Continuous Chest Compressions with Asynchronous Ventilations Increase Carotid Blood Flow in the Perinatal Asphyxiated Lamb Model

BACKGROUND: The neonatal resuscitation program (NRP) recommends interrupted chest compressions (CC) with ventilation in the severely bradycardic neonate. The conventional 3:1 compression-to-ventilation (C:V) resuscitation provides 90 CC/min, significantly lower than the intrinsic newborn heart rate (120–160 beats/min). Continuous CC with asynchronous ventilation (CCCaV) may improve success of return of spontaneous circulation (ROSC). METHODS: Twenty-two near-term fetal lambs were randomized to interrupted 3:1 C:V (90 CC + 30 breaths/min) or CCCaV (120 CC + 30 breaths/min). Asphyxiation was induced by cord occlusion. After five min of asystole, resuscitation began following NRP guidelines. The first dose of epinephrine was given at 6 minutes. Invasive arterial blood pressure and left carotid blood flow were continuously measured. Serial arterial blood gases were collected. RESULTS: Baseline characteristics between groups were similar. Rate of and time to ROSC was similar between groups. CCCaV was associated with a higher PaO(2) (22±5.3 vs. 15±3.5 mmHg, p<0.01), greater left carotid blood flow (7.5±3.1 vs. 4.3±2.6 ml/kg/min, p<0.01) and oxygen delivery (0.40±0.15 vs. 0.13±0.07 mL O(2)/kg/min, p <0.01) compared to 3:1 C:V. CONCLUSION: In a perinatal asphyxiated cardiac arrest lamb model, CCCaV showed greater carotid blood flow and cerebral oxygen delivery compared to 3:1 C:V resuscitation.