34 Risk Factors Associated with Respiratory Distress (RD) in Term Neonates with and Without Air Leak: A Case Controlled Quality Assurance Study

Abstract

Perinatal and neonatal risk factors associated with air leak syndrome in term neonates (≥37 wk) have not been extensively studied. Furthermore, it has been difficult to differentiate air leak syndromes from other respiratory problems on clinical presentation and examination. We sought to investigate this issue with a view to identifying risk factors specific to air leak syndromes. During a two year period (January 2000 to December 2002) neonatal and maternal case records of inborn infants presenting with respiratory distress and air leak were reviewed. These infants were matched with another group of infants with similar presentation without air leak using parameters of birthweight (gms), gender and gestational age (wks). Maternal data included age, parity, type and duration of delivery, pregnancy and labor complications, nature of induction and presence of meconium in amniotic fluid. Infant data collected were: attendance of NICU staff at delivery, need for and description of resuscitation, the type of air leak, need for mechanical ventilation, use of tracheal toilet and direct admission to the NICU from the labor suite Vs later admission from the newborn nursery. The burden of illness was assessed using length of stay in the NICU, number of x-rays performed and number of doses of antibiotics administered. Statistical analysis was carried out using parametric and non-parametric T test where applicable. A value of P<.05 was used for significance. The data below is presented in two groups, those with air leak and those without using Mean ± 2 S.D. There was 27 infants in each group. The following maternal characteristics were significantly different, length of rupture of membranes 1158±60 min Vs 879± 55 min (P<.01), length of first stage of labor 694±45 min Vs 472±35 min (P<.01) and length of second stage of labor 95±10 min Vs 73±13 min (P<.05). All other maternal data among the two groups were similar. 2 infants in the air leak group required needle aspiration, a single infant was mechanically ventilated, and 2 infants required the insertion of chest drains. There were 13 infants with right pneumothoraces, 11 with left pneumothoraces, 3 with bilateral air leaks and 2 infants with mediastinal air. The average number of chest x-rays in the air leak group was 3.2±1 Vs 1±0.2 in the RD group without air leak (P<.001). The average length of stay in the NICU for the air leak group was 3±0.5 days Vs 2.25±0.2 days in the non-air leak group (P<.01). 24 infants in the air leak group received more than 4 doses of antibiotics compared to 10 infants in the RD group (P<.05). All other infant data collected were not significantly different between the two groups. Term infants who developed air leaks were subjected to a longer period of rupture of membranes prior to labor as well as a longer duration of labor. The burden of illness was significantly higher for those infants who developed air leaks. Speculation: Perinatal rather than postnatal factors appear to be more important in the development of air leak syndromes in term infants.