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Are daily chest radiographs and arterial blood gas tests required in ICU patients on mechanical ventilation?

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No, they are not required or needed, but daily radiography and arterial blood gas testing are common practice: eg, 60% of intensive care unit (ICU) patients get daily radiographs,1 even though results provide low diagnostic yield and are unlikely to alter patient management compared with testing only when indicated.

The Choosing Wisely campaign,2 a collaborative effort of a number of professional societies, advises against ordering these diagnostic tests daily because routine testing increases risks to patients and burdens the healthcare system. Instead, testing is recommended only in response to a specific clinical question, or when the test results will affect the patient’s treatment.


Chest radiographs enable practitioners to monitor the position of endotracheal tubes and central venous catheters, evaluate fluid status, follow up on abnormal findings, detect complications of procedures (such as a pneumothorax), and identify otherwise undetected conditions.

And daily chest radiographs often detect abnormalities. A 1991 study by Hall et al3 of 538 chest radiographs in 74 patients on mechanical ventilation reported that 30% of daily routine chest radiographs disclosed a new but minor finding (eg, a small change in endotracheal tube position or a small infiltrate). The new findings were major in 13 (17.6%) of the 74 patients (95% confidence interval [CI] 9%–26%). These included findings that required an immediate diagnostic or therapeutic intervention (eg, endotracheal tube below the tracheal carina, malposition of a catheter, pneumothorax, large pleural effusion).

But most studies say daily radiographs are not needed. In a large prospective study published in 2006, Graat et al4 evaluated the clinical value of 2,457 routine chest radiographs in 754 patients in a combined surgical and medical ICU. Daily chest radiographs revealed new or unexpected findings in 5.8% of cases, but only 2.2% warranted a change in therapy. No differences were found between the medical and surgical patients. The authors concluded that daily routine radiographs in ICU patients seldom reveal unexpected, clinically relevant abnormalities, and those findings rarely require urgent intervention.

A 2010 meta-analysis of 8 studies (7,078 patients) by Oba and Zaza5 compared on-demand and daily routine strategies of performing chest radiographs. They estimated that eliminating daily routine chest radiographs would not affect death rates in the hospital (odds ratio [OR] 1.02, 95% CI 0.89–1.17, P = .78) or the ICU (OR 0.92, 95% CI 0.76–1.11, P = .4). They also found no significant differences in length of stay or duration of mechanical ventilation. This meta-analysis suggests that routine radiographs can be eliminated without adversely affecting outcomes in ICU patients.

A larger meta-analysis (9 trials, 39,358 radiographs, 9,611 patients) published in 2012 by Ganapathy et al6 also found no harm associated with restrictive radiography protocols. These investigators compared a daily chest radiography protocol against a protocol based on clinical indications. The primary outcome was the mortality rate in the ICU; secondary outcomes were the mortality rate in the hospital, the length of stay in the ICU, and duration of mechanical ventilation. They found no differences between routine and restrictive strategies in terms of ICU mortality (risk ratio [RR] 1.04, 95% CI 0.84–1.28, P = .72), hospital mortality (RR 0.98, 95% CI 0.68–1.41, P = .91), or other secondary outcomes.

Clinically indicated testing is better

The conclusion from these studies is that routine chest radiographs in patients undergoing mechanical ventilation does not improve patient outcomes, and thus, a clinically indicated protocol is preferred.

Furthermore, routine daily radiographs have adverse effects such as more cumulative radiation exposure to the patient7 and greater risk of accidental removal of devices (eg, catheters, tubes).8 Another concern is a higher risk of hospital-associated infections from bacterial spread from caregivers’ hands.9

Finally, daily radiographs increase the use of healthcare resources and expenditures. In a 2011 study, Gershengorn et al1 estimated that adopting a clinically indicated radiography strategy could save more than $144 million annually in the United States.

The ACR agrees. Appropriateness criteria published by the American College of Radiology (ACR) in 201510 recommend against routine daily chest radiographs in the ICU, in keeping with the findings of the critical care community. The ACR recommends an initial radiograph at admission to the ICU. However, follow-up radiographs should be obtained only for specific clinical indications, including a change in the patient’s clinical condition or to check for proper placement of endotracheal or nasogastric or orogastric tubes, pulmonary arterial catheters, central venous catheters, chest tubes, and other life-support devices.

Ultrasonography as an alternative

Ultrasonography is widely available and provides an alternative to chest radiography for detecting significant abnormalities in patients on mechanical ventilation without exposing them to radiation and using relatively fewer resources.

A 2012 meta-analysis (8 studies, 1,048 patients) found that bedside ultrasonography reliably detects pneumothorax.11 It can also provide a rapid diagnosis of the cause of acute respiratory failure such as pneumonia or pulmonary edema.12 Ultrasonography, with the appropriate expertise, can also confirm the position of an endotracheal tube13 or central venous catheter.14

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