Prevent Medical Errors in the Field with Cognitive Strategies

EMS is dispatched to the home of an 82-year-old female with a chief complaint of shortness of breath. On arrival, the crew learns she has had a dry cough for a week and is now complaining of significant malaise and shortness of breath when she lies flat, but denies any chest pain.

On examination, they find her respirations to be labored, but she’s not in severe distress. Vital signs are: heart rate of 114 beats per minute (sinus rhythm), respiratory rate of 28 breaths per minute, blood pressure of 154/105 mmHg, oral temperature of 99.5 degrees F, and O2 saturation is 90% on room air.

On auscultation of the lungs, crackles are heard at both bases. Suspecting the patient of having heart failure, the paramedics examine her legs and find mild peripheral edema.

A large number of prescription medication bottles are found near the patient’s bedside, most of them cardiovascular medications: hydrochlorothiazide, ramipril and metoprolol.

Based on a presumptive diagnosis of heart failure, 40 mg of furosemide is administrated by IV. On ED arrival, the EMS crew mentions to the on-duty resident that the “fluid-loaded patient” is hypoxic, and may need more diuretic.

Shortly after, the patient develops a temperature of 103.3 degrees F and a chest X-ray shows left lower lobe pneumonia. Unfortunately, by this time, the patient’s kidneys have suffered some initial injury from the IV furosemide and she requires fluid resuscitation for the next week in hospital.

Prehospital healthcare providers face difficult circumstances every day in their role as emergency responders, dealing with people in their most vulnerable states and often at the pinnacle of emotional intensity. While EMTs and paramedics have been trained to operate in such high-stress environments, they’re ultimately human, and thus make mistakes.

This article discusses the types of medical errors that may occur in prehospital healthcare and suggests ways EMS providers may prevent them from occurring.

The Scope of Medical Errors in Healthcare
Adverse events have been described as unintended complications caused by healthcare management that result in death, disability or prolonged hospital stay.1 The Canadian Adverse Events Study estimated that in 2000, 185,000 adverse events occurred in acute care patients admitted to Canadian hospitals.1 It’s estimated 70,000 of all adverse events in this population were preventable.

Although it may be comforting that the majority of these events didn’t result in long-term impairment or disability, it’s alarming that 15% of them resulted in death.1 The statistics are even more staggering in the United States. The landmark report “To Err is Human” stated that as many as 98,000 Americans die in hospitals each year as a result of medical error, exceeding deaths caused by car crashes, breast cancer and AIDS.2

Unfortunately, the problem isn’t getting better. Follow-up studies tracking American hospitals between 2001 and 2007 showed no improvement in medical error despite efforts in improving patient safety.3

Medical error has become so prevalent some researchers fear the predictable and widespread nature of adverse events has made itself commonplace.4 Such a perception could potentially result in inaction and the continued suffering of patients.

EMS Medical Errors
Not surprisingly, the ED is often the apex of medical error occurrence.5 Recent multi-center studies have determined that rates of medical error in EDs were higher than expected, even with efforts made in patient safety.6

Experts argue conditions in the ED cause it to be error-prone. The concurrent management of high volumes of patients and significant diagnostic uncertainty, matched with frequent disturbances, a hectic work environment, staff fatigue and circadian dyschronicity, presents the perfect storm for medical errors to occur.7

Prehospital care providers face similar challenges. One study determined the majority of errors committed and reported by prehospital care providers were related to clinical judgment (54%), rather than skill-based (21%) or medication errors (15%).8

As with other healthcare workers, prehospital healthcare providers make errors in diagnosis, medication administration and procedures.9—14 Additionally, in a study of the prevalence of error in the prehospital setting, Hobgood determined that while prehospital health providers demonstrated the capacity to identify and disclose error, there was question as to whether error-identifying skills were applied in practice homogeneously.15

From this, we may predict the volume and impact of prehospital error might be largely underrepresented.

Types of Medical Errors
Typically encountered medical errors can be categorized into three types: procedural, affective and cognitive.7

Procedural error: These occur during technical procedures such as IV cannula insertion or endotracheal (ET) intubation. Individuals who have limited experience with the procedure often make procedural errors. Once the individual is familiar with and repeats the procedure, the rate of error usually decreases. In this regard, procedural error might be mitigated by simulations, supervised practice and/or experience over time.7

Affective error: These occur as a result of emotions, such as assuming a known alcoholic patient is unresponsive because they’re intoxicated, when in reality they may have a serious unrelated condition such as a subdural hematoma secondary to trauma.

Because the clinician’s judgment is clouded by emotion, the best and most logical course of action may be ignored for something more in line with the emotional response. The potential solution for affective errors is to recognize and be aware of the emotion and act accordingly.7

Cognitive error: Cognition is the scientific word for “the process of thought.” Thus, cognitive errors are made during the thought process. Research into cognitive error has been quite extensive, likely due to its potential for prevention. However, there’s still limited insight into specific preventative strategies for cognitive error.

Cognitive errors are further subdivided into skill-based, rule-based and knowledge-based errors.7

  • Skilled-based errors have the least to do with cognition because once the skill is learned and practiced, the amount of thought required decreases and the skill is performed in “autopilot.”
  • Rule-based cognition requires thought, but only to the extent of memorization. An example of rule-based activity is the ACLS algorithm. While difficult algorithms require more cognition, errors can be mitigated by creating simpler algorithms or increasing the accessibility of references through decisional aids.16
  • Knowledge-based activities require integration of presented information (e.g., history and physical exam) and the knowledge and experience of the healthcare provider in order to decide on a diagnostic course.

Patient factors such as dementia, language barriers and comorbidities can increase the likelihood of error occurrence.17 However, an element of our own thought process, called heuristics, is the main cause of cognitive error in emergency care settings. Heuristics are strategies that simplify clinical decision-making.

In essence, heuristics are cognitive shortcuts. In situations where time, information and resources are limited, heuristics are valuable in achieving the results you want quickly. However, simplifying the thought process with heuristics, unavoidably leads to “misses” and, consequently, adverse events.18

An example of a heuristic is automatically titrating oxygen to achieve oxygen saturations of 100% in all patients with a chief complaint of shortness of breath, regardless of underlying illness. Although this may be appropriate treatment for the majority of patients with shortness of breath, recent clinical evidence suggests it may be harmful for particular presentations including chronic obstructive pulmonary disease and acute coronary syndromes.19,20 A list of common cognitive errors is presented in the sidebar below.

How to Prevent Errors
As the old dictum states, the first step is recognizing that a problem exists. The next step is achieved by actively using cognitive strategies to rectify those pitfalls in thinking.

The concept of metacognition, or “thinking about your thinking,” is the ideological basis behind creating strategies to intervene in your own thinking process and thus prevent cognitive error. The goal is to train your mind into recognizing when you’re taking inappropriate cognitive shortcuts and correct your approach accordingly.

One way to effectively apply metacognition to practice is by using cognitive forcing strategies. Croskerry defines cognitive forcing strategies as purposeful conscious tactics utilized in specific situations to avert error by specifically recognizing and counteracting cognitive errors themselves. They’re essentially mental checks that offset detrimental heuristics.4

There are two types of cognitive forcing strategies: generic and specific.22 Generic strategies are used to counteract one class of cognitive error. For example, to prevent anchoring, which occurs when you form a diagnosis in your mind with the presented evidence, you force yourself to explain every other piece of evidence in order to consider all possibilities.

Specific cognitive forcing strategies arise after a unique experience that typically has an unexpected or poor outcome. For example, after a failed ET intubation last week, you now force yourself to change one aspect of laryngoscopy (e.g., blade change) following each unsuccessful attempt at intubation.

Other more familiar strategies are also useful in counteracting cognitive error. The use of simulation in prehospital education is an excellent method to observe cognitive errors being made without risk to patients.4 From these simulations, common points of error can be teased out and strategies to prevent them can be created.

Videos highlighting both correct and incorrect approaches to a clinical problem can also be reviewed to help learners. In addition, mentally rehearsing a patient encounter can be a useful strategy when time and resources are few.

Many clinicians have already started to use checklists and handheld computers to assist them in practice. (See “The Value of Checklists: We’ve had the solution all along,” by Shaughn Maxwell, EMT-P, in the June issue.) By decreasing reliance on memory through the use of checklists, devices or handbooks, providers may mitigate errors including drug dosing mistakes and deviations from protocol.4

Finally, obtaining feedback about your care after transferring a patient can provide a starting point for finding errors.4 Ask your medical director to help you obtain information about a patient’s course in hospital to determine if your suspected diagnosis and treatment were correct.

The desired outcome of decreasing medical errors in the field stems from adequate surveillance, reporting and intervention. Leadership from local EMS as well as governing bodies are essential in providing patient-safety infrastructure.21 Suggestions of simple ways to prevent cognitive error in the field are presented below.

Case Review Continued
If we look closely at this case, we can see a number of cognitive errors were made. The provider quickly jumped to the diagnosis of heart failure and strengthened it through confirmation bias–looking for information that supported the idea–such as finding mild leg edema and cardiac medications on the kitchen table.

Completing a thorough history and physical examination and looking for details that disprove your theory, for instance the low-grade elevation in temperature and cough, may help you consider other potential causes of your patient’s presentation. In this way we may prevent premature closure.

Despite some diagnostic uncertainty, this patient was treated with a diuretic. Giving diuretics to a patient with pneumonia or sepsis may be harmful. The feeling that we need to provide some treatment (as opposed to waiting for more evidence to support our treatment) is known as a commission bias.

Finally, passing on the information to hospital staff that the diagnosis is “X” may be harmful to a patient because diagnoses often stick to a patient as they pass from one healthcare provider to another. It makes it difficult to consider other possibilities and may cause a patient to receive an inappropriate treatment. This is known as diagnostic momentum.

What can be done the next time this type of patient is encountered?

1. Review your protocol for acute shortness of breath, and see if anything needs to be adjusted;
2. Have a metacognitive strategy to consider all pieces of information prior to categorizing the cause of shortness of breath; and
3. Contribute to forming a differential diagnosis but leave the final diagnosis to the caregivers who have access to old charts, laboratory and radiologic investigations.

Medical error is a reality for those who practice medicine in a fast-paced and often high-stress acute care environment. It’s important for providers to recognize we’ll often make mistakes. However, as professionals, it’s our duty to attempt to limit medical error by recognizing potential areas where it may occur and preventing errors before they occur. Cognitive forcing strategies can be useful tools in helping prevent errors and provide better care to patients.

10 Cognitive Errors Every EMT & Paramedic Makes4
1. Anchoring: The tendency to perceptually lock onto salient features in the patient’s initial presentation too early in the diagnostic process, and failing to adjust this initial impression in the light of later information.
2. Availability: The disposition to judge things as being more likely, or frequently occurring, if they readily come to mind. Thus, recent experience with a disease may inflate the likelihood of its being diagnosed. Conversely, if a disease hasn’t been seen for a long time (is less available), it may be under-diagnosed.
3. Commission bias: Results from the obligation toward beneficence, in that harm to the patient can only be prevented by active intervention. It’s the tendency toward action rather than inaction. It’s more likely in overconfident clinicians.
4. Confirmation bias: The tendency to look for confirming evidence to support a diagnosis rather than look for disconfirming evidence to refute it, despite the latter often being more persuasive and definitive.
5. Fundamental attribution error: The tendency to be judgmental and blame patients for their illnesses (dispositional causes) rather than examine the circumstances (situational factors) that might have been responsible.
6. Multiple alternatives bias: A multiplicity of options on a differential diagnosis may lead to significant conflict and uncertainty. The process may be simplified by reverting to a smaller subset with which the clinician is familiar but may result in inadequate consideration of other possibilities.
7. Omission bias: The tendency toward inaction and rooted in the principle of nonmaleficence. In hindsight, events that have occurred through the natural progression of a disease are more acceptable than those that may be attributed directly to the action of the clinician. The bias may be sustained by the reinforcement often associated with not doing anything, but it may prove disastrous.
8. Diagnosis momentum: Once diagnostic labels are attached to patients they tend to become stickier and stickier. Through intermediaries (patients, paramedics, nurses, physicians), what might have started as a possibility gathers increasing momentum until it becomes definite, and all other possibilities are excluded.
9. Premature closure: A powerful cognitive error accounting for a high proportion of missed diagnoses. It’s the tendency to apply premature closure to the decision- making process, accepting a diagnosis before it has been fully verified. The consequences of the bias are reflected in the maxim: “When the diagnosis is made, the thinking stops.”
10. Search satisfying: Reflects the universal tendency to call off a search once something is found. Comorbidities, second foreign bodies, other fractures, and coingestants in poisoning may all be missed. Also, if the search yields nothing, diagnosticians should satisfy themselves that they have been looking in the right place.

Five Simple Strategies to Prevent Cognitive Errors
1. Incorporate simulation into your training plan. Search for places where errors may occur and develop ways to prevent them. Mentally running through a patient encounter can be a good use of brief periods of downtime.
2. Force yourself to consider additional diagnoses. Despite the patient having a classical presentation of diagnosis A, mentally consider possible diagnosis B and C.
3. Be wary of diagnostic labels, especially ones passed on from other healthcare professionals. Being labeled a “psych” patient can have serious consequences if incorrect.
4. Regularly ask for feedback and modify your care based upon it. Contact your medical director to obtain patient information. Find out what happened to patient “A” when you dropped him off in the ED.
5. Use checklists, a handbook or electronic handheld device to decrease reliance on memory. Double check drug doses in this manner whenever possible.


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