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

The role of point-of-care ultrasound to monitor response of fluid replacement therapy in pregnancy

Fluid management in obstetrical care is crucial because of the complex physiological conditions of pregnancy, which complicate clinical manifestations and fluid balance management. This expert review examined the use of point-of-care ultrasound to evaluate and monitor the response to fluid therapy in pregnant patients. Pregnancy induces substantial physiological changes, including increased cardiac output and glomerular filtration rate, decreased systemic vascular resistance, and decreased plasma oncotic pressure. Conditions, such as preeclampsia, further complicate fluid management because of decreased intravascular volume and increased capillary permeability. Traditional methods for assessing fluid volume status, such as physical examination and invasive monitoring, are often unreliable or inappropriate. Point-of-care ultrasound provides a noninvasive, rapid, and reliable means to assess fluid responsiveness, which is essential for managing fluid therapy in pregnant patients. This review details the various point-of-care ultrasound modalities used to measure dynamic changes in fluid status, focusing on the evaluation of the inferior vena cava, lung ultrasound, and left ventricular outflow tract. Inferior vena cava ultrasound in spontaneously breathing patients determines diameter variability, predicts fluid responsiveness, and is feasible even late in pregnancy. Lung ultrasound is crucial for detecting early signs of pulmonary edema before clinical symptoms arise and is more accurate than traditional radiography. The left ventricular outflow tract velocity time integral assesses stroke volume response to fluid challenges, providing a quantifiable measure of cardiac function, which is particularly beneficial in critical care settings where rapid and accurate fluid management is essential. This expert review synthesizes current evidence and practice guidelines, suggesting the integration of point-of-care ultrasound as a fundamental aspect of fluid management in obstetrics. It calls for ongoing research to enhance techniques and validate their use in broader clinical settings, aiming to improve outcomes for pregnant patients and their babies by preventing complications associated with both under- and overresuscitation.

Point-of-Care Ultrasound in Critical Care Obstetrics: A Scoping Review of the Current Evidence

OBJECTIVES

To synthesize the current evidence of maternal point-of-care ultrasound (POCUS) in obstetrics. A scoping review was conducted using PubMed, Clinicaltrials.gov, and the Cochrane library from inception through October 2023.

METHODS

Studies were eligible for inclusion if they described the use of POCUS among obstetric or postpartum patients. Two authors independently screened all abstracts. Quantitative, qualitative, and mixed-methods studies were eligible for inclusion. Case reports of single cases, review articles, and expert opinion articles were excluded. Studies describing detailed maternal nonobstetric sonograms or maternal first trimester sonograms to confirm viability and rule out ectopic pregnancy were also excluded. Data were tabulated using Microsoft Excel and summarized using a narrative review and descriptive statistics.

RESULTS

A total of 689 publications were identified through the search strategy and 12 studies met the inclusion criteria. Nine studies evaluated the use of lung POCUS in obstetrics in different clinical scenarios. Lung ultrasound (LUS) findings in preeclampsia showed an excellent ability to detect pulmonary edema (area under the receiver operating characteristic 0.961) and findings were correlated with clinical evidence of respiratory distress (21 of 57 [37%] versus 14 of 109 [13%]; P = .001). Three studies evaluated abdominal POCUS, two of the inferior vena cava (IVC) to predict postspinal anesthesia hypotension (PSAH) and fluid receptivity and one to assess the rate of ascites in patients with preeclampsia. Patients with PSAH had higher IVC collapsibility (area under the curve = 0.950, P < .001) and, in patients with severe preeclampsia, there is a high rate of ascites (52%) associated with increased risk of adverse outcomes. There were no studies on the use of subjective cardiac POCUS.

CONCLUSION

POCUS use in the management of high-risk obstetrics has increased. LUS has been the most studied modality and appears to have a potential role in the setting of preeclampsia complicated by pulmonary edema. Cardiac and abdominal POCUS have not been well studied. Trials are needed to evaluate its clinical applicability, reliability, and technique standardization before widespread use.

Evaluation of extravascular lung water and cardiac function in normal vaginal delivery by intrapartum bedside ultrasound

BACKGROUND

Healthy parturients may experience pulmonary edema and disturbed cardiac function during labor. We aimed to evaluate the extravascular lung water (EVLW), intravascular volume, and cardiac function of normal parturients during spontaneous vaginal delivery by bedside ultrasound. And to explore the correlation between EVLW and intravascular volume, cardiac function.

METHODS

This was a prospective observational study including 30 singleton-term pregnant women undergoing spontaneous vaginal delivery. Bedside ultrasound was performed at the early labor, the end of the second stage of labor, 2 and 24 h postpartum, and 120 scanning results were recorded. EVLW was evaluated by the echo comet score (ECS) obtained by the 28-rib interspaces technique. Inferior vena cava collapsibility index (IVC-CI), left ventricle ejection fraction, right ventricle fractional area change, left and right ventricular E/A ratio, and left and right ventricular index of myocardial performance (LIMP and RIMP) were measured. Measurements among different time points were compared, and the correlations between ECS and other measurements were analyzed.

RESULTS

During the spontaneous vaginal delivery of healthy pregnant women, 2 had a mild EVLW increase at the early labor, 8 at the end of the second stage of labor, 13 at 2 h postpartum, and 4 at 24 h postpartum (P < 0.001). From the early labor to 24 h postpartum, ECS first increased and then decreased, reaching its peak at 2 h postpartum (P < 0.001). IVC-CI first decreased and then increased, reaching its minimum at the end of the second stage of labor (P < 0.001). RIMP exceeded the cut-off value of 0.43 at the end of the second stage of labor. ECS was weakly correlated with IVC-CI (r=-0.373, P < 0.001), LIMP (r = 0.298, P = 0.022) and RIMP (r = 0.211, P = 0.021).

CONCLUSIONS

During spontaneous vaginal delivery, the most vital period of perinatal care is between the end of the second stage of labor and 2 h postpartum, because the risk of pulmonary edema is higher and the right ventricle function may decline. IVC-CI can be used to evaluate maternal intravascular volume. The increase in EVLW may be related to the increase in intravascular volume and the decrease in ventricular function.