Incidence of Interstitial Alveolar Syndrome on Point-of-Care Lung Ultrasonography in Pre-eclamptic Women With Severe Features: A Prospective Observational Study

Abstract

BACKGROUND: Lung interstitial edema is a clinically silent pathology that develops before overt pulmonary edema among pre-eclamptic women with severe features. Point-of-care lung ultrasonography (LUS) has been suggested as an accessible bedside tool that may identify lung interstitial edema before developing clinical signs and symptoms. Thus, we planned to use bedside LUS as a diagnostic tool in admitted pre-eclamptic women with severe features, with the aim of identifying alveolar-interstitial fluid, seen as B-lines. Our primary objective was to assess the incidence of interstitial alveolar syndrome on lung ultrasonography. METHODS: We conducted a prospective, single-center, observational study on parturients with pre-eclampsia with severe features over a period of 15 months. LUS in 4 intercostal spaces (ICS) was performed on all eligible patients. The number of single or confluent B-lines in each space was recorded by an independent observer. A scoring system was used to grade the lung fluid content based on the number of single and confluent B-lines per ICS, with scores ranging from 0 to 32 (low, 0–10; moderate, 11–20; and high, 21+). The incidence of B-lines at admission and before and after delivery was calculated. In addition, bedside 2D echocardiography was performed to assess left ventricular systolic and diastolic function. Any correlation between presence of B-lines on LUS and blood pressure, clinical symptoms, or echocardiography findings was assessed. RESULTS: Seventy patients were enrolled in the study. On LUS, B-lines were seen in 64.3% patients at admission (45/70 vs 25/70 without B-lines; P = .02), 65.7% patients before delivery (46/70 vs 24/70 without B-lines; P = .01), and 58.6% patients 24 hours postpartum (41/70 versus 29/70 without B-lines; P = .15). Nearly all patients (94.3%) exhibited low to moderate severity of pulmonary fluid burden at admission. Echocardiography revealed diastolic dysfunction in 47.1% (n = 33/70) patients with associated B-lines in the majority (n = 32/33). The total B-line score and E/e’ ratio among patients with diastolic dysfunction was found to be strongly correlated (r = 0.848; P < .001). All pre-eclamptic women with presence of breathlessness (11/11; 100%) and facial puffiness (16/16; 100%) on admission had B-lines on LUS. CONCLUSIONS: We conclude that ultrasonographic pulmonary interstitial syndrome is present in more than half of the women with pre-eclampsia with severe features and correlates with diastolic dysfunction, high blood pressure records, and acute-onset breathlessness.