Study Guides/Airway, Oxygen & Ventilation
Guide 03 · Airway & Respiration
Airway, Oxygen & Ventilation
Every airway decision comes down to the same sequence: is it open, is it clear, and is enough oxygen actually moving? This guide walks the full BLS toolbox — positioning, adjuncts, suction, oxygen delivery, and assisted ventilation — with the exact numbers the NREMT expects you to know cold.
1No airway, no patient
Brain cells begin dying within 4–6 minutes without oxygen. Nothing else in your assessment matters if air isn't moving — which is why airway sits at the front of every algorithm you'll ever learn. Before you reach for equipment, listen. An obstructed airway announces itself:
- Snoring — the tongue has relaxed against the back of the throat. The single most common obstruction in an unresponsive patient, and it's fixed with positioning alone.
- Gurgling — fluid (blood, vomit, secretions) is pooling in the airway. That's your cue to suction immediately.
- Stridor — a high-pitched sound on inspiration from swelling or a foreign body narrowing the upper airway. This one you can't fix with a head tilt; it signals a partial obstruction that can become complete.
Key pointSnoring and gurgling are the two sounds you can fix right now with your hands: snoring gets a head-tilt chin-lift or jaw-thrust, gurgling gets suction. If you hear either and move on to something else, you've skipped the step that keeps this patient alive.
2Positioning the airway
Your hands are the first airway device. Which maneuver you choose depends on one question: is there any suspicion of spinal injury?
Opening the airway — choose the maneuver
1
Any mechanism suggesting spinal injury? Falls, MVCs, diving injuries, trauma above the clavicles, unknown mechanism in an unresponsive patient.
No trauma suspected Head-tilt chin-lift — one hand tilts the forehead back, fingers of the other lift the bony part of the chin. Lifts the tongue off the posterior pharynx.
Trauma suspected Jaw-thrust — from above the head, push the angles of the jaw forward with your fingers while holding the head in neutral alignment. Opens the airway without moving the neck.
2
Optimize the position. For a supine medical patient, the sniffing position (neck flexed slightly forward, head extended — like sniffing the air) aligns the airway axes for the best air movement.
For infants, do the opposite of what instinct says: their large occiputs flex the neck forward when supine, kinking the airway. Pad behind the shoulders to bring the head to a neutral position.
3
Protect what you've opened. An unresponsive patient who is breathing adequately, with no trauma suspected, goes in the recovery position (on their side) so gravity drains secretions away from the airway instead of into it.
CautionIf a jaw-thrust fails to open the airway in a trauma patient, airway wins — carefully use a head-tilt chin-lift. A protected spine means nothing on a patient who isn't breathing.
3Airway adjuncts: OPA & NPA
Manual maneuvers tie up your hands. Adjuncts hold the tongue off the back of the throat so you can move on to ventilating. Neither one protects against aspiration — they keep the airway open, not secure.
Oropharyngeal airway (OPA)
- Who gets it: ONLY patients without a gag reflex — deeply unresponsive patients. Insert an OPA in a patient with an intact gag and you'll trigger vomiting, and likely aspiration.
- Sizing: measure from the corner of the mouth to the earlobe (or angle of the jaw).
- Adult insertion: insert with the tip pointing toward the roof of the mouth, then rotate 180° as it passes the tongue so the curve follows the airway.
- Pediatric insertion: no rotation. Use a tongue depressor to hold the tongue down and insert the OPA right-side-up, following the curve of the airway. Rotating can injure a child's soft palate.
Nasopharyngeal airway (NPA)
- Who gets it: patients with a decreased level of consciousness who still have a gag reflex — an NPA is tolerated with a gag reflex, which is exactly why it exists.
- Sizing: measure from the nostril to the earlobe; the diameter should fit the nostril comfortably.
- Insertion: lubricate with a water-soluble lubricant, insert into the larger nostril with the bevel toward the septum, following the floor of the nose straight back. If you meet resistance, try the other nostril.
CautionNever place an NPA when you suspect a basilar skull fracture — the tube can pass through the fractured plate. The tells: raccoon eyes (bruising around both eyes), Battle's sign (bruising behind the ears), or clear fluid (CSF) leaking from the nose or ears. See any of these, keep everything out of the nose.
| OPA (oral) | NPA (nasal) | |
|---|---|---|
| Gag reflex | Must be absent | Tolerated when present |
| Sizing | Corner of mouth → earlobe / angle of jaw | Nostril → earlobe |
| Insertion | Adult: rotate 180°. Pediatric: tongue depressor, no rotation | Lubricate; bevel toward the septum; straight back along the nasal floor |
| Avoid when | Gag reflex intact | Suspected basilar skull fracture (raccoon eyes, Battle's sign, CSF from nose/ears) |
| Best for | Deeply unresponsive patients | Semi-conscious patients, clenched jaws, intact gag |
4Suctioning
Gurgling means fluid, and fluid means suction — before you ventilate. Bag air into an airway full of vomit and you push it into the lungs.
- Rigid (Yankauer) catheter — the workhorse. Wide-bore, easy to control, best for clearing vomit and thick secretions from the mouth and oropharynx.
- Soft (French) catheter — flexible, for the nose, the lumen of an airway adjunct, or anywhere a rigid tip won't reach.
- Measure it like an OPA: corner of the mouth to the earlobe — never insert deeper than you can see.
- Suction only on the way OUT. Insert with no suction applied, then apply suction as you withdraw with a sweeping motion.
- Limit each attempt to about 15 seconds in adults — shorter in children and infants.
CautionSuction removes oxygen along with the fluid. Every second the catheter runs, the patient isn't breathing oxygen — that's why the ~15-second limit exists. Suction, re-oxygenate, and repeat as needed rather than running one long continuous pass.
5Oxygen delivery devices
Once the airway is open and clear, match the device to the patient. The question is always the same: how much oxygen does this patient actually need?
| Device | Flow rate | Delivered O₂ | Use it when |
|---|---|---|---|
| Nasal cannula | 1–6 L/min | ≈ 24–44% | Mild hypoxia or patients who won't tolerate a mask. Comfortable for long transports. |
| Non-rebreather mask (NRB) | 10–15 L/min | Up to ≈ 90%+ | Significant hypoxia or respiratory distress in a patient who is breathing adequately on their own. Inflate the reservoir bag fully before applying. |
| Bag-valve mask (BVM) | 15 L/min | ≈ Nearly 100% | Breathing is inadequate or absent — you are breathing for the patient, not just enriching what they inhale. |
Key point"High-flow O₂ for everyone" is outdated. Titrate to an SpO₂ of ≥ 94% for most patients — a stable patient sitting at 97% on room air doesn't need a non-rebreather. Save the aggressive oxygen for the patients whose numbers and work of breathing demand it, per your local protocol.
6Ventilating with a BVM
A patient breathing too slow, too shallow, or with agonal gasps is not moving enough air — no mask fixes that. Inadequate breathing means you take over with a bag-valve mask.
Assisted ventilation with a BVM
1
Open the airway and insert an adjunct (OPA if no gag, NPA otherwise). Connect the BVM to oxygen at 15 L/min with the reservoir attached.
2
Seal the mask. Two-rescuer BVM is the standard to aim for: one rescuer holds the seal with two hands (thumbs on the mask, fingers pulling the jaw up into it) while the other squeezes the bag. One-rescuer BVM is a genuinely hard skill — get a second set of hands whenever you can.
3
Ventilate at the right rate:
Adult 1 breath every 6 seconds (10/min).
Child / infant 1 breath every 2–3 seconds (20–30/min).
Squeeze over about 1 second, just until you see visible chest rise — then release fully and let the patient exhale.
4
Reassess constantly. Watch for chest rise with every breath, improving color and SpO₂, and gastric distention (a sign you're bagging too hard or too fast, forcing air into the stomach).
CautionThe instinct under stress is to bag fast and hard — resist it. Hyperventilation raises pressure inside the chest, which reduces blood returning to the heart and drops cardiac output, and it forces air into the stomach. Slow, measured breaths to visible chest rise. Count it out loud if you have to.
A word on CPAP
Many BLS systems carry CPAP (continuous positive airway pressure) for the patient who is working hard but still breathing — classically moderate-to-severe respiratory distress from CHF/pulmonary edema. The patient must be alert, breathing on their own, and able to follow commands. Do not use CPAP on a patient who is apneic, can't protect their airway, is hypotensive, or is vomiting. Indications and pressures vary — follow your local protocol.
7Self-check
Answer before you expand. If you miss one, re-read that section — then go drill it for real.
Test yourself
Q1You approach an unresponsive patient and hear gurgling with each breath. What's your immediate action?
Suction the airway now. Gurgling means fluid — blood, vomit, or secretions — in the airway. Insert the catheter no deeper than you can see, suction only on the way out, and limit each attempt to about 15 seconds in an adult before re-oxygenating.
Q2You start to insert an OPA and the patient gags. What do you do instead?
Remove the OPA and use an NPA. An intact gag reflex is an absolute contraindication for an OPA — pushing on will trigger vomiting and risk aspiration. The NPA is tolerated with a gag reflex: size it nostril to earlobe, lubricate, and insert bevel toward the septum.
Q3What finding makes an NPA contraindicated — and what signs would you look for?
Suspected basilar skull fracture. Look for raccoon eyes (bruising around both eyes), Battle's sign (bruising behind the ears), or clear fluid — CSF — leaking from the nose or ears. Any of these, and nothing goes in the nose.
Q4A patient in obvious respiratory distress is breathing adequately on their own with an SpO₂ of 85%. Which oxygen device?
Non-rebreather mask at 10–15 L/min — up to ≈ 90%+ oxygen. They're significantly hypoxic but still breathing adequately, so they need high-concentration oxygen, not assisted ventilation. Fill the reservoir bag completely before you put the mask on, and keep reassessing: if their breathing becomes inadequate, switch to a BVM.
Q5You're assisting an adult's ventilations with a BVM. What rate — and how do you know each breath is enough?
1 breath every 6 seconds (10/min), each squeezed over about 1 second until you see visible chest rise. Faster or harder isn't better — hyperventilation drops cardiac output and pushes air into the stomach.
Now drill it
San Julian Trail — run the calls yourself
Play the demo →
Knowing the flow rates is step one. Now make airway and oxygen decisions on realistic BLS runs — pick the position, the adjunct, and the device while the patient's status changes underneath you. Free, no signup.