Monday, July 6, 2015

Emergency Severity Index

How do we decide who gets to be seen first, anyway?

Like most EDs in this country, we use a triage system called the Emergency Severity Index. It's a set of rules that helps categorize patients and prioritize care. Many such systems exist, but this one is relatively modern and specialized. It was first developed in 2001 specifically for use in hospital emergency departments.

Under ESI rules, every arriving patient is assigned an acuity level from 1 to 5, with level 1 being the most urgently in need of care. Patients are not necessarily seen strictly in order of acuity, but the levels are used to prioritize care, so a patient having a heart attack needn't wait in line behind one with a papercut.

One of the main factors is that triage is fast. At the front desk we don't have the time for a complete head-to-toe assessment. The ESI level is assigned based on apparent immediacy of the problem and, for lower levels, the anticipated amount of resources required. (The presumption is that patients who need more complex care also need it sooner.) Here, "resource" means a process that takes special equipment or skilled intervention, like lab tests, x-rays, sutures, or the like.

The full ESI definition fills a book, but the categories can be generally summed up like so:

Level 1: Resuscitation - The patient is dying. Immediate life-sustaining intervention is necessary. Drop everything else and come a'running, because without help the patient's condition will be incompatible with life. Such a patient will usually (hopefully!) come in by ambulance with care already underway.
Examples: Cardiac arrest. Bullet wound to the chest. Brain injury. Traumatic limb amputation.

Level 2: Emergent - The patient should be seen immediately if at all possible. They are not trying to die at the moment, but are at high risk of having their condition degrade. Delay of care could present jeopardy to their life, limb, or major organ.
Examples: Cardiac chest pain. Eye injury. Acute asthma attack. Two-week-old infant with fever.

Level 3: Urgent - The patient is stable, and care will require two or more types of resource. These are people with vital signs in the normal range and who are not at high risk of immediate harm, but who need in-depth testing or treatment of some sort.
Examples: Abdominal pain. Displaced ankle fracture. Elderly patient with fever.

Level 4: Less Urgent - Also stable, with care expected to require only one type of resource. This is the one without an evocative description. It's just a middle ground between three and five.
Examples: Finger laceration. UTI. Sore throat. Abscess. Healthy adult patient with fever.

Level 5: Nonurgent - Stable, with no resources required except physical examination, routine care, oral or topical medication, and/or written prescriptions. This does not necessarily mean the patient is not sick! They might be miserably uncomfortable, but they are safe to wait an extended period of time for care if necessary.
Examples: Earache. Suture removal. Dental pain. Prescription refill. Work note request.

One thing to remember is that you can't tell just by looking. Lay people often seem confused at who gets up-triaged and brought in earlier, and patients sometimes complain about who got to go in before them, but we always have a reason. If two men present with back pain, one might go first if he recently had a high-risk spinal surgery. If two women complain of cough, one might go first because her pulse is very high and we suspect pulmonary embolism. If two kids have sore throats, one might have to skip the line because his tonsils are so big that his airway is at risk. There's always a reason.

Making triage calls requires significant book knowledge, a lot of professional judgement, and a little bit of intuition. It should always be run by an well-trained and experienced ED RN, because it's arguably the trickiest nursing assignment in the whole hospital.