Interruptions, Memory and Situational Awareness

This entry is part 2 of 7 in the series Tracking Systems

“Unless it produces action, information is overhead.” –Thomas Petzinger

First, a caveat: vendors of HISs (hospital information systems) and EDISs (emergency department information systems) insist that a tracking system is just one component of an integrated system. They point out that there are interactions between a tracking system and CPOE (computer-based practitioner order entry) systems, EMR (electronic medical record) systems, and charting systems. Nonetheless, it’s worth focusing on tracking systems, as central facets of an EDIS, while recognizing it is deeply interconnected (or should be) with other aspects of a full EDIS or HIS.

Slate review of  Consilience

Slate review of Consilience

Dr. Todd Taylor’s article Information management in the emergency department in Emergency Medicine Clinics of North America tells how a bad tracking system can slow down an Emergency Department (ED). There are also multiple reports of how a good tracking system can make an ED more efficient. The trouble is that many of these reports are from people who are deeply invested in the tracking system, either financially or emotionally, and whose objectivity may be questioned. It’s also true that it’s hard to show that tracking systems improve efficiency, as most EDs didn’t have good data on efficiency until they installed a tracking system.

Nonetheless, we can assume that a good tracking system can speed up an ED and help prevent error, just as a bad tracking system can do the opposite.

The question becomes: how do we tell a good tracking system from a bad one?

To oversimplify (and as Bacon once said, we are more likely to reach the truth through error than confusion, so I will take the liberty of simplifying), there are two ways.

First, you can look at what it does. Second, you can look at how well it does it. How well it does what it does is within the discipline of user interaction design and will be addressed in subsequent posts. In this post, we will focus on the what: what is a user’s goal when using a tracking system? In subsequent posts, we will explore more detailed whats: what tasks should the tracking system accomplish, and in the context of tracking systems, this means what should it track? Here, we will focus on why it should track specific things.

The obvious first answer is that it should track those things that make ED operations more efficient and decrease medical error. When nurses, doctors and other medical personnel are in an overcrowded ED, trying to manage more patients than they could realistically manage safely and efficiently, how can a tracking system help? Yes, there are many other things a system can track – ED volumes by time to help arrange shift schedules, logging ED arrivals and other information as required by law, helping compile statistics on individual clinicians’ practice patterns and efficiency – but first we will focus on functione directly related to the efficiency and quality of medical care in the ED.

Because just to generate consciousness requires an astronomically large population of cells, the brain is sharply limited in its capacity to create and hold complex moving imagery. A key measure of that capacity lies in the distinction made by psychologists between short-term and long-term memory. Short-term memory is the ready state of the conscious mind. It composes all of the current and remembered parts of the virtual scenarios. It can handle only about seven words or other symbols simultaneously. The brain takes about one second to scan these symbols fully, and it forgets most of the information within thirty seconds. Long-term memory takes much longer to acquire, but it has an almost unlimited capacity, and a large fraction of it is retained for life. By spreading activation, the conscious mind summons information from the store of long-term memory and holds it for a brief interval in short-term memory. During this time it processes the information, at a rate of about one symbol per 25 milliseconds, while scenarios arising from the information compete for dominance. –E.O. Wilson, Consilience: The Unity of Knowledge, p 110-111

As E. O. Wilson so pithily outlines, our ability to keep things in memory is limited. It’s also true that those working in the ED are interrupted more frequently than other medical workers. We don’t need research to demonstrate that interruptions disrupt short-term memory, but some does exist. One suspects that there is also a type of evolutionary process at work – those who can deal with interruptions, and deal well with the stress of having to continuously multi-task, tend to be attracted to and stay in emergency medicine, and those who don’t tolerate such things go into other medical fields. (One suspects that those in emergency medicine also may deal well with some of the stresses of being parents, which seem to involve some of the same stresses.)

So, a tracking system can serve as a regularly updated “to-do” list for ED personnel – now that I’ve dealt with the latest suddenly-urgent interruption, what was I doing before I was interrupted? And once I’ve dealt with that (which was probably the result of an interruption itself), what was I doing before that?

For those who have a computer-science background, there seems to be a parallel here – layers of interruptions sound like similar processes in computer systems, where interrupts from the hardware (such as when a user presses a key) drive computer processes. There’s also a parallel in x86 assembly language, where one can PUSH a number into a register of the CPU, PUSH a second number into the CPU’s register, then POP the second number off the register to do a calculation, then finally POP the first number off the register.

However, humans don’t have a memory as reliable as an x86 computer CPU. And, the priorities of the interruptions, unlike in a computer, are constantly shifting in their urgency.

In Origins of the Modern Mind: Three Stages in the Evolution of Culture and Cognition, Merlin Donald tells us how, ever since ancient Mesopotamia, we have been relying on external storage to augment our minds – writing. And, just like the accountants of ancient Ur and Lagash, those working in the ED can use a tracking system as an external memory aide.

BTW, I am an obsessive-compulsive grammarian, along the lines of the grammar-vandals described in Eats, Shoots & Leaves: The Zero Tolerance Approach to Punctuation who go out at night with paint and fix the grammar on stores’ signs. I once went into a towering rage when a medical journal editor mis-edited the word “its” into “it’s” in one of my publications. So, why did I use “aide” instead of “aid” above? Because we tend to anthropomorphize computers and software:

Shortly after midnight, a resident of a small town in southern California called the police to report hearing a man inside a house nearby screaming, “I’m going to kill you! I’m going to kill you!” Officers arrived on the scene and ordered the screaming man to come out of the house. The man stepped outside, wearing shorts and a polo shirt. The officers found no victim inside the house. The man had been yelling at his computer. [Based on the preliminary report of the Seal Beach, CA Police Dept. (June 8, 2002) and the police log of the Long Beach (CA) News-Enterprise (June 12, 2002), p. 18]

And thus, “aide” rather than “aid” – a really good tracking system (which doesn’t really exist yet) should be viewed by users as a trusted and helpful friend. Now we will resume the main topic of this post after this interruption.

So, after dealing with an urgent interruption, ED staff can refer to the tracking system to refresh their memories and get back to the task they were working on before the interruption, without worry about having forgotten something important (like that patient in room 12). Or, more precisely, ED staff can refer to the tracking system to assess the current situation, which may now be different than what was going on before the interruption.

Indeed, one can say that the task of the tracking system is to support situational awareness.

Situational awareness has been much bandied-about in relation to human error. Poor situational awareness has been blamed for accidents that have killed thousands of people; the book Normal Accidents: Living with High-Risk Technologies details many such incidents. Situational awareness has become a byword in studies of human error, discussed in detail in James Reason’s Human Error, and of programs designed to prevent human error in high-risk professions, such as CRM, developed for flight crews of commercial-carrier aircraft.


In subsequent posts, we will explore the tasks of an ED tracking system, and how interaction design can help tracking systems provide situational awareness, prevent error, and promote efficiency.

Information management in the emergency department

Series NavigationHistory, How Bad Design Kills, Posture and MetaphorsThe Magic Number 7 (or maybe 4?), Forced Errors, Triage, and Color-Blindness

Tags: , , , , , , , , , , , , , , ,

This entry was posted by kconover on Sunday, March 7th, 2010 at 3:48 pm and is filed under Tutorials . You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

Comments are closed.