Diagnostic time out

What is a diagnostic time out? Succinctly defined, it’s a deliberate exercise in differential diagnosis and systematic clinical reasoning in the care of an individual patient. But wait, I hear someone say… isn’t that what we do already? Well, no. We’re all familiar with the traditional model for clinical reasoning that we’re taught in medical school but those of us in the real world of practice nowadays, if we’re honest, realize that it seldom happens. There’s just not enough time when you’re forced to see too many patients each day. And hospitalist incentives, with their emphasis on speed and quick adoption of specific diagnostic labels, run in opposition. What do we as hospitalists do instead? Well, aside from all the care pathways and metric incentives that tell us what to do, we rely on clinical instincts and rules of thumb. Because they bypass formal analysis, they save time. They serve as cognitive shortcuts. We call these heuristics. This method of thinking (fast, instinctive, intuitive) is sometimes known as system 1 thinking. It has the advantages of being efficient and fast and sometimes, in critical situations, life saving. But it comes at the cost of a certain error rate. In order to better understand the process of system 1 thinking we have given the various heuristics names and categories. I recently listed some of those in this post. 

If system 1 is our usual measure of processing to get around time constraints the alternative is system 2: formal clinical reasoning .  System 2 thinking was the topic of a recent paper in CriticalCare Clinics. Although based on a survey of people working in a NICU the article has general applicability. The authors contrast system 1 and system 2 thinking in this manner:

Dual process theory holds that individuals engaging in medical decision-making use one of 2 distinct cognitive processes: a system 1 process based on heuristics – the use of rapid pattern recognition and rules of thumb – or a system 2 process, based on deliberate analytical modeling and hypothesis generation. While invoking system one processes individuals can think fast and reflexively and can even operate at a subconscious level, using pattern recognition to sort vast amounts of clinical information quickly before an illness script that allows for the rapid elaboration of a differential diagnosis. In contrast system 2 processes require focused attention and are purposefully analytical, relying on deliberate counter-factual reasoning to generate hypotheses regarding the pathophysiologic mechanisms by which a patient’s symptoms are produced.

The authors introduced the concept of the diagnostic time out to describe this shift of thinking because it requires deliberate effort. It’s not going to arise spontaneously in the natural course of the ward routine. (The authors were not the first ones to use this term). The diagnostic time out can be considered the cognitive equivalent of the better known procedural time out.

Why is a diagnostic time out needed? Research on diagnostic error has indicated that while some instances are due to system problems (such as failure to communicate test results) most are cognitive errors. These can be linked to the heuristics of system 1 thinking. The diagnostic time out, or the deliberate exercise of system 2 thinking, is a way to complement these cognitive shortcuts with a more analytical process.

Some opinion leaders in the field of diagnostic error have suggested universal adoption of system 2 thinking. This is problematic due to time constraints. Besides, there are some essential benefits of system 1 thinking, particularly in acute life-threatening situations. The real trick is how best to selectively employ system 2 thinking. In other words what are the situations in which system 2 thinking should be used? The authors suggest handoff situations in complex patients including ER to hospitalist, off service/on service and ICU to ward transfers.

How does it work? The authors propose a template but it’s really just the traditional clinical reasoning process. One of their points really got my attention: during the time out diagnostic labels should be removed and replaced by signs, symptoms, manifestations and clinical concerns. This of course is the opposite of what your coders and hospitalist leaders want you to do.

What are some of the barriers to implementation? In addition to time constraints, fear of ambiguity is an important factor. We are afraid to admit what we don’t know. One thing you will never hear a hospitalist say out loud is “I’ll have to think about that.”