Correlation of functional echocardiography and clinical parameters in term neonates with shock

Neonatal Shock: Current Dilemmas and Future Research Avenues

Neonatal shock presents a complex clinical challenge and is one of the leading causes of mortality. Traditionally, neonatal shock is equated to hypotension, and therapeutics are often initiated based on low blood pressure (BP) values alone. This fails to address the underlying goal of optimizing the tissue perfusion resulting in both over- and under-treatment of neonatal shock. Also, what defines a normal BP in neonates is still a contentious topic. Further, the most appropriate way of measuring BP in neonates with shock is still debated. Shock secondary to transient circulatory instability and patent ductus arteriosus, conditions that are unique to preterm neonates, have not been researched adequately. Treatment of myocardial dysfunction secondary to perinatal asphyxia, a leading cause of neonatal mortality, is still a conundrum. Quite similarly, there are only a handful of controlled trials evaluating therapeutics in some of the other commonly encountered conditions, namely, septic shock and hypoperfusion secondary to pulmonary hypertension. Even the universally practiced intervention of volume expansion with crystalloid boluses in shock is not backed by high-certainty evidence in neonates. Though the diagnostic modalities of functional echocardiography and near-infrared spectroscopy have aided greatly in the management of neonatal shock in recent years, these have not been proven to be associated with improved critical clinical outcomes such as mortality and major brain injury. To conclude, neonatologists often rely on limited evidence, mostly anecdotal, when treating neonatal shock. This review critically examines the current evidence with respect to various aspects of neonatal shock with an objective to identify the lacunae in the literature that may fuel future research, eventually paving the way to efficacious, safe and evidence-based clinical practice.

Assessment of hemodynamic dysfunction in septic newborns by functional echocardiography: a systematic review

BACKGROUND

Neonatal sepsis remains a leading cause of mortality in neonatal units. Neonatologist-performed echocardiography (NPE) offers the potential for early detection of sepsis-associated cardiovascular dysfunction. This review examines available echocardiographic findings in septic neonates.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we systematically reviewed prospective observational, cross-sectional, case control, and cohort studies on septic newborns with echocardiographic assessments from PubMed, Scopus and Embase. Quality assessment employed the Newcastle-Ottawa Scale, with results analyzed descriptively.

RESULTS

From an initial pool of 1663 papers, 12 studies met inclusion criteria after relevance screening and eliminating duplicates/excluded studies. The review encompassed 438 septic newborns and 232 controls. Septic neonates exhibited either increased risk of pulmonary hypertension or left ventricular diastolic dysfunction, and a warm shock physiology characterized by higher cardiac outputs.

DISCUSSION

The included studies exhibited heterogeneity in sepsis definitions, sepsis severity scores, echocardiographic evaluations, and demographic data of newborns. Limited sample sizes compromised analytical interpretability. Nonetheless, this work establishes a foundation for future high-quality echocardiographic studies.

CONCLUSION

Our review confirms that septic neonates show significant hemodynamic changes that can be identified using NPE. These findings underscore the need for wider NPE use to tailor hemodynamics-based strategies within this population.

IMPACT

1. Our study emphasizes the value of neonatologist-performed echocardiography (NPE) as a feasible tool for identifying significant hemodynamic changes in septic neonates. 2. Our study underscores the importance of standardized echocardiographic protocols and frequent monitoring of cardiac function in septic neonates. 3. The impact of the study lies in its potential to increase researchers' awareness for the need for more high-quality echocardiographic data in future studies. By promoting wider use of NPE, neonatologists can more accurately assess the hemodynamic status of septic newborns and tailor treatment approaches, potentially improving patient outcomes.

Correlation of Plethysmograph Variability Index with Inferior Vena Cava Index in Spontaneously Breathing Neonates - A Cross Sectional Study

Inferior vena cava (IVC) indices are commonly used to assess the need for fluid bolus during shock. It needs expertise and is difficult to do during surgical procedures. Plethysmograph variability index (PVI) is a simpler non-invasive tool used to measure fluid responsiveness in adults. However, the data on PVI in neonates is limited. This cross-sectional observational study was done at a tertiary level NICU to correlate PVI and IVC among spontaneously breathing neonates. The PVI was documented using the Masimo Radical 7 pulse oximeter. The IVC collapsibility index (IVC CI) was determined by bedside ultrasound. The Spearman correlation coefficient was analyzed. The PVI showed strong positive correlation with IVC CI (rho = 0.64, 95% CI: 0.474-0.762) (p <0.001). Thus, PVI can be a useful tool for hemodynamic monitoring of neonates. However, further studies are needed before applying it to clinical use.

Functional echocardiographic preload markers in neonatal septic shock

BACKGROUND

There are no established clinical or laboratory markers of preload adequacy and fluid responsiveness in management of neonatal shock. Functional echocardiographic preload markers are evaluated in children and adults, but there is no data in neonatal septic shock. We evaluated five functional echocardiographic preload markers during intravenous volume resuscitation in neonatal septic shock.

OBJECTIVE

(1) To compare baseline functional echocardiographic preload markers between neonates with septic shock and their "matched" healthy controls. (2) To compare echocardiographic preload markers before and after intravenous volume resuscitation.

METHODS

In this cohort study, we enrolled neonates with septic shock (cases) and recorded five preload markers - inferior vena cava collapsibility index (IVC-CI), left ventricular end-diastolic (LVEDV) & end-systolic volume (LVESV) and their indices (LVEDVI, LVESVI) - before initiation of intravenous fluid resuscitation (baseline evaluation). An equal number of "matched hemodynamically stable" controls were recruited, who underwent functional echocardiographic assessment once. In neonates with shock, we recorded these markers again after volume resuscitation.

RESULTS

We analyzed 46 neonates (23 cases and 23 controls). Neonates with shock had significantly elevated baseline IVC-CI as compared to controls [53% (21, 100) vs. 20% (15, 24) respectively, p-value = .01). Rest 4 echocardiographic markers (LVEDV, LVESV, LVEDVI, and LVESVI) were comparable between cases and controls. Sixteen neonates (70% of 23) received intravenous fluid resuscitation and rest 7 (30%) were started directly on vasoactive drugs. None of the preload markers changed significantly after volume resuscitation as compared to the baseline values including IVC-CI, which was almost significant [74% (33, 100) at baseline to 48% (13, 93) after 10 mL/kg and 50% (40, 69) after 20 mL/kg, (p = .05). All preload markers were comparable between survivors and non-survivors.

CONCLUSION

Neonates with septic shock had significantly elevated IVC-CI at baseline as compared to hemodynamically stable neonates. None of the preload markers changed significantly after volume resuscitation as compared to the baseline values including IVC-CI, which was almost significant.