Objective: To assess the relationship between the experience of pediatric housestaff and tests ordered on infants in the neonatal intensive care unit (ICU).
Design: Prospective, cohort study over one full academic year.
Setting: One academic Level III neonatal intensive care nursery.
Patients: Data were collected prospectively on all 785 infants admitted to the neonatal ICU from July 1993 to June 1994. These infants were cared for by 14 different categorical pediatric housestaff.
Measurements and main results: Our neonatal ICU has either a resident or an intern on-call by himself/herself at night, affording us a natural setting to compare intern vs. resident test ordering. The outcomes of interest were number of arterial blood gases, radiographs, and electrolytes ordered per infant by the on-call pediatric houseofficer, as tabulated the morning after the call night. Control variables included the severity-of-illness of the individual infant (using the Neonatal Therapeutic Intervention Scoring System), the workload of the houseofficer (number of patients, number of admissions), and supervision (rounding frequency and on-call attending). Controlling for the severity-of-illness of the infant, the workload on the call night, and supervision with multiple linear regression, we found that interns ordered significantly (p = .02) greater numbers of arterial blood gases per infant than residents, amounting to some 0.33 blood gases per infant per call night (3.22 vs. 2.89 arterial blood gases per infant per night). This increase of 0.33 blood gases per infant amounts to interns ordering $169 more arterial blood gases per call night at our institution. There was no difference between interns and residents in ordering radiographs or electrolytes.
Conclusion: Interns order significantly more arterial blood gases per infant than junior and senior residents on-call in the neonatal ICU. Additional study is required to see if the experience of housestaff is associated with a broader array of neonatal outcomes, such as morbidity and mortality.