Clinicians can use add-on point-of-care ultrasonography in patients with unspecified acute dyspnea in the emergency department (ED) or inpatient setting, according to the American College of Physicians (ACP), although the recommendation is based on a low certainty of evidence.
Combining point-of-care ultrasonography (POCUS) with the standard diagnostic pathway increased the proportion of correct diagnoses by 32%, boosted the sensitivity of standard testing without “a substantial tradeoff in speciﬁcity,” did not seem to be tied to any serious harms, is not a high-cost test, and did not result in a longer length of stay (LOS) for patients, wrote Amir Qaseem, MD, PhD, MHA, of the ACP in Philadelphia, and co-authors on the college’s clinical guidelines committee.
However, the committee “graded this as a conditional recommendation because there was limited evidence examining the effect of POCUS on health outcomes, and there are many uncertainties related to variation in testing protocols, training, clinician experience, clinical setting, and equipment,” they wrote in the Annals of Internal Medicine.
Still, low or absent evidence for POCUS for acute shortness of breath and related symptoms in the ED or inpatient setting “does not preclude clinically meaningful beneﬁts, especially given the supporting evidence on correctness of diagnosis and test accuracy as well as the lack of evidence of serious harms or high costs,” according to Qaseem and co-authors.
The use of POCUS in this setting has had its fair share of champions and critics over the years. Perhaps its greatest advocate has been Maurizio Zanobetti, MD, PhD, of Careggi University Hospital in Florence, Italy. In 2011, Zanobetti and colleagues evaluated if chest US could replace x-ray for dyspnea assessment in the ED.
They reported that “ultrasonography proved to be more accurate in distinguishing free pleural effusion” versus chest x-ray, but noted that the imaging in the study was done by “one highly trained physician.” In a letter to the editor, Andrew R. L. Medford, MBChB, MD, of the North Bristol Lung Centre in England, pointed out that “the training required for detecting the sonographic features of…[acute dyspnea]…is extensive…acquisition and interpretation of sonographic images is notoriously operator dependent…[which] presents issues with how a critical mass of operators who are adequately trained can be generated for the ED environment.”
In 2017, Zanobetti’s group conducted another study looking at “integrated” POCUS for acute dyspnea in the ED, arguing that the imaging exam “can shorten the time needed to formulate a diagnosis, while maintaining an acceptable safety profile.”
While they did find a good overall concordance between POCUS and standard ED diagnosis for stratifying patients who would benefit from additional evaluation, ED physicians in Saudi Arabia argued in a letter to the editor that “[i]n the study, [ED] physicians were not asked about their impressions or possible diagnoses at the time of the primary assessment. A diagnosis is often made clinically during the initial assessment and… the pretest probability should be high enough to suspect the diagnosis and initiate treatment…the difference in time for formulating a diagnosis could be attributed to the design of the study rather than the use of PoCUS.” Zanobetti’s group responded that “a careful history taking and a thorough physical examination can only direct diagnostic suspicion but are unreliable and need to be integrated with laboratory and radiologic testing.”
In 2020, researchers in Canada found that lung POCUS “resulted in no difference in ED length of stay and time to disposition decision, but was associated with faster administration of disease-specific treatments for elderly patients with suspected acute heart failure or COPD [chronic obstructive pulmonary disease].”
Nonetheless, POCUS has made inroads in the ED setting with anesthesiologists developing an “I-AIM (Indication, Acquisition, Interpretation, Medical Decision-making) Framework” for POCUS, while Zanobetti and colleagues offered a review of the appropriate use of POCUS in critical care.
The ACP clinical guideline is based on an evidence review by Gerald Gartlehner, MD, MPH, of Danube University Krems in Austria, and co-authors. They evaluated five randomized controlled trials (RCTs) and 44 prospective cohort-type studies done from January 2004 to August 2020.
Sample sizes ranged from 25 to >2,000 participants, with mean ages ranging from 54 to 86, and women making up the study population ranging from one-third to >60%. Most of the studies were based on data from portable POCUS while five studies used hand-held devices. The majority of the studies (n=29) were deemed to have a high risk of bias, particularly those that used hand-held devices, according to Gartlehner’s group.
In terms of benefits and harms of POCUS, the authors limited outcomes to in-hospital mortality, hospital LOS, and readmission. They found 5.1% of participants who had add-on POCUS died versus 6.6% of participants who only underwent standard diagnosis. LOS findings were similar between the POCUS and control groups (around 3 days) as was the readmission rate.
For correct diagnosis and time to diagnosis, the authors found higher percentages of the former for patients who underwent add-on POCUS, with more patients in the POCUS group getting appropriate treatment after 4 hours versus the control group. One RCT with a high bias risk reported a shorter time to diagnosis with add-on POCUS at 40 minutes versus 60 minutes.
The sensitivities for add-on POCUS went from 79% to 100%, and speciﬁcities from 63% to 100% versus 0% to 83%, and 68% to 100%, respectively, for the standard diagnostic pathway.
No studies “reported on harmful health effects of POCUS, such as consequences of false-positive or false-negative ﬁndings or additional diagnostic interventions because of incidental ﬁndings,” Gartlehner and co-authors stated.
Finally, for costs, Qaseem’s group said no studies were identified that compared POCUS versus standard care, but that the average Medicare reimbursement rate for POCUS was higher, both for physicians and hospital ED or lab.
Qaseem and co-authors offered some conditions for the guidelines:
- They only apply to the inpatient setting.
- Patients in the reviewed studies were ultimately diagnosed with one of the following: congestive heart failure, pleural effusion, pneumonia, pneumothorax, or pulmonary embolism. Most patients with COPD, asthma, acute coronary symptoms, and trauma were excluded.
- The recommendation does not apply to hand-held POCUS.
- Clinicians should be trained in the use and interpretation of POCUS.
A clinical guideline from the American College of Physicians (ACP) stated that clinicians may use point-of-care ultrasonography (POCUS), in combination with the standard diagnostic pathway, when there is diagnostic uncertainty in patients with acute dyspnea in emergency department or inpatient settings.
While the ACP committee graded the recommendation because of limited evidence for the effect of POCUS on health outcomes, POCUS still has clinically meaningful beneﬁts, without evidence of serious harms.
Shalmali Pal, Contributing Writer, BreakingMED™
The evidence review was supported by the ACP.
Qaseem reported no relationships relevant to the contents of this paper to disclose. A co-author reported support from the ACP.
Gartlehner and some co-authors reported support from the ACP. A co-author reported a relationship with the Austrian Society of Ultrasound in Medicine and Biology (ÖGUM).
Cat ID: 254
Topic ID: 253,254,254,728,791,730,192,925