Low-dose vasopressin infusion therapy for refractory hypotension in ELBW infants

The effect of heart rate on systolic and diastolic time intervals and cardiac function in stable and sick preterm infants

BACKGROUND

Diastolic function includes relaxation and filling of the heart and is dependent on heart rate (HR) and time spent in either systole (St) or diastole (Dt). The St/Dt ratio increases as HR increased and is a marker of overall cardiac function in children with heart failure. The aim of this study is to describe cardiac cycle events in preterm infants.

METHODS

Cardiac ultrasounds of preterm infants <32 weeks were retrospectively reviewed for cardiac cycle events from Tissue Doppler images and grouped by clinical indication of the scan as stable or as clinical deterioration with significant illness.

RESULTS

412 scans in 201 preterm infants were analyzed. St/Dt ratio increased with increasing HR. St increased from 50 to 54 % of the cardiac cycle length with shortened diastolic duration. Isovolumetric contraction and relaxation remained unchanged at 9 and 12 % of the cardiac cycle respectively. Mean St, Dt and St/Dt ratio in stable infants were 195(19) msec, Dt 175(24) msec and 1.13 (0.16) respectively. Sick infants without cardiovascular medications showed a significantly shorter St and lower St/Dt ratio. Cardiovascular medications increased isovolumetric times, Dt, and early diastolic duration.

CONCLUSION

Reference values for cardiac cycle durations and St/Dt ratio are presented. Preterm hearts adapt to higher HR by shifting towards systole and shortened early diastole by optimising its force frequency relationship and enhanced relaxation. The St/Dt ratio was altered in preterm infants with significant illness. This simple ultrasound marker could be tested in further studies that investigate cardiovascular medications in preterm infants.

Effect of vasopressin infusion in refractory neonatal shock

BackgroundTo evaluate the effect of vasopressin infusion in refractory neonatal shock.MethodThis was a cohort study involving retrospective review of medical records of all neonates who received intravenous vasopressin infusion for at least 6 h for treatment of refractory shock in a level 3B neonatal intensive care unit of northern India between Jan 2016 to May 2021. Outcome measures assessed were systolic, diastolic, and mean blood pressure, heart rate, urine output, serum sodium level, inotrope score, and oxygenation index at 6, 12, 24, 48, and 72 h of vasopressin therapy. Outcome measures were compared before (T1) and 48 h (T2) after initiation of vasopressin.ResultsA total of 32 neonates received vasopressin. The mean (SD) systolic, diastolic, and mean blood pressure improved significantly between T1 and T2 from 54 (9) to 64 (11) mm Hg (MD (95% CI) = 10.3 (4.2-16.6), p = 0.003), 36 (8) to 42 (10) mm Hg (MD (95% CI) = 6.2 (1.3-11.3), p = 0.01), and 43 (8) to 51 (10) mm Hg (MD (95% CI) = 8.5 (2.3-14.6), p = 0.01), respectively. Median (IQR) urine output improved from 1.25 (0-3.2) to 2.1 (1.6-7) ml/kg/hr, p = 0.004. There was a significant fall in serum sodium from 139 (9) to 134 (8) mEq/l, p = 0.01. Out of 32 infants, 19 (59.4%) survived, while 6 (18.8 %) were transferred out and 7 (21.8%) died.ConclusionVasopressin improved hemodynamic parameters in refractory neonatal shock and can be used as a rescue therapy. Vasopressin therapy is associated with a fall in serum sodium.

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.

Vasopressin as adjunctive therapy in pulmonary hypertension associated with refractory systemic hypotension in term newborns

OBJECTIVE

The use of vasopressin as an adjunctive therapy in pulmonary hypertension associated with refractory systemic hypotension has increased. The objective of our study is to describe its effects on term infants.

STUDY DESIGN

Retrospective observational study. Setting in a referral level IV neonatal intensive care unit from a middle-income region. The patients are term neonates admitted to our NICU who required vasopressin due to severe Pulmonary Hypertension and refractory hypotension during a 49-month period (December 2019 and December 2023).

RESULTS

We identified 68 term infants, all in mechanical ventilation, receiving inhaled nitric oxide (iNO), and a phased protocol management for hypotension. Vasopressin was a started at a mean of 2 days with a mean duration of 80 h. Regarding hemodynamic outcome: diastolic, systolic, and median systemic pressure significantly increased during the first 4 h of treatment, as well as arterial pH and urine output. Accordingly, lactate and Vasoactive Inotropic Score (VIS) score decreased after 4 and 8 h, respectively, after vasopressin was started. Regarding oxygenation markers: oxygen requirements and mean airway pressure decreased significantly (and therefore the oxygenation index decreased in concordance) after 4 h of vasopressin. Echocardiographic indices of pulmonary hypertension progressively improved after vasopressin infusion with a significant decrease of tricuspid ingurgitation velocities and the rate of right-to- left ductal shunt through the ductus arteriosus. In the same way, left and right ventricular output increased after the initiation of vasopressin.

CONCLUSION

This study showed that the use of vasopressin in neonates with persistent pulmonary hypertension was associated with a rapid and significant improvement in oxygenation and hemodynamic markers of perfusion, including blood pressure. Its effects begin early during the first hours of treatment.

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.

Pathogenesis, Prognosis and Outcomes of Multiple Organ Failure in Newborns (Review)

Multiple organ failure (MOF) is the leading cause of neonatal mortality in intensive care units. The prevalence of MOF in newborns is currently unclear, since its incidence varies in asphyxia, sepsis, prematurity, and comorbidity, and depends on the level of development and funding of health care in different countries. Sepsis and acute respiratory distress syndrome prevail among the causes of MOF in this category of patients.

Aim of the review. To summarize the available literature data on the pathogenesis, therapeutic strategies and outcomes of MOF in newborns.

Material and methods. We searched PubMed, Scopus, Web of Science, and RSCI databases using the following keywords: «newborns, multiple organ failure, etiology, pathogenesis, premature, diagnosis, treatment, respiratory support, cardiotonic support», without language limitations. A total of 144 full-text sources were selected for analysis, 70% of which were published in the last five years and 50% were published in the last three years. Criteria for exclusion were low information value and outdated data.

Results. The prevalence of MOF in neonates is currently unclear. This could be due to common association of neonatal MOF (as well as the adult one) with various diseases; thus, its incidence is not the same for asphyxia, sepsis, prematurity, and comorbidities. There is no precise data on neonatal mortality in MOF, but according to some reports, it may be as high as 13-50%.

In newborns, MOF can be caused by two major causes, intrapartum/postnatal asphyxia and sepsis, but could also be influenced by other intranatal factors such as intrauterine infections and acute interruption of placental blood flow.

The key element in the pathogenesis of neonate MOF is cytokinemia, which triggers universal critical pathways. Attempts to identify different clinical trajectories of critical illness in various categories of patients have led to the discovery of MOF phenotypes with specific patterns of systemic inflammatory response. This scientific trend is very promising for the creation of new classes of drugs and individual therapeutic pathways in neonates with MOF of various etiologies.

The pSOFA scale is used to predict the outcome of neonatal MOF, however, the nSOFA scale has higher validity in premature infants with low birth weight.

Central nervous system damage is the major MOF-associated adverse outcome in newborns, with gestational age and the timing of treatment initiation being key factors affecting risk of MOF development in both full-term and premature infants.

Conclusion. The study of cellular messengers of inflammation, MOF phenotypes, mitochondrial insufficiency, and immunity in critically ill infants with MOF of various etiologies is a promising area of research. The pSOFA scale is suggested for predicting the outcome of MOF in full-term infants, while the nSOFA scale should be used in premature infants with low birth weight.

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.

Effect of Vasopressin on Systemic and Pulmonary Hemodynamics in Neonates

OBJECTIVE

Despite its increasing use in neonates, the literature on the use of vasopressin (VP) in neonates is limited. The aim of this study is to evaluate the systemic and pulmonary effects of VP in neonates and to assess its safety among them.

STUDY DESIGN

This retrospective study enrolled all neonates in two level III neonatal intensive care units in Winnipeg, Manitoba, who had received VP therapy between 2011 and 2016. Infants with congenital malformations/chromosomal disorders were excluded. The changes in cardiovascular and pulmonary parameters were collected from patient charts. The primary outcome was the mean blood pressure (MBP) post-VP initiation. Secondary outcomes included systolic blood pressure (SBP) and diastolic blood pressure (DBP), vasoactive inotropic score (VIS), pH, urine output, lactate, base deficit (BD), mean airway pressure (MAP), and oxygen requirement.

RESULTS

A total of 33 episodes from 26 neonates were analyzed. The postnatal age at VP initiation was 14 days (interquartile range [IQR]: 4-25), and the median starting dose was 0.3 mU/kg/min (IQR: 0.2-0.5). MBP improved significantly after VP initiation from 28 to 39 mm Hg 24 hours after VP initiation (p < 0.001). Similar changes are observed with SBP and DBP. VIS declined from 15 to 6 at 24 hours, while pH, lactate, BD, and oxygen requirement improved significantly. While urine output marginally improved, there were no changes to MAP 24 hours post-VP initiation. Hyponatremia was observed in 21 episodes (64%) and severe hyponatremia in 7 episodes (33%).

CONCLUSION

VP appears to be a promising rescue therapy in catecholamine resistant shock or refractory pulmonary hypertension in neonates.

Influence of innate immune activation on endocrine and metabolic pathways in infancy

Prematurity is the leading cause of neonatal morbidity and mortality worldwide. Premature infants often require extended hospital stays, with increased risk of developing infection compared with term infants. A picture is emerging of wide-ranging deleterious consequences resulting from innate immune system activation in the newborn infant. Those who survive infection have been exposed to a stimulus that can impose long-lasting alterations into later life. In this review, we discuss sepsis-driven alterations in integrated neuroendocrine and metabolic pathways and highlight current knowledge gaps in respect of neonatal sepsis. We review established biomarkers for sepsis and extend the discussion to examine emerging findings from human and animal models of neonatal sepsis that propose novel biomarkers for early identification of sepsis. Future research in this area is required to establish a greater understanding of the distinct neonatal signature of early and late-stage infection, to improve diagnosis, curtail inappropriate antibiotic use, and promote precision medicine through a biomarker-guided empirical and adjunctive treatment approach for neonatal sepsis. There is an unmet clinical need to decrease sepsis-induced morbidity in neonates, to limit and prevent adverse consequences in later life and decrease mortality.

Evaluation of urine output, lactate levels and lactate clearance in the transitional period in very low birth weight preterm infants

OBJECTIVE

To assess the association between urine output (UO), arterial lactate levels (LL) and lactate clearance with haemodynamic instability and death in very low birth weight (VLBW) preterm in the transitional period.

STUDY DESIGN

Retrospective cohort study with VLBW newborns born in 2016 and 2017, excluding those with malformations and without data. We evaluated 254 preterm infants with a total of 482 lactate levels measured in the first 72 h. Areas under the curve (AUC) were calculated for receiver-operator characteristics (ROC) curves of UO and LL (alone and combined) and of lactate clearance for prediction of haemodynamic instability and death.

RESULTS

All AUC were below 0.80. Sensitivity and specificity were also not very good. Although patients with poor outcomes had lactate levels higher than those with good outcomes, discrimination was poor.

CONCLUSION

UO and LL and lactate clearance were not good predictors of haemodynamic instability or death within 10 days of life. What is Known • It is already established that blood pressure is not a good marker for haemodynamic stability in the preterm infant. • Others clinical parameters, albeit are largely used, are not fully reliable as well. What is New • In our study we tried to determine the sensibility and specificity of urine output and arterial lactate and also the lactate clearance. • All AUC were below 0.80. Sensitivity and specificity were also not very good. Although patients with poor outcomes had lactate levels higher than those with good outcomes, discrimination was poor.

Use of vasopressin in neonatal hypertrophic obstructive cardiomyopathy: case series

OBJECTIVE

To determine the effect of vasopressin on arterial blood pressure in infants with neonatal hypertrophic obstructive cardiomyopathy (HOCM).

STUDY DESIGN

Retrospective case study in Neonatal ICU involving six infants; five born to mothers with diabetes mellitus (mean gestational age 37.5 ± 0.9 weeks). Vasopressin infusion was started at a mean dose of 0.3 ± 0.2 mU/kg/min.

RESULT

Initiation of vasopressin was followed by improved mean (p = 0.004), systolic (p = 0.028), and diastolic (p = 0.009) arterial pressure within 2 h. Heart rate (p = 0.025) and oxygen requirement (p = 0.021) also declined after initiation. Serum sodium declined initially and recovered by 72 h (p = 0.017).

CONCLUSION

Although there is limited experience with vasopressin use in neonatal HOCM, our case series suggests it may be beneficial for improving systemic hypotension and stabilization of hemodynamics. The potential for hyponatremia is high, necessitating careful fluid/electrolyte management. A prospective randomized trial is necessary to confirm safety and efficacy of vasopressin treatment in neonatal HOCM.

What Inotrope and Why?

Primary function of cardiovascular system is to meet body's metabolic demands. The aim of inotrope therapy is to minimise adverse impact of cardiovascular compromise. Current use of inotropes is primarily guided by the pathophysiology of cardiovascular compromise and anticipated actions of inotropes. Lack of significant reduction in morbidity and mortality associated with cardiovascular compromise despite inotrope use, highlights major gaps in our understanding of circulatory targets, thresholds and choices of inotrope therapy. Thus far, prevention of cardiovascular compromise remains the most effective strategy to optimize outcomes. Studies of alternative design are needed for further advancement in cardiovascular therapy in neonates.

Low vasopressin and progression of neonatal sepsis to septic shock: a prospective cohort study

The study objective was to analyze the association between low plasma vasopressin and progression of sepsis to septic shock in neonates < 34 weeks gestation. Septic neonates of < 34 weeks gestation were consecutively enrolled; moribund neonates and those with major malformations were excluded. Subjects were monitored for progression of sepsis to septic shock over the first 7 days from enrolment. Plasma vasopressin levels and inducible nitric oxide synthase levels were measured at the onset of sepsis (T0), severe sepsis (T1), and septic shock (T2). Primary outcome was plasma vasopressin levels at the point of sepsis in those who progressed to septic shock in comparison with matched nested controls in the non-progression group. Forty-nine (47%) enrolled subjects developed severe sepsis or septic shock. Plasma vasopressin levels (pg/ml) at the onset of sepsis were significantly low in those who progressed to septic shock (median (IQR), 31 (2.5-80) versus 100 (12-156); p = 0.02). After adjusting for confounders, vasopressin levels were independently associated with progression to septic shock (adjusted OR (95% CI), 0.97 (0.96, 0.99); p = 0.01).Conclusion: Preterm septic neonates who progressed to septic shock had suppressed vasopressin levels before the onset of shock. Low vasopressin levels were independently associated with progression to septic shock.What is known:• In animal sepsis models and adult septic patients, exuberant production of nitric oxide metabolites and low vasopressin levels have been reportedly associated with progression to septic shock.• Vasopressin levels have been variably reported as low as well as elevated in children with septic shock.What is New:• Preterm neonates who progressed from sepsis to septic shock had significantly lower levels of vasopressin before the onset of shock in comparison with those who did not progress.• Low vasopressin levels independently predicted the progression from sepsis to septic shock in this population.

Organ blood flow in response to infusion of arginine vasopressin in premature fetal sheep

BACKGROUND

Arginine vasopressin (AVP) infusion has been shown to be a useful strategy for the management of systemic perfusion failure in premature infants. Our objective was to determine the characteristics of the blood flow redistribution induced by AVP infusion in premature fetal sheep.

METHODS

Nine sheep fetuses at 99 to 113 days of gestation were continuously infused with AVP. Measurement of blood flow to individual fetal organs was performed using a colored microsphere technique, with measurements performed at 30 min before and 90 min after the initiation of AVP infusions.

RESULTS

The AVP infusion significantly increased blood flow to the medulla oblongata (P < 0.05), and significantly decreased flow to the adrenal glands (from 492.0 ± 239.6 to 364.9 ± 143.3 mL/min/100 g, P < 0.05) and heart (from 592.6 ± 184.5 to 435.6 ± 137.4 mL/min/100 g, P < 0.05). The infusion significantly increased the vascular resistance in adrenal glands, kidneys, ileum, colon, heart, and cerebellum. In the brain, except for the cerebellum, no significant increase in resistance was identified.

CONCLUSIONS

There was no significant response to AVP infusion in cerebral blood flow in mid-gestation fetal sheep. Our observations suggest that, under AVP stimulation, the blood flow to the adrenal glands and myocardium might be decreased due to an increase in vascular resistance.

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

Objective: To describe the clinical outcomes following treatment with vasopressin for a sub-cohort of critically ill preterm neonates who have refractory persistent pulmonary hypertension of the newborn (PPHN).Design: Case seriesSetting: Tertiary neonatal intensive care unit, Toronto, Canada.Population: Neonates born <37 weeks gestational age (GA) who received vasopressin for refractory PPHN (lack of response to inhaled nitric oxide) over a 4-year period.Measurements: Changes in physiological indices of cardio-pulmonary stability during vasopressin therapy were analyzed using one-way repeated measures ANOVA, compared to pretreatment values. Data regarding survival to discharge and neurodevelopmental outcomes at 18-24 months were described.Main Results: Thirteen neonates with a mean GA of 31.4 ± 3.3 weeks were included. Vasopressin was initiated at 28.5 ± 4.5 h of age. Overall, oxygenation and hemodynamic variables improved significantly following vasopressin therapy (p < .05 at 24 h vs. pretreatment). Oxygenation failure resolved in 8 cases, of which 7 patients survived (6 without disability). Among the 5 cases where oxygenation failure persisted despite vasopressin, 4 died while one survived with disability.Conclusions: Vasopressin offers promise as a therapy for preterm neonates with refractory PPHN and hemodynamic instability, but prospective investigation is needed.

Late-onset glucocorticoid-responsive circulatory collapse in premature infants

Late-onset glucocorticoid-responsive circulatory collapse (LGCC) in infants is characterized by sudden onset of hypotension and/or oliguria, which is resistant to volume expanders and inotropes but responds rapidly to intravenous glucocorticoids. LGCC occurs after the first week of life mainly in relatively stable very low birth weight (VLBW) infants. In Japan, the incidence of LGCC is reported to be 8%. Relative adrenal insufficiency (AI) is considered the most likely cause of LGCC, but its detailed pathophysiology remains unclear. Intrinsic and extrinsic factors may affect the pathophysiological mechanism. LGCC should be recognized as one of the high-risk complications in VLBW infants and managed promptly and properly, because if it is not, it may cause life-long neurological problems. To diagnose relative AI, an accurate evaluation of adrenal function is necessary; however, the interpretation of basal serum cortisol levels is difficult in preterm infants after 7 days of life. To recognize LGCC, it is recommended that blood pressure and urine volume be carefully monitored, even outside of the transitional period. If no underlying causes are documented or volume expansion and inotropic support fail, intravenous hydrocortisone should be initiated, and an additional dose of hydrocortisone is required when the response is inadequate. There are few reports to verify or characterize LGCC and this phenomenon has not been recognized worldwide to date. This review summarizes the current knowledge about LGCC in premature infants and evaluates the most significant new findings regarding its pathophysiology, treatment, and prognosis.

The Use of Cardiotonic Drugs in Neonates

There is a distinct lack of age-appropriate cardiotonic drugs, and adult derived formulations continue to be administered, without evidence-based knowledge on their dosing, safety, efficacy, and long-term effects. Dopamine remains the most commonly studied and prescribed cardiotonic drug in the neonatal intensive care unit (NICU), but evidence of its effect on endorgan perfusion still remains. Unlike adult and pediatric critical care, there are significant gaps in our knowledge on the use of various cardiotonic drugs in various forms of circulatory failure in the NICU.

Treating Hypotension in Preterm Neonates With Vasoactive Medications

Preterm neonates often have hypotension which may be due to various etiologies. While it is controversial to define hypotension in preterm neonates, various vasoactive medications are commonly used to provide the cardiovascular support to improve the blood pressure, cardiac output, or to treat shock. However, the literature on the systemic and regional hemodynamic effects of these antihypotensive medications in neonates is deficient and incomplete, and cautious translation of findings from other clinical populations and animal studies is required. Based on a literature search on published reports, meta-analytic reviews, and selected abstracts, this review discusses the current available information on pharmacologic actions, clinical effects, and side effects of commonly used antihypotensive medications including dopamine, dobutamine, epinephrine, norepinephrine, vasopressin, and milrinone in preterm neonates.

Cardiovascular Supportive Therapies for Neonates With Asphyxia - A Literature Review of Pre-clinical and Clinical Studies

Asphyxiated neonates often have hypotension, shock, and poor tissue perfusion. Various "inotropic" medications are used to provide cardiovascular support to improve the blood pressure and to treat shock. However, there is incomplete literature on the examination of hemodynamic effects of these medications in asphyxiated neonates, especially in the realm of clinical studies (mostly in late preterm or term populations). Although the extrapolation of findings from animal studies and other clinical populations such as children and adults require caution, it seems appropriate that findings from carefully conducted pre-clinical studies are important in answering some of the fundamental knowledge gaps. Based on a literature search, this review discusses the current available information, from both clinical studies and animal models of neonatal asphyxia, on common medications used to provide hemodynamic support including dopamine, dobutamine, epinephrine, milrinone, norepinephrine, vasopressin, levosimendan, and hydrocortisone.

Controversies in the identification and management of acute pulmonary hypertension in preterm neonates

It is increasingly recognized that the abnormal physiologic consequences of pulmonary hypertension (PH) may contribute to poor cardiopulmonary health in premature babies. Conflicting literature has led to clinical uncertainty, pathological misinterpretation, and variability in treatment approaches among practitioners. There are several disorders with overlapping and interrelated presentations, and other disorders with a similar clinical phenotype but diverse pathophysiological contributors. In this review, we provide a diagnostic approach for acute hypoxemic respiratory failure in the preterm neonate, outline the pathophysiological conditions that may present as acute PH, and discuss the implications of high pulmonary vascular resistance (PVR) on the cardiovascular system. Although PVR and respiratory management are highly interrelated, there may be a population of preterm neonates in whom inhaled nitric oxide may improve illness severity and may relate to outcomes. A management approach based on physiology that considers common clinical conundrums is provided. A more comprehensive understanding of the physiology may help in informed decision-making in clinical situations where conclusive scientific evidence is lacking. Regardless, high-quality research is required, and appropriate definition of the target population is paramount. A thoughtful approach to cardiovascular therapy may also provide an avenue to improve neurodevelopmental outcomes while awaiting more clear answers.

Use of Vasopressin in Neonatal Intensive Care Unit Patients With Hypotension

OBJECTIVE

To evaluate the safety and efficacy of vasopressin for the treatment of hypotension in patients admitted to neonatal intensive care units (NICUs).

METHODS

Vasopressin use in 69 infants admitted to our NICU between 2011 and 2014 was examined. Data evaluated included demographics; serum creatinine, sodium, and lactate concentrations; urine output; and systolic, diastolic, and mean blood pressures (BPs). Parameters prior to vasopressin use were compared to those at maximum dose.

RESULTS

Vasopressin use was associated with increased urine output (p < 0.05), and increased systolic (p < 0.0005), diastolic (p < 0.01), and mean (p < 0.001) BP. There were no differences in sodium or lactate concentrations before vs during infusion; vasopressin use was not associated with hyponatremia (sodium < 130 mEq/L) at the maximum dose.

CONCLUSIONS

Vasopressin for the treatment of neonatal hypotension appears safe and was efficacious in raising BP. These data suggest that vasopressin could be considered a viable option in the treatment regimen in hypotensive infants in the NICU.

Management of Neonatal Hypotension

Hypotension is a common problem in neonates with complex underlying pathophysiology. Although treatment of low blood pressure is common, clinicians must use all available information to target neonates with compromised perfusion. Pharmacotherapy should be tailored to the specific physiologic perturbations of the individual neonate. Dopamine is the most commonly utilized agent and may be the most appropriate agent for septic shock with low diastolic blood pressure. However, alternative therapies should be considered for other etiologies of hypotension, including milrinone and vasopressin for persistent pulmonary hypertension of the newborn and dobutamine for patent ductus arteriosus. Additional studies are required to refine the approach to neonatal hypotension and document the long-term outcomes of treated neonates.

Hemodynamic instability in the critically ill neonate: An approach to cardiovascular support based on disease pathophysiology

Hemodynamic disturbance in the sick neonate is common, highly diverse in underlying pathophysiology and dynamic. Dysregulated systemic and cerebral blood flow is hypothesized to have a negative impact on neurodevelopmental outcome and survival. An understanding of the physiology of the normal neonate, disease pathophysiology, and the properties of vasoactive medications may improve the quality of care and lead to an improvement in survival free from disability. In this review we present a modern approach to cardiovascular therapy in the sick neonate based on a more thoughtful approach to clinical assessment and actual pathophysiology. Targeted neonatal echocardiography offers a more detailed insight into disease processes and offers longitudinal assessment, particularly response to therapeutic intervention. The pathophysiology of common neonatal conditions and the properties of cardiovascular agents are described. In addition, we outline separate treatment algorithms for various hemodynamic disturbances that are tailored to clinical features, disease characteristics and echocardiographic findings.

Persistent pulmonary hypertension of the newborn: Advances in diagnosis and treatment

Persistent pulmonary hypertension of the newborn (PPHN) is a frequent cause for admission to the neonatal intensive care unit and is associated with mortality and variable morbidities. It is primarily a state of oxygenation failure representing a failure of the normal postnatal decline in pulmonary vascular resistance that may be associated with right ventricular dysfunction. Enhanced knowledge of the pathophysiologic contributors to this syndrome helps clinicians understand its phenotypic expression and facilitates more focused intensive care decision-making. The approach to treatment should be based on alleviation of the elevation in pulmonary vascular resistance and should include optimization of lung recruitment and judicious use of pulmonary vasodilators. When response to inhaled nitric oxide is suboptimal, the physiologic contributors to impaired oxygenation need further investigation. Targeted neonatal echocardiography provides novel physiologic insights; in particular, it may help assess the adequacy of right ventricular performance, the relative contribution of the fetal shunts and the magnitude of the overall impairment to cardiac output. This information may facilitate therapeutic next steps and whether adjunctive vasodilators or drugs to augment ventricular function are preferable. This article provides a comprehensive overview of the pathological contributors to PPHN, the physiologic constituents of its phenotypic expression, standard approach to therapeutic intervention, and the role of bedside echocardiography in enhancing the decision-making process.

Vasopressin versus dopamine for treatment of hypotension in extremely low birth weight infants: a randomized, blinded pilot study

OBJECTIVE

To evaluate vasopressin vs dopamine as initial therapy in extremely low birth weight (ELBW) infants with hypotension during the first 24 hours of life.

STUDY DESIGN

ELBW infants with hypertension ≤ 30 weeks' gestation and ≤ 24 hours old randomly received treatment with vasopressin or dopamine in a blinded fashion. Normotensive infants not receiving vasopressor support served as a comparison group.

RESULTS

Twenty ELBW infants with hypertension received vasopressin (n = 10) or dopamine (n = 10), and 50 were enrolled for comparison. Mean gestational age was 25.6 ± 1.4 weeks and birth weight 705 ± 154 g. Response to vasopressin paralleled that of dopamine in time to adequate mean blood pressure (Kaplan-Meier curve, P = .986); 90% of infants in each treatment group responded with adequate blood pressure. The vasopressin group received fewer doses of surfactant (P < .05), had lower PaCO2 values (P < .05), and were not tachycardic (P < .001) during vasopressin administration, compared with the dopamine group.

CONCLUSIONS

Vasopressin in ELBW infants as the initial agent for early hypotension appeared safe. This pilot study supports a larger randomized controlled trial of vasopressin vs dopamine therapy in ELBW infants with hypotension.

Vasopressin as a rescue therapy for refractory pulmonary hypertension in neonates: case series

OBJECTIVES

To determine the effect of vasopressin therapy on the efficacy of oxygenation and arterial pressure in infants with severe persistent pulmonary hypertension of the newborn.

DESIGN

Retrospective case study.

SETTING

Neonatal ICU, Hospital for Sick Children, Toronto, Canada.

SUBJECTS

Neonates with severe persistent pulmonary hypertension.

INTERVENTION

Intravenous infusion of vasopressin.

MEASUREMENTS AND MAIN RESULTS

Ten infants satisfied the inclusion criteria. Inhaled nitric oxide was used for median (interquartile range) duration of 15 hours (11-28 hr) prior to vasopressin commencement. Vasopressin was initiated at a mean dose of 0.0002 ± 0.0002 U/kg/min for a median (interquartile range) duration of 49 hours (13-95 hr). Administration of vasopressin was associated with an improvement in oxygenation index, peak effect 6 hours after drug initiation (p = 0.01), and a reduction in inhaled nitric oxide dose (p < 0.05). There was a concomitant improvement in blood pressure (p < 0.05) and urine output (p < 0.05), without drop in the serum sodium level or worsening in serum lactate level.

CONCLUSIONS

Although there is limited experience of vasopressin use in persistent pulmonary hypertension of the newborn infants, our case series suggests it to be a potential adjunctive therapy for improving the efficacy of oxygenation and systemic hypotension. A prospective randomized trial is needed to confirm its efficacy and safety in the management of severe persistent pulmonary hypertension of the newborn.

Vasopressin and its analogues for the treatment of refractory hypotension in neonates

BACKGROUND

Neonatal hypotension that is refractory to volume expansion, catecholamines, or corticosteroids has a mortality of about 50%. Optimization of blood pressure and tissue perfusion in refractory hypotension may be crucial to improve clinical outcomes. Vasopressin, a neuropeptide hormone, or its analogue terlipressin has been used to treat refractory hypotension in neonates and may be effective.

OBJECTIVES

Our primary objective was to evaluate the efficacy and safety of vasopressin and its synthetic analogues (e.g. terlipressin) in decreasing mortality and adverse neurodevelopmental outcomes, and improving survival in neonates with refractory hypotension. Our secondary objectives were to determine the effects of vasopressin and its analogues (terlipressin) on improvement in blood pressure, increase in urine output, decrease in inotrope score, necrotizing enterocolitis (NEC), periventricular leukomalacia, intraventricular hemorrhage, chronic lung disease, and retinopathy of prematurity (ROP) in neonates with refractory hypotension.

SEARCH METHODS

We searched the literature in January 2012, using the search strategy recommended by the Cochrane Neonatal Group. We searched electronic databases (CENTRAL (The Cochrane Library), MEDLINE, CINAHL, EMBASE), abstracts of the Pediatric Academic Societies, web sites for registered trials at www.clinicaltrials.gov and www.controlled-trials.com and in the reference list of identified articles.

SELECTION CRITERIA

Randomized or quasi-randomized trials evaluating vasopressin or its analogues, at any dosage or duration used as an adjunct to standard therapy (any combination of volume expansion, inotropic agents and corticosteroids) to treat refractory hypotension in neonates.

DATA COLLECTION AND ANALYSIS

We followed the standard methods of The Cochrane Collaboration for conducting a systematic review. Two review authors (BS and MP) independently assessed the titles and abstracts of studies identified by the search strategy for eligibility for inclusion. We obtained the full text version if eligibility could not be done reliably by title and abstract. We resolved any differences by mutual discussion. We designed electronic forms for trial inclusion/exclusion, data extraction, and for requesting additional published information from authors of the original reports.

MAIN RESULTS

Our search did not identify any completed or ongoing trials that met our inclusion criteria. Three studies that did not include neonates and one study where the objective was not to treat neonates with refractory hypotension were excluded.

AUTHORS' CONCLUSIONS

There is insufficient evidence to recommend or refute the use of vasopressin or its analogues in the treatment of refractory hypotension in neonates. Well-designed, adequately powered, randomized controlled studies are necessary to address efficacy, optimal dosing, safety and long-term neurodevelopmental and pulmonary outcomes. 

Vasopressin for the treatment of neonatal hypotension

Vasopressin (pitressin), also known as arginine vasopressin (AVP), is an antidiuretic hormone formed in the hypothalamus and secreted from the posterior pituitary gland. Various forms of exogenous vasopressin exist and have been used in neonates to treat conditions such as diabetes insipidus. Vasopressin has also been studied on a limited basis for use in the treatment of catecholamine-resistant hypotension in vasodilatory shock. Hypotension is a significant problem resulting in increased morbidity in preterm, septic, and postsurgical neonates. This article will discuss the role of vasopressin and its use as a therapeutic agent in the treatment of hypotension in the neonate.

Therapeutic applications of vasopressin in pediatric patients

CONTEXT

Reports of successful use of vasopressin in various shock states and cardiac arrest has lead to the emergence of vasopressin therapy as a potentially major advancement in the management of critically ill children.

OBJECTIVE

To provide an overview of physiology of vasopressin, rationale of its use and dose schedule in different disease states with special focus on recent advances in the therapeutic applications of vasopressin.

DATA SOURCE

MEDLINE search (1966-September 2011) using terms vasopressin, terlipressin, arginine-vasopressin, shock, septic shock, vasodilatory shock, cardiac arrest, and resuscitation for reports on vasopressin/terlipressin use in children and manual review of article bibliographies. Search was restricted to human studies. Randomized controlled trials, cohort studies, evaluation studies, case series, and case reports on vasopressin/terlipressin use in children (preterm neonates to 21 years of age) were included. Outcome measures were analysed using following clinical questions: indication, dose and duration of vasopressin/terlipressin use, main effects especially on systemic blood pressure, catecholamine requirement, urine output, serum lactate, adverse effects, and mortality.

RESULTS

51 reports on vasopressin (30 reports) and terlipressin (21 reports) use in pediatric population were identified. A total of 602 patients received vasopressin/terlipressin as vasopressors in various catecholamine-resistant states (septic - 176, post-cardiotomy - 136, other vasodilatory/mixed shock - 199, and cardiac arrest - 101). Commonly reported responses include rapid improvement in systemic blood pressure, decline in concurrent catecholamine requirement, and increase in urine output; despite these effects, the mortality rates remained high.

CONCLUSION

In view of the limited clinical experience, and paucity of randomized controlled trials evaluating these drugs in pediatric population, currently no definitive recommendations on vasopressin/terlipressin use can be laid down. Nevertheless, available clinical data supports the use of vasopressin in critically ill children as a rescue therapy in refractory shock and cardiac arrest.