SURVIVORS OF EXTRACORPOREAL MEMBRANE-OXYGENATION AT 1 YEAR OF AGE - THE RELATIONSHIP OF PRIMARY DIAGNOSIS WITH HEALTH AND NEURODEVELOPMENTAL SEQUELAE

Objective. Although extracorporeal membrane oxygenation (ECMO) has bee n responsible for the improved survival of infants with cardiorespirat ory failure, its use over the last decade has raised concern as to the health of the survivors and the severity of neurodevelopmental sequel ae. Though infants meeting ECMO criteria have a variety of reasons pro mpting the use of this therapy, most studies to date have simply repor ted outcome on the entire population that has survived without regard to the original nature of the child's illness. The purpose of this stu dy was to determine the type and extent of health-related problems and neurodevelopmental sequelae in infants requiring ECMO therapy and the association of these findings with the infants' primary diagnosis. Me thods. Eighty-two neonates required ECMO therapy between May 1990 and December 1993. The most common diagnoses prompting ECMO therapy includ ed 26% with meconium aspiration syndrome, 34% with congenital diaphrag matic hernia (CDH), 16% with persistence of the fetal circulation, and 9% with sepsis. Information concerning the hospital course was obtain ed through chart review, and the infants were seen at 6 and 12 months of age for medical and neurodevelopmental follow-up. Data were analyze d using descriptive statistics and Fisher's exact test, t-tests, and a nalysis of variance where appropriate. Assessment of hospital course a nd discharge data focused on the four main diagnostic groups, whereas follow-up data were further limited to the two most frequently encount ered groups (meconium aspiration syndrome and CDH). Results. Overall s urvival was 79%. Significant differences in survival were noted based on primary diagnostic category. Those with CDH fared the worst, with a n overall survival rate of 68% and a more complicated hospital course with a longer duration of ECMO. At discharge, the CDH group demonstrat ed a greater incidence of bronchopulmonary dysplasia, gastroesophageal reflux, feeding dysfunction, and hypotonia. No significant difference s were noted in the incidence of intraventricular hemorrhage, cerebral infarction, extra-axial fluid collection, or seizures. Hearing loss w as uncommon. During the first year of life, although no differences we re noted in growth rate, infants in the CDH group continued to experie nce a higher incidence of gastroesophageal reflux (43%) and feeding dy sfunction, with 36% of this group requiring tube feedings for nourishm ent. Although 40% of the entire ECMO population was diagnosed with bro nchopulmonary dysplasia before initial discharge, by 1 year of age, 50 % of those with CDH versus 17% of those with meconium aspiration syndr ome continued to be clinically symptomatic. Although the ECMO populati on as a whole scored in the normal range developmentally, CDH infants had significantly lower motor and slightly lower cognitive scores at 1 year of age. Despite finding abnormal muscle tone in a high percentag e of the entire ECMO population at discharge, most demonstrated resolu tion by 1 year of age. Of the CDH infants, however, 75% continued to e vidence some degree of hypotonicity, which affected acquisition and qu ality of gross motor skills. Conclusion. Despite the impact that ECMO has had on the survival of infants with severe respiratory failure, th e efficacy of ECMO cannot be assessed accurately without an analysis o f the extent and morbidity in the surviving population. Most centers a re reporting relatively low morbidity for the entire ECMO population. However, upon separating this population into primary diagnostic categ ories, we found that the CDH population encountered a greater number o f neurodevelopmental, respiratory, and feeding abnormalities during th e first year of life. The reasons for these differences are unclear bu t may be related to the severity of the primary illness itself or the variables associated with prolonged ECMO therapy. Stratifying outcome by primary diagnosis gives the health care provider more information t o improve existing intervention techniques and to provide parents with more accurate counseling.