Results of intensive care for 375 very low birthweight infants

High frequency ventilation in the neonatal period

There are three forms of high frequency ventilation, high frequency jet ventilation (HFJV, up to 400/min), high frequency oscillation (HFO, up to 40 Hz), and high frequency positive pressure ventilation (HFPPV, rates between 60 and 150/min). The first two forms of ventilation are still experimental and have been used only in critically ill children where respiratory failure has been unresponsive to more conventional therapy. Unfortunately, however, HFJV has already been associated with a high incidence of tracheal lesions. High-frequency positive pressure ventilation, on the other hand, using conventional ventilators, has been used and studied widely. Certain neonatal ventilators function suboptimally at increased rates, resulting in a reduction in tidal exchange with a consequent clinical deterioration. Using appropriate ventilators, arterial oxygen tensions improve and carbon dioxide tensions are reduced at fast rates in non-paralysed infants. Air-trapping, however, may be a problem in infants paralysed and ventilated at fast rates. HFPPV have been associated with a reduced incidence of pneumothoraces, but there is no knowledge of the effect of this form of ventilation on subsequent lung growth.

Postnatal growth in infants born before 30 weeks' gestation

The postnatal weight pattern up to 14 weeks after birth was determined in 184 singleton survivors born at 23 to 29 weeks' gestation in whom routine parenteral nutrition was used before milk feeding was established. A mean postnatal weight loss of 14% of birth weight occurred at a mean of 6 days. The more immature infants had significantly higher postnatal weight loss and longer time to regain birth weight despite a higher volume intake in the first week. From the fourth postnatal week all gestational subgroups had a mean weight gain at above intrauterine growth rate. As a result of the initial period of weight loss, however, the mean body weight remained below the 10th percentile of the intrauterine growth curve. The early growth rate in infants small for gestational age was higher than those who were appropriate weight for gestation, although the mean body weight of the former group remained significantly lower at 2 years.

Perinatal risk factors for necrotizing enterocolitis

The perinatal histories of 50 very low birthweight infants weighing 1500 g, or less, with necrotizing enterocolitis were compared with those of the remaining 325 very low birthweight infants who were admitted to this hospital during a four year study period. Many factors previously reported to be associated with necrotizing enterocolitis were found with equal frequency in both groups of babies. The only adverse factor which was more frequently present in patients with necrotizing enterocolitis was hypothermia on admission to hospital. Those infants who developed severe necrotizing enterocolitis also had a higher incidence of polycythaemia. A further controlled study which examined feeding practices showed that the timing, type, and volume of milk feeding were not different in infants with necrotizing enterocolitis and matched controls. Prematurity is clearly the greatest risk factor which predisposes to the development of necrotizing enterocolitis and most of the factors previously implicated in the aetiology may simply represent the descriptive characteristics of a population of sick, very low birthweight infants.

Necrotizing enterocolitis in very low birthweight infants: a four-year experience

Fifty (13%) of 375 infants who weighed 1500 g or less at birth had necrotizing enterocolitis (NEC). Haematological changes suggestive of sepsis occurred in 83% and positive bacteriological cultures were found in 38%, the most common organism isolated being Clostridium perfringens. Complications included intestinal perforation in six patients and recurrence of NEC in five, of whom one subsequently developed an intestinal stricture. Five of the eight nursery deaths were secondary to peritonitis and overwhelming sepsis from NEC. In spite of the discontinuation of milk feeds for prolonged periods, satisfactory caloric intake and weight gain were achieved with parenteral nutrition in the survivors. Of the 41 long-term survivors, six (15%) were found to have a disability at 2 years of age, corrected for prematurity, compared with 48 (20%) of 241 very low birthweight survivors from the same study period who did not have NEC. None had evidence of gastrointestinal dysfunction. Six (15%) children remained below the 10th percentile for both weight and height. This study showed that early diagnosis and therapy for NEC in very low birthweight infants were associated with a favourable short- and long-term outcome.

Growth and development of very low birthweight infants recovering from bronchopulmonary dysplasia

Twenty four infants with birthweights less than or equal to 1500 g had bronchopulmonary dysplasia (BPD). Four died in the neonatal period and four in the postneonatal period-one had been discharged and was aged one year. Sixteen (67%) survived long term and were followed up until they were two years old. Common medical conditions included respiratory illnesses in 14 (88%) children and otitis media in 8 (50%). Eleven (69%) required hospital admission for an average of 5 times; total days in hospital averaged 27 days. The most common reasons for admission were bronchiolitis and bronchopneumonia. At two years 37% were below the 10th centile for weight, as were 25% for height: head circumferences were normal. Two children had cerebral palsy, two had developmental delay, two had multiple disabilities, and one had sensorineural deafness. Of the 24 BPD infants, 8 (33%) died, 7 (29%) survived with a disability (severe in one), and 9 (38%) had a normal neurodevelopmental outcome. From the available perinatal data it was not possible to predict late disabilities in BPD survivors.

Early development of infants 1000 g or less at birth

In a 4-year period the neonatal survival rate for 26 infants weighing 501-750 g was 42% and for 81 infants weighing 751-1000 g it was 61%. All 59 surviving infants have been assessed at follow-up; 39 were at least 2 years old (corrected for prematurity) and data from the remaining 20 were derived from assessment at 1 year corrected age. Five children had cerebral palsy, 4 had multiple handicaps, 4 each had a sensory handicap, 2 had developmental delay, and 1 had a dilated right ventricle without clinical hydrocephalus. Twelve of the 16 children with defined handicaps were considered to have significant functional handicaps. Therefore, of the 107 infants in this series, 48 (45%) died, 12 (11%) survived with significant functional handicaps, and 47 (44%) were considered to be developing within the normal range. No significant differences in the incidence of handicap were observed between inborn and outborn children, boys or girls, those who were small or appropriate for gestation, those who weighed less than or equal to 750 g or greater than 750 g at birth, and those who required or did not require prolonged oxygen or ventilation.