Safety of MRI Examinations Under Sedation: A Nationwide Survey in Japan.

Abstract

Background: MRI is performed under sedation for patients requiring immobility or for those already sedated for clinical management. Although specialist guidelines advocate for anesthesiologist-led care, non-anesthesiologist-led adult sedation is a common practice worldwide. Furthermore, the increase in risk attributable to sedation has not been quantified.

Purpose: To investigate MRI sedation practices in Japan to quantify associated risks and to identify key safety vulnerabilities.

Study type: Survey.

Subjects: Data were collected from 549 Japanese medical institutions.

Assessment: A web-based questionnaire was distributed to members of major Japanese radiological societies to assess institutional policies, sedation management practices, safety measures, and historical adverse events. The survey primarily concerned deep sedation and general anesthesia in adults but also encompassed questions on minimal-to-moderate sedation and pediatric sedation.

Statistical tests: Chi-squared test, Welch's t-test, Fisher's exact test were used. Odds ratios (ORs) were calculated based on the cumulative number of adverse events over 2 years to examine the increased risk from sedation. p < 0.05 was considered significant.

Results: Adult MRI sedation management is typically led by attending physicians (84%) with limited consultation from anesthesiologists for sedation (9.0%) or radiologists for scan indication (5.1%). Safety infrastructure was often inadequate, with MRI-compatible ventilators (48%) or syringe pumps (29%) and capnometers (24%). In an analysis combining both pediatric and adult data, the ORs for the total sedated group versus non-sedated group were 62 (95% confidence interval, 54-73) for peripheral capillary oxygen saturation drop, 48 (32-72) for respiratory arrest, 15 (8.0-28) for cardiac arrest, 6.7 (2.0-23) for physical trauma, and 8.9 (4.0-20) for projectile accidents.

Data conclusion: MRI examinations under sedation are associated with a substantially higher risk of adverse events. Developing and implementing a standardized protocol may mitigate these procedural risks.

Level of evidence: 4:

Stage of technical efficacy: 5.