Analysis of clinical date of 620 very low birth weight infants

Abstract

The rapid decline in mortality of very low birth weight infants (VLBWI) during the past twenty years has been attributed to the establishment of the neonatal intensive care all over the country. Little information was reported on the conditions of VLBWI during the recent few years in China. Objective To investigate the factors in relation to the improved hospital survival rate of VLBWI. Methods The hospital data of 620 VLBWI during the last ten years were analyzed by dividing patients into three groups according to the birth weight, that is, less than 1 000 grams, between 1 001 and 1 250 grams and between 1 251 and 1 500 grams, respectively. The risk factors, the effects of these factors and mortality 1991~1995 and 1996~2000 were analyzed and compared. Results The risk factors causing the premature birth of VLBWI were multiple births (27.3%), pre-rupture of membrane (20.2%), and pregnancy complications (11.5%). In 36.8% cases no reason could be found. All hospitalized VLBWI had at least one complication including apnea (61.9%), which happened at 78.8%, 79.1% and 52.6%, respectively in the three groups; hypothermia (56.1%), at 65.2%, 62.1% and 52.4%, respectively in the three groups; intraventricular hemorrhage (IVH) (41.9%), at 80.3%, 62.1% and 27.9%, respectively in three groups; respiratory distress syndrome (RDS, 35.8%), at 62.1%, 44.4% and 28.2%, respectively in the three groups; patent ductus arteriosus (PDA, 27.2%), at 33.3 %, 26.8% and 26.2%, respectively in three groups and, infection (26.1%), at 27.3%, 37.3% and 9.2%, respectively in the three groups. The highest frequency of complications occurred in the babies with birth weight less than 1 000 grams. The survival rate was 86.5% for all VLBWI and 60.6% for babies less than 1 000 grams. In recent years, the survival rate has been improved significantly (80.8% vs 89.2%, χ2=8.27, P<0.005). RDS, infection and IVH were the primary causes of death. Conclusions The declines in the mortality of VLBWI were attributed to the improved neonatal intensive care, continuous post-natal monitoring and the early finding of complications. Early treatment of VLBWI could increase the survival rate. The prevention of infections, especially in nosocomial infection is one of the most important steps of decreasing mortality. Improved survival rate in RDS may be associated with the introduction of surfactant replacement therapy and high-frequency ventilation. Key words: Infant, very low birht weight; Survival rate; Retrospective studies