A study carried out at the New York University Langone Health Electrophysiology Lab (New York, USA) showed significantly reduced radiation exposure levels after implementing a radiation safety time out before all electrophysiology procedures. Anthony Aizer (New York University School of Medicine, New York, USA) and others write in JACC: Clinical Electrophysiology that “electrophysiology laboratories, as well as other areas of cardiovascular medicine using fluoroscopy, should strongly consider the use of radiation safety time outs to reduce radiation exposure and improve safety”.
The authors hypothesised that, as the use of surgical safety checklists has been proven to reduce the risk of patient morbidity and mortality, and as radiation exposure puts patients as well as operators at risk of adverse outcomes, “a radiation safety time out implemented before all electrophysiology procedures would reduce patient and operator radiation exposure.” They add: “To analyse this, we designed a sequential intervention study comparing radiation exposure prior to versus during implementation of a radiation safety time out.”
In this prospective cohort study, radiation usage was measured for all procedures performed on adults in the laboratory between October 2015 and June 2017. Aizer and colleagues designed a seven-item radiation safety time out checklist that was implemented for use by operators in the electrophysiology laboratory in April 2016 and then withdrawn three months later. The primary endpoint of the study was dose area product, which assesses patient radiation exposure. Secondary endpoints were reference point dose, which assesses peak skin dose, fluoroscopy time, total procedure time, use of optional protective equipment and techniques, and use of alternative imaging.
For 1,040 procedures included in the study, median dose area product reduced by 21% from 18.7Gy∙cm2 before the time out to 14.7Gy∙cm2 during the first three months after implementing the time out (p=0.007). The median reference point dose reduced from 163mGy before the time out to 122mGy during the time out (p=0.011). Secondary endpoints of note are the use of sterile disposable protective shields and ultrasound imaging for access, which increased significantly during the time out period.
During the 12 months after withdrawal of the radiation safety time out, the dose area product remained significantly reduced, as did the reference point dose. However, fluoroscopy time did not show any significant change during or after the time out period.
While some authors have previously suggested that checklists should be implemented to reduce the risks of exposure to radiation in cardiovascular imaging, there is little evidence of their efficacy. One study by Kokorowski et al that involved paediatric ureteroscopy and another by Leschied et al that involved radiology students performing gastrointestinal or genitourinary imaging both demonstrated some reduction in fluoroscopy time with the use of checklists. However, both studies were limited with small sample sizes and a lack of assessment of permanence of the interventions.
In comparison, the present study included more than 1,000 patients and demonstrated a reduction in radiation levels for 12 months after the intervention was withdrawn. According to the authors, this is the first study to “demonstrate that a radiation safety time out reduces radiation exposure levels in the electrophysiology lab.”
The authors also note: “in our analyses, one year after the radiation safety time out was withdrawn, radiation levels remained reduced, suggesting that the time out was not only effective, but also educational.”
However, Aizer and colleagues point out that there were some safety measures which the operators did not continue to use after the radiation safety time out was withdrawn. Few practitioners “checked to save fluoroscopy images over fluorography/cine images” and “only attending physicians checked for beam collimation.” Use of both of these safety techniques would help reduce the radiation that patients are exposed to and should be recommended, the authors suggest.
Some limitations of this study are noted. For example, the study only involved a single centre so further research is needed to confirm the results in other institutions and in other types of procedures involving radiation. Radiation exposure of operators in this study was estimated using dose area product and reference point dose but more accurate results may have been obtained using radiation dosimeter badges.
The authors conclude: “in light of the findings in our study … expansion of a preprocedure radiation safety time out to additional areas of medicine should be considered.”