Different Respiratory Rates during Resuscitation in a Pediatric Animal Model of Asphyxial Cardiac Arrest

Aims
Actual resuscitation guidelines recommend 10 respirations per minute (rpm) for advanced pediatric life support. This respiratory rate (RR) is much lower than what is physiological for children. The aim of this study is to compare changes in ventilation, oxygenation, haemodynamics and return of spontaneous circulation (ROSC) rates with three RR.
Methods
An experimental model of asphyxial cardiac arrest (CA) in 46 piglets (around 9.5 kg) was performed. Resuscitation with three different RR (10, 20 and 30 rpm) was carried out. Haemodynamics and gasometrical data were obtained at 3, 9, 18 and 24 minutes after beginning of resuscitation. Measurements were compared between the three groups.
Results
No statistical differences were found in ROSC rate between the three RR (37.5%, 46.6% and 60% in the 10, 20 and 30 rpm group respectively P = 0.51). 20 and 30 rpm groups had lower PaCO2 values than 10 rpm group at 3 minutes (58 and 55 mmHg vs 75 mmHg P = 0.08). 30 rpm group had higher PaO2 (61 mmHg) at 3 minutes than 20 and 10 rpm groups (53 and 45 mmHg P = 0.05). No significant differences were found in haemodynamics or tissue perfusion between hyperventilated (PaCO2 <30 mmHg), normoventilated (30–50 mmHg) and hypoventilated (>50 mmHg) animals. PaO2 was significantly higher in hyperventilated (PaO2 153 mmHg) than in normoventilated (79 mmHg) and hypoventilated (47 mmHg) piglets (P<0.001).
Conclusions
Our study confirms the hypothesis that higher RR achieves better oxygenation and ventilation without affecting haemodynamics. A higher RR is associated but not significantly with better ROSC rates.