EFFECT OF VEHICLE ON THE NASAL ABSORPTION OF EPINEPHRINE DURING CARDIOPULMONARY-RESUSCITATION

Study Objectives. We have shown in previous studies that epinephrine a dministered intranasally is a feasible route of administration during cardiopulmonary resuscitation (CPR). To promote the absorption of epin ephrine we administered phentolamine prior to epinephrine and used a b ile salt as a vehicle to dissolve the epinephrine. The purpose of this study was to compare the effect of two different vehicles (bile salt vs surfactant) in promoting the absorption of nasally administered epi nephrine during CPR and to determine their effects on the nasal mucosa . Study Design. A randomized, blinded study. Setting. A controlled lab oratory environment. Subjects. Eleven mongrel dogs. Interventions. Eac h dog underwent 3 minutes of unassisted ventricular fibrillation (VF) followed by 7 minutes of VF with CPR. Five minutes after the start of VF, 10 dogs received intranasal phentolamine 0.25 mg/kg/nostril follow ed 1 minute later by intranasal epinephrine 7.5 mg/kg/nostril. The epi nephrine was dissolved in a randomly assigned vehicle consisting of ei ther taurodeoxycholic acid (group A, bile salt) or polyoxyethylene-9-l auryl ether (group B, surfactant). One animal acted as a control and r eceived 0.9% sodium chloride nasally. Measurements and Main Results. D ata from eight dogs (one control) were included for analysis. Histolog y of the nasal cavity demonstrated severe multifocal erosion and ulcer ation of the respiratory epithelium for groups A and B compared with t he control. The severity was similar between the two groups. In additi on, no significant differences in plasma epinephrine concentrations or blood pressure responses were seen between the groups. Conclusion. Ba sed on histology, polyoxyethylene-9-lauryl ether offered no advantage over taurodeoxycholic acid in its effect on the nasal mucosa. The data available for changes in epinephrine concentration and pressure also suggest no difference between the two vehicles in promoting the absorp tion of epinephrine during CPR in an animal model.