This post is likely to get a few people talking. Some valid points made in the comment section also.
May 21, 2015 — Emergency room (ER) physicians often perform bedside obstetric ultrasound studies on first-trimester patients in the ER, but these patients should also receive radiology ultrasound scans to avoid potentially dangerous missed diagnoses, according to research from Santa Barbara Cottage Hospital in California.
In a retrospective review, a research team led by radiology resident Dr. Myrna Wallace-Severa found that point-of-care ultrasound studies on first-trimester patients by ER physicians had a 24% discrepancy rate with exams performed in the radiology department and interpreted by radiologists. They shared their findings in an e-poster at the American College of Radiology’s ACR 2015 meeting this week in Washington, DC.
“As radiologists, we need to be very present and still encourage ER physicians to go ahead and get that official ultrasound when it comes to first-trimester ultrasound patients, because misinterpretation or just missing things on those patients can be life-threatening,” she told AuntMinnie.com.
While point-of-care ultrasound is becoming more common in managing first-trimester patients in the emergency setting, interpretation of these exams is often complicated and difficult, Wallace-Severa said. Ultrasound is an operator-dependent modality, and misinterpretation can have fatal consequences.
At Santa Barbara Cottage Hospital, ER physicians perform and interpret bedside obstetric ultrasounds — frequently just transabdominal studies — using compact ultrasound systems, while radiology ultrasound exams, which include both transabdominal and transvaginal studies, are supervised and interpreted by radiologists. The radiology ultrasound exams are performed in the radiology department by sonographers certified by the American Registry for Diagnostic Medical Sonography (ARDMS), who are available 24/7 to scan patients, according to the group.
A previous study in 2012 at the hospital showed a significant discrepancy between ER physicians and radiologists in the interpretation of first-trimester obstetric ultrasounds; the researchers wanted to perform a follow-up study to see if there had been any change. The retrospective study included all ultrasound studies found on the hospital’s PACS from June 2013 through December 2014 that had separate interpretations by ER physicians and radiologists.
Cases were excluded from the research if more than 24 hours had passed between the ER-performed studies and the radiology ultrasound exams, or if exams were performed during two different emergency department visits. ER ultrasounds without documented reported findings were also left out of the analysis.
For the remaining 75 cases, three radiologists certified by the American Board of Radiology independently reviewed just the final reports of both the emergency medicine physicians and the radiologists. The reviewers determined if there was significant concordance or discordance in a yes/no fashion, and a majority vote was used to make the final ruling; discrepancies were considered significant if they included disagreement over the presence of intrauterine pregnancy, gestational sac, fetal demise, and ectopic pregnancy in the presence of a positive pregnancy exam.
High discrepancy rate
The researchers found a significant discrepancy rate between the emergency medicine physicians and the radiologists.
|ER vs. radiology ultrasound findings|
|Positive ER ultrasound findings||Negative ER ultrasound findings|
|Positive radiology findings||48 cases||17 cases|
|Negative radiology findings||1 cases||9 cases|
The ER physicians and radiologists differed in their interpretation of 18 of the 75 cases, for a discrepancy rate of 24%. When compared with the radiology ultrasound findings, the emergency room studies showed the following:
- Sensitivity: 73.9%
- Specificity: 90%
- Accuracy: 76%
Interestingly, the 24% misclassification rate was nearly identical to the 24.2% misclassification rate found in the hospital’s 2012 study, Wallace-Severa said.
“The practices around bedside [ER] obstetric ultrasounds and just really the overall appropriateness of the studies should be looked at because the discrepancy rate is still pretty high,” she said.
The discrepancy differences could be due to a number of factors, including training and experience, according to the researchers. For example, guidelines from the American College of Emergency Physicians (ACEP) for training pathways and the use of bedside ultrasound recommend that residents perform a minimum of 150 bedside ultrasound scans in their residency training to reach competency.
“I think any radiologist who does ultrasounds can tell you they do that amount in a week,” Wallace-Severa said.
Furthermore, a 2010 survey of emergency medicine residency programs in the U.S. found that the average number of ultrasound scans was 137 fewer than the ACEP benchmark. And only 47% of the responding programs in that survey said more than half of their faculty members were credentialed in ultrasound, according to the researchers.
Other reasons for the high discrepancy rate could be the fact that only difficult cases are referred for official radiology ultrasound studies, and that different equipment and techniques are used between the two groups of studies.
Additional retrospective and/or prospective studies may be useful to evaluate practices considering ER-performed obstetric ultrasounds and the overall appropriateness of these studies in settings where official ultrasound services are available 24/7, the researchers noted.
Copyright © 2015 AuntMinnie.com
Last Updated np 5/21/2015 1:21:47 PM
Forum Comments5 comments so far …
5/21/2015 8:09:58 AM
Had a kid with a grade IV renal lac and grade II splenic lac day before yesterday… bedside ER ultrasound negative. So yeah, perhaps not the whole picture.
5/21/2015 1:34:44 PM
Emergency department (ED) point of care ultrasound in obstetrics is not intented to diagnose ectopic pregnancy, rather to answer a specific question: is there an intrauterine pregnancy or not? If the answer is no, and the patient is has a positive HCG, they appropriately go on to get a formal ultrasound, as demonstrated in the case above.
In trauma, ED ultrasound is not intented to diagnose renal, splenic or liver lacerations, rather to answer a specific question: is there free fluid or not?
5/21/2015 1:55:30 PM
Well I assume if the bedside ultrasound was ‘negative’, then that presumably means they didn’t see free fluid?
And I would assume with that trauma there was probably some free fluid!
5/21/2015 2:20:41 PM
Keep in mind this study only looked at cases where ED and Radiology ultrasounds were performed on the same patient on the same day. It does not start with the denominator of all first-trimester evaluations performed at the point of care by the emergency physicians which is critical in interpreting this information. When no definitive intrauterine pregnancy is found by the emergency physician, or there is some finding of concern, that warrants a Radiology study.
In this study, about once per week (75 studies in 18 months), the ED consulted Radiology on a first trimester pregnancy evaluation. When they did, 76% of the time there was no difference between the ED and Radiology interpretation, but one quarter of those consults may have yielded additional information. So about once per month Radiology noted a finding not picked up by the Emergency Physicians who consulted them for their input on that case. How is this not simply appropriate and judicious use of resources and consultation?
Also I agree with the other comment that when the ED found “No IUP” and consulted Radiology who found “Ectopic” that is entirely consistent and appropriate. Because an ectopic pregnancy is not an IUP. I would not count that in the discrepant column.
I’m glad this article by AuntMinnie is generating discussion, though I would caution against too much weight being placed on a study which has not undergone peer review. And the resident who conducted this study should not find themselves peer-reviewed in the comments page! We should encourage all specialties to research ways to best deliver care to our shared patients.
I hope AuntMinnie’s staff writers do not jump the shark to garner pageviews, and rather help their readers appropriately interpret data and place it into the context of clinical care.
5/21/2015 2:36:15 PMDavidTSchwartz
The author of the ePoster does not seem to fully understand the role of ED-US, which is generally to answer specific question that is within the scope of ED-US practice.
In the one case illustrated, an ED-US was presumably done in a patient in early pregnancy to look for an intrauterine pregnancy. If an IUP is not seen and the concern is for an ectopic pregnancy, it is entirely appropriate to consult gynecology and/or obtain a radiology department ultrasound to look directly for an ectopic pregnancy, as was done in the illustrated case.
It is therefore unclear how many of the “discrepancies” reported in the ePoster were really discrepancies.
Confirming fetal demise is generally something that the ED would want a radiology-performed US to confirm, if this is needed during the ED visit.It is also incorrect to simply refer to the results of imaging tests as only “positive” or “negative.” The purpose and particular imaging findings should be more completely described.