Discussion
COVID-19 has been associated with acute respiratory failure leading to acute respiratory distress syndrome. While the treatment of acute respiratory distress syndrome in pregnancy generally mirrors the non-pregnant population, it remains unclear if COVID-19 pneumonia in pregnancy has a single characteristic clinical course or is more variable. Recent literature has proposed different clinical ‘phenotypes’ of COVID-19 pneumonia depending on infection severity, ventilatory responsiveness, and time elapsed from onset of disease.1 Optimal intensive care interventions and ventilatory support settings require an appreciation of the potential variable clinical course of COVID-19 pneumonia, particularly in pregnancy.
The physiologic changes of pregnancy are important to account for in the setting of respiratory collapse and mechanical ventilation. The normal compensated respiratory alkalosis of pregnancy (PCO228-32 mm Hg) should influence the selected respiratory rate. Studies show that ‘permissive hypercapnia’ (up to 50 mm Hg) has not been associated with adverse fetal effects.2 A target PaO2 of 70 mm Hg is appropriate during pregnancy, in contrast to 55-80 mm Hg in the non-pregnant state and facilitates maintenance of maternal oxygen saturation at greater than 95%. These targets guide ventilator FiO2 parameters.
Fetal considerations, particularly in the periviable gestational age window, often complicate clinical decision making. The guiding principle that optimal management of maternal status is also optimal management for the fetus is too often not adhered to. We have too little experience with respiratory collapse requiring mechanical ventilation for COVID-19 pneumonia to determine if delivery (regardless of route) facilitates maternal resuscitation or hinders it.
Given these uncertainties, it is critical to have a conversation with the patient, or her surrogate decision maker (durable power of attorney) if the patient is incapacitated, regarding interventions for fetal indications, especially in patients at an early gestational age. Counseling should highlight the balance of risk and benefit for maternal status and fetal status but should accentuate the precept that a disassociation between maternal and fetal interests is rare. A multidisciplinary approach with neonatology consultation is also valuable under these critical circumstances to provide information regarding fetal prognosis and wishes for neonatal resuscitation in the periviable gestational age window. It is also important to discuss, and prepare for, the possibility of perimortem cesarean section if maternal cardiac arrest occurs.
Oral hydroxychloroquine has been recommended at our institution for all COVID-19 patients requiring treatment. The Maternal Fetal Medicine team counseled obstetric patients about hydroxychloroquine use in pregnancy when applicable. The American College of Obstetrics and Gynecology recommends use of hydroxychloroquine when indicated; it is a low-risk drug in pregnancy despite its ability to cross into placental circulation.3 It is uncertain whether our institution’s empiric use of hydroxychloroquine and prednisone facilitated our patients’ recovery. Currently, there is no treatment for COVID-19 approved by the U.S. Food and Drug Administration. Our institution’s empiric use of hydroxychloroquine and prednisone is based upon novel studies that indicated its potential benefit as a treatment for severe COVID-19 infection.4-7
The use of proning appeared crucial in 2 of our patients. Placing an individual in the prone position allows for recruitment of alveoli and corrects ventilation perfusion mismatch, which occurs in acute respiratory distress syndrome.8 Patients selected for this treatment continued to be hypoxic despite optimizing mechanical ventilation in the supine position. The criteria for pregnant patients to be placed in prone positioning are the same as non-pregnant individuals.9 Clinicians previously were hesitant to place pregnant patients in the prone position because of uncertainty regarding fetal response. During the 2009 influenza pandemic, however, many pregnant patients underwent prone ventilation as rescue therapy. Case reports described successful proning in pregnancy without apparent adverse maternal or fetal effects.10
It is important to notice that many of the risk factors that increase the risk of severe COVID-19 infection in the non-pregnant patient are mirrored in the pregnant patient. Most critically ill patients in this case series were obese and African American. Review of the demographics of patients hospitalized with COVID-19 revealed that the African American population is disproportionately affected.11,12 Additionally, studies also illustrate an inverse correlation between age and BMI, indicating that younger patients with severe disease were more likely to be obese.13 These characteristics are imperative to identify those at high risk for severe disease given the potential for rapid clinical deterioration and need for mechanical ventilation.