Effect of a Larger Flush Volume on Bioavailability and Efficacy of Umbilical Venous Epinephrine during Neonatal Resuscitation in Ovine Asphyxial Arrest

Direct Umbilical Vein Injection of Epinephrine with Cut-Cord Milking in an Ovine Model of Neonatal Resuscitation

BACKGROUND

An umbilical venous catheter (UVC) is the preferred route of epinephrine administration during neonatal resuscitation but requires specialized equipment, expertise, and time.

HYPOTHESIS

Direct injection of epinephrine into the umbilical vein (UV) followed by milking a ~20 cm segment of cut umbilical cord to flush the epinephrine (DUV + UCM) will lead to a quicker administration and earlier return of spontaneous circulation (ROSC) compared with epinephrine given through a UVC.

DESIGN

Eighteen near-term asphyxiated lambs were randomized to receive a low-UVC or DUV + UCM of epinephrine at 0.02 or 0.03 mg/kg doses.

OUTCOME MEASURES

A total of 16/18 lambs achieved ROSC with a similar mean (±SEM) time to ROSC [DUV + UCM vs. low-UVC (4.67 ± 0.67 vs. 3.99 ± 0.58 min); p = 0.46]. Two out of ten lambs in the DUV + UCM group required UVC placement for additional epinephrine. The administration of the first dose of epinephrine was similar (DUV + UCM-2.97 ± 0.48 vs. UVC-4.23 ± 0.58 min; p = 0.12). Both methods yielded similar epinephrine concentrations (peak concentrations of 253 ± 63 and 328 ± 80 ng/mL for DUV + UCM and UVC EPI, respectively).

CONCLUSIONS

DUV + UCM resulted in a ROSC success of 78% following the first epinephrine dose and showed similar epinephrine concentrations to UVC. Clinical studies evaluating DUV + UCM as an alternate route for epinephrine while intravenous access is being established are warranted.

Chest compression rates of 60/min versus 90/min during neonatal cardiopulmonary resuscitation: a randomized controlled animal trial

Background

To compare chest compression (CC) rates of 60/min with 90/min and their effect on the time to return of spontaneous circulation (ROSC), survival, hemodynamic, and respiratory parameters. We hypothesized that asphyxiated newborn piglets that received CC at 60/min vs. 90/min during cardiopulmonary resuscitation would have a shorter time to ROSC.

Methods

Newborn piglets (n = 7/group) were anesthetized, tracheotomized and intubated, instrumented and exposed to 45 min normocapnic hypoxia followed by asphyxia and cardiac arrest. Piglets were randomly allocated to a CC rate of 60/min or 90/min. CC was performed using an automated CC machine using CC superimposed with sustained inflation. Hemodynamic parameters, respiratory parameters, and applied compression force were continuously measured.

Results

The mean (IQR) time to ROSC was 97 (65-149) s and 136 (88-395) s for CC rates of 60/min and 90/min, respectively (p = 0.31). The number of piglets that achieved ROSC was 5 (71%) and 5 (71%) with 60/min and 90/min CC rates, respectively (p = 1.00). Hemodynamic parameters (i.e., diastolic and mean blood pressure, carotid blood flow, stroke volume, end-diastolic volume, left ventricular contractile function) and respiratory parameters (i.e., minute ventilation, peak inflation and peak expiration flow) were all similar with a CC rate of 60/min compared to 90/min.

Conclusion

Time to ROSC, hemodynamic, and respiratory parameters were not significantly different between CC rates of 60/min vs. 90/min. Different CC rates during neonatal resuscitation warrant further investigation.

Epinephrine vs placebo in neonatal resuscitation: ROSC and brain MRS/MRI in term piglets

BACKGROUND

We aimed to investigate the effect of epinephrine vs placebo on return of spontaneous circulation (ROSC) and brain magnetic resonance spectroscopy and imaging (MRS/MRI) in newborn piglets with hypoxic cardiac arrest (CA).

METHODS

Twenty-five piglets underwent hypoxia induced by endotracheal tube clamping until CA. The animals were randomized to CPR + intravenous epinephrine or CPR + placebo (normal saline). The primary outcome was ROSC, and secondary outcomes included time-to-ROSC, brain MRS/MRI, and composite endpoint of death or severe brain MRS/MRI abnormality.

RESULTS

ROSC was more frequent in animals treated with epinephrine than placebo; 10/13 vs 4/12, RR = 2.31 (95% CI: 1.09-5.77). We found no difference in time-to-ROSC (120 (113-211) vs 153 (116-503) seconds, p = 0.7) or 6-h survival (7/13 vs 3/12, p = 0.2). Among survivors, there was no difference between groups in brain MRS/MRI. We found no difference in the composite endpoint of death or severe brain MRS/MRI abnormality; RR = 0.7 (95% CI: 0.37-1.19).

CONCLUSIONS

Resuscitation with epinephrine compared to placebo improved ROSC frequency after hypoxic CA in newborn piglets. We found no difference in time-to-ROSC or the composite endpoint of death or severe brain MRS/MRI abnormality.

IMPACT

In a newborn piglet model of hypoxic cardiac arrest, resuscitation with epinephrine compared to placebo improved the rate of return of spontaneous circulation and more than doubled the 6-h survival. Brain MRS/MRI biomarkers were used to evaluate the effect of epinephrine vs placebo. We found no difference between groups in the composite endpoint of death or severe brain MRS/MRI abnormality. This study adds to the limited evidence regarding the effect and safety of epinephrine; the lack of high-quality evidence from randomized clinical trials was highlighted in the latest ILCOR 2020 guidelines, and newborn animal studies were specifically requested.

Is epinephrine effective during neonatal resuscitation?

In the original research article published in Pediatric Research, Anderson et al provide valuable data from a placebo-controlled randomized trial on epinephrine in 12-hour-old piglets in cardiac arrest. In this commentary, we discuss briefly the existing evidence supporting use of epinephrine during neonatal resuscitation.

Chest Compression Rates of 90/min versus 180/min during Neonatal Cardiopulmonary Resuscitation: A Randomized Controlled Animal Trial

BACKGROUND

To compare chest compression (CC) rates of 90/min with 180/min and their effect on the time to return of spontaneous circulation (ROSC), survival, hemodynamic, and respiratory parameters. We hypothesized that asphyxiated newborn piglets that received CC at 180/min vs. 90/min during cardiopulmonary resuscitation would have a shorter time to ROSC.

METHODS

Newborn piglets (n = 7/group) were anesthetized, intubated, instrumented and exposed to 45 min normocapnic hypoxia followed by asphyxia and cardiac arrest. Piglets were randomly allocated to a CC rate of 180/min or 90/min. CC was performed using an automated chest compression machine using CC superimposed with sustained inflation. Hemodynamic and respiratory parameters and applied compression force were continuously measured.

RESULTS

The mean (SD) time to ROSC was 91 (34) and 256 (97) s for CC rates of 180/min and 90/min, respectively (p = 0.08). The number of piglets that achieved ROSC was 7 (100%) and 5 (71%) with 180/min and 90/min CC rates, respectively (p = 0.46). Hemodynamic parameters (i.e., diastolic and mean blood pressure, carotid blood flow, stroke volume, end-diastolic volume, left ventricular contractile function) and respiratory parameters (i.e., minute ventilation, peak inflation and peak expiration flow) were all improved with a CC rate of 180/min.

CONCLUSION

Time to ROSC and hemodynamic and respiratory parameters were not statistical significant different between CC rates of 90/min and 180/min. Higher CC rates during neonatal resuscitation warrant further investigation.

Physiology of neonatal resuscitation: Giant strides with small breaths

The transition of a fetus to a newborn involves a sequence of well-orchestrated physiological events. Most neonates go through this transition without assistance but 5-10% may require varying degrees of resuscitative interventions at birth. The most crucial event during this transition is lung inflation with optimal concentrations of oxygen. Rarely, extensive resuscitation including chest compressions and medication may be required. In the past few decades, significant strides have been made in our understanding of the cardiorespiratory transition at birth from a fetus to a newborn and the subsequent resuscitation. This article reviews the physiology behind neonatal transition at birth and various interventions during neonatal resuscitation.

Stabilization and Resuscitation of Newborns

The majority of newborns do not need medical interventions to manage the neonatal transition after birth [...].

Role of Volume Replacement during Neonatal Resuscitation in the Delivery Room

Volume expanders are indicated in the delivery room when an asphyxiated neonate is not responding to the steps of neonatal resuscitation and has signs of shock or a history of acute blood loss. Fetal blood loss (e.g., feto-maternal hemorrhage) may contribute to perinatal asphyxia. Cord compression or a tight nuchal cord can selectively occlude a thin-walled umbilical vein, resulting in feto-placental transfusion and neonatal hypovolemia. For severe bradycardia or cardiac arrest secondary to fetal blood loss, Neonatal Resuscitation Program (NRP) recommends intravenous volume expanders (crystalloids such as normal saline or packed red blood cells) infused over 5 to 10 min. Failure to recognize hypovolemia and subsequent delay in volume replacement may result in unsuccessful resuscitation due to lack of adequate cardiac preload. However, excess volume load in the presence of myocardial dysfunction from hypoxic–ischemic injury may precipitate pulmonary edema and intraventricular hemorrhage (especially in preterm infants). Emergent circumstances and ethical concerns preclude the performance of prospective clinical studies evaluating volume replacement during neonatal resuscitation. Translational studies, observational data from registries and clinical trials are needed to investigate and understand the role of volume replacement in the delivery room in term and preterm neonates. This article is a narrative review of the causes and consequences of acute fetal blood loss and available evidence on volume replacement during neonatal resuscitation of asphyxiated neonates.

The Use of a Disposable Umbilical Clamp to Secure an Umbilical Venous Catheter in Neonatal Emergencies—An Experimental Feasibility Study

Recent guidelines recommend the umbilical venous catheter (UVC) as the optimal vascular access method during neonatal resuscitation. In emergencies the UVC securement may be challenging and time-consuming. This experimental study was designed to test the feasibility of new concepts for the UVC securement. Umbilical cord remnants were catheterized with peripheral catheters and secured with disposable umbilical clamps. Three different securement techniques were investigated. Secure 1: the disposable umbilical clamp was closed at the level of the inserted catheter. Secure 2: the clamp was closed at the junction of the catheter and plastic wings. Secure 3: the setting of Secure 2 was combined with an umbilical tape. The main outcomes were the feasibility of fluid administration and the maximum force to release the securement. This study shows that inserting peripheral catheters into the umbilical vein and securing them with disposable umbilical clamps is feasible. Rates of lumen obstruction and the effectiveness of the securement were superior with Secure 2 and 3 compared to Secure 1. This new approach may be a rewarding option for umbilical venous catheterization and securement particularly in low-resource settings and for staff with limited experience in neonatal emergencies. However, although promising, these results need to be confirmed in clinical trials before being introduced into clinical practice.