Effects of Patent Ductus Arteriosus on Organ Blood Flow in Infants Born Very Preterm: A Prospective Study with Serial Echocardiography.

OBJECTIVE: To characterize the effects of a patent ductus arteriosus (PDA) on different organ blood flows in infants born preterm. STUDY DESIGN: Infants born preterm at ≤30 weeks of gestational age had daily echocardiography and Doppler assessments of middle cerebral artery, celiac artery, superior mesenteric (SMA), and renal arteries (RA) during the first postnatal week. Abnormal organ blood flow was defined as either reverse or absent diastolic flow, abnormally low mean or systolic velocities, or abnormally high pulsatility or resistance index. RESULTS: Twenty-five infants born very preterm (gestational age 27.0 ± 2.1 weeks) were enrolled. PDA presence at time of measurement increased the risk of abnormal organ blood flows (39% vs 8%, P < .001). Ductal diameter and left atrium-to-aortic root (LA/Ao) ratio correlated positively with resistance index (celiac artery, SMA, RA), and negatively with mean velocity (ductal diameter: SMA, RA; LA/Ao ratio: RA). A PDA >2.0 mm, LA/Ao ratio >1.4, and their combination were associated with 8.0 (95% CI 1.6-39.4)-, 6.7 (1.3-34.7)-, and 38.2 (3.2-455.5)-fold increase in risk of abnormal organ blood flow index, respectively. Abnormal descending aorta flow was detected in only 2% of measurements. CONCLUSIONS: Ductal size >2.0 mm and LA/Ao >1.4, especially in combination, are associated with a greater risk of abnormal organ blood flows. We suggest that Doppler assessment of the renal and superior mesenteric arteries are more likely to detect systemic hypoperfusion than the descending aorta.

Initial hematocrit values after birth and peri/intraventricular hemorrhage in extremely low birth weight infants.

OBJECTIVE: Ischemia followed by reperfusion plays a significant role in the pathogenesis of peri/intraventricular hemorrhage (P/IVH). Delayed cord clamping promotes placental transfusion to newborn and is associated with decreased P/IVH. We hypothesized that extremely low birth weight (ELBW) infants with higher initial hematocrit (Hct) after birth are less likely to develop P/IVH. STUDY DESIGN: Pre- and postnatal data on inborn ELBW infants over 7 years were reviewed. We examined the relationship between P/IVH in the first week and initial Hct using logistic regression modeling. RESULTS: We studied 225 infants with a median gestational age (GA) 25.7 (22.4-31.7). Forty-one percent had grade I-IV P/IVH. In univariate analysis, cesarean section (CS) and higher GA, birth weight, 5-minute Apgar, and initial Hct were associated with decreased likelihood of P/IVH while higher maximum PCO2 in first 3 days and use of inotropes/vasopressors, postnatal steroid for hypotension, hypernatremia, transfusion, and use of insulin for hyperglycemia during the first week of life were associated with increased likelihood of P/IVH. In multiple regression analysis, only GA, CS, and initial Hct remained significantly associated with P/IVH. Adjusting for GA and CS, the odds of P/IVH was higher with Hct < 40% (OR 2.04, 95% CI [1.11, 3.76]) and Hct < 45% (2.38 [1.19, 4.76]). CONCLUSION: Higher initial Hct is associated with decreased P/IVH. Initial Hct < 45% was associated with a 2-fold increase in P/IVH. We speculate that lower initial Hct represents a lower intravascular volume status and promotes cerebral hypoperfusion preceding P/IVH.