Congenital diaphragmatic hernia in Minnesota. Impact of antenatal diagnosis on survival.

OBJECTIVE: We characterized the natural history and true mortality of congenital diaphragmatic hernia (CDH) in newborn patients by identifying all infants born with this condition in a fixed geographic region over a 2-year period. We examined this population to determine the frequency of intrauterine diagnosis, the outcome of prenatally diagnosed infants, and the impact of deaths in infants with an unsuspected diagnosis (the "hidden mortality") on the overall outcome of this condition.

DESIGN: This was a retrospective population survey of all infants born with CDH in Minnesota between June 1988 and June 1990.

SETTING: All Minnesota birth and death records were reviewed to identify patients with the diagnosis of CDH. A separate survey of all level 3 intensive care nurseries was conducted and the record of each identified patient was reviewed. Extracorporeal membrane oxygenation was available throughout the study period.

MAIN OUTCOME MEASURE: Survival to hospital discharge and short-term morbidity were examined for each patient.

RESULTS: Survival was 60% (29/48). Eleven of 19 deaths occurred in patients born prematurely and/or with coexisting major anomalies. Eight percent (4/48) of patients died within the first hour of life prior to diagnosis (hidden mortality). Intrauterine diagnosis of CDH was made in 15 patients. Survival was 60% (9/15) in infants whose conditions were diagnosed in utero, a rate identical to that for infants whose conditions were diagnosed in the postnatal period (61% [20/33]). There was no relationship between age at fetal diagnosis and mortality.

CONCLUSIONS: The hidden mortality of CDH was low. Almost half of the total mortality for CDH was associated with coexisting, additional anomalies. Patients who were not offered extracorporeal membrane oxygenation owing to prematurity, other major anomalies, or birth at a center that did not offer extracorporeal membrane oxygenation accounted for 84% (16/19) of deaths. These data will be useful for determining the impact of new therapeutic strategies on the mortality of CDH.