RESUMEN
INTRODUCTION: Patent ductus arteriosus (PDA) is a common complication in preterm infants. While two-dimensional echocardiography is the method of choice for diagnosing a PDA, clinical signs are known to be of limited value. STUDY DESIGN: Haemodynamically significant PDA (hs-PDA) was defined as a ductal left-to-right shunt with elevated left atrial/aortic root ratio ( > 1.6:1), a ductal diameter > 2 mm, retrograde diastolic flow exceeding 30% of the anterograde flow and anterograde peak diastolic flow velocity in left pulmonary artery > 50 cm/s. A hs-PDA may affect the cerebral circulation and skin color is known to be related to local perfusion. In this study, we tested the value of a caudal-to-cephalic skin reflectance differential in detecting preterm infants with hs-PDA. The study was blinded and prospective. SUBJECTS: Fifteen infants with a hs-PDA (M: 8, F: 7; gestational age: 28.0 +/- 2.0 weeks, birth weight: 880 +/- 130 g) and 15 gender- and gestational age-matched infants without a haemodynamically significant PDA (M: 8, F: 7; gestational age: 28.2 +/- 2.3 weeks, birth weight: 885 +/- 135 g) participated to the study. OUTCOME MEASURE: Skin reflectance measurements were performed using a reflectance spectrophotometer (CM-2600d/2500d, Minolta, Osaka, Japan). Sole ("postductal" site) to forehead ("preductal" site) skin reflectance ratio (caudal-to-cephalic ratio). RESULTS: hs-PDA infants showed significantly lower forehead light reflectance values on for the whole visible spectrum (p < or = 0.043) with the exception of 580-590 nm (p = 0.058), whereas no statistically significant differences were observed for the sole skin reflectance between the two groups in the examined visible spectrum. Consequently, hs-PDA infants showed a significantly higher caudal to cephalic ratio in the 410-430 nm (p < or = 0.042), 460-530 nm (p < or = 0.027) and 590-700 nm (p < or = 0.011) wavelength ranges. CONCLUSIONS: These findings may provide a previously unrecognised clinical marker for haemodynamically significant PDA in preterm infants, thus predicting those preterm infants who may require intervention for PDA.