Patient Safety Tip of the Week Archive

Patient Safety Tip of the Week

July 26, 2022

More Risks in the Radiology Suite

You’ve seen our multiple columns describing the radiology suite as being high-risk for patient safety events. In our October 22, 2013 Patient Safety Tip of the Week “How Safe Is Your Radiology Suite” and the other columns listed below we’ve discussed the multitude of safety issues seen in radiology suites that have little to do with radiology per se. That’s because sick patients with multiple medical problems and vulnerabilities are being taken to the radiology suite and staying there, sometimes for prolonged periods. The events include things like falls, medication errors, patient mixups, IV connection errors, running out of oxygen, conscious sedation incidents, suicides, and others.

But sometimes factors related to the imaging procedure may also contribute to patient safety events. Sanchez et al. (Sanchez 2022) recently discussed cases of 2 patients given IV sedation to facilitate MRI scans. In one, a 43-year-old woman with acute neurological symptoms and signs was given lorazepam 2 mg intravenously (IV) as premedication to reduce agitation after a first attempt at doing the MRI was unsuccessful. The MRI was again unsuccessful, despite anxiolysis. After returning to the medical unit, flumazenil 0.2 mg was given due to somnolence, with subsequent improvement in mental status.

In the second case, a 71-year-old man with a possible epidural abscess following a bout of sepsis was sent for an MRI scan. He was unable to tolerate the scan due to back pain, so hydromorphone 0.5 mg IV was administered. Because of continued restlessness, additional doses of lorazepam 1 mg IV and hydromorphone 0.4 mg IV were ordered. After the patient received a 3rd dose of lorazepam 1mg IV, he became obtunded, hypotensive, and developed respiratory depression with oxygen saturation around 60%. The rapid response team was called, and naloxone and flumazenil were administered. The patient was placed on bilevel positive airway pressure (BiPAP) and given a fluid bolus before being transported to the intensive care unit (ICU), where he was emergently intubated. The patient remained intubated for several days due to severe acute respiratory distress syndrome (ARDS), which was attributed to aspiration while in the MRI machine.

Sanchez et al. provide a nice discussion of the risks of minimal-to-moderate sedation for imaging procedures, especially in high-risk patients, when multiple medication doses are required, and when monitoring is limited or inadequate (e.g., inside an MRI machine). They highlight the need for risk assessment prior to administering such drugs and consideration of patient-specific risk factors for respiratory depression. They stress such risk factors for oversedation as obesity, hepatic, renal, and lung disease; substance use disorder, and obstructive sleep apnea. They recommend looking for higher American Society of Anesthesia (ASA) physical status classification and checking a STOP-BANG score to help identify patients who might have unrecognized obstructive sleep apnea. In addition, they note that lower BMI values are associated with higher plasma concentrations of fentanyl or midazolam, two commonly used medications for diagnostic imaging sedation. They also suggest assessing the patient for potential aspiration risk and considering NPO (nothing by mouth) orders prior to diagnostic imaging procedures with sedation.

They caution against “dose-stacking” of medications (administering medications multiple times and/or from various routes before each dose reaches its peak therapeutic effect).

Monitoring is very important. Because of variability and risk for oversedation, patients must be assessed before and after each dose or medication administration. They note that consistent sedation assessments are important throughout the duration of action of the medication(s) administered. They emphasize “Continuous electronic monitoring is indicated for moderate levels of sedation or higher and should be considered for high-risk patients receiving opioids and/or benzodiazepines.”

They also stress an important point that is often overlooked – sedation might be avoided all together in many patients. They discuss non-pharmacologic techniques that can be used to minimize anxiety, agitation, and claustrophobia prior to such imaging studies. These include positioning issues, use of movie goggles, mirrors, 2-way communications, call buttons, and even fragrance administration.

Nice, practical discussion of a problem we continue to see all too often in patients undergoing imaging studies.

Some of our prior columns on patient safety issues in the radiology suite: