A Tale of Two Women: Is There a Benefit to Bilevel Ventilation in Pregnancy?

Abstract

The patient is a 24 year-old pregnant female at 31 and 6/7 weeks estimated gestational age, who presented to the emergency department with complaint of intermittent right-sided abdominal pain, nausea, vomiting and fevers over the past twenty-four hours. The patient's vital signs at presentation were significant for a heart rate of 130 beats/minute and a blood pressure of 90/32 mm Hg. Her physical examination was otherwise unremarkable, and she was initially admitted to the maternal-fetal medicine service and started on intravenous fluids. Over the next 12 hours, the patient remained tachycardic with blood pressures in the 80s/40s. She began to develop respiratory distress, and an ICU evaluation was requested.At the time of evaluation, the patient's physical exam revealed a well-developed, gravid woman in moderate distress. Her temperature was 100.7º Fahrenheit, pulse was 136 beats/minute, blood pressure was 94/41 mm Hg, respiratory rate was 38 breaths/ minute, and pulse oximetry was 99% on a 100% non-rebreather mask. She was anicteric with moist mucous membranes and normal skin turgor. On cardiac examination, her heart rate was tachycardic and regular, without any murmurs. Her lungs were clear to auscultation and abdomen was soft and gravid without any tenderness to palpation. She had no peripheral edema. On vaginal exam, her cervix was long and one centimeter dilated.Laboratory results were significant for a white blood cell (WBC) count of 19.8 B/L and CO2 of 17 mmol/L. Arterial blood gas was 7.46/25/125/18/99% on a 100% non-rebreather mask. Broad spectrum antibiotics were started, and a stat CT of the chest, abdomen and pelvis was performed, which showed dense consolidation of the left lower lobe, consistent with pneumonia.The patient was maintained on a non-rebreather with stable oxygen saturations for several hours, but eventually decompensated, requiring emergent intubation. She was initially placed on assist-control ventilation; however, her oxygen saturations remained in the 60s to 70s. She was noted to have decreased left-sided breath sounds, despite pulling back the endotracheal tube. A stat chest radiograph was performed, which showed near complete collapse of the left lung.The patient was subsequently switched to bilevel ventilation with eventual improvement in her oxygenation (see Figures 1 and 2). She initially required high level settings, with an inspiratory/ expiratory pressure of 35/10 mm Hg. The patient's status improved over the next few days with antibiotic treatment, and cultures all remained negative, but serologies were positive for Mycoplasma IgM. Pressure support was discontinued on hospital day four, and ventilatory support was titrated down slowly over the next few days. On hospital day seven, the patient was successfully extubated. Antibiotics were narrowed to oral azithromycin to complete a fourteen day course of antibiotics for mycoplasma pneumonia. Case Presentation 2The patient is a 19 year-old pregnant woman at 29 and 6/7 weeks estimated gestational age, transferred from an outs...