Mortality and the related factors of hypoxemic respiratory failure in late preterm infants

Objective To discuss the case distribution and the influencing factors of mortality of late preterm infants with hypoxemic respiratory failure in middle and east of Shandong province. And to provide a theoretical basis for the improvement of the level of clinical diagnosis and treatment in late preterm infants with respiratory failure and provide reference evidence for the related researches in Shandong province and even the whole country. Methods Two hundred and sixteen late preterm infants with respiratory failure were selected as the study objects to carry out prospective trial by cluster sampling from 7 hospitals of the middle and east of Shandong province from Jan 1, 2010 to Dec 31, 2012. The basic information, primary disease, clinical diagnosis and treatment methods, clinical outcome, mortality and influencing factors were analyzed. Results (1) All 216 investigation questionnaires were received. The ratio of male to female was 1.3∶1. The pathogenesis that leaded to the incidence of respiratory diseases were not identical in various places. (2) Mean birth weight was (2 660±686) g, the minimum birth weight was 1 900 g and the maximum birth weight was 3 600 g. There were 38 cases with congenital anomalies, including 6 cases with 2 or more kinds of malformation, and congenital heart disease (including patent ductus arteriosus) was 16 cases. Mean age of mothers with respiratory failure infants was 32 years, the minimum one was 18 years and the maximum one was 42 years. The overall cesarean section rate was same to the one of spontaneous labor (106 cases vs 110 cases). One hundred and thirty-seven cases with acute respiratory failure received antenatal steroids. (3) The main primary diseases of infants with respiratory failure were respiratory distress syndrome (112 cases), pulmonary infection and sepsis (52 cases). The complications were, in turn, pulmonary infection and sepsis (23 cases), patent ductus arteriosus (89 cases) and vital organs hemorrhage (7 cases). (4) The case fatality rate of infants within 34 to 35 weeks and 35 to 36 weeks were 10.2% and 8.7% respectively, which were significantly higher than those of infants within 36 to 37 weeks (χ2=157.148, P=0.000). (5) Congenital malformation [OR=2.063, 95%CI (1.297, 3.264)], low birth weight [OR=4.335, 95%CI (1.636, 11.497)], vital organs hemorrhage[OR=4.598, 95%CI (1.370, 14.925)] and mechanical ventilation alone [OR=0.531, 95%CI (0.314, 0.902)] linked to higher risk of death after respiratory failure for the late preterm infants. Conclusion At present, respiratory failure caused by various diseases occurred at low frequencies in the middle and east of Shandong province. The primary diseases are respiratory distress syndrome, pulmonary infection, and severe asphyxia. It takes more time to treat the late preterm infants with respiratory distress and the prognosis can be improved by a variety of treatments. Key words: Late preterm infant; Respiratory failure; Epidemiology