RESUMEN
<p><b>OBJECTIVE</b>To assess the predisposing factors, frequency and mortality of pneumothorax (PTX) among the newborns hospitalized in a neonatal intensive care unit (NICU) in Isfahan, Iran.</p><p><b>METHODS</b>The data of 43 cases of PTX among the 738 neonates hospitalized in the NICU were analyzed retrospectively according to gestational age, birth weight, Apgar score, type of delivery, age of mother, parity, perinatal asphyxia, resuscitation at birth, side of PTX, mechanical ventilation, surfactant therapy, and underlying lung disorders.</p><p><b>RESULTS</b>Mean gestational age was 31 weeks and birth weight was 1 596 g in the PTX cases. The gestational age of 12 (28%) neonates was less than 28 weeks. Twenty-eight (65%) neonates were below 1,500 g. In total, PTX occurred in 43 (5.8%) neonates. Sixty-three episodes of PTX (97%) were unilateral and 2 (3%) were bilateral. Respiratory distress syndrome (RDS) (40/43, 93%) and mechanical ventilation (37/43, 86%) were common predisposing factors of PTX. Overall, 28 (65%) neonates with PTX died. Birth weight, gestational age and chest tube duration were significantly different between dead and surviving infants. The mortality rate was significantly higher in neonates who required surfactant therapy than that in those who did not require it.</p><p><b>CONCLUSIONS</b>The incidence and mortality of PTX in this study were higher than some other reports and this might be attributed to lower birth weight and gestational age. RDS and mechanical ventilation were the most common predisposing factors for the development of neonatal PTX, and mortality increased with lower birth weight, lower gestational age and more severe underlying primary lung disease.</p>