Superior mesenteric artery Doppler is poor at predicting feed intolerance and NEC in preterm small for gestational age neonates

Abstract

Objective: To study SMA Doppler for predicting feed intolerance and necrotizing enterocolitis (NEC) in preterm SGA neonates with umbilical artery absent/reversed end diastolic flow (A/REDF).Study design: Prospective study.Patients: SGA neonates <36 weeks born with antenatally diagnosed A/REDF formed cases. Those with normal Doppler formed controls. Primary outcomes were feed intolerance and NEC. Peak systolic velocity, end diastolic velocity (EDV), time-averaged mean velocity, pulsatility index and resistive index (RI) were measured in SMA Doppler done postnatally on days 1 and 5.Results: Fifty neonates were enrolled in each group. Gestation, birth weight, gender and Apgar scores were comparable. Feed intolerance rate was similar (A/REDF: 26% versus controls: 20%, p 0.48), NEC was commoner in A/REDF group (32% versus 4%, p < 0.001). Baseline SMA Doppler indices were similar; RI on day 1 was higher in babies with A/REDF [5.4 (IQR 3.3, 7.3)] who developed NEC compared to controls [3.3 (IQR 1.7, 3.9)], (p 0.049). RI of 3.63 on day 1 had only a sensitivity of 61% and a specificity of 57% in predicting NEC in A/REDF group (area under curve (AUC) 0.61, 95% CI: 0.43–0.79, p = 0.25). Similarly, EDV of 8.7 cm/s had only a sensitivity of 61% and a specificity of 60% for the prediction of NEC (AUC of 0.64, 95% CI: 0.47–0.81, p = 0.16).Conclusions: Postnatal SMA Doppler indices do not predict feed intolerance and NEC in preterm SGA babies with A/REDF.