Evaluation of lung ultrasound as a diagnostic tool in pregnant patients.

The objective of this study is to evaluate lung ultrasound as a tool in pregnant patients. This tool has not been well studied in pregnancy but has the potential to detect pulmonary edema in patients with preeclampsia before they become critically ill. In addition, the presence of pulmonary edema is a criterion for the diagnosis for severe preeclampsia, and if detected early, may change management and decrease morbidity in these patients. The investigators hypothesize that healthy pregnant women and women with preeclampsia in the third trimester have normal lung ultrasound patterns in the absence of clinical signs or symptoms of poor lung aeration.

The investigators propose a prospective cross-sectional study to compare pregnant patients with and without a diagnosis of preeclampsia treated at the Long Island Jewish Medical Center (LIJ) and North Shore University Hospital (NSUH) from August 2016 - May 2018. A cohort of healthy gestational age-matched pregnant patients from 32 - 41 weeks without a diagnosis of preeclampsia will serve as controls. Inclusion criteria include singleton pregnancies over 31 6/7 weeks gestational age treated at LIJ or NSUH. Exclusion criteria include age less than 18 years and refusal to participate in the study. Informed consent will be obtained for all study participants.

A diagnosis of preeclampsia will be made based on standard criteria as outlined by the American Congress of Obstetrics and Gynecology (ACOG). Interstitial edema will be defined as an ultrasound finding of three or more B-lines in an interstitial space in two or more lung regions. B-line dominant lung fields are suggestive of alveolar interstitial syndrome. The clinical diagnosis of pulmonary edema is based on findings including dyspnea, tachypnea, tachycardia, hypoxemia (measured by non-invasive pulse oximeter), and diffuse crackles on lung exam. The patient characteristics and ultrasound findings will be compared between the cohort of preeclamptic patients and healthy controls. A secondary analysis will be performed on the images that were obtained before and after magnesium sulfate therapy in patients diagnosed with preeclampsia with severe features to determine the effect on sonographic findings. If a preeclamptic patient received a chest x-ray as part of her management plan because of a clinical suspicion of pulmonary edema, the reported results will be collected and compared to lung sonogram results.

Lung sonography will be performed on a SonoSite portable ultrasound machine with a C60e 5 - 2 MHx 30cm probe using a modified standard technique examining four lung regions; anterior mid-clavicular high and low on left and right sides, and one on each side posteriorly) in the semi-recumbent position. Still images and video clips will be reviewed by an expert in lung ultrasound who is blinded to the patients' clinical information (Dr. Seth Koenig). Lung sonography will be performed on two occasions for each preeclamptic patient who is treated with magnesium sulfate; 1) at the time of diagnosis of preeclampsia, and 2) after completion of magnesium sulfate bolus. Lung sonography will be performed on only one occasion for gestational age-matched controls and for preeclamptic patients who are not treated with magnesium sulfate. Patients will not be given a diagnosis of pulmonary edema nor will their management plans be altered based on the results of the lung sonography performed for this study.

Data will be collected and stored in RedCap. The investigators will collect data on patient demographics, past medical and surgical history, blood pressure measurements at time of diagnosis, results of routine lab values that are drawn for evaluation of preeclamptic patients, and the review of four ultrasound examination regions to determine if they are B-line dominant or A-line dominant. Descriptive statistics and appropriate comparison tests will be used to analyze the data.

Inclusion Criteria:

• ≥ 18 years old
• Singleton pregnancy
• 32 0/7 weeks - 41 6/7 weeks gestational age

Exclusion Criteria:

• Inability to provide informed consent
• Refusal to participate
• Already treated for acute lung pathology prior to enrollment
• Cognitive impairment that precluded understanding of research procedures

The subject population is 262 pregnant female participants between ages 18 to approximately 49 years old. Pregnant patients must be used in the study population because the objective is to evaluate lung ultrasound as a tool in the pregnant population.