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.