Doppler Analysis of Postprandial Intestinal Blood Flow in Healthy Preterm Infants

ABSTRACT

PURPOSE: The newborn period is a time of rapid physiological change in the gastrointestinal tract, when adaptation from a state of parenteral nutrition to the demands of enteral feeding take place. little is known about the intestinal vascular responses that accompany intestinal adaptive changes, although there is much speculation about the relationship between entreral feeding, alterations in gut perfusion, and the development of necrotizing enterocolitis.. Doppler ultrasound can be readily used to measure intestinal blood flow velocities in human newborn. It provides a noninvasive technique for investigating adaptive postnatal changes in the intestinal circulation, and, in particular, the response to feeds. In this study, we have measured blood flow indices in both the superior mesenteric artery and ceLiac axis, Looking for postprandial changes in response to feeding in 16 healthy preterm infants. METHODS: By using the Doppler ultrasound, PSV(peak systolic blood flow velocity), EDV(end diastolic blood flow velocity), Pulsatility index and blood flow per minute were measured pre and postprandially on day 1, 3, and 5 of life. Since the postprandial changes were similar during the study periods, the pre- and postfeed values are presented as combined resuLts. RESULTS: 1) The PSV and EDV from the superior mesenteric artery before the feed were 65.12+/-11.16 cm/sec and 15.40+/-3.58 cm/sec, respectively, and rose to 74.55+/-13.11 cm/sec and 19.10+/-4.81 cm/sec (p<0.001)(p<0.001). The pulsatility index fell from 0.761+/-0.053 to 0.735+/-0.055 (p<0.05) and blood flow per minute was increased from 0.110+/-0.032 l/min to 0.123+/-0.027 l/min (p<0.05). 2) Similar results were obtained from the celiac axis The PSV and EDV increased from 68.23+/-16.29 cm/sec, 16.54+/-5.77 cm/sec to 77.92+/-15.08 cm/sec, 21.14+/-6.95 cm/sec, respectively (p<0.05) (p<0.001). The pulsatility index fell from 0.760+/-0.068 to 0.722+/-0.077 (p<0.001) and blood flow per minute was increased from 0.126+/-0.029 l/min to 0.153+/-0.033 l/min, posprandially (p<0.001). 3) The magnitude of increment in velocity was independent of gestational age, sex, and initial body weignt. CONCLUSIONS: We have measured intestinal blood flow indices in response to feeding by Doppler ultrasound and Doppler ultrasound may be able to provide evidence regarding disturbed perfusion as a potential etiological agent in the pathogenesis of necrotizing enterocolitis.