Vasopressin for refractory persistent pulmonary hypertension of the newborn in preterm neonates - a case series

Vasopressin induced hyponatremia in infants <3 months of age in the neonatal intensive care unit

Objectives

Vasopressin is used for shock and acute pulmonary hypertension in the neonatal intensive care unit (NICU) and is associated with hyponatremia. The purpose of this study was to determine the incidence, severity, contributing risk factors associated with vasopressin-induced hyponatremia in neonates and infants <3 months of age in the NICU. The primary objective was to determine the incidence of hyponatremia (<130 mEq/L) and severe hyponatremia (<125 mEq/L). The secondary objectives were to compare clinical characteristics and the vasopressin regimen between those with and without hyponatremia.

Methods

This retrospective cohort study included neonates and infants <3 months from 1/1/2017-12/31/2022 receiving vasopressin for >6 h. Analyses were performed using SAS v9.4, with a priori less than 0.05. A multiple variable logistic regression was employed to assess odds of hyponatremia.

Results

Of the 105 patients included, 57 (54.3%) developed hyponatremia, and 17 (29.8%) were classified as severe hyponatremia. Overall, the median (interquartile range, IQR) gestational and postnatal age at vasopressin initiation were 35.4 (27-38.7) weeks and 2 (1-12) days. There was no difference in vasopressin dose, but duration of treatment was longer in those with hyponatremia. Higher baseline serum sodium was associated with decreased odds of hyponatremia [adjusted odds ratio (OR): 0.90 (95% CI: 0.83-0.99), p = 0.03], and increased vasopressin duration was associated with increased odds of hyponatremia [aOR: 1.02 (95% CI: 1.01-1.03), p < 0.001].

Conclusions

Hyponatremia occurred in half of patients included. The pre-vasopressin sodium value and the vasopressin duration were independently associated with hyponatremia.

Evaluation of Hyponatremia in Infants on Vasopressin Therapy

OBJECTIVE

Vasopressin has systemic vasoconstrictive yet pulmonary vasodilatory effects, making it an ideal agent for hypotension management in infants with congenital diaphragmatic hernia (CDH)-associated pulmonary hypertension. The side effects of vasopressin in this population, such as hyponatremia, are understudied. This study aims to characterize the effect of vasopressin on sodium concentrations in infants with and without CDH.

METHODS

This was a retrospective review of patients who received vasopressin while admitted to a level IV neonatal intensive care unit. The primary outcome was the incidence of hyponatremia (blood sodium <135 mmol/L) during vasopressin therapy. Secondary outcomes included time to hyponatremia, dose and duration of vasopressin, incidence of severe hyponatremia (blood sodium <125 mmol/L), and hypertonic saline use. Both blood serum and blood gas sample sodium concentrations were used to compare CDH vs non-CDH patients.

RESULTS

The average difference between baseline and lowest blood sodium was significant for both CDH and non-CDH patients for all samples (p < 0.001). There was no significant difference in the primary outcome, nor in the secondary outcomes of time to hyponatremia or duration of vasopressin infusion. The average dose of vasopressin was higher in the CDH vs non-CDH group (p = 0.018). The incidences of severe hyponatremia and hypertonic saline use were greater in the CDH vs non-CDH group for patients who had blood serum sodium samples collected (p = 0.049 and p = 0.033, respectively).

CONCLUSIONS

This study showed that severe hyponatremia occurred more frequently in CDH vs non-CDH patients. Extreme caution is necessary when managing total body sodium in patients with CDH.

Use of Vasopressin as Rescue Therapy in Refractory Hypoxia and Refractory Systemic Hypotension in Term Neonates with Severe Persistent Pulmonary Hypertension-A Prospective Observational Study

OBJECTIVE

Persistent pulmonary hypertension of the newborn (PPHN) is a serious cardiorespiratory problem. PPHN is frequently associated with refractory hypoxia and hypotension, and optimal management has the potential to improve important clinical outcomes including mortality. The primary objective is to evaluate the efficacy and safety of rescue vasopressin (VP) therapy in the management of severe (refractory) hypoxia and refractory systemic hypotension in term neonates with severe PPHN.

STUDY DESIGN

Neonates with refractory hypoxia and refractory hypotension due to severe PPHN needing VP were prospectively enrolled in the study. Refractory hypoxia was defined as oxygenation index (OI) ≥ 25 for at least 4 hours after the commencement of high-frequency oscillatory ventilation and nitric oxide at 20 ppm. Refractory hypotension was defined as mean blood pressure lesser than mean gestational age lasting for more than 15 minutes in spite of dopamine infusion at 10 µg/kg/min, adrenaline infusion at 0.3 µg/kg/min, and noradrenaline infusion at 0.1 µg/kg/min.

RESULTS

Thirty-two neonates with PPHN were recruited. The baseline OI (mean ± standard deviation [SD]) before starting VP was 33.43 ± 16.54 which started decreasing significantly between 1 and 6 hours after the commencement of VP (p < 0.05). The mean blood pressure also increased concomitantly with a significant effect seen by 1 hour (p < 0.05). The vasoactive infusion score before the commencement of VP was mean 46.07 (SD = 25.72) and started decreasing after 12 to 24 hours of commencement of VP (p < 0.05). Lactate levels (mean ± SD) before starting VP were 7.8 ± 8.6 mmol/L and started decreasing between 6 and 12 hours (p < 0.05). Two neonates died due to refractory hypoxia and refractory hypotension (overall mortality 6.2%) CONCLUSION:  Rescue VP therapy is a useful adjunct in the management of neonates with severe PPHN with refractory hypoxia and/or refractory hypotension. Improvement in oxygenation and hemodynamics with the use of VP results in reduced mortality.

KEY POINTS

· Rescue vasopressin is a useful adjunct in the management of neonates with severe PPHN.. · Vasopressin helps reduce OI.. · Vasopressin reduces the vasoactive inotrope score..

Vasopressin in newborns with refractory acute pulmonary hypertension

BACKGROUND

Acute pulmonary hypertension (aPH) in newborns can be life threatening and challenging to manage. In newborns with refractory aPH, there is currently limited therapeutic agents.

METHODS

Retrospective single-center cohort study in newborns less than one month old who were treated with vasopressin for a minimum of one hour in the context of refractory aPH in the neonatal and pediatric intensive care units of a tertiary university center between 2016 and 2022. The objective was to evaluate the efficacy and safety of vasopressin in newborns as an adjuvant treatment for refractory aPH.

RESULTS

Twenty-five patients met inclusion criteria. In patients who received vasopressin, oxygenation index improved from 28.4 to 14.4 (p = 0.004) after twelve hours of continuous infusion. Oxygen requirements (FiO2) decreased from 0.91 to 0.50 (p = 0.004) and mean arterial pressure increased from 41 to 51 mmHg (p = 0.001). In our cohort, 68% of patients presented an episode of hyponatremia (serum sodium <130 mmol/L).

CONCLUSIONS

The use of vasopressin may be associated with improvement in oxygenation and hemodynamic status of neonatal patients with aPH refractory to initial therapy. Further prospective studies are needed to establish the safety profile of vasopressin in newborns, particularly in preterm infants.

IMPACT

Vasopressin may be an effective cardiotropic agent to improve oxygenation and hemodynamic status in newborns with acute pulmonary hypertension. Careful monitoring of serum sodium levels are warranted in newborns who are receiving vasopressin infusion. This provides additional evidence for the consideration of vasopressin in newborns with acute pulmonary hypertension refractory to inhaled nitric oxide.

An Update on Pharmacologic Management of Neonatal Hypotension: When, Why, and Which Medication

Anti-hypotensive treatment, which includes dopamine, dobutamine, epinephrine, norepinephrine, milrinone, vasopressin, terlipressin, levosimendan, and glucocorticoids, is a long-established intervention in neonates with arterial hypotension (AH). However, there are still gaps in knowledge and issues that need clarification. The main questions and challenges that neonatologists face relate to the reference ranges of arterial blood pressure in presumably healthy neonates in relation to gestational and postnatal age; the arterial blood pressure level that potentially affects perfusion of critical organs; the incorporation of targeted echocardiography and near-infrared spectroscopy for assessing heart function and cerebral perfusion in clinical practice; the indication, timing, and choice of medication for each individual patient; the limited randomized clinical trials in neonates with sometimes conflicting results; and the sparse data regarding the potential effect of early hypotension or anti-hypotensive medications on long-term neurodevelopment. In this review, after a short review of AH definitions used in neonates and existing data on pathophysiology of AH, we discuss currently available data on pharmacokinetic and hemodynamic effects, as well as the effectiveness and safety of anti-hypotensive medications in neonates. In addition, data on the comparisons between anti-hypotensive medications and current suggestions for the main indications of each medication are discussed.

Targeted Neonatal Echocardiography in the Management of Neonatal Pulmonary Hypertension

Pulmonary hypertension (PH) in neonates, originating from a range of disease states with heterogeneous underlying pathophysiology, is associated with significant morbidity and mortality. Although the final common pathway is a state of high right ventricular afterload leading to compromised cardiac output, multiple hemodynamic phenotypes exist in acute and chronic PH, for which cardiorespiratory treatment strategies differ. Comprehensive appraisal of pulmonary pressure, pulmonary vascular resistance, cardiac function, pulmonary and systemic blood flow, and extrapulmonary shunts facilitates delivery of individualized cardiovascular therapies in affected newborns.

The early use of inhaled nitric oxide in premature infants requiring respiratory support

Background: Earlier studies on the use of inhaled nitric oxide (iNO) for premature infants born at <34 weeks of gestation requiring respiratory support did not provide conclusive evidence of benefit. National guidelines generally discouraged the use in this population. More recent national guidelines endorsed the use of iNO in premature infants with hypoxic respiratory failure (HRF) associated with persistent pulmonary hypertension of the newborn (PPHN).Recent Studies: Two recently published observational studies evaluated the effect of administering iNO on oxygenation in the first week of life. These studies compared premature infants born at the gestational age (GA) of <34 weeks with HRF associated with PPHN to term and late preterm infants born at the GA of ≥34 weeks who received iNO. Both studies showed a similar effect of iNO on oxygenation in the two infant cohorts. The response rate in the premature infant cohort was 59% in the first study and 90% in the second. The mean response time was 9.2 h and 10.3 h, and the mean duration of therapy was 3.5 days and 8.2 days, respectively.Conclusion: The results of these studies support a trial of iNO in premature infants with persistent hypoxia despite optimum respiratory support. Obtaining a timely echocardiogram to exclude cardiac diseases and diagnose PPHN is logistically challenging for many clinicians, thus, a clinical diagnosis of PPHN might have to be made in these situations. Questions remain regarding the optimum dose of iNO and the duration of the initial iNO trial in these patients.KEY MESSAGESIn the most recently published studies, the improvement of oxygenation in iNO-treated infants born at <34 weeks of gestation with HRF and PPHN physiology was as effective as in infants born ≥34 weeks.These studies provide evidence supporting a trial of iNO in the subpopulation of premature infants with HRF associated with PPHN.

Early vasopressin infusion improves oxygenation in infants with congenital diaphragmatic hernia

Objective

Congenital Diaphragmatic Hernia (CDH) is a complex disease including a diaphragmatic defect, lung hypoplasia, and pulmonary hypertension. Despite its increasing use in neonates, the literature on the use of vasopressin in neonates is limited. The aim of this work is to analyze the changes in clinical and hemodynamic variables in a cohort of CDH infants treated with vasopressin.

Methods

Among CDH infants managed at the Neonatal Intensive Care Unit (NICU) of our hospital from May 2014 to January 2019, all infants who were treated with vasopressin, because of systemic hypotension and pulmonary hypertension, were enrolled in this retrospective study. The primary outcome was the change in oxygenation index (OI) after the start of the infusion of vasopressin. The secondary outcomes were the changes in cerebral and splanchnic fractional tissue oxygen extraction (FTOEc and FTOEs) at near-infrared spectroscopy, to understand the balance between oxygen supply and tissue oxygen consumption after the start of vasopressin infusion. We also reported as secondary outcomes the changes in ratio of arterial oxygen partial pressure (PaO2) to fraction of inspired oxygen (FiO2), heart rate, mean arterial pressure, serum pH, and serum sodium.

Results

We included 27 patients with isolated CDH who received vasopressin administration. OI dramatically dropped when vasopressin infusion started, with a significant reduction according to ANOVA for repeated measures (p = 0.003). A global significant improvement in FTOEc and FTOEs was detected (p = 0.009 and p = 0.004, respectively) as a significant reduction in heart rate (p = 0.019). A global significant improvement in PaO2/FiO2 ratio was observed (p < 0.001) and also at all time points: at 6 h since infusion (p = 0.015), 12 h (p = 0.009), and 24 h (p = 0.006), respectively. A significant reduction in sodium levels was observed as expected side effect (p = 0.012). No significant changes were observed in the remaining outcomes.

Conclusion

Our data suggest that starting early vasopressin infusion in CDH infants with pulmonary hypertension could improve oxygenation index and near-infrared spectroscopy after 12 and 24 h of infusion. These pilot data represent a background for planning future larger randomized trials to evaluate the efficacy and safety of vasopressin for the CDH population.

Update on pre-ECMO evaluation and treatment for term infants in respiratory failure

The epidemiology, diagnostic and management approach to severe hypoxemic respiratory failure in the term and near-term neonate has evolved over time, as has the need for extracorporeal membrane oxygenation (ECMO) support in this patient population. Many patients who historically would have required ECMO support now respond to less invasive therapies, with patients requiring ECMO generally representing a higher risk and more heterogenous group of underlying diagnoses. This review will highlight these changes over time and the current available evidence for the diagnosis and management of these infants, as well as the current indications and relative contraindications to ECMO support when oxygen delivery cannot meet demand with less invasive management.

How to diagnose and treat acute pulmonary hypertension when you have no cardiology support

Acute pulmonary hypertension (aPH) is a complex, physiology-driven disorder that causes critical illness in newborns, the hallmark of which is elevated pressure in the pulmonary vascular bed. Several underlying hemodynamic phenotypes exist, including classic arterial aPH with resistance-driven elevations in pulmonary arterial pressure (PAP), alongside flow-driven aPH from left-to-right shunt lesions, and primary left ventricular dysfunction with pulmonary venous hypertension and elevated left atrial pressure. Targeted neonatal echocardiography (TnECHO) is an important tool for evaluation of hemodynamics in aPH and is highly useful for evaluating modulators of disease and targeting cardiovascular therapy. The diagnostic approach to aPH includes confirmation of elevation of PAP, evaluation of the cause and exclusion of structural cardiac disease, assessment of the response of the myocardium to adverse loading conditions, and appraisal of the adequacy of systemic blood flow. Therapeutic goals include support of right ventricular (RV) function, RV afterload reduction, and selection of cardiotropic agents that support underlying pathophysiology without adverse effects on heart rate or pulmonary vascular resistance in addition to routine supportive intensive care. Training programs for TnECHO exist across multiple jurisdictions and strong correlation with pediatric cardiology assessment has been demonstrated. Future directions include adapting TnECHO training with a greater focus on achieving competency, and further research into the role of the modality in providing individualized cardiovascular care for patients with heterogenous underlying physiology, and its effect on key neonatal outcomes.

Efficacy and Safety of Vasopressin and Terlipressin in Preterm Neonates: A Systematic Review

INTRODUCTION

The use of arginine vasopressin (AVP) and terlipressin to treat hypotension in preterm neonates is increasing. Our aim was to review the available evidence on the efficacy and safety of AVP and terlipressin for use in preterm neonates.

METHODS

MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, Web of Science, and Google Scholar from inception to September 2021 were searched for studies of AVP and terlipressin in the treatment of hypotension of any cause in preterm neonates. Primary outcomes were improvement in end-organ perfusion and mortality. The risk of bias assessment and certainty of the evidence were performed using appropriate tools.

RESULTS

Fifteen studies describing the use of AVP (n = 12) or terlipressin (n = 3) among 148 preterm neonates were included. Certainly, the available evidence for the primary outcome of end-organ perfusion rated as very low. AVP or terlipressin were used to treat 144 and 4 neonates, respectively. Improvement in markers of end-organ perfusion was reported in 143 (99%) neonates treated with AVP and 3 (75%) treated with terlipressin. The mortality rate was 41% (n = 59) and 50% (n = 2) for neonates who received AVP and terlipressin, respectively. Hyponatremia was the most frequently reported adverse event (n = 37, 25%).

CONCLUSION

AVP and terlipressin may improve measured blood pressure values and possibly end-organ perfusion among neonates with refractory hypotension. However, the efficacy-safety balance of these drugs should be assessed on an individual basis and as per the underlying cause. Studies on the optimal dosing, efficacy, and safety of AVP and terlipressin in preterm neonates with variable underlying conditions are critically needed.

Precision in Cardiovascular Care Using Targeted Neonatal Echocardiography in Lethal Neonatal Disseminated Herpes Infection: A Case Series

Neonates with disseminated neonatal herpes simplex virus infection often present with cardiorespiratory failure. The pathophysiological contributors to the disease phenotype, biologic mechanisms underlying the hemodynamic instability and optimal approach to cardiovascular treatment have not been well described. We describe clinical and echocardiography features of cardiovascular dysfunction, in a case series of neonates with disseminated herpes simplex virus, and response to physiology-based hemodynamic management. The biologic phenotype includes low systemic vascular resistance state, hypovolemia secondary to third space losses, myocardial dysfunction and pulmonary hypertension. Early targeted neonatal echocardiography provided hemodynamic insights on blood flow, shunt characterization, vascular resistance and cardiac function, that were difficult to gauge clinically (eg, differentiating parenchymal from pulmonary vascular disease) thereby positively impacted clinical care. All patients were stabilized hemodynamically without utilizing extracorporeal membrane oxygenation, although all patients died of multiorgan failure.

Severe neonatal pulmonary artery hypertension rescued with vasopressin

An inborn term neonate weighing 2600 g developed meconium aspiration syndrome at birth. Baby had respiratory failure requiring high-frequency oscillatory ventilation support at 15 hours of life. He additionally developed hypotension with left ventricular dysfunction noted on point-of-care echocardiography (POCE), which required dopamine and epinephrine infusions. At 28 hours of life, he was started on inhaled nitric oxide (iNO), followed by milrinone due to hypoxaemic respiratory failure and the POCE revealed severe pulmonary artery hypertension (PAH). As PAH was refractory to iNO and milrinone, vasopressin was added which resulted in rapid improvement in oxygenation and normalisation of pulmonary artery pressures. Baby was weaned off from vasoactive support in the next 120 hours. Vasopressin proved to be the rescue agent in this case of iNO refractory PAH without any side effects during therapy. Baby was successfully extubated on day 18 and was discharged with a normal neurological examination finding.