Effects of airway management and tidal volume feedback ventilation during pediatric resuscitation in piglets with asphyxial cardiac arrest

Abstract

To compare the effect on the recovery of spontaneous circulation (ROSC) of early endotracheal intubation (ETI) versus bag-mask ventilation (BMV), and expiratory real-time tidal volume (VTe) feedback (TVF) ventilation versus without feedback or standard ventilation (SV) in a pediatric animal model of asphyxial cardiac arrest. Piglets were randomized into five groups: 1: ETI and TVF ventilation (10 ml/kg); 2: ETI and TVF (7 ml/kg); 3: ETI and SV; 4: BMV and TVF (10 ml/kg) and 5: BMV and SV. Thirty breaths-per-minute guided by metronome were given. ROSC, pCO2, pO2, EtCO2 and VTe were compared among groups. Seventy-nine piglets (11.3 ± 1.2 kg) were included. Twenty-six (32.9%) achieved ROSC. Survival was non-significantly higher in ETI (40.4%) than BMV groups (21.9%), p = 0.08. No differences in ROSC were found between TVF and SV groups (30.0% versus 34.7%, p = 0.67). ETI groups presented lower pCO2, and higher pO2, EtCO2 and VTe than BMV groups (p < 0.05). VTe was lower in TVF than in SV groups and in BMV than in ETI groups (p < 0.05). Groups 1 and 3 showed higher pO2 and lower pCO2 over time, although with hyperventilation values (pCO2 < 35 mmHg). ETI groups had non significantly higher survival rate than BMV groups. Compared to BMV groups, ETI groups achieved better oxygenation and ventilation parameters. VTe was lower in both TVF and BMV groups. Hyperventilation was observed in intubated animals with SV and with 10 ml/kg VTF.

Figure 1

Brief summary of the experimental protocol. CA cardiac arrest, CPR cardiopulmonary resuscitation, ROSC recovery of spontaneous circulation.

Figure 2

Linear mixed models comparing the following parameters over time among the five groups: pCO2, pO2, VTe, MAP and EtCO2. The differences between groups over the study period for each parameter were as follows: pCO2 < 0.01, pO2 p < 0.01, VTe p < 0.01, MAP p = 0.55 and EtCO2 p < 0.01. Significant differences (p < 0.05) among groups at specific time points during CPR are marked as *.

Figure 3

Linear mixed models comparing the following parameters over time between the two airway strategies (BMV and ETI groups): pCO2, pO2, EtCO2 and VTe. The differences between groups over the study period for each parameter were as follows: pCO2 p < 0.01, pO2 p < 0.01, VTe p = 0.04 and EtCO2 < 0.01. Significant differences (p < 0.05) between groups at specific time points during CPR are marked as *.

Figure 4

Linear mixed models comparing the following parameters over time between the animals which achieved ROSC and did not (non-ROSC): pO2, MAP and EtCO2. The differences between groups over the study period for each parameter were as follows: pO2 p < 0.01, MAP p < 0.01 and EtCO2 < 0.01. Significant differences (p < 0.05) between groups at specific time points during CPR are marked as *.