Changes in intracranial arterial blood flow velocities during surgical ligation of the patent ductus arteriosus.

A combined continuous and range-gated Doppler instrument was used to assess intracranial arterial blood flow velocity changes in infants and neonates undergoing surgical ligation of the Ductus Arteriosus (DA). Continuous recordings during DA closure in six infants (3.5-10 months old), showed an abrupt increase in diastolic blood flow velocity simultaneous with an increase in systolic and diastolic arterial blood pressure. In five infants, these changes were followed by a rapid fall in systolic and diastolic blood pressure without a concomitant change in blood flow velocity, which may be secondary to a rapid fall in intracranial vascular resistance. The mean blood flow velocity increase following DA closure was 27% (8-43%) and the changes in diastolic and mean blood flow velocity were significant (p less than 0.01). In seven preterm neonates (24-28 weeks) studied before and after surgery, a mean blood flow velocity increase of 50% (14-115%) (p less than 0.01), mainly due to an increase in diastolic blood flow velocity (p less than 0.01), was recorded. These rapid intracranial hemodynamic changes during surgical DA closure should be taken into consideration when selecting techniques for DA closure.