Sinusoidal fetal heart rate pattern during cardiopulmonary bypass

A gravida 3, para 2 woman underwent an emergency mitral valve replacement at 24 weeks' gestation. A sinusoidal fetal heart pattern was recorded throughout cardiopulmonary bypass. This pattern persisted despite a pump flow maintained at 31 ml/m2 min and an intravenous infusion of phenylephrine to maintain the mean systemic arterial pressure at 50 mm Hg.