Cardiovascular Responses to Neuromuscular Blockade in the Anemic Ovine Fetus

Currently little is known about the cardiovascular responses of the anemic fetus to neuromuscular blockade. We hypothesized that, despite marked anemia with potentially decreased cardiac reserve, the fetal responses to Pancuronium neuromuscular blockade would differ significantly when compared with neuromuscular blockade with Atracurium (a cardiovascular sparing agent). Ten fetal sheep (137 ± 1 (SE) days gestation) were divided into three groups (21 experiments): Pancuronium (n = 7), Atracurium (n = 6), and Control (n = 8). Fetal anemia (Hct = 21.8 ± 0.7%) was produced by serial hemorrhage over 3 days. Fetal arterial (FAP) and venous (FVP) pressures, heart rate (FHR), and arterial pH, pO2, and pCO2 were measured at −20, 0, 10, 20, 30, 60, and 90 minutes relative to neuromuscular blockade. Data were analyzed by three-way ANOVA for repeated measures. Pancuronium neuromuscular blockade increased FHR (15-20 bpm, P