ABSTRACT
The question when to feed a sick preterm neonate remains a clinical challenge. The dominant argument to postpone enteral feeding is the risk of necrotizing entero-colitis [NEC]. Predicting feeding tolerance is still largely dependent on clinical observation. Changes in superior me-senteric artery [SMA] blood flow velocity measured by Duplex Doppler in PT neonates have been shown to occur in response to feeds. The aim of this study was to evaluate whether serial Doppler measurements of SMA blood flow velocity could predict early enteral feeding tolerance in preterm infants. The study included 32 preterm neonates subjected to history taking, clinical evaluation, and determination of cause of prematurity.The need for resuscitation after 5 minutes of birth, the exposure to phototherapy or aminophylline intake were determined. Preterms with clinical signs of suspected or confirmed NEC or PDA were excluded from the study. On the day of start of enteral feeding as decided by the nursery clinician, blood pressure, heart rate and urine output were recorded and SMA Duplex Doppler sonography was performed. Blood flow velocity in SMA was assessed 15 minutes prepr and ial, a test feed was given, then re-evaluated 60 minutes postpr and ial. Values of peak systolic velocity [PSV], end diastolic velocity [EDV], time-averaged mean velocity [TAMV], pulsatility index [PI] and resistive index [RI] were presented. PT neonates were subjected to close clinical follow-up and the duration from test feed to full enteral feeding was estimated for each neonate. Accordingly, survived neonates were grouped into: Group I: neonates who achieved full enteral intake within 7 days, which included 17 preterm neonates and group II: neonates who achieved full enteral intake after 7 days, which included 13 preterm neonates. A significant negative correlation existed between TAMV at 60 min and the number of days needed to achieve full enteral intake. Early feeders showed an adequate hemodynamic response to the test feed as demonstrated by a significant rise of EDV and a significant drop of RI and PI. Late feeders showed poor hemodynamic response as illustrated by non-significant change in all parameters. Late tolerance to enteral feeding and poor postpr and ial hemodynamic response were significantly more frequent among c and idates of resuscitation and neonates exposed to phototherapy. Percentage of postpr and ial drop of RI was more significant in the early as compared to the late tolerance group. Clinical and Doppler predictions of tolerance to enteral feeding in terms of RI% postpr and ial drop were properly matched in two thirds of cases. Tolerance to enteral feeding in preterm neonates can be predicted from postpr and ial hemodynamic response to the initial trophic feed. By Doppler sonographic investigation of the SMA in preterm infants, the percentage of postpr and ial Doppler change at 60 min after the first feed might be a good tool for the clinician in predicting early tolerance to enteral feeding.