[A survey of infants requiring long-term neonatal intensive care in Tokyo: 1989-1998].

In order to grasp the characteristics and outcomes with infants hospitalized long-term in NICUs, we reviewed all summary charts of 18 perinatal medical centers in Tokyo for the period from January 1989 to December 1998. We sampled 3,000 infants who required neonatal intensive care over 90 consecutive days out of 46,309 registered cases during the decade. The duration of hospital stay, making a comparative analysis of the number of days for the 50 percentile, was as follows. As a whole the infants required 125 days until discharge. Infants with 29-30 weeks gestation and infants with birth weights 1,000-1,499 g required shorter stays (106 days in both cases). The "discharge with complications" group required 136 days, and the "discharge on remission" group 119 days. Within the 31-32 weeks gestation group, those with "discharge with complications" required 107 days. Within the 29-30 weeks gestation group, those with "discharge on remission" required 104 days. Infants with 1,000-1,499 g birth weights for the "discharge with complications" and "discharge on remission" groups required 116 and 104 days respectively. Focusing on birthplace, the group of "inside-born" (born at perinatal medical centers) infants required 124 days, and the "outside-born" (born at non-perinatal medical centers) required 127 days. Respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD) and chronic lung disease (CLD) were often seen in patients under 29 weeks gestation and under 1,000 g birth weight. Hypoxic ischemic encephalopathy (HIE), convulsions, congenital malformations and chromosomal abnormalities were frequent in the groups over 31 weeks and over 1,500 g. Apnoea and transient tachypnoea of newborn (TTN) often occurred in these at 29-30 weeks and 1,000-1,499 g. Also, apnoea and TTN were often seen in the "discharge on remission" group. RDS, apnoea and TTN occurRed frequently in the "inside-born" infants with over 31 weeks of gestation and over 1,500 g birth weight. There were many cases of HIE and convulsions in the "outside-born" infants of these groups. We found infants who required long-term intensive care to comprise three main groups. The first group consisted of infants of 29-30 weeks gestation and 1,000-1,499 g birth weight and demonstrated mild or few complications. The second consisted of under 29 weeks and under 1,000 g and exhibited complications of chronic lung diseases caused by immaturity of respiratory organs. The third was the group of over 31 weeks and over 1,500 g who had complications due to central nervous system disease, congenital malformations and chromosomal abnormalities.