Randomised trial of early rapid saline bolus versus epinephrine during resuscitation in perinatal haemorrhagic cardiac arrest in newborn lambs.

OBJECTIVE

To determine the impact of early rapid saline bolus during resuscitation on (1) time to achieve return of spontaneous circulation (ROSC), and (2) systemic haemodynamics, oxygenation, myocardial stress markers and pulmonary oedema.

DESIGN

Randomised controlled trial.

SETTING

Lamb delivery suite.

SUBJECTS: Term lambs in haemorrhagic, asphyxial cardiac arrest.

INTERVENTIONS: Fetal lambs were exsanguinated (~45 mL/kg) followed by umbilical cord occlusion to arrest. After 5 min of asystole, ventilation was followed by coordinated chest compressions. Asystolic lambs were randomised to epi-first (intravenous epinephrine, 0.02 mg/kg and if no ROSC, a 10 mL/kg saline bolus over 5 min), or bolus-first (10 mL/kg saline bolus over 2 min and if no ROSC, followed by intravenous epinephrine). Haemodynamics and blood gases were monitored.

RESULTS

In the epi-first group, none of the lambs achieved ROSC after epinephrine; ROSC occurred in 11/11 lambs during or immediately after saline bolus. In the bolus-first group, none of the lambs achieved ROSC with bolus alone and 8/9 lambs had ROSC after epinephrine. Mean time to ROSC from start of resuscitation was shorter in epi-first (4.9±1.3 vs 6.6±0.9 min, p=0.004), but time to ROSC from the time of epinephrine administration was shorter with bolus-first (86±43 vs 40±21 s, p=0.004). The fetal heart rate did not change significantly despite fetal blood loss.

CONCLUSIONS

Our findings support current neonatal resuscitation guidelines of intravenous epinephrine followed by a bolus in neonates with suspected hypovolaemic arrest. Early saline bolus delays epinephrine and ROSC. Careful clinical assessment of haemodynamics in the post-resuscitation phase is critical.