Basic Ventilator Use in EMS: Teaching Guide

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Basic Ventilator Use in EMS: Teaching Guide

Target Audience:

 AEMTs, I-99s, Paramedics, and Critical Care Transport Providers

Objective:

Provide foundational understanding of mechanical ventilation used in prehospital and interfacility transport settings, with a focus on safe application, basic troubleshooting, and clinical reasoning.

1. Introduction to Mechanical Ventilation

What Is Mechanical Ventilation?

Mechanical ventilation is the use of a machine (ventilator) to assist or replace spontaneous breathing in patients who cannot breathe adequately on their own.

Common Indications in EMS:

  • Respiratory failure (hypoxemic or hypercapnic)

  • Post-intubation ventilatory support

  • Severe trauma or TBI (to maintain normocapnia)

  • Cardiac arrest with ROSC

  • Transport of ventilator-dependent patients

2. Key Concepts and Terminology

Term Definition
FiO₂ Fraction of inspired oxygen (21%–100%)
PEEP Positive End-Expiratory Pressure (prevents alveolar collapse)
RR (f) Respiratory rate (breaths per minute)
Vt (Tidal Volume) Volume of air delivered per breath (typically 6–8 mL/kg ideal body weight)
I:E Ratio Inspiratory:Expiratory time ratio (usually 1:2 or 1:3)
PIP (Peak Inspiratory Pressure) Max pressure during inspiration
EtCO₂ End-tidal carbon dioxide (monitors ventilation status)

3. Common Ventilator Modes Used in EMS

1. Assist-Control (AC) / Volume Control (VC)

  • Delivers preset tidal volume with every breath (patient- or machine-triggered).

  • Used for full ventilatory support.

2. Synchronized Intermittent Mandatory Ventilation (SIMV)

  • Delivers preset breaths but allows spontaneous breathing in between.

  • Useful for weaning or partial support.

3. CPAP/BiPAP (Non-invasive)

  • Continuous or bilevel positive airway pressure.

  • EMS use often limited to BiPAP-capable transport ventilators or CPAP-only devices.

4. EMS Ventilator Setup and Safety Checks

A. Pre-use Checklist

  • Verify oxygen supply and battery charge

  • Inspect tubing and circuit for integrity

  • Calibrate if required

  • Select appropriate circuit for invasive vs. non-invasive use

B. Post-Intubation Vent Settings (Adult, Default)

  • Mode: Assist-Control (AC)

  • Vt: 6–8 mL/kg ideal body weight

  • RR: 12–16 bpm

  • PEEP: 5 cm H₂O

  • FiO₂: 100% initially, titrate as needed

  • I:E: 1:2

Adjust based on EtCO₂, SpO₂, patient condition, and capnography waveform.

5. Monitoring and Troubleshooting

Monitoring Parameters

  • SpO₂ for oxygenation

  • EtCO₂ for ventilation

  • PIP for pressure problems (increased = resistance, decreased = leak)

  • Chest rise, breath sounds, skin color

Troubleshooting Tips

Symptom Possible Cause Action
High PIP alarm Bronchospasm, kinked tube, secretions Suction, check tubing, administer bronchodilators
Low pressure alarm Disconnection or leak Reconnect, check cuff inflation
Low SpO₂ Poor oxygenation Increase FiO₂, check positioning
High EtCO₂ Hypoventilation Increase rate or tidal volume
Low EtCO₂ Hyperventilation or disconnection Decrease rate, check connections

6. Special Populations

Pediatrics

  • Use weight-based settings (4–6 mL/kg Vt)

  • More sensitive to pressure and volume

  • Always monitor closely with EtCO₂ and SpO₂

Trauma/TBI

  • Maintain normocapnia (EtCO₂ ~35–40 mmHg)

  • Avoid hyperventilation unless for acute herniation signs

7. Documentation Essentials

Document:

  • Vent settings at start and end of transport

  • Changes made during transport

  • Patient response (vitals, SpO₂, EtCO₂)

  • Alarms encountered and resolved

8. Summary Tips for EMS Providers

  • Always confirm ETT placement and secure it well
  • Use EtCO₂ to guide ventilation — not just respiratory rate
  • Start with safe default settings and titrate to clinical response
  • Understand your ventilator model — know how to change modes and troubleshoot quickly
  • Communicate with receiving facility about any changes made

Further Learning Resources


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