Common carotid artery blood flow volume in extremely preterm infants.

AIM The aim of this study was to determine carotid blood flow volume, a surrogate for cerebral blood flow, using Doppler ultrasound in extremely preterm infants. METHODS In infants <29 weeks, right common carotid artery flow volume (RCCAF) was calculated from vessel diameter and intensity weighted mean velocity measured using Doppler ultrasound on day 1 and 3. In addition, left ventricular output (LVO), ductus arteriosus characteristics, and invasive mean arterial blood pressure (MABP) were obtained. RESULTS Sixty infants with mean gestation of 25.8 weeks were studied. The median RCCAF increased from 12(IQR 9-15) ml/kg/min on day 1, to 14(IQR 12-18) ml/kg/min on day 3(p=0.007). RCCAF was positively correlated with invasive MABP on day 1 and 3. RCCAF significantly correlated with LVO in infants with closing or closed ductus arteriosus on day 1. Using multiple regression analysis, RCCAF was significantly associated with invasive MABP on day 1 and to inotropic treatment on day 3. CONCLUSION Doppler ultrasound can be used to measure RCCAF in extremely preterm infants receiving intensive care. RCCAF increased during the first three days and was positively related to invasive MABP on day 1. Values were lower than previously described in more mature infants.