Vasopressin improves systemic hemodynamics without compromising mesenteric perfusion in the resuscitation of asphyxiated newborn piglets: a dose-response study

Vasopressin versus epinephrine during cardiopulmonary resuscitation of asphyxiated newborns: A study protocol for a prospective, cluster, open label, single-center, randomized controlled phase 2 trial - The VERSE-Trial

Introduction

Current neonatal resuscitation guidelines recommend the use of epinephrine during neonatal cardiopulmonary resuscitation (CPR). However, newborns receiving epinephrine continue to have high rates of mortality and neurodevelopmental disability. The infrequent need for neonatal CPR, coupled with an inability to consistently anticipate which newborn infants are at risk of requiring CPR, explains the lack of high-quality evidence (i.e., large randomized clinical trials) to better guide healthcare providers in their resuscitative effort. Therefore, we need neonatal data to determine the optimal vasopressor therapy during neonatal CPR. The current pilot trial will examine the efficacy of vasopressin versus epinephrine during CPR of asphyxiated newborn infants.

Methods and analysis

The trial will be a prospective, cluster, open label, single-center, randomized controlled trial on two alternative cardiovascular supportive medications. This study will assess the primary outcome of time to return of spontaneous circulation (ROSC) in newborns requiring CPR in the delivery room who were treated with either vasopressin (intervention) or epinephrine (control). Secondary outcomes such as infant mortality and other clinical outcome measures will also be collected. An estimated 20 newborns will be recruited, and comparisons will be made between asphyxiated infants treated with either drugs.

Ethics and dissemination

This study has been approved by the Research Ethics Board at the University of Alberta (June 16, 2023). Study findings will be published in peer-reviewed journals, presented at conferences, and communicated to relevant participants and stakeholders.Trial registration: ClinicalTrial.gov Identifier: NCT05738148. Registered February 21, 2023.

Vasopressin versus epinephrine during neonatal cardiopulmonary resuscitation of asphyxiated post-transitional piglets

Background

Epinephrine is currently the only recommended cardio-resuscitative medication for use in neonatal cardiopulmonary resuscitation (CPR), as per the consensus of science and treatment recommendations. An alternative medication, vasopressin, might be beneficial in neonatal CPR due to its combined pulmonary vasodilation and systemic vasoconstriction properties.

Aim

We aimed to compare the time to return of spontaneous circulation (ROSC) with administration of vasopressin or epinephrine during CPR of asphyxiated post-transitional piglets.

Methods

Newborn piglets (n = 8/group) were anesthetized, tracheotomized and intubated, instrumented, and exposed to 50 min normocapnic hypoxia followed by asphyxia and cardiac arrest. Piglets were randomly allocated to receive vasopressin (Vaso, 0.4 U/kg) or epinephrine (Epi, 0.02 mg/kg) during CPR. Piglets were resuscitated with chest compressions superimposed with sustained inflations, and were administered either Vaso or Epi intravenously every 3 min until ROSC (max. 3 doses). Hemodynamic and cardiac function parameters were collected.

Main Results

The median (IQR) time to ROSC was 106 (93-140) s with Vaso and 128 (100-198) s with Epi (p = 0.28). The number of piglets that achieved ROSC was 8 (100%) with Vaso and 7 (88%) with Epi (p = 1.00). Vaso-treated piglets had a significantly longer post-resuscitation survival time (240 (240-240) min) than Epi-treated piglets (65 (30-240) min, p = 0.02). Vaso-treated piglets had significantly improved carotid blood flow immediately after ROSC (p < 0.05), had longer duration of post-resuscitation hypertension (p = 0.05), and had significantly improved heart rate, arterial pressure, and cerebral blood oxygen saturation 4 h after ROSC (p < 0.05).

Conclusions

Vasopressin improved post-resuscitation survival and hemodynamics, and might be an alternative cardio-resuscitative medication during neonatal CPR, but further studies are warranted.

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.

Hemodynamic optimization for neonates with neonatal encephalopathy caused by a hypoxic ischemic event: Physiological and therapeutic considerations

Neonatal encephalopathy due to a hypoxic-ischemic event is commonly associated with cardiac dysfunction and acute pulmonary hypertension; both therapeutic hypothermia and rewarming modify loading conditions and blood flow. The pathophysiological contributors to disease are complex with a high degree of clinical overlap and traditional bedside measures used to assess circulatory adequacy have multiple confounders. Comprehensive, quantitative echocardiography may be used to delineate the relative contribution of lung parenchymal, pulmonary vascular, and cardiac disease to hypotension and/or hypoxemic respiratory failure. In this review, we provide a detailed overview of the contributors to hemodynamic instability following perinatal hypoxic-ischemic injury. Our proposed approach to therapy focuses on physiopathological considerations with interventions individualized to this potentially complex condition and considers the pharmacological idiosyncrasies, which may occur among neonates with NE presenting with multiorgan dysfunction while undergoing therapeutic hypothermia.

Pediatrics: An Evolving Concept for the 21st Century

Pediatrics is rapidly evolving, and the diagnostic tools are expanding the spectrum of diagnoses that can be identified at the bedside [...].

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.

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.

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.

Controversies in neonatal resuscitation

Despite recent advances in perinatal medicine and in the art of neonatal resuscitation, resuscitation strategy and treatment methods in the delivery room should be individualized depending on the unique characteristics of the neonate. The constantly increasing evidence has resulted in significant treatment controversies, which need to be resolved with further clinical and experimental research.

Adrenaline, terlipressin, and corticoids versus adrenaline in the treatment of experimental pediatric asphyxial cardiac arrest

OBJECTIVE

To analyze if treatment with adrenaline (epinephrine) plus terlipressin plus corticoids achieves higher return of spontaneous circulation than adrenaline in an experimental infant animal model of asphyxial cardiac arrest.

DESIGN

Prospective randomized animal study.

SETTING

Experimental department in a University Hospital.

SUBJECTS

Forty-nine piglets were studied.

INTERVENTIONS

Cardiac arrest was induced by at least 10 minutes of removal of mechanical ventilation and was followed by manual external chest compressions and mechanical ventilation. After 3 minutes of resuscitation, piglets that did not achieve return of spontaneous circulation were randomized to two groups: adrenaline 0.02 mg kg every 3 minutes (20 animals) and adrenaline 0.02 mg kg every 3 minutes plus terlipressin 20 μg kg every 6 minutes plus hydrocortisone 30 mg kg one dose (22 animals). Resuscitation was discontinued when return of spontaneous circulation was achieved or after 24 minutes.

MEASUREMENT AND MAIN RESULTS

Return of spontaneous circulation was achieved in 14 piglets (28.5%), 14.2% with only cardiac massage and ventilation. Return of spontaneous circulation was achieved in 25% of piglets treated with adrenaline and in 9.1% of those treated with adrenaline plus terlipressin plus hydrocortisone (p = 0.167). Return of spontaneous circulation was achieved in 45.4% of animals with pulseless electric activity, 20% with asystole, and 0% with ventricular fibrillation (p = 0.037). Shorter duration of cardiac arrest, higher mean blood pressure and EtCO2 and lower PaCO2 before resuscitation, and higher mean blood pressure during resuscitation were associated with higher return of spontaneous circulation.

CONCLUSIONS

Treatment with adrenaline plus terlipressin plus corticoids does not achieve higher return of spontaneous circulation than that with adrenaline in an infant animal model of asphyxial cardiac arrest.

Reduced cardiac output and its correlation with coronary blood flow and troponin in asphyxiated infants treated with therapeutic hypothermia

Perinatal asphyxia can lead to multi-organ insult which includes cardiovascular dysfunction. The objective was to study the relationship between cardiac function, perfusion and troponin. Unit database was accessed to identify infants with perinatal asphyxia over the last 2 years. Information from medical records and archived echocardiographic images was retrieved. Comparisons for echocardiographic information were made with healthy term infants. Seventeen infants with perinatal asphyxia were identified, of which three were excluded (one-33 weeks gestation, two-coagulopathy and pulmonary hypertension); 14 infants received therapeutic hypothermia. Median (range) gestation and birthweight were 39 (37-42) weeks and 3,550 (2,380-3,992) g respectively. Mean (S.D.) rectal temperature and time of echocardiogram were 33.5 ± 0.5 °C and median (range) 7.7 h [3-10] respectively. Majority of infants had low biventricular outputs. Median (range) SVC flow was 29.8 ml/kg/min (13-96.2). Median (range) troponin was 0.77 μg/L (0.17-2.6); normal ≤ 0.08 μg/L. Markedly low coronary flows (diastolic VTI median (range) 2.1 (1.3-2.9) cm were noted compared to controls. Coronary flow had a significantly positive correlation with left ventricular output. Higher troponin levels were associated with lower aortic stroke velocity. A close association between cardiac output, perfusion and troponin was noted. A dichotomy between blood pressure and flow parameters was noted, indicating the wide variation in vascular resistance in these infants. Biventricular output, coronary and SVC flows were significantly higher in the control population. In conclusion, inter-variable relationship between cardiac output, coronary flow and troponin is an important addition to the understanding of cardiovascular impact of perinatal asphyxia.