NCLEX-RN® Oxygenation and Ventilation: O₂ Devices, Airway Suctioning, and Ventilator Alarms
A practical guide to oxygen delivery devices, suctioning technique, and mechanical ventilator alarm troubleshooting — exactly what the NCLEX-RN® tests in the Physiological Adaptation category.
The big picture
Oxygenation and ventilation questions appear throughout the NCLEX-RN® — in med-surg, critical care, pediatrics, and post-op scenarios. The core skill isn't memorizing device specs; it's choosing the right device, recognizing hypoxia before it becomes a crisis, and knowing exactly when to suction or respond to a ventilator alarm. This guide covers oxygen delivery, airway management, suctioning, and ventilator care.
Oxygen delivery devices
Matching the right device to the right patient is a classic NCLEX® task. The key variables are: how much O₂ does the patient need, and does the concentration need to be precise?
Low-flow vs. high-flow systems
| System type | Delivers | FiO₂ control | Best for |
|---|---|---|---|
| Low-flow | Variable FiO₂ (mixes with room air) | Approximate | Spontaneously breathing, stable patients |
| High-flow | Fixed, precise FiO₂ | Exact | Patients who need controlled delivery (COPD, titrated O₂) |
Oxygen devices: quick reference
| Device | Flow rate | Approximate FiO₂ | Key points |
|---|---|---|---|
| Nasal cannula | 1–6 L/min | 24–44% | Comfortable; patient can eat and talk; for mild hypoxia |
| Simple face mask | 6–10 L/min | 35–50% | Minimum 6 L/min (to flush CO₂ from mask) |
| Partial rebreather mask | 10–15 L/min | 60–70% | Has reservoir bag; bag should NOT fully deflate on inhalation |
| Non-rebreather mask (NRB) | 10–15 L/min | 80–95% | One-way valves; highest O₂ without intubation; bag must stay inflated |
| Venturi mask | Varies by adapter | 24–60% (precise) | Most precise FiO₂; ideal for COPD; colored adapters set exact percentage |
| High-flow nasal cannula (HFNC) | Up to 60 L/min | Up to 100% | Heated, humidified; reduces work of breathing; used in moderate-severe hypoxia |
NCLEX® priority: If a patient has a non-rebreather mask and the reservoir bag is completely deflating, increase the flow rate. If the patient's SpO₂ remains < 90% despite a non-rebreather mask, prepare for intubation.
COPD and oxygen delivery
For patients with chronic CO₂ retention, use the Venturi mask — it delivers a precise, controlled FiO₂ (starting at 24–28%) to avoid suppressing hypoxic drive. Target SpO₂ is 88–92%, not the standard 94–98%.
Airway management
Positioning as the first intervention
Before any device or medication, the nurse's first airway action is positioning:
- Unconscious, no spinal injury: Head-tilt chin-lift (opens the airway mechanically)
- Suspected spinal injury: Jaw thrust only (does not move the cervical spine)
- Conscious patient with dyspnea: High Fowler's or tripod position
Oral and nasopharyngeal airways
| Device | Use | Key concern |
|---|---|---|
| Oropharyngeal airway (OPA) | Unconscious patients without gag reflex | Never use if gag reflex is present — triggers vomiting and aspiration |
| Nasopharyngeal airway (NPA) | Conscious or semiconscious patients | Use water-soluble lubricant; contraindicated in facial/basilar skull fracture |
Endotracheal tube (ETT) — nursing management
- Confirm placement after intubation: auscultate bilateral breath sounds, watch for chest rise, end-tidal CO₂ capnography, CXR to confirm tip position (2–3 cm above carina)
- Secure the tube and document centimeter marking at the teeth/lip
- Cuff pressure: Maintain at 20–30 cm H₂O (too high = tracheal necrosis; too low = aspiration)
- Mouth care every 2 hours — reduces ventilator-associated pneumonia (VAP)
- Suction only when needed — not on a schedule
Suctioning
Suctioning clears secretions that the patient cannot clear independently. NCLEX® tests the order of steps and key safety parameters.
When to suction
Suction when the patient shows signs of retained secretions:
- Audible gurgling or noisy breathing
- SpO₂ dropping without other cause
- Visible secretions in the tube or oropharynx
- Patient appears distressed and unable to clear airway
Do not suction on a schedule — each pass carries risk (hypoxia, trauma, bronchospasm, vagal bradycardia).
Oropharyngeal vs. nasopharyngeal vs. endotracheal suctioning
| Type | Patient | Key points |
|---|---|---|
| Oropharyngeal (Yankauer) | Conscious or unconscious; clearing mouth/pharynx | Rigid tip; safe for mouth care suctioning |
| Nasopharyngeal | Conscious with secretions; can't cough effectively | Flexible catheter; lubricate; gentle insertion |
| Endotracheal/tracheostomy | Intubated/trach patients | Sterile technique (open suctioning) or closed inline system |
Endotracheal suctioning: step-by-step
- Explain procedure and position patient (semi-Fowler's)
- Hyperoxygenate (100% O₂ for 30–60 seconds before and after each pass) — prevents hypoxia
- Insert catheter with suction OFF; advance until resistance (carina), then pull back 1 cm
- Apply suction while withdrawing — use a rotating motion; suction for no longer than 10–15 seconds per pass
- Allow patient to rest and re-oxygenate between passes
- Limit to 2–3 passes maximum per episode
- Reassess SpO₂, breath sounds, and secretion characteristics
Tracheostomy care
- Clean inner cannula with sterile normal saline and brush per facility protocol (or replace disposable inner cannula)
- Change trach ties when soiled, but have a second nurse assist — tube can be accidentally dislodged
- Keep an obturator at the bedside at all times (used to reinsert tube if it falls out)
- Keep a same-size and one-size-smaller spare trach at bedside
- If tracheostomy tube is dislodged: Call for help, maintain airway with jaw thrust or face mask, prepare emergency equipment
Mechanical ventilation
Mechanical ventilators take over or assist breathing. Nurses manage the patient and troubleshoot alarms — they do not independently change ventilator settings.
Common ventilator modes
| Mode | What it does | When used |
|---|---|---|
| AC (assist-control) | Delivers full breath with every patient trigger; gives full backup rate if no trigger | Initial intubation, full support needed |
| SIMV | Synchronizes machine breaths with patient effort; allows spontaneous breaths between | Weaning phase |
| Pressure support (PSV) | Augments spontaneous breaths; patient controls rate and timing | Weaning; conscious patients |
| CPAP | Maintains continuous positive airway pressure; patient breathes entirely spontaneously | Weaning; sleep apnea |
Key ventilator settings
| Parameter | Typical value | What it does |
|---|---|---|
| FiO₂ | 21–100% | Fraction of inspired oxygen |
| Tidal volume (Vt) | 6–8 mL/kg ideal body weight | Volume per breath; too high → barotrauma |
| Rate (RR) | 12–20 breaths/min | Machine backup rate |
| PEEP | 5 cm H₂O (standard) | Keeps alveoli open at end-expiration; reduces atelectasis |
Ventilator alarms: what each means and what to do
NCLEX® frequently presents a ventilator alarm scenario. The rule: first check the patient, then the ventilator.
| Alarm | Common cause | First action |
|---|---|---|
| High pressure | Coughing, biting tube, secretions, bronchospasm, kink in tubing, pneumothorax | Assess patient; suction if secretions; check tube placement |
| Low pressure / disconnect | Disconnected tubing, cuff leak, accidental extubation | Check all connections; check cuff; re-bag if needed |
| Low SpO₂ | Mucus plug, position change, secretions, worsening condition | Assess, suction, re-bag, notify provider |
| Apnea | Patient not breathing above set rate | Assess patient immediately; check connections |
NCLEX® rule: If a ventilator alarm sounds and you cannot quickly identify and fix the cause, manually ventilate the patient with a bag-valve-mask (BVM) while you troubleshoot — never leave the patient without ventilation.
VAP (ventilator-associated pneumonia) prevention bundle
VAP is a leading complication of mechanical ventilation and is heavily tested on NCLEX®:
- HOB elevation 30–45° at all times
- Oral care with chlorhexidine every 2 hours
- Spontaneous awakening trials (SAT) and spontaneous breathing trials (SBT) daily to assess readiness for extubation
- Hand hygiene before any contact with the circuit
- Subglottic secretion suctioning (specialized ETT)
- Maintain cuff pressure 20–30 cm H₂O
Extubation readiness — signs the nurse monitors
The provider makes the decision, but nurses document the clinical picture:
- Patient is awake and following commands
- Able to cough and protect airway
- FiO₂ ≤ 40–50% to maintain SpO₂ ≥ 92%
- PEEP ≤ 5 cm H₂O
- Spontaneous tidal volume adequate
After extubation: monitor closely for stridor (laryngeal edema), have re-intubation equipment at bedside, apply supplemental O₂, encourage deep breathing and coughing.
NCLEX® clinical judgment focus
Oxygenation questions usually present a clinical picture and ask: what does the nurse do first?
Framework:
- Check the patient first (before adjusting any device or calling anyone)
- Position the patient upright
- Oxygen — increase delivery if SpO₂ is dropping
- Notify the provider if oxygen adjustments don't help or if the patient deteriorates
Common NCLEX® traps:
- Leaving an OPA in when a patient starts gagging — remove it immediately
- Applying suction on insertion (creates trauma) — suction only on withdrawal
- Ignoring a low-pressure ventilator alarm — this could mean disconnection or extubation
- Continuing a ventilator check before assessing the patient — assess patient first
FAQ
What does SpO₂ of 88% mean for a COPD patient?
For a COPD patient with known CO₂ retention, SpO₂ of 88–92% is the target range — not a cause for alarm. Giving high-flow oxygen to reach 98% can suppress hypoxic drive and cause respiratory depression. Only go higher if the patient is in acute distress.
How long should each suction pass take?
Each individual suction pass should take no more than 10–15 seconds — the time it takes to hold your breath. Longer passes cause hypoxia. Between passes, allow the patient to recover with 100% oxygen for 30–60 seconds.
When should the nurse call the doctor about a ventilator?
Call if the patient's condition is worsening despite troubleshooting, if SpO₂ cannot be maintained, if there are signs of pneumothorax (sudden increase in peak pressures + decreased breath sounds + hemodynamic instability), or if the patient requires settings outside the ordered range.
What is the difference between a partial rebreather and a non-rebreather mask?
Both have a reservoir bag. The non-rebreather has one-way valves on the exhalation ports that prevent room air from mixing with the delivered O₂, resulting in 80–95% FiO₂. The partial rebreather allows the patient to re-breathe the first portion of exhaled air (rich in O₂) — FiO₂ is 60–70%.
What does PEEP do?
Positive end-expiratory pressure (PEEP) keeps alveoli from collapsing at the end of each breath, improving oxygenation by maintaining functional residual capacity. Too much PEEP (auto-PEEP or iatrogenic) can cause barotrauma and reduce venous return.
Key takeaways
- O₂ delivery: Match device to need. Venturi mask = most precise FiO₂ (best for COPD). Non-rebreather = highest without intubation. Check that the NRB reservoir bag stays inflated.
- Airway: Head-tilt chin-lift unless spinal injury suspected (then jaw thrust). OPA only for unconscious patients without a gag reflex.
- Suctioning: Suction on withdrawal only. 10–15 seconds per pass. Hyperoxygenate before and after.
- Ventilator alarms: Patient first, then ventilator. Low-pressure alarm = disconnection. High-pressure alarm = obstruction. When in doubt, manually bag the patient.
- VAP prevention: HOB 30–45°, oral care, daily waking/breathing trials, cuff pressure 20–30 cm H₂O.
Sources: NCSBN NCLEX-RN® 2023 Test Plan; AHRQ Preventing Ventilator-Associated Events; U.S. National Library of Medicine MedlinePlus — Oxygen Therapy.
See also:
- NCLEX-RN® Respiratory Disorders
- NCLEX-RN® Patient Safety Guide
- Perioperative Nursing Guide
- NCLEX-RN® Cardiac Disorders
- NCLEX-RN® Neurology Guide (Airway in Neuro Patients)
Practice on RN Clarity: Question Bank · Flashcards · Mock Tests