What is the recommended emergency department triage protocol, including acuity levels (ESI levels) and target evaluation times for each level?

Emergency Department Triage Protocol

The Emergency Severity Index (ESI) is the recommended 5-level triage system for emergency departments, with patients categorized from ESI Level 1 (most urgent, requiring immediate life-saving intervention) to ESI Level 5 (least urgent), and target evaluation times of <10 minutes for high-acuity patients (Levels 1-2). 1, 2, 3

ESI Triage Levels and Target Times

ESI Level 1: Immediate (0 minutes)

• Patients requiring immediate life-saving interventions with conditions such as cardiac arrest, severe respiratory distress requiring immediate airway management, or unresponsive patients with GCS ≤13 4, 3
• These patients bypass the waiting room entirely and proceed directly to a resuscitation bay 3

ESI Level 2: Emergent (<10 minutes)

• High-risk situations requiring rapid assessment even when vital signs appear stable 1, 2
• Includes patients with severe pain, altered mental status, or time-sensitive conditions (e.g., stroke symptoms, sexual assault victims, chest pain) 5, 2
• Target evaluation time: within 10 minutes of ED arrival 5, 1
• Examples include unstable trauma patients, critical cardiac patients, and sexual assault victims regardless of visible injuries 2

ESI Level 3: Urgent (30-60 minutes)

• Patients requiring multiple diagnostic resources (typically 2 or more) but who are hemodynamically stable 3, 6
• This represents the majority of ED patients and includes conditions requiring laboratory tests, imaging, and specialist consultation 3

ESI Level 4: Less Urgent (1-2 hours)

• Patients requiring one diagnostic resource (single lab test, X-ray, or simple procedure) 3, 6
• Stable patients with minor injuries or illnesses 3

ESI Level 5: Non-Urgent (2-24 hours)

• Patients requiring no diagnostic resources and can be managed with examination alone 3, 6
• Minor complaints that could be managed in primary care settings 3

Trauma-Specific Triage Algorithm

For trauma patients, a four-step field triage algorithm should be applied sequentially 5, 4, 1:

Step One: Physiologic Criteria (Highest Priority)

• GCS ≤13 → Transport to highest-level trauma center 4
• Systolic blood pressure <90 mmHg → Transport to highest-level trauma center 4
• Respiratory rate <10 or >29 breaths/min (or need for ventilatory support) → Transport to highest-level trauma center 4
• Meeting any Step One criterion mandates immediate transport to a Level I trauma center when available, as these patients have demonstrated reduced mortality when treated at the highest-level facilities 5, 4

Step Two: Anatomic Criteria

• Penetrating injuries to head, neck, torso, or extremities proximal to elbow/knee 5, 4
• Flail chest or chest wall instability 4
• Two or more proximal long-bone fractures 4
• Crushed, degloved, mangled, or pulseless extremity 4
• Amputation proximal to wrist or ankle 4
• Pelvic fractures 4
• Open or depressed skull fracture 4
• Paralysis 4

Step Three: Mechanism of Injury

• Falls >20 feet (adults) or >10 feet (children) 5, 4
• High-risk motor vehicle crash with intrusion >12 inches (occupant site) or >18 inches (any site) 5, 4
• Ejection from vehicle 5, 4
• Death in same passenger compartment 5, 4
• Auto vs. pedestrian/bicyclist with impact >20 mph 5, 4
• Motorcycle crash >20 mph 5, 4

Step Four: Special Considerations

• Age >55 years (increased injury/death risk) 5, 4
• Anticoagulation or bleeding disorders 5, 4
• Pregnancy >20 weeks 5, 4
• EMS provider judgment 5, 4
• When in doubt, transport to a trauma center 5, 4

Stroke-Specific Triage

Rapid Screening and Assessment

• Use validated screening tools (FAST, Los Angeles Prehospital Stroke Screen, or Cincinnati Prehospital Stroke Scale) at triage 5, 1
• Assign high-severity triage category to be seen within <10 minutes of ED arrival 5
• Initiate "Code Stroke" protocol with prenotification to stroke team 5
• Target brain imaging within 25 minutes of ED arrival 5
• Assess stroke severity using NIHSS on arrival and before/after treatment 5
• Goal: door-to-needle time <60 minutes for thrombolytic therapy when indicated 5

Implementation Considerations

Nurse-Driven Triage

• Five-level triage systems demonstrate superior validity and reliability compared to 3-level systems (p<0.01) 3
• ESI has been validated in German-speaking countries and shows good to very good reliability (κ-statistics: 0.7 to 0.95) 3
• Triage should be performed by trained nursing staff using standardized assessment tools 7, 3

Common Pitfalls to Avoid

• Do not be misled by stable vital signs alone in high-risk situations such as sexual assault, elderly trauma patients, or those on anticoagulants 4, 2
• Avoid undertriage of elderly patients (>55 years) who have increased mortality risk even with seemingly minor injuries 5, 4
• Do not delay triage for complete registration; use preregistration aliases for critical patients 5
• Reassess patients regularly as clinical status can deteriorate while waiting 3

System-Level Protocols

• Establish clear communication pathways between EMS, triage nurses, and specialty teams 5, 1
• Maintain priority access to diagnostic resources (CT scanner, laboratory) for high-acuity patients 5
• Document triage category, time stamps, and reassessment findings for continuity of care 1