A guest post by Rory Spiegel (@EMNerd_) who blogs on nihilism and the art of doing nothing at emnerd.com.
A landmark paper recently published in Lancet Respiratory Medicine is certainly destined to send the ED Ultrasound world into a tizzy. This is the first RCT examining the utility of Emergency Department based Point of Care ultrasound (POCUS) for patients presenting with undifferentiated respiratory complaints. Authors randomized patients presenting to the ED with signs or symptoms concerning for a respiratory etiology to either a standard work up as determined by the treating physician or the addition of POCUS performed by a single experienced operator. The US protocol consisted of sonographic examination of the heart, lungs and lower extremity deep veins to identify possible causes of patients' symptoms. The authors' primary outcome was the percentage of patients with a correct presumptive diagnosis 4 hours after presentation to the Emergency Department as determined by two physicians blinded to ED POCUS findings, but with access to the records of the entire hospital stay.
Using this POCUS protocol the authors found stunning success in their primary endpoint. Specifically, the rate of correct diagnoses made at 4-hours in the POCUS group was 88% compared to 63.7% in the standard work up group. Furthermore 78% of the patients in the POCUS group received "appropriate" treatment in the Emergency Department compared to 56.7% in the standard work up group.
Though promising, these benefits did not translate into improvements in true patient oriented benefits. Though not statistically significant, the observed in-hospital and 30-day mortality trended towards harm in the POCUS arm ( 8.2% vs 5.1% and 12% vs 7% respectively). Nor was there any meaningful difference in length of stay or hospital-free days between those in the POCUS group and those in the control group. Even more concerning, was the significant increase in downstream testing that occurred in patients randomized to the POCUS group. Specifically the amount of chest CTs (8.2% vs 1.9%), echocardiograms (10.1% vs 3.8%) and diagnostic thoracocenthesis (5.7% vs 0%). This, of course, may be statistical whimsy, but these findings are concerning for a certain degree of overdiagnosis. Unless detected pathology results in improved patient outcomes secondary to treatment, are we truly helping, or just piling on potential costs of increased vigilance?
I’m sure we all have experienced firsthand the utility of bedside US and this is by no means a call to abandon our probes, but rather an acknowledgement of the possibility of subtle harms. We must keep in mind, all testing comes at a price no matter how non-invasive and radiation-free it appears. The cost in this case is information and how we choose to act on it. This would certainly not be the first time increased access to medical technology has lead to such unintended consequences.
"Point-of-Care Ultrasonography in Patients Admitted With Respiratory Symptoms: a Single-Blind, Randomised Controlled Trial"