[Pharmacokinetics and dynamics of endogenously released and therapeutically administered adrenaline in resuscitation....

In this study, catecholamine plasma levels and hemodynamic response were measured to compare the effects of endogenously released (group A; n = 8), intravenously injected (group B; 10 micrograms/kg; n = 8), and endobronchially instilled (e.b.) epinephrine (group C; 100 micrograms/kg; n = 8) on resuscitation. Although the endogenous release of epinephrine produced peak plasma concentrations of 214 +/- 86 ng/ml (mean +/- SEM) during cardiac massage, only 5 animals were successfully resuscitated in group A. Mean arterial pressure and cardiac output were significantly lower in the first hour of restored spontaneous circulation compared to groups B and C. Endobronchial and intravenous epinephrine administration proved equally effective with regard to resuscitability and hemodynamic response during cardiac massage. All animals in groups B and C were successfully resuscitated and peak plasma concentrations of epinephrine were achieved with comparable onset times (317 +/- 53 ng/ml after 2.5 min in group B, 634 +/- 202 ng/ml after 3 min in group C). The tenfold epinephrine dose administered endobronchially was able to generate only a twofold increase in peak plasma epinephrine concentrations. The mean bioavailability with this route of administration, however, was 40% (5-71%). The ongoing absorption and therefore significantly longer half life of e.b. epinephrine compared to i.v. administration improved the hemodynamic situation of group C animals during the early postresuscitation period. More extensive use of e.b. epinephrine administration can be recommended, especially in out-of-hospital resuscitation, when intubation is achieved before an intravenous line can be established.(ABSTRACT TRUNCATED AT 250 WORDS)