European Journal of Cardiovascular Medicine

Critically ill obstetric patients represent a unique hemodynamic population in whom rapid physiological transitions (pregnancy to puerperium), hypertensive disorders, hemorrhage, sepsis, and cardiopulmonary complications frequently coexist. In these settings, balancing adequate perfusion against iatrogenic fluid overload is particularly challenging, because conventional clinical markers may not reliably distinguish true intravascular volume deficit from venous congestion or capillary leak. Point-of-care ultrasound (POCUS) has emerged as an attractive bedside tool to individualize hemodynamic management by integrating venous congestion assessment with clinical decision-making.

Systemic venous congestion is increasingly recognized as a clinically important and measurable phenomenon in the ICU. Andrei et al. (2023) demonstrated that venous congestion assessed by the Venous Excess Ultrasound Grading System (VExUS) is prevalent in general ICU populations and is associated with acute kidney injury (AKI), supporting the concept that Doppler-based venous congestion phenotyping provides actionable physiologic information beyond standard monitoring. [1] While these data originate from mixed ICU cohorts, the mechanistic relevance is compelling for obstetric critical care, where AKI and pulmonary edema are common and fluid management is often high-stakes.

Doppler assessment of the hepatic and portal venous systems is particularly relevant in pregnancy and the postpartum period, where venous return and abdominal venous capacitance change substantially. Pekindil et al. (1999) described measurable postpartum alterations in hepatic venous pulsatility and portal venous velocity using Doppler ultrasonography, indicating that splanchnic venous waveforms are dynamic in the puerperium and may plausibly reflect evolving loading conditions in critically ill obstetric patients as well. [2] Building on this physiologic foundation, Beaubien-Souligny et al. (2018) showed that portal vein flow abnormalities and intrarenal venous Doppler alterations are associated with AKI in a prospective cohort, reinforcing the clinical link between venous congestion signatures and kidney injury and supporting the inclusion of these Doppler components within congestion frameworks such as VExUS. [3]

Beyond diagnostic assessment, the potential value of POCUS lies in guiding therapy. Premkumar et al. (2025) reported that POCUS-guided volume management is feasible and clinically informative in a high-risk population (cirrhosis) and explored how underlying cardiomyopathy modifies AKI outcomes, underscoring how bedside ultrasound can be operationalized to personalize volume strategy in complex physiology. [4] Although not an obstetric study, it supports the broader concept that ultrasound-guided congestion/perfusion assessment can be integrated into hemodynamic decision-making pathways—an approach with face validity in obstetric ICU practice, where cardiopulmonary reserve and fluid tolerance can vary widely between patients.

In obstetric critical illness, endothelial dysfunction may further complicate hemodynamic management by promoting capillary leak, microvascular dysregulation, and organ dysfunction—particularly in hypertensive disorders of pregnancy. Edvinsson et al. (2022) evaluated ICU patients with preeclampsia and identified clinical risk factors and biomarker patterns reflecting oxidative stress and angiogenic imbalance that discriminated severe disease, highlighting the relevance of measurable endothelial injury pathways in obstetric ICU populations. [5] More broadly, disruption of the endothelial glycocalyx—an important regulator of vascular permeability and mechanotransduction—has been recognized across critical illness states; Hahn et al. (2021) systematically reviewed human glycocalyx shedding and emphasized its potential clinical implications, supporting the rationale for incorporating endothelial dysfunction markers alongside ultrasound congestion metrics in hemodynamic assessment. [6]

Despite growing evidence for venous congestion scoring in general critical care and expanding biomarker literature in obstetric ICU syndromes, there remains limited prospective work integrating POCUS-derived venous congestion phenotyping with endothelial dysfunction markers to guide real-time hemodynamic management in critically ill obstetric patients. The present prospective feasibility study at Mahabodhi Medical College & Hospital, Bihar, therefore evaluates whether combining these two physiologic domains is practicable in routine care and whether the derived measures demonstrate clinically meaningful associations with hemodynamic decisions and early organ outcomes.

Objectives

Primary objective:

To evaluate the feasibility of integrating point-of-care ultrasound (POCUS)–derived venous congestion assessment (VExUS components) together with endothelial dysfunction markers in the hemodynamic management of critically ill obstetric patients admitted to the ICU/HDU.

Secondary objectives:

To assess the association between venous congestion severity and early clinical outcomes, including fluid balance and acute kidney injury (AKI).

To examine the relationship between endothelial dysfunction markers and venous congestion indices, and their combined ability to identify patients at higher risk of early organ dysfunction.

To determine the proportion of patients in whom POCUS and biomarker findings led to a documented change in hemodynamic management (e.g., fluid restriction/diuretic initiation/vasopressor adjustment).

Study design, setting, and duration This was a prospective feasibility study conducted over 1 year in the obstetric high-dependency unit (HDU)/intensive care unit (ICU) services of Mahabodhi Medical College & Hospital, Naknupa, Bihar, India. Consecutive eligible critically ill obstetric patients were enrolled until the target sample size of 50 was reached. Study population and eligibility Critically ill obstetric patients (pregnant or postpartum) requiring HDU/ICU level monitoring were screened for inclusion. Inclusion criteria • Pregnant women (any gestational age) or postpartum women (up to 6 weeks) • Admission to obstetric HDU/ICU for critical illness requiring close hemodynamic monitoring and/or organ support (e.g., hypertensive crisis/preeclampsia-eclampsia/HELLP, sepsis, hemorrhage/shock, cardiopulmonary compromise) • Written informed consent from patient or legally authorized representative Exclusion criteria • Age <18 years • Known structural cardiac lesions where venous Doppler interpretation was deemed unreliable by the treating team (e.g., severe tricuspid regurgitation) • Poor ultrasound windows preventing completion of key venous Doppler components despite repeat attempt • Refusal of consent Sample size and sampling technique A sample of 50 patients was selected as a feasibility target, consistent with pilot designs intended to estimate completion rates, protocol adherence, and signal direction for associations. Consecutive sampling was used during the study period. Study procedures and timing After enrolment, all patients underwent a standardized evaluation comprising: 1. baseline clinical assessment and routine laboratory investigations, 2. POCUS-based venous congestion assessment, and 3. collection of endothelial dysfunction biomarker samples. The index assessment was performed within 6 hours of HDU/ICU admission (or as soon as clinically feasible), and management decisions were recorded prospectively. Clinical and laboratory data collection Baseline variables included maternal age, gestational age/postpartum status, primary diagnosis category (e.g., preeclampsia/eclampsia/HELLP, sepsis, hemorrhage/shock, cardiac/pulmonary edema, others), vital signs, vasopressor requirement, urine output, and respiratory support. Routine laboratory parameters included hemoglobin, platelet count, serum creatinine, liver enzymes, and lactate where available. Acute kidney injury (AKI) was assessed using KDIGO criteria based on serum creatinine change and/or urine output, as applicable. POCUS protocol for venous congestion POCUS was performed by trained clinicians (anesthesiology/critical care/obstetrics team members trained in basic echocardiography and venous Doppler) using available bedside ultrasound systems. The protocol was derived from the Venous Excess Ultrasound Grading System (VExUS) framework and included the following components: 1. Inferior vena cava (IVC) assessment IVC diameter (subcostal long-axis) and collapsibility (spontaneously breathing) or distensibility (mechanically ventilated), recorded as per standard technique. 2. Hepatic vein Doppler Hepatic vein waveform pattern categorized as normal (S>D), blunted S, or systolic reversal. 3. Portal vein Doppler Portal vein pulsatility assessed using spectral Doppler; pulsatility fraction (%) was recorded where feasible or categorized by severity (low/moderate/high pulsatility). 4. Intrarenal venous Doppler Interlobar renal venous flow pattern classified as continuous, biphasic, or monophasic. A composite VExUS grade (0–3) was assigned using standard interpretive thresholds: grade 0 (no congestion), grade 1 (mild), grade 2 (moderate), grade 3 (severe), based on IVC findings plus the number/severity of abnormal venous Doppler waveforms. If any component could not be obtained, the reason (e.g., body habitus, patient positioning constraints, ventilation) was documented. Endothelial dysfunction markers Blood samples were collected at the time of index assessment (within 6 hours of admission) for endothelial dysfunction evaluation. Based on availability, the following were measured: • Biomarkers of angiogenic imbalance/oxidative stress relevant to hypertensive disorders of pregnancy (panel as per institutional laboratory capability) • Glycocalyx/endothelial injury marker(s) (e.g., syndecan-1 where available) Samples were processed according to institutional laboratory protocols and stored/analyzed as per manufacturer instructions for assay-based tests. Hemodynamic management and “POCUS/biomarker-guided change” documentation All patients received standard management as per unit protocol. Treating clinicians had access to POCUS and biomarker results in real time. A “POCUS/biomarker-guided management change” was defined as a documented change within 6 hours after the index assessment attributable to congestion/endothelial findings, including: • withholding further fluid bolus / initiating fluid restriction • diuretic initiation or escalation • vasopressor initiation or dose titration • escalation of organ support related to congestion assessment (e.g., non-invasive ventilation for pulmonary edema) The type and timing of decisions were recorded prospectively. Outcomes Primary feasibility outcomes • Proportion of patients in whom the full venous congestion protocol (IVC + hepatic + portal + renal Doppler) could be completed within the target time window • Time required to perform the POCUS congestion protocol • Proportion of patients with a documented management change attributed to POCUS/biomarker findings Secondary clinical outcomes (exploratory) • Net fluid balance at 24 and/or 48 hours • AKI occurrence and stage (KDIGO) • Need for diuretics, renal replacement therapy (if applicable) • Duration of ventilatory/vasopressor support (where applicable) • ICU length of stay and in-hospital mortality Statistical analysis Feasibility outcomes were summarized as proportions with 95% confidence intervals and/or median (IQR) as appropriate. Continuous variables were reported as mean ± SD or median (IQR) depending on distribution. Associations between VExUS grade (or congestion category) and AKI/other binary outcomes were assessed using chi-square or Fisher’s exact test. Correlation between endothelial biomarkers and congestion indices was evaluated using Spearman’s correlation. Given the feasibility design and expected limited event counts, multivariable regression was planned only for exploratory purposes when clinically and statistically appropriate. A two-sided p-value <0.05 was considered statistically significant. Ethical considerations The study was approved by the Institutional Ethics Committee of Mahabodhi Medical College & Hospital. Written informed consent was obtained from participants or legally authorized representatives. Data were anonymized and stored securely. Clinical care was not withheld; POCUS and biomarker testing were used as adjuncts to standard management.

Participant inclusion and Baseline characteristics

During the 1-year study period, 50 consecutively admitted critically ill obstetric patients requiring HDU/ICU-level care were enrolled and included in the final analysis; 30 (60%) were pregnant and 20 (40%) were postpartum at admission.

Baseline characteristics of the cohort are summarized in Table 1. In brief, most admissions were due to hypertensive disorders of pregnancy, followed by sepsis, hemorrhage/shock, and cardiopulmonary causes. A substantial proportion required hemodynamic and/or respiratory support at enrollment, and baseline physiologic and laboratory indices (including renal function and lactate) reflected moderate acuity consistent with an obstetric critical care population (Table 1).

Primary feasibility outcomes

Feasibility outcomes are summarized in Table 2 and Figure 1. The complete POCUS venous congestion protocol (IVC with hepatic, portal, and intrarenal venous Doppler) could be performed within the target time window in 47/50 patients (94.0%). The median time required to complete the congestion assessment was 15 minutes (IQR 12–17). Endothelial biomarker sampling and processing were successfully completed in 46/50 patients (92.0%).

A documented hemodynamic management change attributable to the combined POCUS and/or biomarker findings occurred in 29/50 patients (58.0%). Among those with a management change, the most frequent actions were diuretic initiation/escalation (13/29, 44.8%) and fluid restriction/withholding additional boluses (11/29, 37.9%), while vasopressor initiation/titration (4/29, 13.8%) and escalation of ventilatory support (1/29, 3.4%) were less common (Table 2).

Table 2. Feasibility outcomes and POCUS/biomarker-attributed management changes (N=50)

Figure 1. Feasibility metrics for integrating POCUS-derived venous congestion assessment and endothelial biomarkers in critically ill obstetric patients (N=50). The bar chart shows the proportion with (i) completion of the full venous congestion POCUS protocol within 6 hours of admission, (ii) successful biomarker sampling/processing, and (iii) a documented hemodynamic management change attributed to POCUS/biomarker findings.

Venous congestion severity and patterns

The distribution of venous congestion severity by VExUS grading is shown in Figure 2. Overall, 9/50 (18.0%) participants had VExUS grade 0, 17/50 (34.0%) had grade 1, 9/50 (18.0%) had grade 2, and 15/50 (30.0%) had grade 3, indicating that nearly half the cohort had moderate-to-severe congestion (grades 2–3: 24/50, 48.0%).

Across VExUS grades, the individual Doppler components demonstrated a stepwise pattern consistent with increasing systemic venous congestion. Portal vein pulsatility increased with severity, while abnormal hepatic vein waveforms and discontinuous intrarenal venous flow (biphasic/monophasic patterns) were more frequent in higher grades, supporting internal consistency of the congestion phenotype represented by the composite VExUS grading.

Figure 2. Distribution of VExUS grades among critically ill obstetric patients (N=50). Bar chart shows the proportion of patients classified as VExUS grade 0–3 at index assessment, reflecting increasing severity of systemic venous congestion.

Biomarkers and relationship with congestion

Endothelial dysfunction biomarkers were successfully obtained in 46/50 (92.0%) participants. Overall, the median syndecan-1 level was 84.0 ng/mL (IQR 70.8–99.6) and the median sFlt-1/PlGF ratio was 264 (IQR 165–403).

Biomarker levels showed a graded relationship with venous congestion severity. Compared with low congestion (VExUS 0–1), participants with higher congestion (VExUS 2–3) had higher syndecan-1 levels (88.3 vs 76.5 ng/mL, respectively) and a higher sFlt-1/PlGF ratio (311.5 vs 226.0, respectively). Syndecan-1 demonstrated a moderate positive correlation with VExUS grade (Spearman ρ = 0.48; p = 0.0008), while the sFlt-1/PlGF ratio showed a weaker but statistically significant correlation (Spearman ρ = 0.32; p = 0.032). These findings are illustrated in Figure 3, where syndecan-1 values increase across VExUS grades.

Figure 3. Syndecan-1 levels across venous congestion severity (VExUS grade) in critically ill obstetric patients. Points represent the median syndecan-1 concentration (ng/mL) at each VExUS grade (0–3), and vertical error bars indicate the interquartile range (IQR). The plot demonstrates a stepwise increase in syndecan-1 with higher VExUS grades, consistent with greater endothelial injury in patients with more severe systemic venous congestion.

Exploratory clinical outcomes (signals of utility)

Exploratory outcomes stratified by venous congestion severity are presented in Table 3. In brief, AKI and negative fluid balance were more frequent in patients with moderate–severe congestion (VExUS 2–3) compared with those with none–mild congestion (VExUS 0–1). Differences in ICU length of stay and mortality were small, consistent with the feasibility design and limited sample size (Table 3).

In this prospective feasibility study of critically ill obstetric patients, a structured venous congestion POCUS protocol integrated with endothelial dysfunction markers was implementable within routine HDU/ICU workflows. We achieved high completion of the full venous Doppler–based congestion assessment (94%) and high biomarker acquisition (92%), and the combined assessment was associated with frequent, documented hemodynamic decision changes (58%). Clinically, the cohort carried a substantial congestion burden, with 48% classified as VExUS grade 2–3, and higher congestion was associated with a higher AKI occurrence (45.8% in VExUS 2–3 vs 19.2% in VExUS 0–1; crude OR 3.55) alongside more negative net fluid balance at 24 and 48 hours.

Natraj et al. (2024) evaluated venous congestion assessed by VExUS in a pediatric critical care population with right ventricular dysfunction and linked higher venous congestion severity to AKI, reinforcing the biological plausibility of “venous side” renal injury across ICU settings. [7] In our obstetric cohort, the same directional relationship was observed: AKI was more frequent in patients with moderate–severe congestion (VExUS 2–3), suggesting that congestion phenotyping may help identify an at-risk subgroup even when clinical volume assessment is challenging in pregnancy and the puerperium. [7]

Bhardwaj et al. (2020) reported that a composite VExUS approach—integrating IVC metrics with hepatic venous flow and portal vein pulsatility—helped predict AKI in cardiorenal syndrome, supporting the concept that multi-bed Doppler congestion assessment can outperform isolated static measures. [8] Our data similarly support the clinical value of a composite congestion phenotype rather than a single ultrasound sign: management changes attributed to POCUS/biomarkers were predominantly decongestive (diuretic escalation or fluid restriction/withholding boluses), consistent with the notion that identifying congestion can meaningfully shift bedside strategy. [8]

Fujii et al. (2023) specifically examined intrarenal venous Doppler in septic critical care and demonstrated a strong association between intrarenal venous flow abnormalities and clinically important kidney outcomes, reporting an odds ratio of 9.67 (95% CI 2.13–44.03) for severe AKI/death in those with abnormal intrarenal venous patterns. [9] Although only 20% of our cohort had sepsis, the same mechanistic thread is relevant: venous congestion signatures (including renal venous Doppler abnormalities embedded in VExUS grading) aligned with a higher AKI burden, supporting intrarenal venous Doppler as a physiologically meaningful “downstream” marker in heterogeneous obstetric ICU etiologies. [9]

Malagón et al. (2024) extended congestion assessment into prognostication by showing that residual or subclinical congestion identified by POCUS at discharge predicted readmission in acute heart failure, with reported odds ratios of 7.22 for interstitial syndrome, 24.61 for portal venous pulsatility >30%, and 13.19 for a composite congestion measure. [10] While our endpoints were early in-ICU organ outcomes rather than post-discharge events, the overarching message is consistent: Doppler- and ultrasound-defined congestion can identify a subgroup with higher subsequent risk. In our data, VExUS 2–3 patients concentrated more AKI and had higher in-hospital mortality (group-wise 8.3% vs 3.8%), even within a small feasibility sample. [10]

Guinot et al. (2022) provide a practice-facing bridge between congestion measurement and therapy by demonstrating that portal and renal venous Doppler variables can predict response to diuretic therapy in the ICU; notably, portal vein indices demonstrated useful discrimination (AUC 0.80, 95% CI 0.70–0.92), exceeding the discrimination of the overall VExUS score in their dataset (AUC 0.66, 95% CI 0.53–0.79). [11] Our management-impact profile—where nearly half of attributed changes involved diuretic initiation/escalation—fits this framework: venous Doppler information appears most actionable when it informs “de-resuscitation” decisions rather than generic severity labeling. The observed divergence in net fluid balance by congestion category in our cohort (median 24-hour +0.81 L in VExUS 0–1 vs −0.81 L in VExUS 2–3) is also consistent with clinicians responding to a congestion phenotype by limiting further positive balance. [11]

In hypertensive disorders of pregnancy, the clinical relevance of bedside ultrasound extends beyond venous Doppler. Gokkus et al. (2021) demonstrated that sonographic assessment of pulmonary interstitial edema in preeclampsia correlates strongly with echocardiographic filling pressure surrogates, reporting a correlation of r = 0.768 (p < 0.001) between B-lines and E/e′. [12] Given that hypertensive disorders comprised the majority of our admissions (56%), a combined ultrasound approach—systemic venous congestion plus pulmonary congestion assessment—has strong clinical rationale in this population where pulmonary edema risk can coexist with renal vulnerability and where fluid tolerance is often narrow. [12]

Edvinsson et al. (2022) studied ICU patients with preeclampsia and highlighted the discriminative value of biomarkers reflecting oxidative stress and angiogenic imbalance for severe disease, supporting the centrality of endothelial dysfunction pathways in obstetric critical illness. [13] Our biomarker findings are directionally concordant with that paradigm: sFlt-1/PlGF ratio and syndecan-1 both tracked upward with congestion severity, and syndecan-1 in particular showed a moderate correlation with VExUS grade (ρ = 0.48, p = 0.0008). The coexistence of higher endothelial injury markers and more severe congestion suggests overlapping pathophysiology—capillary leak, altered vascular tone, and impaired venous return handling—that complicates purely pressure- or volume-based bedside heuristics in this setting. [13]

O’Neil et al. (2024) linked syndecan-1 to perinatal inflammatory exposure (chorioamnionitis) and proposed it as a clinically relevant marker of glycocalyx degradation in the perinatal context. [14] Although their focus was fetal/neonatal, the mechanistic relevance supports syndecan-1 as a biologically plausible endothelial injury marker in obstetric critical illness states characterized by inflammation and vascular barrier disruption. In our cohort, syndecan-1 levels were higher in those with greater congestion (median 88.3 ng/mL in VExUS 2–3 vs 76.5 ng/mL in VExUS 0–1), aligning endothelial injury signatures with a clinically meaningful congestion phenotype. [14]

Fernández-Sarmiento et al. (2023) synthesized evidence across sepsis studies and reported that syndecan-1 was higher in non-survivors (255 ng/mL, IQR 139–305) than survivors (83 ng/mL, IQR 40–111), and that elevated syndecan-1 was associated with mortality (OR 2.32, 95% CI 1.89–3.10) and organ failure outcomes. [15] Against these outcome-linked distributions, our cohort’s overall syndecan-1 central tendency (median 84.0 ng/mL; IQR 70.8–99.6) sits close to the survivor-range values reported in sepsis meta-analyses, which is consistent with the relatively low in-hospital mortality observed (6%) while still showing within-cohort stratification by congestion severity. [15]

Finally, Lapinsky et al. (1995) emphasized that pregnancy alters cardiopulmonary physiology and volume distribution in ways that complicate standard critical care assessment and mandates tailored hemodynamic approaches. [16] Our feasibility findings address this practical need: a bedside framework that integrates systemic venous Doppler congestion with endothelial dysfunction markers can be delivered rapidly and appears to influence real-world management decisions in a population where both under-resuscitation and fluid overload carry high risk.

Taken together, our study supports the feasibility of combined congestion-and-endothelial phenotyping in obstetric critical care and demonstrates coherent early signals of utility: higher venous congestion aligned with greater AKI burden and more negative fluid balance, while endothelial injury markers rose with congestion severity. Differences in diagnostic mix (preeclampsia-dominant vs sepsis-dominant cohorts), timing of ultrasound (early ICU vs discharge), and outcome selection (AKI vs readmission) likely explain the variation in effect sizes and discriminative performance across studies, but the directionality remains consistent across the cited literature. Larger, stratified obstetric cohorts will be needed to quantify independent effects, establish clinically useful thresholds, and test whether congestion- and endothelial-informed decision pathways can reduce renal and pulmonary complications without compromising perfusion.

Limitations         

This was a single-center feasibility study with a small sample size (N=50), limiting statistical power and precision of effect estimates for clinical outcomes. The cohort had a mixed case-mix (hypertensive disorders, sepsis, hemorrhage, cardiopulmonary causes), and the observational design cannot exclude confounding by illness severity or clinician preference in management decisions. Biomarkers were not available for all patients and were measured at limited timepoints, and ultrasound acquisition/interpretation may have operator-dependent variability, which may affect generalizability.

In critically ill obstetric patients, integrating POCUS-derived venous congestion assessment (VExUS framework) with endothelial dysfunction markers was feasible, rapidly performed, and frequently associated with actionable hemodynamic decision-making. Moderate–severe venous congestion was common and aligned with higher AKI burden and distinct fluid balance trajectories, while endothelial injury markers increased with congestion severity. These findings support the need for larger, stratified prospective studies to validate thresholds and test whether congestion- and endothelial-guided hemodynamic pathways can improve maternal organ outcomes.

[1] Andrei, S., Bahr, P. A., Nguyen, M., Bouhemad, B., & Guinot, P. G. (2023). Prevalence of systemic venous congestion assessed by Venous Excess Ultrasound Grading System (VExUS) and association with acute kidney injury in a general ICU cohort: A prospective multicentric study. Critical Care, 27(1), 224.

[2] Pekindil, G., Varol, F. G., Yüce, M. A., & Yardim, T. (1999). Evaluation of hepatic venous pulsatility and portal venous velocity with Doppler ultrasonography during the puerperium. European Journal of Radiology, 29(3), 266–269.

[3] Beaubien-Souligny, W., Benkreira, A., Robillard, P., Bouabdallaoui, N., Chassé, M., Desjardins, G., … & Denault, A. (2018). Alterations in portal vein flow and intrarenal venous flow are associated with acute kidney injury after cardiac surgery: A prospective observational cohort study. Journal of the American Heart Association, 7(19), e009961.

[4] Premkumar, M., Kajal, K., Roy, A., Izzy, M., Divyaveer, S., Kulkarni, A. V., … & Reddy, K. R. (2025). Point-of-care ultrasound (POCUS) guided volume management and the effect of cirrhotic cardiomyopathy on acute kidney injury outcomes in cirrhosis. Hepatology, 10–1097.

[5] Edvinsson, C., Hansson, E., Nielsen, N., Erlandsson, L., & Hansson, S. R. (2022). Intensive care patients with preeclampsia—Clinical risk factors and biomarkers for oxidative stress and angiogenic imbalance as discriminators for severe disease. Pregnancy Hypertension, 30, 88–94.

[6] Hahn, R. G., Patel, V., & Dull, R. O. (2021). Human glycocalyx shedding: Systematic review and critical appraisal. Acta Anaesthesiologica Scandinavica, 65(5), 590–606.

7. Natraj, R., Bhaskaran, A. K., Rola, P., Haycock, K., Siuba, M. T., & Ranjit, S. (2024). Venous congestion assessed by venous excess ultrasound (VExUS) and acute kidney injury in children with right ventricular dysfunction. Indian journal of critical care medicine: peer-reviewed, official publication of Indian Society of Critical Care Medicine, 28(5), 447.

8. Bhardwaj, V., Vikneswaran, G., Rola, P., Raju, S., Bhat, R. S., Jayakumar, A., & Alva, A. (2020). Combination of inferior vena cava diameter, hepatic venous flow, and portal vein pulsatility index: venous excess ultrasound score (VEXUS score) in predicting acute kidney injury in patients with cardiorenal syndrome: a prospective cohort study. Indian journal of critical care medicine: peer-reviewed, official publication of Indian Society of Critical Care Medicine, 24(9), 783.

9. Fujii, K., Nakayama, I., Izawa, J., Iida, N., Seo, Y., Yamamoto, M., ... & Iwata, M. (2023). Association between intrarenal venous flow from Doppler ultrasonography and acute kidney injury in patients with sepsis in critical care: a prospective, exploratory observational study. Critical Care, 27(1), 278.

10. Malagón, S. V., Acosta-Gutiérrez, E., Nuñezramos, J. A., Salinas, S., & Pabón, G. M. (2024). Subclinical congestion evaluated by point of care ultrasound (POCUS) at discharge predicts readmission in patients with acute heart failure: prognostic cohort study. POCUS journal, 9(2), 125.

11. Guinot, P. G., Bahr, P. A., Andrei, S., Popescu, B. A., Caruso, V., Mertes, P. M., ... & Bouhemad, B. (2022). Doppler study of portal vein and renal venous velocity predict the appropriate fluid response to diuretic in ICU: a prospective observational echocardiographic evaluation. Critical Care, 26(1), 305.

12. Gokkus, H., Cosgun, Z., Cosgun, M., Ekici, M. A., & Kalaycioglu, O. (2021). Sonographic evaluation of pulmonary interstitial edema in patient with preeclampsia. Ultrasound Quarterly, 37(3), 267-271.

13. Edvinsson, C., Hansson, E., Nielsen, N., Erlandsson, L., & Hansson, S. R. (2022). Intensive care patients with preeclampsia–Clinical risk factors and biomarkers for oxidative stress and angiogenic imbalance as discriminators for severe disease. Pregnancy Hypertension, 30, 88-94.

14. O’Neil, M., Demeulenaere, S. K., DeChristopher, P. J., Holthaus, E., Jeske, W., Glynn, L., ... & Muraskas, J. (2024). Syndecan-1 level, a marker of endothelial glycocalyx degradation, is associated with fetal exposure to chorioamnionitis and is a potential biomarker for early-onset neonatal sepsis. Pediatric and Developmental Pathology, 27(4), 318-326.

15. Fernández-Sarmiento, J., Molina, C. F., Salazar-Pelaez, L. M., Flórez, S., Alarcón-Forero, L. C., Sarta, M., ... & Villar, J. C. (2023). Biomarkers of glycocalyx injury and endothelial activation are associated with clinical outcomes in patients with sepsis: a systematic review and meta-analysis. Journal of intensive care medicine, 38(1), 95-105.

16. Lapinsky, S. E., Kruczynski, K., & Slutsky, A. S. (1995). Critical care in the pregnant patient. American journal of respiratory and critical care medicine, 152(2), 427-455.