Asthma & COPD Crisis Ventilation

Why this matters

Severe asthma and chronic obstructive pulmonary disease (COPD) can look like a reason to bag harder. That can cause arrest.

Tight lower airways need time to empty. Fast rates and big squeezes trap air. That trapped air is auto-PEEP. Auto-PEEP is leftover pressure at the end of a breath. The next squeeze has to fight it.

Pressure in the chest rises. Blood returning to the heart falls. The rhythm can look like pulseless electrical activity (PEA).

Clinical sequence

1. If the patient still has a pulse, sit them up. Give the lung medicines in your protocol. Use noninvasive ventilation when that picture fits. Do not place a tube only because the patient is wheezing.
2. If you must bag, use a slow rate and a modest volume. Watch the chest fall before the next squeeze.
3. A shark-fin EtCO₂ waveform means obstructed exhalation. The upstroke slopes. It does not rise straight up. Slow the rate and leave time to exhale. This shape is common in severe asthma and COPD.
4. Watch the blood pressure when positive pressure starts. The bag can drop the blood returning to the heart.
5. A silent chest is critical. It does not mean the patient is improving. If the bag becomes nearly impossible to squeeze, disconnect it briefly so trapped air can leave. Then bag again carefully, the way you were trained.

What Is Happening in Those Lungs

• Air trapping means the chest does not empty between breaths.
• Auto-PEEP is stacked air that cannot get out. The next breath has to push against that leftover pressure.
• A shark-fin EtCO₂ trace is the usual waveform when exhalation is obstructed and you have a trace.
• Low oxygen and high carbon dioxide can happen together. A faster bag rate is not the first fix.
• Do not put a non-rebreather mask on a talking patient with asthma who is already saturating well. Global Initiative for Asthma (GINA) 2026 teaching is to give oxygen when the oxygen saturation (sat) is low, about under 92%, not as a default. If you give oxygen, the upper target is about 95% in adults and older children. A crashing patient still gets oxygen now. Your protocol owns the target.
• Pulse oximetry can read higher than the true sat in a patient with dark skin. Look at work of breathing, not the number alone.

How to Bag These Lungs

1. Leave a long time to exhale. Use a slower rate than you use for healthy lungs. Your protocol and training own the exact number.
2. Use a modest volume. Stop when you see the chest rise. Do not empty the bag on every breath.
3. If the bag locks up, disconnect it briefly so air can leave, then start again carefully. Follow your protocol.
4. Medicines still matter. Use bronchodilators, steroids, and epinephrine pathways when your protocol includes them. Noninvasive ventilation also matters when you are allowed to use it. That includes continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BiPAP). For many COPD flares, noninvasive ventilation is preferred over a tube when the patient can still cooperate. Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2026 supports noninvasive ventilation for selected COPD. Follow your protocol.
5. Intubation is high risk in severe obstruction. Be ready for the blood pressure to fall, and for arrest, when you induce. This lesson does not teach rapid sequence intubation doses.

Teaching points

• A silent chest is a late finding. Treat it as critical.
• The fast bag rate used in cardiac arrest is the wrong rate for severe asthma or COPD when a pulse is present.
• Watch blood pressure and alertness when positive pressure starts.
• Heart failure, pulmonary embolism, pneumothorax, and anaphylaxis can look the same. Use the history and the exam.
• If this looks like anaphylaxis plus asthma, GINA 2026 teaching is epinephrine first, then bronchodilators. Do not start a nebulizer and delay intramuscular epinephrine.

Common errors

• Bagging at 20 breaths per minute because the oxygen saturation (SpO₂) is low.
• Missing a tension pneumothorax after hard positive-pressure ventilation.
• Treating every wheeze as COPD and missing heart-failure wheezing.
• Sedating an awake patient to calm an asthma attack. GINA 2026 says those drugs can slow or stop breathing. A drug for placing a tube is a separate protocol decision.

Practice

Related: Waveform Capnography, Effective BVM.

Sources & Further Study

Named guidelines for further study. They are not clinical orders and do not replace your protocol or medical direction.

• NASEMSO National Model EMS Clinical Guidelines (2022) — U.S. EMS model language; follow your protocol
• GINA 2026 Strategy Report — slow the bag, treat bronchospasm; oxygen if the sat is low (about <92%), not a default non-rebreather mask. If oxygen is given, the upper target is about 95% in adults and older children. A crashing patient still gets oxygen now. Pulse oximetry can read high in dark skin. Anaphylaxis plus asthma: epinephrine first, then bronchodilators. Do not sedate an awake patient to calm the attack.
• GOLD 2026 COPD Report — NIV preferred over jumping to a tube in selected COPD exacerbations
• AHA 2025 Part 10: Special Circumstances — asthma: avoid stacked breaths / auto-PEEP when ventilating
• Your asthma/COPD, CPAP/NIV, and ventilation protocols.