Let us use a simplified cardiac arrest resuscitation scenario to illustrate the high cognitive load due to concurrent and interactive medical activities. As shown in Fig. 6.1, a physician is performing CPR (Cardiopulmonary resuscitation), which should be continued for at least two minutes according to AHA guidelines, so s/he needs to keep track of the time while maintaining high-quality CPR. In the middle of CPR, in order to improve patient’s cardiac function, a drug, called epinephrine, should be administered every three to five minutes; therefore, the medical staff also needs to keep track whether another dose of epinephrine should be administered or not. In addition, when another dose of epinephrine should be administered, the medical staff needs to recall the guideline of epinephrine. According to the guideline, the dosage of epinephrine is 1 mg and may be ineffective when the patient’s blood pH value is lower than 7.2. Consequently, the medical staff needs to check if the patient condition, i.e. blood pH, is appropriate for another dose of epinephrine.
Moreover, the patient conditions may suddenly worsen, for instance, the patient’s oxygen saturation level (SpO2) drops below 90. In this situation, the medical staff needs to provide proper treatments,
High cognitive load
tasks:
1. Recall workflow steps
2. Recall treatment guidelines
3. Recall diagnosis and performed treatments
4. Recall pending medication orders
5. Assemble clinical information from scattered medical devices and monitors
6. Real-time tracking of temporal progress
7. Real-time tracking of patient’s condition changes
CPR for 2 minutes
6* Recall workflow
steps and prepare
for next assessment
and treatment.
1Another dose of epinephrine
6* Recall
epinephrine
guidance
2, 5* Verbally order
the medication
4Sudden drop of SpO
21, 5, 7* Perform treatments for
increasing SpO
2.
2, 3, 4Figure 6.1: Assessments and treatments during cardiac arrest resuscitation. The arrows indicate the concurrent medical processes. The text boxes below the arrows are the corresponding assessments and treatments. The numbers shown as superscripts are the sources of cognitive load.
such as assisted ventilation. In addition, during the whole process, the medical staff also has to keep recalling best practice workflows in order to decide the next assessment and treatment. The above high-cognitive-load situation could be worsened as more patient conditions become abnormal and more treatments need to be performed.
In collaboration with physicians and nurses from the Carle Foundation Hospital, we conducted a series of interviews, compiled a list of cognitive tasks that significantly contribute to cognitive load, and categorized these tasks into three categories: information assembling, recall, and real-time tracking.
M1. Assemble clinical information: Medical staff needs to mentally gather patient’s physiological measurements from scattered medical devices and monitors, such as EKG monitor, oximeter, and blood
pressure cuff, and diagnose the patient. M2. Recalls:
• Recall workflow steps: Medical staff can perform treatments more effectively if they can antici- pate the next move and follow best practice workflows.
• Recall treatment guidelines: Medical staff needs to validate the preconditions, administer the drug based on the guideline dosage, and set the time for another dose. In an interview, one physicians mentioned
We know that epinephrine could be less effective to a patient with acidosis (blood pH value lower than 7.2); in this situation we may consider using sodium bicarbonate to treat acidosis.
Another physician added that
Moreover, before using sodium bicarbonate, there are many other factors(preconditions) we need to consider. For instance, we need to check patient is provided with adequate ventilation.1 Unfortunately, sometimes we just forget to check it because we are so busy doing other things.
• Recall pending medication order: In clinical practices, physician in charge gives a verbal med- ication order, and other physicians and nurses need to prepare the drug and administer it to the patient. However, because of the high-stress and chaotic environment, the verbal medication or- der may be neglected. The medical staff needs to recall if any medication is ordered but has not yet been administered.
• Recall the previous diagnosis and performed treatments: Medical staff needs to recall this infor- mation in real-time to decide upon future treatment plans.
M3. Real-time tracking:
• Track real-time changes of the patient conditions: Medical staff needs to keep track of the changes of the patient conditions and perform treatments accordingly.
1
• Track temporal progress of the treatment: Certain treatments are time sensitive, and medical staff is required to closely monitor and assure compliance with temporal task constraints. As the Carle Foundation Hospital Director of ICU put it:
Timely and correctly performing treatments is crucial for us to treat patients. In cardiac arrest resuscitation, CPR should continue for at least two minutes. Unfor- tunately, the environment we deal with is very chaotic and requires multitasking, so correctly keeping track of the time sometimes is hard for us.
In addition to the above three categories, we also discovered that calculation is another major source of cognitive load. Medical staff sometimes needs to calculate the drug dosage based on patient’s sex, weight and age. However, in cardiac arrest resuscitation, most of the drug dosage does not depend on this information, so our system does not provide dosage calculation. It is worth mentioning that recalls are difficult for the medical staff who does not practice resuscitation routinely but may be easier for the experienced medical staff. On the other hand, assembling clinical information and real-time tracking significantly increases the cognitive load for both inexperienced and experienced medical staff.