Fetal exposure to magnesium chloride-adenosine triphosphate (MgCl2-ATP) results in alterations in cerebral blood flow and a metabolic acidosis.

OBJECTIVE: Magnesium chloride-adenosine triphosphate (MgCl(2)-ATP), advocated as an adjunct treatment in shock resuscitation, might be useful for pregnant women who develop hypovolemia secondary to conditions such as placental abruption. The effects of this treatment on the fetus, however, have never been investigated. This study determined the direct, acute effects of MgCl(2)-ATP on fetal organ blood flow, hemodynamic measurements, and metabolic parameters before and after maternal hemorrhage. DESIGN: Experimental, randomized, nonblinded, control study. SETTING: Animal laboratory at a university research facility. SUBJECTS: This study was performed on 11 chronically instrumented, 123-day gestational age, pregnant ewes (term = 147 days) and their fetuses. INTERVENTIONS: Ewes were randomly allocated to either experimental (Expt, n = 5) or control (Cntl, n = 6) groups. After a 60-min baseline period, Expt fetuses received a 60-min iv infusion of MgCl(2)-ATP (150 &mgr;mole/hr each of MgCl(2) and ATP; at 3 mL/hr), and Cntl fetuses received an equivalent volume of 0.9% NaCl. After this infusion-only period, the infusion was continued, and ewes were intermittently bled over 1 hr for a total blood loss of 20 mL/kg (hemorrhage-plus-infusion period). After this, the infusions were continued, and ewes and fetuses were monitored for 1 additional hr (posthemorrhage period). Measurements: At the end of all periods, fetal and maternal blood pressures, blood gases, oxygen saturation, hemoglobin, serum electrolytes, and serum glucose concentrations were measured. At the end of the baseline, infusion-only, and hemorrhage-plus-infusion periods, fetal organ blood flows were determined using a fluorescent microsphere technique. Nonparametric statistics were used for comparisons (2-tailed, p 更多