Point-of-Care Lung Ultrasound Pattern in Healthy Parturients: Prevalence of Pulmonary Interstitial Syndrome Following Vaginal Delivery, Elective and Unplanned Intrapartum Cesarean Delivery

Abstract

BACKGROUND: Pregnancy-related cardiovascular physiologic changes increase the likelihood of pulmonary edema, with the risk of fluid extravasating into the pulmonary interstitium being potentially at a maximum during the early postpartum period. Data on the impact of labor and peripartum hemodynamic strain on lung ultrasound (LUS) are limited, and the prevalence of subclinical pulmonary interstitial syndrome in peripartum women is poorly described. The primary aim of this exploratory study was to estimate the prevalence of pulmonary interstitial syndrome in healthy term parturients undergoing vaginal (VD), elective (eCD), and unplanned intrapartum cesarean deliveries (uCD). Secondary aims were to estimate the prevalence of positive lung regions (≥3 B-lines on LUS per region) and to assess the associations between positive lung regions and possible contributing factors. METHODS: In this prospective observational cohort study, healthy women at term undergoing VD, eCD, or uCD were enrolled. Following international consensus recommendations, a LUS examination was performed within 4 hours after delivery applying an 8-region technique. Pulmonary interstitial syndrome was defined by the presence of 2 or more positive lung regions per hemithorax. Ultrasound studies were reviewed by 2 blinded reviewers and assessed for interobserver reliability. RESULTS: Seventy-five women were assessed (n = 25 per group). No pulmonary interstitial syndrome was found in the VD and eCD groups (each 0 of 25; 0%, 95% confidence interval [CI], 0-13.7). Pulmonary interstitial syndrome was found in 2 of 25 (8%, 95% CI, 1-26) women undergoing an uCD (P = .490 for VD versus uCD and P = .490 for eCD versus uCD). In 1 woman, this correlated clinically with the development of pulmonary edema. One or more positive lung regions were present in 5 of 25 (20%), 6 of 25 (24%), and 11 of 25 (44%) parturients following VD, eCD, and uCD, respectively (P = .136). Positive lung regions were predominantly found in lateral lung regions. The number of positive lung regions showed a weak correlation with patient age (r = 0.25, 95% CI, 0.05-0.47; P = .033). No significant association was found between LUS pattern and parity, duration of labor, labor augmentation, labor induction, estimated total intravenous fluid intake, or net intravenous fluid intake. CONCLUSIONS: Although many focal areas of increased extravascular lung water (20%–44% prevalence) can be identified on LUS, the overall prevalence of pulmonary interstitial syndrome was 2.7% (2 of 75; 95% CI, 0.3-9.3) among healthy term parturients soon after delivery. Focal areas of positive lung water regions were weakly correlated with maternal age.

Point‐of‐Care Ultrasound in Critical Care Obstetrics

“…Twelve studies met the inclusion criteria and were included in this review. [16][17][18][19][20][21][22][23][24][25][26][27] Study Characteristics Overall, most of the studies had small sample sizes with significant heterogeneity observed. They were all observational studies, with the majority of them being prospective cohorts, [16][17][18][19][20][21]24 with the exception of 2 cross-sectional studies 23,25 and 1 case series.…”

“…[16][17][18][19][20][21][22][23][24][25][26][27] Study Characteristics Overall, most of the studies had small sample sizes with significant heterogeneity observed. They were all observational studies, with the majority of them being prospective cohorts, [16][17][18][19][20][21]24 with the exception of 2 cross-sectional studies 23,25 and 1 case series. 22 See detailed characteristics of all studies in Table 1.…”

“…22 See detailed characteristics of all studies in Table 1. Nine studies evaluated the use of lung POCUS [16][17][18][19][20][21][22][23][24] and three studies evaluated abdominal POCUS in • LUS was performed by one investigator who was trained in critical care echocardiography using a GE Logiq S8 with a C1-5 curvilinear transducer at 5 MHz and 100% acoustic output power. • LUS was performed within 4 hours of delivery by evaluating 2 anterior regions and 2 lateral regions in each hemithorax.…”

“…LUS in pregnancy has been evaluated in healthy women, mostly in the third trimester of pregnancy, intrapartum, and early postpartum. 16,17,23 Studies report that approximately 75% of healthy women in the third trimester of pregnancy have a LUS pattern similar to nonpregnant individuals showing A-lines in all regions, 23 suggesting that physiologic changes of pregnancy and postpartum do not alter the normal LUS pattern. During labor and early postpartum, healthy pregnant women with uncomplicated labor presented with abnormal LUS findings related to a higher number of focal B-lines, 17 which are generally considered of little clinical significance.…”

Will Point-of-Care Ultrasound Be the New Standard of Care in the Management of Women Diagnosed With Preeclampsia?

“…4,5 One single B-line is a frequent observation in healthy pregnant and nonpregnant subjects and may explain the low specificity of B-lines observed by Yagani et al in predicting diastolic dysfunction. 10 In addition, the high number of excluded patients and the short postdelivery study window may not have captured the full spectrum of disease. Finally, absolute conclusions about the pathophysiology of pulmonary edema in preeclampsia are not possible with an observational design, and future trials with small fluid bolus challenges or other hemodynamic interventions may provide more definitive results.…”