Defining patient safety
Patient safety can, at its simplest, be defined as:
The avoidance, prevention and amelioration of adverse outcomes or injuries stemming from the process of healthcare.
(VINCENT, 2006)
This definition goes some way to differentiate patient safety from more general concerns about the quality of healthcare; the focus is on the ‘dark side of quality’ (Vincent, 1997), care that is actually harmful rather than just not of a good standard. Healthcare is, in many cases at least, inherently hazardous and the definition implicitly acknowledges this. The definition also refers to the amelioration of adverse outcomes or injuries, which broadens the definition beyond traditional safety concerns towards an area that would, in many industries, be called disaster management. In healthcare, amelioration firstly refers to the need for rapid medical intervention to deal with the immediate crisis, but also to the need to care for injured patients and to support the staff involved.
The short definition given above however, does not really capture the defining characteristics of patient safety and its associated conceptual background. The US National Patient Safety Foundation sought to do this when setting out a research agenda for patient safety (Box 3.1). They pointed particularly to the fact that traditional quality initiatives had not fully addressed error and harm, that safety resides in systems as well as people, and that safety has to be actively pursued and promoted. Simply trying to avoid damage is not enough; rather one must reduce errors of all kinds and pursue high reliability as an essential component of high quality care.
BOX 3.1 Defining characteristics of patient safety
Patient safety is concerned primarily with the avoidance, prevention and amelioration of adverse outcomes or injuries stemming from healthcare itself. It should address events that span the continuum of ‘errors’ and ‘deviations’ to accidents.
Safety emerges from the interaction of the components of the system. It is more than the absence of adverse outcomes and it is more than avoidance of identifiable ‘preventable’ errors or occurrences. Safety does not reside in a person, device or department. Improving safety depends on learning how safety emerges from the interaction of components.
Patient safety is related to ‘quality of care’, but the two concepts are not synonymous. Safety is an important subset of quality. To date, activities to manage quality have not focused sufficiently on patient safety issues.
(© [2000] NATIONAL PATIENT SAFETY FOUNDATION. REPRINTED WITH PERMISSION OF NPSF. ALL RIGHTS RESERVED)
Patient safety – reducing harm or reducing error?
Patient safety is sometimes equated with preventing error. This seems innocent enough, but is a potentially limiting assumption. There is no question that an understanding of error is fundamental to patient safety; however, there are differences of view as to whether the focus of patient safety research and practice should be on error or on harm. Formulating an objective of a specific programme purely in terms of error reduction makes sense when, for instance, your aim is simply to reduce failures in a clinical process in the reasonable belief that this will increase overall reliability, efficiency and safety. However, when we consider the overall aim of patient safety, there are a number of reasons for keeping harm in the forefront of our minds.
The first reason is very simple. Harm is what patients care most about. We will all put up with errors in our care, to some extent at least, as long as we do not come to harm.
Second, consider all the myriad forms of harm that can come from healthcare: complications of surgery, infection from unsafe injections, infection from over crowded hospitals, adverse drug reactions, overdoses from badly designed infusion pumps and so on. Should we assume that all these are necessarily due to error?If we equate patient safety with error reduction, we run the risk of not addressing any form of harm which is either not due to error, or only partly due to error.
Third, many errors do not lead to harm and, indeed, may be necessary to the learning and maintenance of safety. Surgeons for instance, may make quite a number of minor errors during a procedure, none of which really compromise the safety of the patient or the final outcome of the operation (Joice, Hanna and Cuschieri, 1998). As Hofer, Kerr and Hayward (2000) have argued, identifying errors does not equate to identifying them as causes of harm. They imagine a hypothetical study of a series of blood transfusion reactions, which reveals errors in the process of care in 60% of patients with reactions. This finding should certainly alert us to the possibility that errors are causing harm. However, they go on to argue:
Now, suppose that in transfusions in which no reaction occurred there was also an error rate of 60%. Can we argue that the errors caused the adverse event? Can we infer that by engineering out the errors, transfusion reactions would be eliminated? It is clear we cannot.
(HOFER, KERR AND HAYWARD, 2000)
This difficulty of linking errors to harm is an instance of the more general problem of linking process measures to outcome (Lilford et al., 2004) and is not particular to patient safety. We may in fact attempt to reduce harm without considering error at all. In their paper ‘Patient safety efforts should focus on medical injuries’, Peter Layde and colleagues (2002) describe the well established public health approach to reduction of injuries, which is rooted in efforts to control infectious disease. The injury prevention model sets out the host factors that predispose to injury, which are essentially those pertaining to the patient (being old or otherwise vulnerable for instance), the agent factors (the various hazards of drugs and interventions) and the social, physical and environmental aspects of the environment.
Two particular points emerge from this brief summary. First, it is possible to think about injury reduction without even mentioning the term error. Second, while sophisticated models of the causes of injury can be built, problems can sometimes be circumvented simply by intervening at a critical point in the causal chain:
While numerous factors undoubtedly contributed to fatal childhood falls in New York City, including personality characteristics and behavioural characteristics of the children and their caretakers, the New York City Health Department proposed a classic injury prevention strategy – installation of window barriers.
(LAYDE ET AL., 2002)
Let’s start with the big picture, the coverage of healthcare across organizations and countries. The World Health Organization defines effective health coverage as the probability of an individual receiving health gain if needed, which is influenced by a range of clinical, economic, political and other factors. In this framework, quality of care is defined as the proportion of potential health gain actually delivered by a healthcare organization for its set of patients. The essential idea is that quality reflects the gap between what can be achieved and what actually happens. When the gap is small, quality is good; when the gap is large, quality is poor. Potential health gain may not be achieved due to a variety of quality problems, including inequity of provision, lack of access to care, and inefficient and unsafe, perhaps harmful, healthcare.
The quality gap has been nicely expressed by Donabedian in a simple diagram, which depicts the course of an untreated or partially treated disease, against the course of a disease when the patient receives correct and timely treatment. I have added an additional curve to depict a situation in which the patient is actually made worse by their treatment, essentially to underline the safety dimension. This is, of course, a highly idealized picture; in reality a typical patient’s course, on whatever index it might be plotted, is an uneven path towards recovery in which good treatment is intermingled with quality and safety problems. However, the quality gap is both real and substantial, in fact a chasm according to the Institute of Medicine (2001).
Figure 3.1 Trajectories of Healthcare and Disease (Adapted from Donabedian, 2003).
Elizabeth McGlynn and colleagues carried out a study of 6712 adults in the United States, by examining their medical records and conducting telephone interviews (McGlynn et al., 2003). Whereas most studies of the quality of care delivered have focused on a particular disease or a particular type of treatment, they wanted to make a general assessment of the quality of care delivered to adult Americans with significant health problems. Quality of care indicators were developed for a range of both acute and chronic conditions, which reflected the standard care that should have been delivered according to national guidelines (Table 3.1).
Incredibly, even in the United States with its legendarily high health costs, albeit mainly spent on 80% of the population, patients received only 55% of recommended care overall. Both overuse of care, unnecessary tests and treatment, and underuse were assessed, but underuse of healthcare was the more frequent problem. The extent of underuse varied considerably between different medical conditions, ranging from almost 80% of correct care provided for senile cataract and breast cancer, down to below 25% for atrial fibrillation, hip fracture and alcohol dependence (Table 3.2). While the researchers acknowledge that more care could have been given than was recorded or remembered by patients, previous studies suggest that this would at most add a few percentage points to the indicator scores. They concluded soberly that:
Table 3.2 Safety and quality, causality and immediacy
Reproduced from Quality & Safety in Health Care, C Brown, T Hofer, A Johal et al. “An epistemology of patient safety research: a framework for study design and interpretation. Part 3. End points and measurement”. 17, no. 3, [158–162], 2008, with permission from BMJ Publishing Group Ltd.
Our results indicate that on average Americans receive about half of recommended medical care processes.… These deficits, which pose serious threats to the health and well-being of the US public, persist despite initiatives by both the federal government and private healthcare delivery systems to improve care.
(MCGLYNN ET AL., 2003)
McGlynn and her colleagues argue that these findings have important implications for the general health of the population implying, in a sense, avoidable harm. For example, only 24% of the diabetics in the study had regular blood tests, a requirement for close blood glucose control and the avoidance of complications. People with hypertension received 65% of the recommended care; uncontrolled hypertension increases risk for heart disease, stroke and death. Naturally, we cannot assess the implications for individual patients, many of whom may not have been affected, but the overall picture is alarming to say the least. Recent studies on children reveal a similar picture (Mangione-Smith et al., 2007).
As this particular study is set in the United States, it is difficult to predict whether the results would be similar in different kinds of health system. In a publicly funded and more tightly controlled system, such as the British NHS, one might expect a closer adherence to procedure and protocol; on the other hand, most US physicians have financial incentives to investigate and treat, so one might expect higher rates of intervention.
The relationship between safety and quality
Avedis Donabedian, the great theorist of healthcare quality, made the now classic distinction between the structure, process and outcome of healthcare, which was fundamental to understanding that quality depended on the relationship between many components and that process and outcome could be separately assessed (Donabedian, 1968). Donabedian (1968) also emphasized that quality of care encompassed not only technical excellence of the care but also the manner and humanity with which it was delivered, a commonplace distinction nowadays but not in the 1960s. This is not to say that clinicians were not caring and compassionate, only that this was not viewed as a component of quality of care, still less that these subtle, human features of healthcare might be measured. Maxwell (1984) took this idea further, identifying six core dimensions of quality: technical excellence, social acceptability, humanity, cost, equity and relevance to need.
Safety does not feature at all in Maxwell’s list of quality dimensions, although it is certainly related to technical excellence and acceptability. Why is this? It seems the most basic requirement of any public or privately delivered service where risk is involved. If we travel by road or train, if we fly, stay in hotels, or live near nuclear power plants, we want above all to be safe. It is easy now, with the benefit of hindsight, to see that safety is an essential part of quality, but at that time the language of error and harm had not entered healthcare discourse. By 1999 however, The Institute of Medicine report ‘To Err is Human’ put safety to the forefront, describing it as the first dimension of quality (Kohn, Corrigan and Donaldson, 1999).
The relationship between safety and quality of care has been variously expressed, presenting safety as a dimension of quality or, in contrast, on a broad continuum. Many people are content to describe the relationship between safety and quality as a continuum, with safety issues simply being the ‘hard edge’ of more general quality concerns. However, this does little more than sidestep the issue, and tends to suggest that safety and quality concerns are necessarily complementary. The quality of healthcare has been described in a number of different ways by various authors (Donabedian, 1968; Maxwell, 1984; Langley et al., 1996 – all from Boaden), but the most important aspects, including safety, are well captured by the six dimensions that provide the foundation of the Institute of Medicine’s ‘Crossing the Quality Chasm’ report (Box 3.2). Making sense of all this is not straightforward. However, it does become clearer when we start to examine specific instances of unsafe or poor quality care.
BOX 3.2 Six specific aims for improvement
Safe – avoiding injuries to patients from the care that is intended to help them;
Effective – providing services based on scientific knowledge to all who could benefit and refraining from providing services to those not likely to benefit (avoiding underuse and overuse);
Patient-centred – providing care that is respectful of and responsive to individual patient preferences, needs and values and ensuring that patient values guide all clinical decisions;
Timely – reducing waits and sometimes harmful delays for both those who receive and those who give care;
Efficient – avoiding waste, in particular waste of equipment, supplies, ideas and energy;
Equitable – providing care that does not vary in quality because of personal characteristics such as gender, ethnicity, geographic location and socio-economic status;
(REPRINTED WITH PERMISSION FROM THE NATIONAL ACADEMIES PRESS, © 2001, NATIONAL ACADEMY OF SCIENCES.)
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