Bag-mask ventilation that is inflating the stomach, not the lungs
You are leading the resuscitation in a 12-bed outpatient clinic when a 47-year-old man collapses in the waiting room. He is unresponsive with agonal gasps. You start compressions and send a colleague for the bag-mask device, oropharyngeal airway, AED, and suction. Two rescuers are now working: compressions at about 100/min with an estimated depth of 4 cm, and the rescuer's hands are not fully lifting off the chest between compressions. The mask seal looks acceptable, but the chest does not visibly rise with each squeeze, and air is heard gurgling into the stomach while the abdomen progressively distends. The AED analyzes and displays "No shock advised." No advanced airway is on site yet, and the pulse oximeter is not reading. The next rhythm check is in 90 seconds.
1. Why is the chest not rising despite a seemingly good mask seal, and how do you correct the ventilation technique?
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Gastric insufflation with no chest rise means gas is going down the esophagus, not the trachea - the common final pathway is an unopened airway plus excessive pressure. The seal being fine does not help if the airway itself is obstructed by the tongue or if the head is in a sniffing position that is actually flexed.
Corrections:
- Reposition the head: head-tilt/chin-lift (jaw thrust if trauma suspected). Re-check every time ventilation fails.
- Switch to a two-person technique: one rescuer holds the mask with both hands (E-C grip or thenar eminence on the mask body, fingers on the mandible) while the second squeezes the bag. This is the single highest-yield change.
- Change the squeeze: deliver each breath over about 1 second with just enough volume to make the chest rise visibly (roughly 500–600 mL in an adult). A hard, fast, high-volume squeeze is what forces gas into the stomach.
- Slow the rate: two breaths after every 30 compressions, and never more than 10 breaths/min regardless of how it feels.
- Recheck the OPA: size it from the corner of the mouth to the angle of the mandible; a too-small or too-long OPA can obstruct or provoke gagging and incomplete seal.
- Do not apply routine cricoid pressure - it does not prevent aspiration and it can worsen ventilation.
- If ventilation still fails, suspect a foreign body, suction the airway, and consider an airway adjunct or a supraglottic device.
Excess volume and pressure raise intrathoracic pressure, cut venous return, drop coronary perfusion pressure, and increase aspiration risk - this is a hemodynamic problem, not just an aesthetic one.
2. Evaluate the compressions you are receiving and state the corrections, including how you handle the upcoming rhythm check.
Read the worked answer
Two deviations from high-quality CPR:
- Depth too shallow. 4 cm is below the adult target of at least 5 cm but no more than 6 cm. Coach in real time, use a backboard if the surface is a soft mattress or a gurney, and use the CPR feedback device if the AED has one.
- Incomplete chest recoil. Hands staying on the chest between compressions raises intrathoracic pressure and reduces venous return and coronary perfusion pressure. Cue "let it come all the way back up" every few seconds.
What is already acceptable: the rate of about 100/min is within the 100–120/min target - do not push them to go faster.
Handling the rhythm check:
- Keep the compressor pushing until the AED is ready; pre-charge the AED so the pause is delivery-only.
- Pause for no more than 10 seconds, and in practice aim for under 5.
- Swap the compressor during the pause (rotate every 2 minutes to prevent fatigue-related decay in depth), and resume compressions immediately after the analysis.
- Have a third rescuer ready to take over ventilation so the compressor never has to multitask.
3. The AED says "No shock advised." What happens next, and how does the arrival of a supraglottic airway change your ventilation strategy?
Read the worked answer
"No shock advised" means the rhythm is non-shockable (PEA or asystole). Electricity would only delay CPR.
Immediate actions:
- Resume compressions at once - no pulse check after this analysis. Do not stop to ask whether there is a pulse; the AED has already told you there is no shockable rhythm, and the algorithm is 2-minute cycles of CPR.
- Epinephrine 1 mg IV/IO as soon as access exists, repeated every 3–5 minutes.
- Search for reversible causes: the Hs and Ts (hypovolemia, hypoxia, hydrogen ion/acidosis, hypo/hyperkalemia, hypothermia; tension pneumothorax, tamponade, toxins, thrombosis - pulmonary and coronary). Naloxone is reasonable if opioid toxicity is possible, but it never replaces CPR and must not interrupt compressions.
- At each rhythm check, do a pulse check of no more than 10 seconds.
When the supraglottic airway arrives:
- Insert it when a trained provider is available without interrupting compressions (or during the planned pause, with the compressor ready).
- Confirm placement - waveform capnography is the standard; a favorable waveform plus a reasonable EtCO2 is the confirmation.
- Once an advanced airway is in place, the compression-to-ventilation coupling changes: continuous compressions with 1 breath every 6 seconds (10 breaths/min), and the 30:2 cycle is retired.
- Watch the capnography trace, not just the number - a sudden loss of waveform suggests dislodgement, which should trigger a fast reassessment rather than a pause in compressions.