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HiQuiPs: Patient Safety in the ED Part 2 – Key Concepts in the Systems-Based Patient Safety Paradigm

Updated: Feb 27, 2022

Authors: Ryan Tam, Ahmed Taher, Amy Cheng, Lucas Chartier

You are working a busy shift in your local ED, which has a paper-based system for documentation and orders. You have seen two patients with the first name ‘Ben’, and two patients with the last name ‘Chen’. As you are reflecting on this, you realize that the last order you placed for one of the ‘Bens’ was placed on the wrong patient chart. You quickly grab the chart, put a line through the order and place it on the correct chart. You wonder whether this “near miss” counts as a medical error, but you are unsure since no harm came to anyone. You are concerned, however, about the potential for a similar error to cause harm in the future, and decide to bring it up at the next ED staff monthly meeting.

Welcome to Part 2 of our patient safety series of HiQuIPs! In our last post, we discussed the evolution of patient safety paradigms, shifting from a focus on individual errors towards a systems-based approach. We also defined key principles that guide High-Reliability Organizations (nuclear power plants, air traffic control centres, and aircraft carriers). In this month’s post, we delve deeper into the patient safety terminology and concepts that support the systems-based approach.


The patient safety literature discusses a number of terms that are relevant to our discussion of the patient safety issue presented above. Several high-yield concepts are as follows:

  • Medical Error: Although many definitions exist, a practical one is that a medical error is an “act of omission or commission in planning or execution that contributes, or could contribute to, an unintended result.”(1)

  • Near Miss: This is defined as an “act of commission or omission that could have harmed the patient but did not cause harm as a result of chance, prevention, or mitigation.”(2)

  • Adverse Event: This is an “event that results in unintended harm to the patient by an act of commission or omission rather than by the underlying disease or condition of the patient.”(3)

  • Preventable Adverse Events: These are adverse events that are “avoidable by any means currently available unless that means was not considered standard care.”(3)

  • Negligent Adverse Events: These include a “failure to meet the standard of care reasonably expected of an average physician qualified to take care of the patient in question.”(4)

These concepts are related to one another in a way that is presented in Figure 1 below. Therefore, the vignette presented above classifies as a medical error, and more specifically a near miss. Appreciating events such as this as a medical error is an important aspect of the systems-based patient safety paradigm. This allows recognition of elements of the ED process that carry potential harm. It also focuses their mitigation not on instructing providers to focus more, or work smarter, but instead to create a better system that avoids this type of error.

Medical errors concepts in patient safety (source: RM Wachter,

Medical Errors and the Swiss Cheese Model

The systems-based patient safety paradigm views our complex adaptive health systems as having many layers of interaction, these layers can also act as redundancies against potential adverse events. For example, as illustrated in our “root cause analysis” post, the blood transfusion process contained multiple steps with checks prior to transfusing our patient including checks at the lab, by the porter, and by the nurses prior to administration. However, there are times when the system fails during one or more of these checkpoints to ultimately result in an adverse event. This is referred to as the Swiss Cheese Model, where latent errors line up and result in an adverse event. This is demonstrated in Figure 2.

To illustrate this point further, following the two “Bens” in the ED, let’s say one needed a blood transfusion. The transfusion was ordered for Ben A, but the crossmatch was done with Ben B’s blood. No system flag was in place to draw attention to the name similarity in the ED. When the blood arrived from the blood bank, only one nurse (instead of two) checked the blood and started the transfusion. Ben A had a major transfusion reaction. Several latent errors have lined up to cause an adverse event in this vignette.

Depiction of the swiss cheese model (source: J Reason,

This systems-based paradigm for patient safety supports a proactive approach to seek latent errors, respond to active errors, and follow a non-shaming and non-blaming approach. This is best done in a multidisciplinary team environment with wide stakeholder involvement. Many of the Quality Improvement concepts discussed in previous posts may be used to engage your stakeholders through these patient safety concerns to optimize the current system. Furthermore, when root cause analyses are completed, attention may be given to potential latent errors in the system. In our transfusion error vignette a root cause analysis was completed and several changes were instituted: a new system to flagging similar names differently on patient charts and the white board, a similar flagging system in the blood bank, a CME was held to remind nursing staff of the need for two people to check the blood product before transfusion, and a new blood product signing sheet was instituted for the two people who complete the final check.

To support a systems-based patient safety paradigm, it is important to reflect on the culture of patient safety in your ED and your larger institution. What are the barriers to creating a strong patient safety culture? What are some important elements of this culture to nurture? Stay tuned to our next post where we will discuss these elements as we build a stronger understanding of the role of the patient safety culture in the systems-based approach.

Senior Editor: Lucas Chartier

Copyedited by: Paula Sneath


  1. Grober E, Bohnen J. Defining medical error. Can J Surg. 2005;48(1):39-44. [PMC]

  2. Aspden PCJ, Corrigan JM, Woolcott J, Erickson SM. Near-Miss Analysis. In: Patient Safety: Achieving a New Standard of Care. 1st ed. Washington, DC: National Academies Press; 2003:528.

  3. Aspeden PCJ, Corrigan JM, Wolcott J, Erickson SM. Adverse Event Analysis. In: Patient Safety: Achieving a New Standard of Care. 1st ed. Washington, DC: The National Academies Press; 2003:528.

  4. Brennan T, Leape L, Laird N, et al. Incidence of adverse events and negligence in hospitalized patients: results of the Harvard Medical Practice Study I. 1991. Qual Saf Health Care. 2004;13(2):145-151; discussion 151-2. [PubMed]

  5. Wachter R. Understanding Patient Safety. 2nd ed. New York, NY: McGraw Hill Professional; 2012.

  6. Reason J. Human error: models and management. BMJ. 2000;320(7237):768-770. [PubMed]

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