Acute and protracted effects of intratracheal surfactant application on internal carotid blood flow velocity, blood pressure and carbondioxide tension in very low birth weight infants.

As a part of a multicentre clinical trial of prophylactic treatment with bovine surfactant (SF-RI 1) given to immature infants below 31 gestational weeks, short term and protracted effects on cerebral haemodynamics were assessed by Dopplersonographic measurements of the right internal carotid artery. Measurements were performed every 10 min for 1 h after intratracheal application of the surfactant in ten treated infants. The results of additional measurements every 12 h up to the age of 100 h were compared with a control group. In single cases there were changes of time averaged mean maximum velocity (Vmax) of as much as 100% immediately after intratracheal surfactant application, although the mean short term and protracted variability of Vmax was the same as the protracted variability in the control group. Variability of mean arterial blood pressure and transcutaneous carbondioxide tension (tcpCO2) was even less. With proper adjustment of ventilatory settings intratracheal treatment with surfactant does not affect variability or absolute values of internal carotid Vmax, mean arterial blood pressure and transcutaneous pCO2 in low birth weight infants within 100 h after application.