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Patient Safety: Original Clinical Research Report

Anesthesia Adverse Events Voluntarily Reported in the Veterans Health Administration and Lessons Learned

Neily, Julia RN, MS, MPH*; Silla, Elda S. MHS, CRNA, MBA*; Sum-Ping, Sam (John) T. MBChB, FRCA‡,§,‖; Reedy, Roberta DNSc, CRNA; Paull, Douglas E. MD, MS†,#; Mazzia, Lisa MD; Mills, Peter D. PhD, MS**,*; Hemphill, Robin R. MD, MPH

Author Information
doi: 10.1213/ANE.0000000000002149
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Patient safety continues to be a priority in health care, particularly within anesthesia care. Anesthesia providers were pioneers in patient safety and continue as leaders through partnerships with the Anesthesia Patient Safety Foundation, the American Society of Anesthesiologists, and the American Association of Nurse Anesthetists. This attention to safety has led to reductions in operative mortality. For example, Mellin-Olsen et al1 found that specific anesthesia-related death occurs in fewer than 1 in 100,000 patients. However, despite anesthesia providers’ commitment to safe care, anesthesia-related adverse events still occur, with some resulting in malpractice claims, permanent injury, or death.1–6

To date, most studies of anesthesia adverse events have been based on closed claims malpractice data,7 with only 1 study based on voluntary reporting.6 Munting et al6 shared voluntary reports of anesthesia-related critical incidents from a tertiary care hospital in the Netherlands. The current study is unique because it shares anesthesia-related events reported from more than 130 hospitals in the largest integrated health care system in the United States: the Veterans Health Administration (VHA).

The goal of this study is to provide in-depth information on reported anesthesia-related adverse events, with root causes and suggested actions for improvement. A secondary goal of this study is to recommend actions based on human factors engineering (HFE) principles to prevent future occurrences of similar events. HFE principles focus on the design and analysis of interactions between people, equipment, and the environment.8,9 Well-designed user-friendly equipment and standardized processes can improve the interaction of humans with their environment to mitigate errors.8


Study Design

This is a descriptive analysis of reported anesthesia adverse events examined with root cause analysis (RCA) that occurred between May 30, 2012, and May 1, 2015. The Dartmouth College Committee for the Protection of Human Subjects reviewed and approved this project.

Reported adverse events and close calls in the VHA are reviewed at the local facility, and the patient safety manager rates the severity and probability of harm using a Safety Assessment Code Matrix. Those events with the highest severity of harm whether actual or potential require an RCA. The RCA process uses a team to examine what happened, why it happened, and what should be done to prevent it from happening again.10 The focus of the RCA is on the systemic and organizational factors that contributed to the adverse event.11,12

Inclusion/Exclusion Criteria

We searched the National Center for Patient Safety database for RCA reports related to anesthesia care from all VHA facilities between 2012 and 2015. We included adverse events in which an anesthesia provider played a primary role and could have a direct impact on the systems issues contributing to the event. An adverse event, as opposed to a complication, required an error of commission or omission and was not due to the patient’s underlying condition or illness. We excluded reported events with inadequate information about the occurrence.

We drafted a codebook that categorized type of events, root causes, and action plans (Table 1). The codebook was similar to that used in previous studies and modified for the current study, and is available on request.13,14 Root causes and severity ratings were coded based on facility reports. Events were coded by consensus by 2 authors (E.S.S. and J.N.). The events were read and then codes were entered into a Microsoft Excel (version 2010; Microsoft Corporation, Redmond, WA) database for analysis and summary reporting. The patient safety manager rates the severity of the outcome to the patient on a range from 1 to 4: minor, moderate, major, and catastrophic, respectively15 (Table 2).

Table 1.:
VHA Anesthesia Adverse Events May 30, 2012 to May 1, 2015
Table 2.:
Severity Descriptions

We calculated the in-operating room (OR) anesthesia adverse event rates as the reported events that were in-OR over the number of in-OR surgical procedures performed with anesthesia between May 30, 2012, and May 1, 2015, multiplied by 100,000 to produce the number of adverse event per 100,000 cases.


Types of Adverse Events

A total of 292 RCA reports related to anesthesia care were identified between May 2012 and May 2015 (Figure 1).

Figure 1.:
Data selection process for anesthesia-specific RCAs. RCA indicates root cause analysis.

Excluded reports from this data set were 211 cases in which the anesthesia provider did not play a primary role in the event, 4 were lacking sufficient information, and 14 did not result in any harm. In addition, 27 out-of-OR airway management events not involving an anesthesia provider were excluded, resulting in 36 events for this analysis.

There were 3228 total RCA reports in VHA during the same time period; the 36 cases in this study represent 1% of these cases. The reports were from all areas of the United States.

The RCA reports were classified into 9 categories (Table 1). Medication errors were the most commonly reported event (28%, n = 10). These involved high-risk medications such as heparin and epinephrine, syringe swaps, intravenous pump line confusion related to labeling issues, and medication dilution errors. Regional block errors and airway management complications (both 14%, n =5) and skin integrity events and other unexpected events were the next most frequently reported categories (both, 11%, n =4). Incomplete consents for anesthesia and procedures were also reported (8%, n = 3). Two of these consent-related cases were scored as moderate severity because they resulted in unnecessary cancellation and rescheduling of procedures. Reported equipment events were related to lack of clarity regarding directions for sterilization or cleaning processes (8%, n = 3). One event involving a ventilator failure after induction was rated with a severe outcome. Although this did not cause direct patient injury, the case was cancelled and the patient was safely transferred to postanesthesia care unit for recovery. The 2 remaining events included a retained wire from a central line insertion intraoperatively (3%, n = 1) and one case of patient awareness during anesthesia (3%, n = 1). The severity of these 2 events was reported as major.

Reported Event Rates

Overall, 28% or 78% of our cases were categorized as in OR events. Consequently, the rate of in-OR anesthesia adverse events was 4.84 per 100,000 cases.

Severity of Outcome

Of the 36 anesthesia events reported, 5 (14%) were identified as being catastrophic, 10 (28%) major, 12 (34%) moderate, and 9 (26%) minor (Table 2).

Root Causes

The 36 RCA reports contained 76 root causes and 114 action plans (Figures 2 and 3). Reports were categorized into 9 overall adverse event categories (Table 1).

Figure 2.:
Root causes of anesthesia-specific adverse events as identified by local Veterans Health Administration teams.
Figure 3.:
Planned actions to address anesthesia-specific adverse events developed by local Veterans Health Administration teams.

The most frequently cited root cause was a process or policy that needed improvement (25%, n = 19). Not having a standardized process or policy (ie, variation in how staff performed functions) was the second most frequently reported root cause/contributing factor (19.7%, n = 15). For example, sites reported variation in how medications were stocked, diluted, or obtained. Problems with communication among medical staff and ancillary departments (ie, pharmacy) accounted for 14.4% (n = 11) of the root causes. Need for staff education accounted for 9.2% (n = 7) of the root causes. Human factors were identified for both medication and regional block errors (7.8%, n = 6). For example, varying concentrations of the same medicine were stored in close proximity to one another, or repositioning the patient after the extremity was identified but before the regional block, all while the equipment and provider position remained unchanged. Challenges with staffing and scheduling of various staff members (secretary, pharmacist, medical, and nursing) accounted for 5.2% (n = 4) of the root causes. Unclear equipment instructions (3.9%, n = 3) and inaccessible equipment (3.9%, n = 3) and “other category” (3.9%, n = 3) were less frequently cited as root causes. The failure to double-check medications, lack of appropriate equipment/supplies, and patient education each accounted for 1.3% (n = 1) events (Figure 2).

Action Plans

The most common action plans involved process or policy improvements (51.8%, n =59), followed by staff education (19%, n = 22; Figure 3).

Table 1 lists the adverse event types with the root causes and additional suggestions for actions based on HFE principles. Ninety-one of the 155 outcome measures were rated for effectiveness at the time of data extraction. Of these 91 outcome measures, 84 (92%) were rated by the patient safety manager at the facility as making care better or much better.


This study identified 36 reported anesthesia-specific adverse events during a 3-year period. The most commonly reported adverse events were medication errors accounting for 10 of the events. One of the second most commonly reported adverse events in our study was airway management problems (n =5; or 14%). These results are similar to other studies in which respiratory events (such as unexpected difficult intubation and re-intubation) were the most commonly reported critical incidents.6,7 However, our results differ from Munting et al,6 in that we found that regional block errors were common in our data set. This difference may be due to the fact that we may have had more reports of regional block errors because, in the VHA, a wrong-sided block is a critical incident that must be reported.

The majority of root causes (45%) indicated a need to establish or improve a process or policy. This is similar to a study of surgical adverse events in the VHA, in which lack of standardization of clinical processes was the most common root cause.13 It is possible that there are more processes within the OR setting than other areas that allow for variation and thus point to the need for more standardization.

Fifty-two percent of action plans were related to process or policy improvements. However, HFE principles suggest that process and policy changes are unlikely to result in durable improvements. Rather, structural changes are stronger actions.9 It is possible that individual sites did not suggest structural changes because they lacked the resources to enact wide-sweeping system changes such as instituting bar coding medication systems in the OR. Another example of a strong human factors action is to make physical and structural changes (eg, the inability to move/rotate an OR table unless safety belts are secured across the patient). Standardization is another key principle of HFE providing consistent processes to help minimize errors. Standardization helps limit workarounds and shortcuts and provides a process supported by checklists and guidelines. Lack of standardization may leave opportunities for variability and potential errors. We suggest several HFE-based actions such as forcing functions, elimination of storage of look-alike soundalike medications, limiting stock of high-risk medication strengths, bar coding medications, and the use of cognitive aids and checklists to standardize care.17 Implementing HFE actions creates efficiency and can improve patient satisfaction and safety.18

Medications errors could be addressed by double-packaging high-risk/high-dose medications requiring providers to pause once more before administration, prefilling syringes with bar-coded labels,19 using well-designed and user-friendly infusion pumps,20 and point-of-care bar code–assisted anesthesia documentation systems.19 Look-alike packaging of drugs can contribute to error and should be avoided whenever possible. Vendor selection with safety in mind and staff training could work synergistically to decrease medication errors.19,21

Regional block errors addressed by HFE actions could include adapting and promoting the “Stop Before You Block” campaign,22 developing a standard timeout process, and avoiding patient position changes during the preblock process. Posters and cognitive aids could facilitate preanesthetic site verification. Currently, VHA policy requires that “the operative site must be marked prior to the anesthesia provider proceeding with performance of a regional nerve block.”23

Increasing collaboration (preprocedural briefings, clear and consistent handoffs, etc) for difficult intubations and unusual extubation situations (ie, halos, jaw wiring, head and neck surgery) and using postoperative airway checklists can also improve safety in these situations. High-fidelity simulation and team-based training for airway crisis management could also help avoid catastrophic events.24 Emergency scenarios should include training in surgical cricothyroidotomy in the simulation laboratory.25 VHA has been using a simulation-based curriculum for several years to train staff in airway management, including those managing patient airways in non-OR settings.26 Identification of difficult airways or patients with potential extubation precautions needs to be recognized and documented both within the medical record and with “special” markings/taping around in-dwelling endotracheal tubes so that all providers are aware of the high risks involved with these patients’ airways. This would inform providers that special attention and the presence of anesthesia providers could increase safety for non-OR high-risk extubations.

While individual events were discussed, we also examined the larger context of reporting rates. We found a rate of 4.84 reported adverse events per 100,000 cases, while Munting et al6 reported on both close calls and actual incidents and found 354 events per 10,000 anesthetics. We recognize these rates vary greatly from each other. Their study differs in several ways. First, Munting et al6 included close calls, and our study did not. Second, we only included cases with an RCA, while Munting et al6 included all reported critical incidents. Last, we limited cases in our study to those considered solely within the anesthesia provider’s sphere of influence to improve. While this can make sense from an improvement perspective, it may have been too limiting, since we deliver care as an interdisciplinary team, and ideally, patient safety analyses would be conducted from a team perspective. We realize these 2 concepts are at odds with each other; we advocate for an interdisciplinary team approach to deliver the highest quality care, and yet in this study, we focused on cases specifically related to anesthesia care. We did this as a starting point to accept that current care in the VHA and in other arenas is organized by discipline.


This study has several limitations. First, these reports represent only those reported to the patient safety manager at the local facility and for which the decision was made to conduct an RCA. In addition, individual centers may vary in applying the scoring matrix to determine the need for an RCA. Therefore, this is a factor that may lead to variation in reporting by centers and variation in which events are considered for RCA. Self-reported events may also result in only the most severe events being reported or underreporting. Another limiting factor in this study is that RCA reports do not contain patient-specific information, and therefore, we are not able to report patient characteristics or risk factors. As such, we recognize there may have been other factors not reported in the RCA that contributed to the adverse events. Any retrospective review can lend itself to hindsight bias as well. It is also possible that practice patterns changed over the 3 years of data analysis, changing the adverse events and the reasons for them.


Although anesthesia care is safe, there are still some gaps that need to be filled. Standardization, simulation, and adoption of available technology could help close those gaps. This study makes several suggestions for actions to address anesthesia adverse events, such as forcing functions, separating storage of look-alike sound-alike medications, limiting stock of high-risk medication strengths, bar coding medications, the use of cognitive aids such as checklists, and standardization of processes. Individual sites may not have the resources to implement widespread HFE-based changes, such as bar coding of medications in the OR, but this systemwide analysis can point to such a need. High-fidelity simulation for training in airway management and other skills could also be effective in helping prevent the anesthesia-related adverse events described in this study.


Name: Julia Neily, RN, MS, MPH.

Contribution: This author helped with study design and methods; data review, coding, analysis, and interpretation; and writing and/or editing of the manuscript.

Name: Elda S. Silla, MHS, CRNA, MBA.

Contribution: This author helped with study design and methods; data review, coding, analysis, and interpretation; and writing and/or editing of the manuscript.

Name: Sam (John) T. Sum-Ping, MBChB, FRCA.

Contribution: This author helped with data interpretation and writing and/or editing of the manuscript.

Name: Roberta Reedy, DNSc, CRNA.

Contribution: This author helped with data interpretation and writing and/or editing of the manuscript.

Name: Douglas E. Paull, MD, MS.

Contribution: This author helped with data interpretation and writing and/or editing of the manuscript.

Name: Lisa Mazzia, MD.

Contribution: This author helped with data interpretation and writing and/or editing of the manuscript.

Name: Peter D. Mills, PhD, MS.

Contribution: This author helped with study design and methods, data interpretation, and writing and/or editing of the manuscript.

Name: Robin R. Hemphill, MD, MPH.

Contribution: This author helped with data interpretation and writing and/or editing of the manuscript.

This manuscript was handled by: Richard C. Prielipp, MD.


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