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

Abstract

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.

Single versus continuous sustained inflations during chest compressions and physiological-based cord clamping in asystolic lambs

“…Epinephrine (10 µg/kg estimated body weight) was given intravenously 1 min after CCs were initiated, and every 3 min thereafter for a maximum of four doses. On ROSC, defined as end-diastolic blood pressure >20 mm Hg and spontaneous unassisted heart contractions,14 lambs were transferred to volume guaranteed ventilation targeting 7 mL/kg with warm humidified air (Dräeger Babylog 8000+ ventilator; Dräeger, Lübeck, Germany). The fraction of inspired oxygen was adjusted to maintain arterial oxygen saturation between 90% and 95% and ventilation parameters adjusted to maintain PaCO 2 between 45 and 55 mm Hg.…”

Chest compressions superimposed with sustained inflation during neonatal cardiopulmonary resuscitation: are we ready for a clinical trial?

“…Wagner et al performed a secondary analysis of prior animal randomised controlled trials and reported that piglets with pulseless electric activity and asystole had a longer median time to ROSC compared with piglets with bradycardia when resuscitated with CC+SI (bradycardia 35 (28–68) s, pulseless electric activity 120 (80–175) s, asystole 69 (60–111) s; p<0.001) 45. All arrest types resulted in a reduction of mean arterial pressures and carotid blood flow 4 hours after ROSC, but the bradycardia group had higher values compared with pulseless electric activity and asystole 45…”