Introduction:
Neonatal chest compression (CC) should be performed to a 1/3 anterior-posterior (AP) chest diameter depth, however, the optimal AP depth is unknown.
Hypothesis:
We hypothesized that in asphyxiated neonatal piglets a 40% AP depth compared to 1/3, or 1/4 AP depth will reduce time to achieve return of spontaneously circulation and improve survival.
Methods:
Newborn piglets (n=8/group) were anesthetized, intubated, instrumented, and exposed to 45-minute normocapnic hypoxia followed by asphyxia and cardiac arrest. Piglets were randomly allocated to four intervention groups (“AP 12.5% depth”, “AP 1/4 depth”, “AP 1/3 depth” or “AP 40% depth“). CCs were performed using an automated CC machine with a rate of 90/min. Hemodynamic and respiratory parameters were continuously measured.
Results:
Median (IQR) time to return of spontaneously circulation was 70 (60-117), 85 (72-90), 90 (90-130), and 600 (600-600) sec with AP 40% depth, AP 1/3 depth, AP 1/4 depth, AP 12.5% depth, respectively. No piglet in the AP 12.5% depth group achieved ROSC while the short-term survival (1h) in the other groups was 100%. Systolic and diastolic blood pressure, central venous pressure, carotid blood flow, tidal volume, and minute ventilation increased with increasing AP depth.
Conclusions:
Time to return of spontaneously circulation and survival was similar between 1/4, 1/3, and 40% AP depth, while 12.5% AP depth did not result in return of spontaneously circulation. Hemodynamic and respiratory parameters improved with increasing AP depth suggesting that 40% AP depth might provide improved organ perfusion and oxygen delivery.