Electrocardiography vs. Auscultation to Assess Heart Rate During Cardiac Arrest With Pulseless Electrical Activity in Newborn Infants

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.

Non-invasive measurements of respiration and heart rate across wildlife species using Eulerian Video Magnification of infrared thermal imagery

BACKGROUND

An animal's metabolic rate, or energetic expenditure, both impacts and is impacted by interactions with its environment. However, techniques for obtaining measurements of metabolic rate are invasive, logistically difficult, and costly. Red-green-blue (RGB) imaging tools have been used in humans and select domestic mammals to accurately measure heart and respiration rate, as proxies of metabolic rate. The purpose of this study was to investigate if infrared thermography (IRT) coupled with Eulerian video magnification (EVM) would extend the applicability of imaging tools towards measuring vital rates in exotic wildlife species with different physical attributes.

RESULTS

We collected IRT and RGB video of 52 total species (39 mammalian, 7 avian, 6 reptilian) from 36 taxonomic families at zoological institutions and used EVM to amplify subtle changes in temperature associated with blood flow for respiration and heart rate measurements. IRT-derived respiration and heart rates were compared to 'true' measurements determined simultaneously by expansion of the ribcage/nostrils and stethoscope readings, respectively. Sufficient temporal signals were extracted for measures of respiration rate in 36 species (85% success in mammals; 50% success in birds; 100% success in reptiles) and heart rate in 24 species (67% success in mammals; 33% success in birds; 0% success in reptiles) using IRT-EVM. Infrared-derived measurements were obtained with high accuracy (respiration rate, mean absolute error: 1.9 breaths per minute, average percent error: 4.4%; heart rate, mean absolute error: 2.6 beats per minute, average percent error: 1.3%). Thick integument and animal movement most significantly hindered successful validation.

CONCLUSION

The combination of IRT with EVM analysis provides a non-invasive method to assess individual animal health in zoos, with great potential to monitor wildlife metabolic indices in situ.

Feasibility of handheld ultrasound to assess heart rate in newborn nursery

BACKGROUND AND OBJECTIVES

Heart rate (HR) assessment is important during neonatal resuscitation. The most reliable ways of assessing HR at birth are pulse oximetry (PO) and/or electrocardiograph (ECG). However, delayed recording time due to poor perfusion or probe and electrode placement has been a concern. Point-of-care ultrasound (POCUS) provides a real-time instant view of the heart. The aim of this study was to look at the feasibility of POCUS in assessing the heart rate of stable, healthy, term neonates.

METHODS

The study was approved by the institutional review board, and informed consent was obtained from the subject's mother. A real-time video image was obtained from the POCUS probe using the app on the smartphone. The principal investigator (PI) counted the heart beats for six seconds using a stopwatch, which was then multiplied by 10 to give the HR per minute. The assistant recorded the simultaneous HR using the PO. The HRs obtained from both methods were recorded and then compared using the Pearson correlation and Bland-Altman plot.

RESULTS

A total of 30 HR observations were made using the POCUS and PO simultaneously. The correlation coefficient (r) was noted to be 0.75 with a p-value of <0.0001 for pairwise correlation. A strong agreement was noted between the two methods using Bland-Altman Plot.

CONCLUSION

We were able to demonstrate the feasibility of using handheld POCUS in assessing the HR of stable NB infants in the newborn nursery. A follow-up study is planned to evaluate its feasibility in the delivery room.

Recent Update on Neonatal Resuscitation

Every 5 y, the International Liaison Committee on Resuscitation publishes consensus on cardiopulmonary resuscitation, and emergency cardiovascular science and treatment recommendations. The latest update on neonatal resuscitation guidelines was published in 2020. Here, the authors review the important changes in the recent recommendations, including initial steps of resuscitation, umbilical cord management, management of nonvigorous infants born through meconium-stained amniotic fluid, sustained inflation in preterm infants, epinephrine, vascular access, timing of discontinuation of resuscitative effort, and team briefing and debriefing.

Is Chest Compression Superimposed with Sustained Inflation during Cardiopulmonary Resuscitation an Alternative to 3:1 Compression to Ventilation Ratio in Newborn Infants?

Approximately 0.1% for term and 10-15% of preterm infants receive chest compression (CC) in the delivery room, with high incidence of mortality and neurologic impairment. The poor prognosis associated with receiving CC in the delivery room has raised concerns as to whether specifically-tailored cardiopulmonary resuscitation methods are needed. The current neonatal resuscitation guidelines recommend a 3:1 compression:ventilation ratio; however, the most effective approach to deliver chest compression is unknown. We recently demonstrated that providing continuous chest compression superimposed with a high distending pressure or sustained inflation significantly reduced time to return of spontaneous circulation and mortality while improving respiratory and cardiovascular parameters in asphyxiated piglet and newborn infants. This review summarizes the current available evidence of continuous chest compression superimposed with a sustained inflation.

Return of Spontaneous Circulation Depends on Cardiac Rhythm During Neonatal Cardiac Arrest in Asphyxiated Newborn Animals

Objective: Pulseless electrical activity (PEA) occurs in asphyxiated newborn piglets and infants. We aimed to examine whether different cardiac rhythms (asystole, bradycardia, PEA) affects the resuscitation outcomes during continuous chest compressions (CC) during sustained inflations (CC+SI). Design: This study is a secondary analysis of four previous randomized controlled animal trials that compared CC+SI with different CC rate (90 or 120/min), SI duration (20 or 60 s), peak inflation pressure (10, 20, or 30 cmH₂O), and oxygen concentration (18, 21, or 100%). Setting and Subjects: Sixty-six newborn mixed breed piglets (1-3 days of age, weight 1.7-2.4 kg) were obtained on the day of experimentation from the University Swine Research Technology Center. Interventions: In all four studies, piglets were randomized into intervention or sham. Piglets randomized to "intervention" underwent both hypoxia and asphyxia, whereas, piglets randomized to "sham" received the same surgical protocol, stabilization, and equivalent experimental periods without hypoxia and asphyxia. Measurements: To compare differences in asphyxiation time, time to return of spontaneous circulation (ROSC), hemodynamics, and survival rate in newborn piglets with asystole, bradycardia or PEA. Main Results: Piglets with PEA (n = 29) and asystole (n = 13) had a significantly longer asphyxiation time and time to ROSC vs. bradycardia (n = 24). Survival rates were similar between all groups. Compared to their baseline, mean arterial pressure and carotid blood flow were significantly lower 4 h after resuscitation in all groups, while being significantly higher in the bradycardia group. Conclusion: This study indicates that cardiac rhythm before resuscitation influences the time to ROSC and hemodynamic recovery after ROSC.

Delivery Room Management of Asphyxiated Term and Near-Term Infants

Approximately 800,000 newborns die annually due to birth asphyxia. The resuscitation of asphyxiated term newly born infants often occurs unexpected and is challenging for healthcare providers as it demands experience and knowledge in neonatal resuscitation. Current neonatal resuscitation guidelines often focus on resuscitation of extremely and/or very preterm infants; however, the recommendations for asphyxiated term newborn infants differ in some aspects to those for preterm infants (i.e., respiratory support, supplemental oxygen, and temperature management). Since the update of the neonatal resuscitation guidelines in 2015, several studies examining various resuscitation approaches to improve the outcome of asphyxiated infants have been published. In this review, we discuss current recommendations and recent findings and provide an overview of delivery room management of asphyxiated term newborn infants.

Heart Rate Assessment during Neonatal Resuscitation

Approximately 10% of newborn infants require some form of respiratory support to successfully complete the fetal-to-neonatal transition. Heart rate (HR) determination is essential at birth to assess a newborn’s wellbeing. Not only is it the most sensitive indicator to guide interventions during neonatal resuscitation, it is also valuable for assessing the infant’s clinical status. As such, HR assessment is a key step at birth and throughout resuscitation, according to recommendations by the Neonatal Resuscitation Program algorithm. It is essential that HR is accurate, reliable, and fast to ensure interventions are delivered without delay and not prolonged. Ineffective HR assessment significantly increases the risk of hypoxic injury and infant mortality. The aims of this review are to summarize current practice, recommended techniques, novel technologies, and considerations for HR assessment during neonatal resuscitation at birth.

Enhanced monitoring during neonatal resuscitation

Immediately after birth through spontaneous breaths, infants' clear lung liquid replacing it with air, and gradually establishing a functional residual capacity to achieve gas exchange. Most infants start breathing independently after birth and ~3% of infants who require positive pressure ventilation. When newborns fail to start breathing the current neonatal resuscitation guidelines recommend initiatingpositive pressure ventilationusing a face mask and a ventilation device. Adequate ventilation is the cornerstone of successful neonatal resuscitation; therefore, it is mandatory that anybody involved in neonatal resuscitation is trained in mask ventilation techniques. One of the main problems with mask ventilation is that it is very subjective with direct feedback lacking and not uncommonly, the resuscitator does not realise that their technique is unsatisfactory. Many studies have shown that monitoring tidal volume and leak around the mask or endotracheal tube enables the resuscitator to identify the problem and adjust their technique to reduce the leak and deliver and appropriate tidal volume. This chapter discusses the currently available monitoring devices used during stabilization/resuscitation in the delivery room.

Evaluation of a Tap-Based Smartphone App for Heart Rate Assessment During Asphyxia in a Porcine Model of Neonatal Resuscitation

Objectives: Heart rate (HR) is the most significant parameter to assess a newborn's clinical status at birth. Recently, novel technologies including smartphone applications have been suggested for HR assessment during neonatal resuscitation. The aim of this study was to evaluate the accuracy, speed, and precision of the NeoTapLifeSupport (NeoTapLS) smartphone application using a digital stethoscope (DS) for HR assessment during neonatal resuscitation. Design: Newborn piglets (n = 20, 1-3 days, 1.7-2.4 kg) were anesthetized, intubated, mechanically ventilated, and subjected to 30 min of hypoxia, followed by asphyxia. Asphyxia was induced by clamping the endotracheal tube and disconnecting the ventilator, until asystole was confirmed by zero carotid blood flow (CBF). Setting: Experimental setting. Subjects: Asphyxia-induced newborn piglets. Interventions: During asphyxia, HR assessments were performed with a DS using the NeoTapLS smartphone application, and compared to 6-s method (6 s), and 10-s method (10 s). Measurements and Main Results: Accuracy of obtained HRs was compared to CBF and electrocardiogram and assessment time using NeoTapLS, 6 s, and 10 s were also measured. The mean(SD) HR with the NeoTapLS was 68(26), compared to CBF with 68(27) bpm, 6 s with 68(27), and 10 s with 66(26) bpm during asphyxia. Bland-Altman analysis revealed no difference between HR using the NeoTapLS, 6 s, 10 s, compared to CBF HR, with NeoTapLS showing the smallest difference between 95% limits of agreement. The median (IQR) time required to obtain a HR using the NeoTapLS was 3(2-4) s, compared to 6(6-7), and 10(10-11) s for 6 and 10 s, respectively. Conclusions: Our data suggests that the NeoTapLS is accurate, fast, and precise during neonatal asphyxia to assess heart rate.

Cardiac arrest with pulseless electrical activity rhythm in newborn infants: a case series

The 2015 neonatal resuscitation guidelines added ECG to assess an infant's heart rate when determining the need for resuscitation at birth. However, a recent case report raised concerns about this technique in the delivery room. We report four cases of pulseless electrical activity during neonatal cardiopulmonary resuscitation in levels II-III neonatal intensive care units in Canada (Edmonton [n=3] and Winnipeg [n=1]).Healthcare providers should be aware that pulseless electrical activity can occur in newborn infants during cardiopulmonary resuscitation. We propose an adapted neonatal resuscitation algorithm to include pulseless electrical activity. Furthermore, in compromised newborns, heart rate should be assessed using a combination of methods/techniques to ensure accurate heart rate assessment. When ECG displays a heart rate but the infant is unresponsive, pulseless electrical activity should be suspected and chest compression should be started.

Non-perfusing cardiac rhythms in asphyxiated newborn piglets

Aim

We recently demonstrated that asphyxiated piglets commonly had bradycardia displayed on electrocardiography (ECG) while no carotid blood flow (CBF) or audible heart sounds could be detected. Such pulseless electrical activity (PEA) in newborn infants has not previously been thoroughly described. The aim of this study was to further investigate the occurrence of non-perfusing cardiac rhythms in asphyxiated piglets and the potential implications for the success of cardiopulmonary resuscitation (CPR) and short-term survival.

Methods

Neonatal piglets (1–4 days, 1.7–2.4kg) had their right common carotid artery exposed and enclosed with a real-time ultrasonic flow probe. Heart rate (HR) was continuously measured and recorded using ECG. This allowed simultaneous monitoring of HR via ECG and CBF. The piglets were asphyxiated until cardiac arrest, defined as no CBF and no audible beat upon precordial auscultation. CPR was performed until return of spontaneous circulation (ROSC, defined as a HR ≥100 bpm). ECG traces were retrospectively assessed.

Results

Nine out of 21 piglets (43%) had QRS-complexes on their ECG while no CBF and no audible heart sounds could be detected. Five (56%) of the piglets with PEA and 12/12 (100%) piglets with asystole at cardiac arrest obtained ROSC (p = 0.02). Thirty-three per cent of the piglets with PEA versus 58% with asystole survived to 4 hours post-ROSC (p = 0.39).

Conclusion

Cardiac arrest in the presence of a non-perfusing cardiac rhythm on ECG is common in asphyxiated piglets. Clinical arrest in the presence of a non-perfusing cardiac rhythm on ECG may reduce the success of CPR.