Threat and Error Management (TEM) is an overarching safety concept that originated in aviation in the 1990s. SCT’s Mario Pierobon reports on the application of TEM in medical operating rooms.

Managing patients in the operating room is an iterative dynamic process that is highly dependent on the cooperation among team members and relies on sophisticated technology. In such a context, operatives are exposed to threats and errors on a constant basis. 

In this first part of a two-part story on threat and error management in the operating room we shall specify the operating room as an environment prone to threats and errors, and the threat and error management (TEM) analytical model as it applies to the operating room.

Complex Environment and the Role of the Patient

“The operating room itself is a complex environment that is intolerant of errors. In many cases, adverse events are caused by multiple, small errors, which on their own may have no impact, but can combine to become life-threatening” according to Ruskina et al in a 2013 academic paper entitled ‘Threat and error management for anesthesiologists: a predictive risk taxonomy’[i].

The medical industry adopts the personal approach to error. “Accordingly, error is considered to be a result of the shortcomings of a person or small group of individuals, on whom responsibility for the error is therefore deemed to rest,” say Hickey et al in a 2014 journal paper entitled ‘National Aeronautics and Space Administration ‘‘threat and error’’ model applied to pediatric cardiac surgery: Error cycles precede ∼ 85% of patient deaths’ [ii]. Hickey et al stress that a key differential between aviation and medicine is the patient, as “aviation involves a human-machine interface, with environmental/system modifiers, whereas medicine involves a human-patient interface, with many modifiers, including machinery, system factors, etc. Consequently, surgery is more complex, perhaps evidenced by the <10% of all patient journeys that proceed as the metaphorical ideal with no patient threats, errors, or unintended states.”

The TEM Model

The TEM model describes events that are adverse in terms of risks that can be found in an operational environment and personnel actions that potentiate or exacerbate those threats. “TEM focuses not only upon error prevention, but also upon mitigating the likelihood of patient harm resulting from an error that has occurred. TEM is an overarching safety concept that describes adverse events in terms of risks or challenges that are present in an operational environment (threats) and the actions of specific personnel that potentiate or exacerbate those threats (errors)," say Ruskina et al.[iii]. Threats are those events that are outside the control of the operator, which can decrease the margin of safety and require action in order to prevent further incident. “Errors are physician or treatment team actions that deviate from intentions in a way that increases risk. An error can, in turn, lead to an undesired state, in which options are limited and an immediate response is necessary in order to prevent an adverse event,” say Ruskina et al[iv].

Robert L. Helmreich and David M. Musson define threats as factors that increase the likelihood of an error being committed - these may be environmental (such as lighting), physician-related (fatigue), staff-related (communication), or patient-related (a difficult intubation). The researchers also introduce the definition of latent threats as aspects of the hospital or medical organization that are not always easily identifiable, but that predispose the commission of errors or the emergence of overt threats (call schedules and health policies, for example).[v]

Operator Errors are Endemic

Conditions that facilitate or provoke errors are the main points used by TEM for predicting risk, according to Ruskina et al.[vi] “This may allow proactive management of latent errors or error-producing situations, in contrast to root cause analysis, which responds to an adverse event that has already occurred,” they say. “A critical component of TEM is the assumption that threats and errors cannot always be prevented; threats and operator errors are a routine occurrence that must be detected and mitigated. In this sense, aviation and medicine are similar in that operator errors are endemic and an expected result of human activity.”


[i] Keith J. Ruskina, Marjorie P. Stieglerb, Kellie Parka, Patrick Guffeyc, Viji Kurupa, and Thomas Chidester, Threat and error management for anesthesiologists: a predictive risk taxonomy,
[ii] Edward J. Hickey, Yaroslavna Nosikova, Eric Pham-Hung, Michael Gritti, Steven Schwartz, Christopher A. Caldarone, Andrew Redington, and Glen S. Van Arsdell, National Aeronautics and Space Administration ‘‘threat and error’’ model applied to pediatric cardiac surgery: Error cycles precede ∼ 85% of patient deaths,
[iii] Ruskina et al.
[iv] Ruskina et al.
[v] Robert L. Helmreich and David M. Musson, The University of Texas Threat and Error Management Model: Components and Examples
[vi] Ruskina et al.