Asthma & COPD Crisis Ventilation

Why This Is Hard

Severe asthma and COPD look like “just bag harder.” That instinct can kill. Obstructed lower airways need time to empty. Fast rates and large tidal volumes stack air (auto-PEEP), raise intrathoracic pressure, drop venous return, and can cause PEA-like arrest physiology.

Street Physiology (Education)

• Air trapping — incomplete exhalation between breaths.
• Auto-PEEP — residual pressure at end-exhalation that the next breath fights against.
• Shark-fin EtCO₂ — classic obstructive waveform when available.
• Hypoxia and hypercarbia may coexist; rushing rate is not the first fix.

BVM / Vent Strategy Themes

1. Allow prolonged exhalation — slower rates than you use for healthy lungs (exact targets follow protocol/training).
2. Modest volumes — chest rise enough, not maximal squeeze every time.
3. If bagging becomes nearly impossible — disconnect briefly to allow exhalation per training, then resume carefully (know your protocol guidance).
4. Medical therapy still matters — bronchodilators, steroids, epi pathways, CPAP when authorized — airway support is only one arm.
5. Intubation is high risk in severe obstruction — prepare for hypotension and arrest at induction; this lesson does not teach RSI doses.

Key Points for Paramedics

• Silent chest is a late, terrifying finding — treat as critical.
• Hyperventilation culture from ACLS arrest defaults is wrong for pure severe asthma/COPD with a pulse.
• Watch BP and mentation when positive pressure starts.
• Differential: CHF, PE, pneumothorax, anaphylaxis can mimic — use history and exam.

Field Pitfalls

• Bagging at 20/min “because SpO₂ is low.”
• Missing tension pneumothorax after aggressive positive pressure.
• Assuming all wheezes are COPD without considering cardiac asthma/CHF.

Practice

Talk through a severe asthma arrest risk scenario: rate, volume, disconnect strategy, and meds per your protocol. Related: Waveform Capnography, Effective BVM.

Sources & Further Study

• EMS obstructive airway education; your asthma/COPD and ventilation protocols.