Clinical Utility of Out-of-Hours Chest Radiographs

In Australia, radiology services are provided as full 24-hour services, 24-hour urgent out-of-hours (on-call) services, and business hours-only service. The primary purpose of this study was to determine whether out-of-hours (11 PM-7 AM) chest x-ray (CXR) referrals are consistent with out-of-hours service expectations associated with the cost and inconvenience of calling staff in from home. A secondary objective was to determine whether the mobile chest plain film examinations are consistent with expectations of a patient's increased degree of infirmary.

A retrospective analysis was undertaken over 6 contiguous months for patients referred from the emergency department for CXRs out-of-hours and within standard hours (in-hours). The study population included 436 out-of-hours patients recruited into the investigation cohort and a matched cohort of 438 CXR examinations performed in-hours. The key information gleaned from the study was concordance or discordance between the clinical details relating to the actual referral and the findings of the CXR.

The total sample comprised 414 females (47.4%) and 460 males (52.6%). The mean age was 55.3 years, median was 56.5 years, with a range of 0-97 years. The examination type performed was 8.9% mobile compared with 91.1% departmental for the sample. It was found that there was 43.5% prevalence of abnormalities, 27.0% significant abnormalities, and 8.7% clinically significant abnormality. The predictors found for clinically significant abnormalities were increasing patient age (P < .001) and the need for mobile examination (P < .001). Performing the examination out-of-hours did not predict a clinically significant abnormality (P = .491) and similarly, gender did not predict clinically significant abnormality (P = .152).

The results suggest that similar approaches to referrals for CXRs are applied in-hours and during the out-of-hours period which are inconsistent with the "urgent" philosophy that should accompany an out-of-hours service. Only increasing patient age and the need for a mobile CXR offered predictors of a clinical significant abnormality and this offers an insight into the potential approach to the development of referral guidelines for out-of-hours procedures.