Plasma epinephrine levels after epinephrine administration using different tracheal administration techniques in an adult CPR porcine model

The aim of the study was to compare arterial plasma epinephrine levels after tracheal epinephrine application using three different tracheal instillation techniques at different tracheal levels in a porcine adult cardiopulmonary resuscitation model. In the prospective, randomized study, electrically-induced cardiopulmonary arrest was applied to 32 anaesthetized and paralyzed domestic pigs. After 3 min of cardiopulmonary arrest and 2 min of external chest compressions using a pneumatic compression device and mechanical ventilation, epinephrine was administered intravenously (20 μg/kg) or tracheally (50 μg/kg): using either direct injection into the upper end of the tracheal tube, via a catheter placed into the bronchial system and using a special tracheal application tube. In each group, there were eight pigs. Arterial blood samples were taken before and up to 10 min after epinephrine administration. Regression analysis was performed of the correlated data. The values of mean arterial blood pressure and end-tidal CO₂ during the time of observation did not differ between groups. Total plasma epinephrine concentrations showed a significant increase in all groups, but with no difference between the tracheal groups. However, peak epinephrine levels in the intravenous group were significantly higher than in tracheal groups. We conclude that administration using three different tracheal instillation levels result in similar onset and peak plasma epinephrine levels in this setting and therefore the preferred method of tracheal epinephrine application for cardiopulmonary resuscitation may be selected by other criteria.