CPAP Quick Reference

Prehospital Continuous Positive Airway Pressure (CPAP) reference for EMS providers. Covers indications, contraindications, setup, monitoring, and troubleshooting for field use.

CPAP Quick Reference

Indications for Prehospital CPAP

Acute Pulmonary Edema / CHF

Acute respiratory distress from fluid overload. CPAP reduces preload, afterload, and improves oxygenation.

Note: Most common prehospital CPAP indication. Consider concurrent nitroglycerin per protocol.

COPD Exacerbation

Acute worsening of chronic obstructive pulmonary disease with increased work of breathing.

Note: Start at lower pressures (5 cmH₂O). Monitor closely for CO₂ retention.

Severe Asthma

Severe bronchospasm unresponsive to initial nebulizer therapy.

Note: Use as adjunct to bronchodilators. Can deliver nebulized meds inline with some CPAP devices.

Pneumonia

Community-acquired pneumonia with significant hypoxia and respiratory distress.

Note: Supportive use. Does not treat underlying infection.

Near-Drowning

Submersion injury with pulmonary edema and hypoxia after initial airway clearance.

Note: Ensure airway is clear of water/debris first. Monitor for vomiting.

Post-Extubation Support

Respiratory support following field extubation or failed intubation attempt.

Note: Bridge therapy while preparing for definitive airway if needed.

Sources: NAEMSP Position Statement: Prehospital Use of CPAP (2019); AHA/ACC 2022 Guidelines for Heart Failure Management; Pace J, Fuller K. "Out-of-hospital continuous positive airway pressure for acute respiratory failure." Cochrane Database Syst Rev. 2019.; Goodacre S et al. "Prehospital CPAP for acute cardiogenic pulmonary edema." JAMA. 2019.; NHTSA National EMS Education Standards (2021); Weitz G et al. "Prehospital CPAP vs standard therapy in acute pulmonary edema." Am J Emerg Med. 2007;25(7):802-807.

How CPAP Works

Mechanism:

Delivers continuous positive pressure to keep alveoli open, improving gas exchange and reducing work of breathing.

Hemodynamic Effects:

Reduces venous return (preload) and left ventricular afterload — particularly beneficial in CHF/pulmonary edema.

Key Principle:

CPAP does NOT ventilate — the patient must be breathing spontaneously. It augments their own respiratory effort.

Equipment Essentials

CPAP Device:

Disposable or reusable flow generator with adjustable pressure (5–10 cmH₂O typical)

O₂ Supply:

Requires 10–15 LPM flow. Verify adequate tank volume for transport time.

Mask Sizes:

S, M, L — proper fit is critical. Mask should seal from bridge of nose to below lower lip.

Always Have Ready:

Suction, BVM, backup O₂ tank, NRB mask as fallback.

Signs of Improvement

• SpO₂ increasing toward target
• Respiratory rate decreasing
• Reduced accessory muscle use
• Patient reporting easier breathing
• Improved mental status

Warning Signs

• No improvement after 5–10 minutes
• Increasing agitation or anxiety
• Persistent air leak
• Abdominal distention
• Decreasing blood pressure

Escalation Triggers

• SpO₂ < 85% despite CPAP
• Respiratory rate < 10 or > 40
• Loss of consciousness
• SBP < 80 mmHg
• Respiratory arrest

Clinical Pearls

Coach your patient: "Breathe normally — the machine is doing the work for you." Patient cooperation dramatically improves outcomes.

Position matters: Keep the patient sitting upright at 45° or greater. Never lay a CPAP patient flat.

Think ahead: Calculate your O₂ supply duration before applying CPAP. A D-tank at 15 LPM lasts approximately 15 minutes.

Early application: Research shows early CPAP in acute pulmonary edema reduces intubation rates and ICU stays.