Effects of epinephrine and vasopressin on cerebral microcirculatory flows during and after cardiopulmonary resuscitation.
OBJECTIVE
Both epinephrine and vasopressin increase aortic and carotid arterial pressure when administered during cardiopulmonary resuscitation. However, we recently demonstrated that epinephrine reduces cerebral cortical microcirculatory blood flow. Accordingly, we compared the effects of nonadrenergic vasopressin with those of epinephrine on cerebral cortical microvascular flow together with cortical tissue Po2 and Pco2 as indicators of cortical tissue ischemia.


METHODS
Randomized, prospective animal study.


METHODS
University-affiliated research laboratory.


METHODS
Domestic pigs.


RESULTS
The tracheae of ten domestic male pigs, weighing 40 +/- 2 kg, were noninvasively intubated, and the animals were mechanically ventilated. A frontoparietal bilateral craniotomy was created. Microcirculatory blood flow was quantitated with orthogonal polarization spectral imaging. Blood flow velocity in pial and cortical penetrating vessels measuring <20 microm was graded from 0 (no flow) to 3 (normal). Cerebral cortical tissue carbon dioxide and oxygen tensions (Pbco2 and Pbo2) were measured concurrently using miniature optical sensors. Ventricular fibrillation, induced with an alternating current delivered to the right ventricular endocardium, was untreated for 3 mins. Animals were then randomized to receive central venous injections of equipressor doses of epinephrine (30 microg/kg) or vasopressin (0.4 units/kg) at 1 min after the start of cardiopulmonary resuscitation. After 4 mins of cardiopulmonary resuscitation, defibrillation was attempted. Spontaneous circulation was restored in each animal. However, postresuscitation microvascular flows and Pbo2 were greater and Pbco2 less after vasopressin when compared with epinephrine. We observed that a significantly greater number of cortical microvessels were perfused after vasopressin.


CONCLUSIONS
Cortical microcirculatory blood flow was markedly reduced after epinephrine, resulting in a greater severity of brain ischemia after the restoration of spontaneous circulation in contrast to the more benign effects of vasopressin.
Ristagno
Giuseppe
G
Weil Institute of Critical Care Medicine, Rancho Mirage, CA, USA.
Sun
Shijie
S
Tang
Wanchun
W
Castillo
Carlos
C
Weil
Max Harry
MH
D000818:Animals; D002245:Carbon Dioxide / Q000032:analysis; D016887:Cardiopulmonary Resuscitation; D002540:Cerebral Cortex / Q000737:chemistry; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D004837:Epinephrine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D010100:Oxygen / Q000032:analysis; D011446:Prospective Studies; D011897:Random Allocation; D013552:Swine; D014667:Vasopressins / Q000008:administration & dosage / Q000494:pharmacology*
D014667:Vasopressins; D002245:Carbon Dioxide; D010100:Oxygen; D004837:Epinephrine