Comparison of the Cerebrovascular Effects of a 2mg/kg I.V. Cocaine Injection in Fetal, Newborn, and Adult Sheep • 1897

Cocaine may cause stroke, seizures, and neurobehavioral abnormalities in fetuses(F), newborns(N), and adults(A). There may be developmental differences in the mechanisms for these cocaine-induced cerebral effects. Therefore, we compared the cerebrovascular response to a 2 mg/kg I.V. dose in unanesthetized F(n=8, direct fetal injection), N(n=6), and A(n=12) sheep. We measured cerebral blood flow(CBF), mean arterial blood pressure (MAP), arterial(CaO₂), and venous O₂ content, and calculated cerebral 0₂ consumption(CMRO₂) and cerebral vascular resistance(CVR) at baseline, and at 0.5, 5, 15, and 60min after cocaine injection. Results(Mean±SEM) are shown in the table below.

Table 1 No caption available.

Conclusions:

Cocaine causes increased CMRO₂, increased CBF and cerebral vasodilation (decreased CVR) at 5 minutes in F and N, but not until 15 minutes in A. Cocaine also causes an immediate increase in MAP, but this response was less in N compared to F and A. We observed a persistent decrease in CaO₂ in F not seen in the N or A. Clinical differences in response to IV cocaine may be explained, in part, by these developmental differences in cerebrovascular and systemic oxygenation responses.