Patient safety

An issue which is of concern to anyone who receives treatment in a hospital is the topic of patient safety. How likely is it that there will be a serious mistake in treatment — wrong-site surgery, incorrect medication or radiation dose, exposure to a hospital-acquired infection? The current evidence is alarming. (Martin Makary et al estimate that over 250,000 deaths per year result from medical mistakes — making medical error now the third leading cause of mortality in the United States (link).) And when these events occur, where should we look for assigning responsibility — at the individual providers, at the systems that have been implemented for patient care, at the regulatory agencies responsible for overseeing patient safety?

Medical accidents commonly demonstrate a complex interaction of factors, from the individual provider to the technologies in use to failures of regulation and oversight. We can look at a hospital as a place where caring professionals do their best to improve the health of their patients while scrupulously avoiding errors. Or we can look at it as an intricate system involving the recording and dissemination of information about patients; the administration of procedures to patients (surgery, medication, radiation therapy). In this sense a hospital is similar to a factory with multiple intersecting locations of activity. Finally, we can look at it as an organization — a system of division of labor, cooperation, and supervision by large numbers of staff whose joint efforts lead to health and accidents alike. Obviously each of these perspectives is partially correct. Doctors, nurses, and technicians are carefully and extensively trained to diagnose and treat their patients. The technology of the hospital — the digital patient record system, the devices that administer drugs, the surgical robots — can be designed better or worse from a safety point of view. And the social organization of the hospital can be effective and safe, or it can be dysfunctional and unsafe. So all three aspects are relevant both to safe operations and the possibility of chronic lack of safety.

So how should we analyze the phenomenon of patient safety? What factors can be identified that distinguish high safety hospitals from low safety? What lessons can be learned from the study of accidents and mistakes that cumulatively lead to a hospitals patient safety record?

The view that primarily emphasizes expertise and training of individual practitioners is very common in the healthcare industry, and yet this approach is not particularly useful as a basis for improving the safety of healthcare systems. Skill and expertise are necessary conditions for effective medical treatment; but the other two zones of accident space are probably more important for reducing accidents — the design of treatment systems and the organizational features that coordinate the activities of the various individuals within the system.

Dr. James Bagian is a strong advocate for the perspective of treating healthcare institutions as systems. Bagian considers both technical systems characteristics of processes and the organizational forms through which these processes are carried out and monitored. And he is very skilled at teasing out some of the ways in which features of both system and organization lead to avoidable accidents and failures. I recall his description of a safety walkthrough he had done in a major hospital. He said that during the tour he noticed a number of nurses’ stations which were covered with yellow sticky notes. He observed that this is both a symptom and a cause of an accident-prone organization. It means that individual caregivers were obligated to remind themselves of tasks and exceptions that needed to be observed. Far better was to have a set of systems and protocols that made sticky notes unnecessary. Here is the abstract from a short summary article by Bagian on the current state of patient safety:


The traditional approach to patient safety in health care has ranged from reticence to outward denial of serious flaws. This undermines the otherwise remarkable advances in technology and information that have characterized the specialty of medical practice. In addition, lessons learned in industries outside health care, such as in aviation, provide opportunities for improvements that successfully reduce mishaps and errors while maintaining a standard of excellence. This is precisely the call in medicine prompted by the 1999 Institute of Medicine report “To Err Is Human: Building a Safer Health System.” However, to effect these changes, key components of a successful safety system must include: (1) communication, (2) a shift from a posture of reliance on human infallibility (hence “shame and blame”) to checklists that recognize the contribution of the system and account for human limitations, and (3) a cultivation of non-punitive open and/or de-identified/anonymous reporting of safety concerns, including close calls, in addition to adverse events.

(Here is the Institute of Medicine study to which Bagian refers; link.)

Nancy Leveson is an aeronautical and software engineer who has spent most of her career devoted to designing safe systems. Her book Engineering a Safer World: Systems Thinking Applied to Safety is a recent presentation of her theories of systems safety. She applies these approaches to problems of patient safety with several co-authors in “A Systems Approach to Analyzing and Preventing Hospital Adverse Events” (link). Here is the abstract and summary of findings for that article:


This study aimed to demonstrate the use of a systems theory-based accident analysis technique in health care applications as a more powerful alternative to the chain-of-event accident models currently underpinning root cause analysis methods.


A new accident analysis technique, CAST [Causal Analysis based on Systems Theory], is described and illustrated on a set of adverse cardiovascular surgery events at a large medical center. The lessons that can be learned from the analysis are compared with those that can be derived from the typical root cause analysis techniques used today.


The analysis of the 30 cardiovascular surgery adverse events using CAST revealed the reasons behind unsafe individual behavior, which were related to the design of the system involved and not negligence or incompetence on the part of individuals. With the use of the system-theoretic analysis results, recommendations can be generated to change the context in which decisions are made and thus improve decision making and reduce the risk of an accident.


The use of a systems-theoretic accident analysis technique can assist in identifying causal factors at all levels of the system without simply assigning blame to either the frontline clinicians or technicians involved. Identification of these causal factors in accidents will help health care systems learn from mistakes and design system-level changes to prevent them in the future.

Crucial in this article is this research group’s effort to identify causes “at all levels of the system without simply assigning blame to either the frontline clinicians or technicians involved”. The key result is this: “The analysis of the 30 cardiovascular surgery adverse events using CAST revealed the reasons behind unsafe individual behavior, which were related to the design of the system involved and not negligence or incompetence on the part of individuals.”

Bagian, Leveson, and others make a crucial point: in order to substantially increase the performance of hospitals and the healthcare system more generally when it comes to patient safety, it will be necessary to extend the focus of safety analysis from individual incidents and agents to the systems and organizations through which these accidents were possible. In other words, attention to systems and organizations is crucial if we are to significantly reduce the frequency of medical and hospital mistakes.

(The Makary et al estimate of 250,000 deaths caused by medical error has been questioned on methodological grounds. See Aaron Carroll’s thoughtful rebuttal (NYT 8/15/16; link).)

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