Ventilatory Parameters in Obstetric Patients With COVID-19 and Impact of Delivery: A Multicenter Prospective Cohort Study.

Background: Current evidence on obstetric patients requiring advanced ventilatory support and impact of delivery on ventilatory parameters is retrospective, scarce, and controversial.

Research Question: What are the ventilatory parameters for obstetric patients with COVID-19 and how does delivery impact them? What are the risk factors for invasive mechanical ventilation (IMV) and for maternal, fetal, and neonatal mortality?

Study Design And Methods: Prospective, multicenter, cohort study including pregnant and postpartum patients with COVID-19 requiring advanced ventilatory support in the ICU.

Results: Ninety-one patients were admitted to 21 ICUs at 29.2 ± 4.9 weeks; 63 patients (69%) delivered in ICU. Maximal ventilatory support was as follows: IMV, 69 patients (76%); high-flow nasal cannula, 20 patients (22%); and noninvasive mechanical ventilation, 2 patients (2%). Sequential Organ Failure Assessment during the first 24 h (SOFA) score was the only risk factor for IMV (OR, 1.97; 95% CI, 1.29-2.99; P = .001). Respiratory parameters at IMV onset for pregnant patients were: mean ± SD plateau pressure (PP), 24.3 ± 4.5 cm HO; mean ± SD driving pressure (DP), 12.5 ± 3.3 cm HO; median static compliance (SC), 31 mL/cm HO (interquartile range [IQR], 26-40 mL/cm HO); and median Pao to Fio ratio, 142 (IQR, 110-176). Respiratory parameters before (< 2 h) and after (≤ 2 h and 24 h) delivery were, respectively: mean ± SD PP, 25.6 ± 6.6 cm HO, 24 ± 6.7 cm HO, and 24.6 ± 5.2 cm HO (P = .59); mean ± SD DP, 13.6 ± 4.2 cm HO, 12.9 ± 3.9 cm HO, and 13 ± 4.4 cm HO (P = .69); median SC, 28 mL/cm HO (IQR, 22.5-39 mL/cm HO), 30 mL/cm HO (IQR, 24.5-44 mL/cm HO), and 30 mL/cm HO (IQR, 24.5-44 mL/cm HO; P = .058); and Pao to Fio ratio, 134 (IQR, 100-230), 168 (IQR, 136-185), and 192 (IQR, 132-232.5; P = .022). Reasons for induced delivery were as follows: maternal, 43 of 71 patients (60.5%); maternal and fetal, 21 of 71 patients (29.5%); and fetal, 7 of 71 patients (9.9%). Fourteen patients (22.2%) continued pregnancy after ICU discharge. Risk factors for maternal mortality were BMI (OR, 1.10; 95% CI, 1.006-1.204; P = .037) and comorbidities (OR, 4.15; 95% CI, 1.212-14.20; P = .023). Risk factors for fetal or neonatal mortality were gestational age at delivery (OR, 0.67; 95% CI, 0.52-0.86; P = .002) and SOFA score (OR, 1.53; 95% CI, 1.13-2.08; P = .006).

Interpretation: Contrary to expectations, pregnant patient lung mechanics were similar to those of the general population with COVID-19 in the ICU. Delivery was induced mainly for maternal reasons, but did not change ventilatory parameters other than Pao to Fio ratio. SOFA score was the only risk factor for IMV. Maternal mortality was associated independently with BMI and comorbidities. Risk factors for fetal and neonatal mortality were SOFA score and gestational age at delivery.