% (N=11) delivering preterm. Mean infant birth weight was 2348g ± 14.6. There were 3 perinatal demises (2 intrauterine, 1 neonatal). In pregnant and non-pregnant patients respectively, weighted average daily tidal volume was 7.8 ml/kg ±1.2 and 7.27 ml/kg ±1.55, and overall LTVV use was 87.0% and 81.9%. LTVV was utilized in 93.3% of patients in the first, 85.1% in the second, and 71.0% in the third trimester. Use of LTVV in the third trimester was significantly less than the first and second (p=0.05). Pregnant patients with ARDS encountered significant adverse maternal and fetal outcomes, with half delivering preterm and over 20% developing preeclampsia. LTVV use was comparable between pregnant and non-pregnant patients, but was utilized more frequently in the first and second trimesters compared to the third. Given the significant morbidity seen with ARDS in pregnancy, additional multi-center studies are needed to evaluate factors associated with increased utilization of LTVV, and the effect of LTVV on maternal and fetal outcomes.