303 - Neonatal Resuscitation During Pulseless Electrical Activity Using an Asphyxiated Term Ovine Model

Publication Number: 303.5894

Mausma I. Bawa, University At Buffalo, Buffalo, NY, United States; Sylvia Gugino, SUNY at Buffalo, Buffalo, NY, United States; Justin Helman, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Buffalo, NY, United States; Nicole Bradley, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Buffalo, NY, United States; Mary Divya Kasu, University of Maryland Children's Hospital, Baltimore, MD, United States; Arun Prasath, UT Southwestern Medical Center, Dallas, TX, United States; Clariss Blanco, NYC Health + Hospitals/ Harlem, New York, NY, United States; Munmun Rawat, University at Buffalo, Buffalo, NY, United States; Praveen Chandrasekharan, Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, Buffalo, NY, United States

Background: During asphyxia, various cardiac activities can occur including tachycardia, bradycardia, arrhythmia, pulseless electrical activity (PEA) and complete arrest. Current neonatal resuscitation program (NRP) guidelines recommend using electrocardiography (EKG) to assess heart rate (HR). However, challenges like PEA can complicate resuscitation if not identified clinically or by cardiac ultrasound. There are no studies evaluating NRP algorithm for managing PEA at birth.

Objective: Evaluate the effect of NRP recommended and an alternate approach of resuscitation for PEA in an asphyxiated ovine model on i)incidence ii) time to return of spontaneous circulation (ROSC) iii) gas exchange & hemodynamics.

Design/Methods: 138-140 days gestational age lambs were used after approval by the Institutional Animal Care and Use Committee (IACUC) and instrumented to measure hemodynamics & gas exchange. Asphyxia was induced by umbilical cord occlusion. This secondary analysis examined a previously randomized study comparing two protocols:CONTROL: standard guidelines (30sec positive pressure ventilation (PPV) followed by chest compressions (CC), endotracheal epinephrine (ETTEPI), and intravenous epinephrine (IVEPI); STUDY: continue PPV with ETTEPI and IVEPI, initiating CC only if PEA progressed to full arrest (HR=0). The current study included lambs with PEA, defined as presence of electrical activity with a non-perfusing rhythm and absence of forward flows. We defined ROSC as HR≥100bpm and diastolic blood pressure (DBP) ≥20mmHg. Data on timing/incidence of ROSC, pH, arterial carbon dioxide (PaCO2), arterial oxygen (PaO2) and peak coronary (CoBF), left carotid (CaBF), and left pulmonary (PBF) blood flows over a 30 min post-resuscitation period was recorded. Statistical analyses was conducted using chi-square tests, unpaired t-tests, and ANOVA.

Results: Baseline characteristics of lambs with PEA are shown in Fig1(N=14). 7/8 lambs (88%) in the CONTROL and 5/6 (83%) in the STUDY achieved ROSC. The time required to achieve ROSC was similar in both groups. There was no difference in HR between the groups (Fig2). The pH, PaCO2, and PaO2 were not different (Fig3). The peak CoBF, CaBF, and PBF were not different between the groups (Fig4)

Conclusion(s): Our study suggests that non-perfusing rhythms/PEA occur during asphyxia before complete cardiac arrest. The data suggest no significant difference in outcomes with the two approaches. As recommended by NRP, the focus should remain on ventilation and chest compressions during PEA. Further research is warranted to diagnose & provide guidelines for managing PEA during neonatal resuscitation.

Fig 1 shows the demographics and the baseline characteristics in lambs with PEA. Figure 2a shows the heart rate before, during and post resuscitation. Figure 2b shows the BIOPAC snapshot of the EKG and the coronary, carotid and pulmonary flows during PEA
There was no difference in heart rate between the groups.
The BIOPAC snapshot shows absence of carotid and pulmonary flows despite the presence of electrical activity during asphyxia.

Figure 3 shows the gas exchange between the CONTROL and the STUDY group.
There was no difference in arterial pH, arterial PaCO2, and arterial O2 before, during and post resuscitation between the CONTROL and STUDY groups.

Figure 4 shows the peak coronary, peak pulmonary and peak carotid flows before, during and post resuscitation.
In lambs that had PEA, there was absence of blood flow in the coronary, pulmonary and carotid artery. During asphyxia, the coronary flow was <1ml/kg/min in both groups while the pulmonary flow and carotid flow was <2ml/kg/min