Are Routine’ Daily Chest X-Rays Justifiable in ICU Patients?

Abstract & Commentary

Synopsis: For patients who required > 48 hours of mechanical ventilation, daily routine chest radiographs and films obtained based on clinical indications produced similar outcomes.

Source: Krivopal M, et al. Chest. 2003;123:1607-1614.

Two different schools of thought exist regarding the need for daily routine chest radiographs (CXRs) in the ICU: 1) they are essential because there is a high prevalence of unsuspected findings; and 2) they are unnecessary because they rarely discover findings that change management decisions. This study was conducted to systematically examine this question by randomizing patients on mechanical ventilation for > 48 hours to routine or nonroutine CXRs, and evaluating findings in regard to their diagnostic, therapeutic, and outcome efficacy. New findings were defined as any process that had not been seen on the prior CXR. Subjects were 94 patients admitted to a medical ICU who were randomized to routine (n = 43) or nonroutine (n = 51) CXRs and were followed to extubation or death. There were no significant differences between groups, with respect to age, medical insurance, major comorbidities, or reason for mechanical ventilation.

In the routine arm, 33.4% of 293 CXRs indicated new findings, as compared to 53.1% of 226 CXRs in the nonroutine arm (P = 0.004). Only 13.3% of the CXRs in the routine arm prompted an intervention, as compared to 50% of those in the nonroutine arm (P = 0.002). The proportion of CXRs with new findings was 1.59 times greater in the nonroutine arm (95% confidence interval [CI], 1.16-2.18). The interventions were further evaluated in terms of whether they were major (eg, diuresis, antibiotic added, thoracentesis, bronchoscopy, chest tube placement) or minor (eg, tube or line adjustments, chest physical therapy). Only 18 (9%) of routine CXRs led to any intervention and only 9 (4.5%) of these resulted in a major intervention. There was no difference in the mean duration of mechanical ventilation (P = 0.2606), ICU stay (P = 0.1936), or total hospital stay (P = 0.2199) between groups. There was also no difference in the final discharge site or mortality between groups.

Comment by Leslie A. Hoffman, RN, PhD

Findings of this study support the concept that patients who are mechanically ventilated for > 48 hours receive no additional benefit from mandated daily routine CXRs in terms of diagnostic or therapeutic efficacy. Further, there were no differences in the duration of mechanical ventilation, ICU or hospital lengths of stay, disposition, or mortality. Prior studies that have addressed this question have reached different conclusions, despite similar results. In one study, unanticipated findings were reported in 3.4% of routine CXRs, prompting a recommendation for daily routine CXRs.1 However, most of these unanticipated findings related to malpositioning of endotracheal and nasogastric tubes. A second study also reported a 3.4% incidence of unsuspected CXR findings.2 Again, most unanticipated findings related to malpositioning of endotracheal and nasogastric tubes. However, Silverstein and associates recommended CXRs only when clinically indicated.

In the present study, patients were enrolled after they had been on mechanical ventilation for > 48 hours. This time period was chosen to avoid the initial hours after intubation when CXRs are typically ordered for various clinical reasons. Perhaps the best strategy is a combination of both approaches—routine daily CXRs during the first 48 hours of intubation, followed by CXRs when clinically indicated. As expected, the number of CXRs was greater in the routine group. However, the differences were not as great as might be anticipated (routine group = 6.8 per patient; nonroutine group = 4.4 per patient). Accordingly, it appears that patient condition indicated the need for a CXR on most study days. Those CXRs that were eliminated likely would have been ordered for stable patients at low risk for problems. Krivopal and colleagues were also able to demonstrate high diagnostic efficacy for a strategy that involved nonroutine CXRs. More than 50% of CXRs ordered for a clinical indication demonstrated a new finding, and half of these prompted a new intervention. Of the 293 CXRs in patients in the routine group, 93 (15%) were done when there was a clinical indication for the procedure. With these eliminated, only 9 of 200 CXRs resulted in a major intervention.

Findings of this study provide additional support for the assertion that patients receiving mechanical ventilation for > 48 hours receive no additional benefit from a daily CXR. An added benefit of this strategy is the decreased cumulative radiation exposure and reduced cost.

References

1. Hall JB, et al. Crit Care Med. 1991;19:689-693.

2. Silverstein DS, et al. J Trauma. 1993;35:643-646.