Development and testing of a trigger tool to identify cases at risk of adverse events in non-operating room anesthesia (NORA)

Karen Domino, MD, MPHKaren Domino, MD, MPh
Professor of Anesthesiology and Pain Medicine
University of Washington

Dr. Domino’s Clinical Research submission is entitled Development and testing of a trigger tool to identify cases at risk of adverse events in non-operating room anesthesia (NORA).”

Background: Providing anesthesia services in non-operating room anesthesia (NORA) settings is a rapidly changing and growing challenge. NORA cases in the North American Clinical Outcome Registry (NACOR) increased from 28% in 2010 to 36% in 2014.1 Nearly 75% of NORA cases occurred in the outpatient setting, with sicker and older patients than receiving anesthesia care in the OR.1 Additionally, NORA cases were more frequently started after normal working hours (17% vs. 10% of OR cases, p<0.001).1 The combination of more procedures, patient comorbidities, suboptimal case planning, lack of standard OR equipment, isolation, and limited resources creates the high potential for adverse events (AEs) in NORA settings.2 Most of the understanding of risk associated with NORA comes from retrospective registry analysis or facility-based data.3,4

Trigger tools are an important new development in detection of adverse events.5 Trigger tool methodology uses surveillance algorithms to identify patients at high risk for an adverse event. The presence of risk factors identified via a pre-procedure checklist could trigger a change in location, anesthetic plan, and additional staffing and equipment support to reduce potential patient harm.

Aims: We will adapt trigger tool technology to the NORA clinical context and to the need for prospective action to prevent patient harm. Potential triggers include patient factors (e.g., advanced age, comorbidities), anesthetic planning (e.g., lack of preoperative evaluation and preparation), procedure type and complexity, procedure site (e.g. office vs. other settings), anesthetic factors (e.g., deep sedation without ventilation monitoring; availability of equipment, supplies, and personnel), and timing of procedures (daytime hours vs. nighttime or weekend). We will develop the NORA Trigger Tool to identify cases at risk for AEs in NORA using the modified Delphi technique with an Expert Panel of anesthesiologists, CRNAs, NORA RNs, and proceduralists. We will utilize data from the Anesthesia Closed Claims Project with case comparison with NACOR, and a systematic literature search to inform the trigger tool. We will incorporate feedback from an expert user panel and then test user acceptance and modify the TT based results. We will prospectively test the sensitivity and specificity of the NORA TT to identify cases at risk for AEs in NORA using low-fidelity simulation.

Implications: NORA care has grown significantly over the past decade with 30-40% of anesthesia cases occurring in NORA areas. There were over 2 million NORA cases in 2019 alone, which represents only a sample of total NORA cases in the US. While severe AEs are rare, given the high prevalence of NORA, even a small reduction of preventable harm with pre-procedural use of a NORA TT to result in actionable changes in the anesthetic plan, will improve patient safety for a large number of patients.

Funding: $149,879 (January 1, 2021-December 30, 2022). This grant designated as the APSF/Medtronic Research Award and was also designated the APSF Ellison Pierce, MD, Merit Award for $5000 of unrestricted research.


  1. Nagrebetsky A, Gabriel RA, Dutton RP, et al.: Growth of nonoperating room anesthesia care in the United States: a contemporary trends analysis. Anesth Analg 2017; 124:1261-7.
  2. Chang B, Urman RD. Non-operating room anesthesia: The principles of patient assessment and preparation. Anesthesiol Clin 2016; 34:223-240.
  3. Bhananker SM, Posner KL, Cheney FW, et al.: Injury and liability associated with monitored anesthesia care. A closed claims analysis. Anesthesiology 2006; 104:228-34.
  4. Metzner J, Posner KL, Domino KB: The risk and safety of anesthesia at remote locations: the US closed claims analysis. Curr Opin Anaesthesiol 2009; 22:502-8.
  5. Griffin FA, Resar RK: IHI Global Trigger Tool for measuring adverse events (second edition). IHI Innovation Series white paper. Institute for Healthcare Improvement, Cambridge, MA 2009 (available on