g) Quality of survival: The impact of the advances in care of premature infants over the past decade also have been reflected in an improvement in prognosis of very low birthweight infants. The outlook for these infants born in the 1950's and 1960's revealed a uniformly poor prognosis for survivors who weighed less than 1500 grams at birth with handicap rates ranging from 33% to 60%. In general, the smaller the infant, the worse the outlook. The recent study by Stewart and Reynolds (Ref. No189) evaluating infants weighing 1500 grams or less at birth and cared for in their intensive care unit from 1965 to 1970 is representative of the improved prognosis and survival that have occurred. 90.5% (86) of these children had no detectible handicap, while 4.2% (4) had mental handicaps and 5. 3% motor handicaps. An analysis of the individual children revealed "a clear relationship between the presence of a handicap and the occurrence of neonatal illness, particularly those presumed to have caused severe hypoxia." Many of the changes in care in Stewart and Reynolds' premature unit were directed primarily at decreasing the incidence of hypoxia. The constellation of these advances which were associated with this improved prognosis included the use of maternal hormone assays (estriol) and ultrasonic biparietal diameter measurements to determine a more optimal time for delivery; continuous electronic fetal heart rate monitoring and fetal acid-base monitoring to decrease the incidence and severity of intrauterine asphyxia; improved resuscitation at birth, oxygen therapy closely adjusted to blood measurements; electronic monitoring of respiratory rate in the management of apneic infants; improvements in artificial and assisted ventilation. 31. Several examples of specific advances taken from other centers are illustrative of the nature of the kind of improvements that have occurred for certain subsets of patients that result in improved prognosis. At Babies Hospital, Columbia-Presbyterian Medical Center, long-term follow-up of the low birthweight premature infants with Apgar scores of 3 or less at 5 minutes, in association with intrauterine asphyxia, revealed an incidence of handicap approaching 80%. Fig. 12 depicts a changing morbidity rate as assessed by the Apgar score at 1 and 5 minutes over three time periods at Babies Hospital. The first is prior to continuous intrauterine monitoring of fetal heart rate and intermittent fetal blood acid-base monitoring. The second is during 13% acid-base and 25% heart rate monitoring. The third is during 25% acid-base and 52% heart rate monitoring. The number of patients included in the first period is small. They were the only infants at that time who were scored at 1 and 5 minutes and were part of a large group of 37, 000 patients from 12 centers in a collaborative project. Nearly 25% of these infants had a 1-minute Apgar score of 6 or less. This particular incidence of depressed infants at 1 minute was similar for the 37,000 infants of the combined data obtained from the national collaborative project and appeared for many years to be an irreducible number, considered a standard figure both in the United States and Great Britain. With the increasing use of intraut Ane monitoring of high risk patients and those that showed evidence of fetal difficulty during labor in period 2, the number of depressed infants at 1 minute fell to 13. 1% and at 5 minutes to 3.3%. This decrease in morbidity in 1972 was associated with 13% acid-base monitoring and 25% heart-rate 33. monitoring. This lower number of depressc ants persisted into the third period when acid-base monitoring increased to 25% and heart-rate monitoring to 52%. For the number of patients considered, the reduction in the number of depressed infants at 1 and 5 minutes both from the first to the second and from the first to the third period is substantial. When morbidity is measured in terms of duration of hospitalization, a similar improvement is documented. Fig. 13 indicates the duration of stay in the newbom intensive care unit for 398 infants; 213 were monitored during labor, while 181 were not. Although the number of monitored patients admitted to the unit was greater than those who were not monitored, the proportion of monitored infants requiring extended recovery periods was markedly less than for unmonitored infants for all admissions of 1,000 grams or more. When only those infants weighing 2500 grams or more were considered, the difference became even more striking. Fig. 14 Illustrates that the mean duration for the monitored infants was six days and for the unmonitored infants ten days. Only 20% of the monitored patients required nine days or more of hospitalization as compared to 40% in the unmonitored group. Another specific example of decreased morbidity relates to infants with respiratory distress syndrome or hyaline membrane disease. When the changes in mortality and morbidity are analyzed in terms of the major cause of neonatal and premature infant death, respiratory disease, the central importance of advances in respiratory care designed to improve oxygenation is recognized, e. g., improved mechanical ventilation |