What is the Emergency Severity Index or ESI?
The ESI guides nurses’ in the evaluation of patient acuity and the resources that will be needed to treat the patient. Acuity is defined as the stability of a patient’s vital functions and the potential threat to life, limb or organ. Resources are defined as the number of resources to stabilize and initiate treatment. The result is a triage decision that stratifies patients’ need for emergency treatment into five levels of urgency. It was developed by a group of emergency nurses, physicians, managers, educators and researchers in collaboration with the Agency for Healthcare Research and Quality (AHRQ) who continue to update the tool and related training material.
How does it work?
The ESI is an algorithm that incorporates only four questions and the answers lead to a triage conclusion. The four questions are:
- Does the patient require immediate life-saving intervention? If so the patient is triaged as ESI level 1. No further triage is necessary and life saving measures are initiated immediately. Life saving measures are those which secure an airway, maintain breathing, support circulation or address a major change in level of consciousness. If the answer is no then go to the next question.
- Can the patient wait to be seen medically? Three criteria are used to make this determination.
- Is it a condition that could deteriorate quickly or for which treatment is time-critical?
- Is the patient confused, lethargic or disoriented?
- Is the patient in severe pain or distress?
A yes answer to any of the above means that the patient cannot wait and so is triaged as ESI level 2. No further triage evaluation is necessary and the nurse’s focus shifts to ensuring prompt initiation of treatment. If the patient does not need to be seen urgently then proceed to the next question.
- How many different resources are needed to address the patient’s chief complaint? The nurse uses their experience to predict how many different kinds of interventions will be necessary to diagnose and treat the patient. Resources are those beyond basic first aid, point of care testing and medications. Diagnostic tests, procedures, consults, and inpatient admission are considered resources.
If more than two different resources will be needed (i.e. lab and an EKG) the patient is triaged ESI level 3. If one resource will be needed (i.e. x rays) the patient is triaged ESI level 4. If no resources will be needed (i.e. injury dressed, ice applied and medication administered) the patient is triaged ESI level 5. These level determinations may be altered by the presence of abnormal vital signs, which is considered next.
- Does the patient have abnormal vital signs? Any patient with an elevated heart rate, increased respirations or a low oxygen saturation rate should be reconsidered for ESI level 2 and seen urgently.
What are the advantages of using the ESI?
The ESI has been found to be more accurate than other triage systems because it is simple and reduces subjectivity. One benefit is that it identifies patients in need of immediate attention more rapidly than other methods. The ESI can help prioritize clinical staff attention and resources and it facilitates communication about patient acuity more effectively. It also has been used as the foundation for facility policy and procedure. The jail referred to at the beginning of this post has since drafted policy and procedure setting timeframes for response to each of the ESI levels. By keeping track of emergencies by ESI level the data can be used to determine if practices could be improved with targeted training or enhanced resources. Finally, the AHRQ maintains a website on the ESI that includes an implementation handbook that can be downloaded for free. There are also DVDs that include lectures and case studies that can be used to support training in use of the ESI. There is no charge for these materials but they must be requested from the site.
How easy and reliable is it?
The ESI has been found to be an easy, reliable and valid measure of patient acuity and resource need in multiple hospital settings and comparison groups. If you want to try it out, use your experience to determine the ESI rating for the patients in these four examples which come from the training material provided at the AHRQ site:
- A 58-year-old male complains of left lower-quadrant abdominal pain for 3 days. He denies nausea, vomiting, or diarrhea. No change in appetite. past medical history HTN. Vital signs: T 100°F, RR 18, HR 80, BP 140/72, SpO2 98%. Pain 5/10.
- An 18-year-old female is brought to medical because her cell mate found her lethargic and “not acting right”. The patient has a history of depression. On exam, you notice multiple superficial lacerations to both wrists. Her respiratory rate is 10, and her SpO2 on room air is 86 percent.
- A 72-year-old male fell and hit his head in the cell. He is awake, alert, and oriented and remembers the fall. He has a past medical history of atrial fibrillation and is on multiple medications, including warfarin. His vital signs are within normal limits.
- “I have had a cold for a few days, and today I started wheezing. I need a breathing treatment,” reports a 39-year-old female with a history of asthma. T 98°F, RR 22, HR 88, BP 130/80, SpO2 99%, No meds, no allergies.
- ESI level 3: Two or more resources. Abdominal pain in a 58-year-old male will require two or more resources. At a minimum, he will need labs and an abdominal CT.
- ESI level 1: Requires immediate lifesaving intervention. The patient’s respiratory rate, oxygen saturation, and inability to protect her own airway indicate the need for immediate endotracheal intubation.
- ESI level 2: High risk. Patients taking warfarin who fall are at high risk of internal bleeding. Although the patients’ vital signs are within normal limits and he shows no signs of a head injury, he needs a prompt evaluation and a head CT.
- ESI level 4: One resource. This patient only needs a nebulizer treatment for her wheezing. No labs or x-ray should be necessary because the patient does not have a fever.
How did you do? Was it easy to use? There are hundreds of case examples included in the ESI training materials which is a great resource for correctional nurses. There also is a chapter devoted to evaluating competency in the use of the ESI tool.
This blog post is dedicated to bringing down to earth, practical resources and advice for nurses who practice in correctional settings. The ESI is described here because it is increasingly being used by emergency departments in the United States and may be used in your community. If so, you may want to consider using it at your facility as well. If you use the ESI at your facility, please share your experience by replying in the comments section of this post.
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