NEONATAL SOCIETY ABSTRACTS
Neonatal necrotizing enterocolitis is associated with high resistance flow in the superior mesenteric artery on day 1 of life in preterm infants
Presented at the Neonatal Society 2005 Summer Meeting (programme).
Murdoch EM1, Smith GCS2, Sinha AK3, Shanmugalingam ST4, Kempley ST3
1 Neonatal Unit, Addenbrookes Hospital, Cambridge, UK
2 Department of Obstetrics and Gynaecology, Cambridge University, UK
3 Neonatal Unit, Royal London Hospital, Whitechapel, London, UK
4 Neonatal Unit, UCLH NHS Trust, UK
Background: Necrotising enterocolitis (NEC) is the most severe gastrointestinal complication associated with preterm birth and has a 25-40% mortality (1). Mucosal injury is thought to be the initiating event that ultimately leads to the development of NEC. Intestinal ischemia may be a key factor in determining such injury.
Hypothesis: We hypothesized that infants who subsequently developed NEC would have evidence of increased mesenteric arterial resistance in early neonatal life.
Objective: To relate Doppler indices of mesenteric arterial resistance to the risk of developing NEC.
Study Design & Methods: Prospective cohort study. Ethical approval was gained and parental consent taken prior to the study. We studied 64 infants admitted for neonatal intensive care. We analyzed the Doppler waveform of the superior mesenteric artery on day 1 of life. Clinical management and diagnosis of NEC were performed blind to the Doppler results. Results were analysed using multivariate logistic regression relating Doppler SMA indices with risk of NEC.
Results: When adjusted for gestational age at birth, the following Doppler parameters (expressed as adjusted odds ratio [95% CI] of NEC), were significantly predictive of the risk of NEC: diastolic flow (OR for a 1cm/s change: 0.77, 0.63-0.94, P=0.009), mean velocity (OR for a 1cm/s change: 0.89, 0.80-0.99, P=0.04) and pulsatility index (OR for a 1 unit change 4.03, 1.27-12.8, P=0.02). The association between NEC and Doppler waveforms indicative of high vascular resistance was independent of a range of other factors and co-morbidities (race, mode of delivery, umbilical arterial catheter, growth restriction, patent ductus arteriosus, respiratory distress syndrome, mechanical ventilation and hypotension).
Discussion: This is the first demonstration, to our knowledge, that babies with high resistance patterns of blood flow velocity in the superior mesenteric artery on day 1 of life are at increased risk of developing NEC. This suggests that impaired perfusion of the mesenteric circulation in early neonatal life has a role in the pathophysiology of NEC. We speculate that failure of perfusion may reflect underdevelopment of the vascular tree in fetal life or vaso-constriction in the early neonatal period.
1.Chandler Semin.Pediatr.Surg. 2000;9:63-72.
2.Bisquera JA Pediatrics 2002;109:423-8.