Common Diseases Encountered by EMS and Their Pre-Hospital Management
Emergency Medical Services providers most frequently encounter acute coronary syndromes (ACS), cardiac arrest, stroke, trauma, respiratory distress, and seizures, with cardiovascular emergencies requiring the most time-sensitive interventions that directly impact mortality.
Cardiovascular Emergencies: The Highest Priority
Acute Coronary Syndromes (ACS/STEMI)
EMS providers must administer 160-325 mg of chewed non-enteric aspirin immediately to all chest pain patients unless contraindicated 1, 2. This is the single most critical intervention, as half of ACS deaths occur before hospital arrival, primarily from ventricular fibrillation 2.
Key management steps:
- Aspirin administration (160-325 mg chewed) is Class I evidence 1, 3
- 12-lead ECG acquisition should occur as soon as possible on scene 3, 2
- Oxygen therapy only if dyspneic, hypoxemic, or signs of heart failure—titrate to SpO2 94% 1, 2
- Nitroglycerin up to 3 doses (3-5 minute intervals) unless:
- SBP <90 mmHg or >30 mmHg below baseline
- Right ventricular infarction suspected
- PDE-5 inhibitor use within 24 hours (48 hours for tadalafil) 2
- Morphine for chest pain unresponsive to nitrates in STEMI, but use cautiously in NSTEMI due to mortality concerns 1, 2
Critical pitfall: Dispatchers can instruct patients to chew aspirin while awaiting EMS arrival, potentially saving critical minutes 1, 4. However, routine oxygen in uncomplicated ACS lacks evidence and should be avoided 2.
Cardiac Arrest
Early defibrillation and high-quality CPR are the cornerstones—all EMS first responders must be trained and equipped to provide early defibrillation 3. The chain of survival (early access, early CPR, early defibrillation, early ACLS) must be optimized at the community level 3.
Stroke: Time-Critical Neurological Emergency
EMS personnel must use standardized stroke screening tools (like FAST—Face, Arms, Speech, Time) during on-scene assessment 5. The goal is "recognize and mobilize"—minimize scene time to expedite transport 5.
Essential actions:
- Standardized stroke screening on scene (Class B evidence) 5
- Determine symptom onset time or time last known well 5
- Transport to stroke center if within reasonable distance/time for acute interventions 6
- Prehospital notification to receiving facility 5
- ECG monitoring for atrial fibrillation detection 5
Common pitfall: Neurological assessment is frequently omitted in difficult patient groups (demented, intoxicated, children), with 75% of providers feeling uncomfortable with pediatric neurological assessment 7.
Respiratory Emergencies
Respiratory distress accounts for approximately 13.7% of pediatric EMS transports and is among the most common adult presentations 8. Management focuses on maintaining oxygenation and supporting ventilation, with specific attention to asthma exacerbations requiring bronchodilator therapy.
Trauma
Trauma represents a significant portion of EMS calls (29% in some registries), particularly in pediatric populations (12% of pediatric transports) 8. Blunt trauma is most common, requiring:
- Airway management (advanced airways used in 0.4% of pediatric cases) 8
- Hemorrhage control through direct pressure 9
- Spinal precautions when indicated
- Rapid transport to appropriate trauma centers
Key consideration: Traumatic brain injury protocols vary significantly across states, with inconsistent adoption of evidence-based guidelines for managing hypoxia, hypotension, and suspected herniation 10.
Seizures
Seizures account for 12.4% of pediatric EMS encounters 8 and are among the most common reasons for medication administration and IV placement in the field. Management priorities include:
- Airway protection and oxygenation
- Blood glucose assessment (glucometry performed in 16.9% of pediatric cases) 8
- Benzodiazepine administration for prolonged seizures
- Determination of seizure history and medication compliance
Altered Mental Status
All patients with altered mental status require immediate blood glucose assessment—this is universally recommended across all EMS protocols 11. The mnemonic AEIOU TIPS helps systematically evaluate causes:
- Alcohol, Epilepsy, Insulin (hypoglycemia), Opiates/overdose, Uremia
- Trauma, Infection, Psychiatric, Stroke
Treatment algorithm:
- Blood glucose check (treat adults at <60 mg/dL with dextrose) 11
- Naloxone for suspected opioid overdose 11
- Consider 12-lead ECG (recommended by only 24% of agencies but clinically important) 11
- Supplemental oxygen only as needed based on SpO2 11
Critical gap: Only 52% of California EMS agencies recommend considering toxicological causes beyond opioids, and only 39% provide specific parameters for naloxone administration 11.
Less Common but High-Acuity Conditions
Obstetric Emergencies
Obstetric events comprise only 0.6% of EMS activations but carry significant morbidity risk 12. Early or threatened labor (15%) and abdominal pain (29%) are most common presentations, with approximately 3% resulting in out-of-hospital delivery (43% of which are preterm) 12. One-third of obstetric emergencies are high-acuity 12.
Pediatric Considerations
Children represent only 8.7-10% of EMS call volume, creating challenges for skill maintenance 8. The most common pediatric presentations are respiratory distress, seizures, trauma, and "other" undefined assessments 8. Critical concern: 61.5% of transported children have abnormal vital signs, yet documentation is incomplete (pulse oximetry documented in only 33.5% of cases) 8.
System-Level Factors Affecting Care
Agency characteristics significantly influence encounter patterns: ALS and critical care agencies see higher trauma and airway intervention volumes; urban agencies have more pediatric encounters; mixed/volunteer agencies encounter more cardiac arrests and strokes 13. These patterns should inform targeted training and resource allocation.
Major challenge: EMS providers face substantial mental health burdens from chronic stress, sleep disorders, high workload, and violence exposure, which can compromise care quality 14, 15.