Appropriate education about the safe use of ultrasound is not routinely taught to residents and fellows, with few trainees using the ultrasound output display standard and nearly as few able to find the displays, according to a survey published in the Jan. issue of the Journal of Ultrasound in Medicine.
"Although most studies have not shown adverse clinical outcomes from ultrasound exposure, thermal and mechanical mechanisms are recognized as potential sources of biological effects," wrote Laura E. Houston, MD, of the Medical University of South Carolina in Charleston, and colleagues. For ultrasound machines capable of producing mechanical indexes (MI) or thermal indexes (TI) of greater than one, American Institute of Ultrasound in Medicine and the National Electrical Manufacturers Association standards require the TI or MI be displayed on the screen.
The authors investigated whether these safety standards were being taught to obstetrics and gynecology residents and maternal-fetal medicine fellows in the United States. Of the 1,200 postgraduate fourth-year obstetrics and gynecology residents in Accreditation Council for Graduate Medical Education-accredited programs, and of the 265 national maternal-fetal medicine fellows, 3 percent of residents and 26 percent of fellows returned the surveys over the two-year study period.
Thirty-nine percent of residents and 38 percent of fellows reported no limitations to the use of ultrasound in the first trimester of use on pregnant women, while 27 percent of residents and 22 percent of fellows reported no limitations to the use of Doppler ultrasound in the first trimester.
"Regarding the output display standard, knowledge was generally low for both residents and fellows. Just 13.4 percent of residents reported that they could find or use the TI or MI, and 10.9 percent stated that they use the TI or MI during their ultrasound examinations," Houston and colleagues found. Similarly, 23 percent of maternal-fetal medicine fellows could find the TI/MI and 21 percent reported using it.
Seventy-three percent of residents and fellows correctly identified thermal mechanisms as potential sources of harm from ultrasound exposure, whereas 35 percent of all respondents were able to recognize mechanical mechanisms as potential sources of harm. Approximately 50 percent of residents and fellows said they felt comfortable educating patients on the safety of ultrasound.
The survey did reveal a significant increase in knowledge of mechanical mechanisms with each year of training, from 21 percent in trainees' first years to 61 percent in their third years.
"This study provides evidence that it [ultrasound safety] is not routinely being included in resident education; it appears to be more represented in maternal-fetal medicine fellow education, although not thoroughly," the authors wrote. Houston and colleagues pointed out that their low response rate (3 percent for residents and 26 percent for fellows) and voluntary self-selection bias may have slanted their findings.
"This study provides evidence of the current need to bring ultrasound safety more consistently into obstetrics and gynecology and maternal-fetal medicine fellow education," the authors concluded.