4.4 Artificial Airways and Suctioning
Key Takeaways
- Artificial-airway items test indication, placement confirmation, cuff management, humidification of the bypassed upper airway, suctioning technique, and complication recognition.
- An oropharyngeal airway is for an unconscious patient with no gag reflex; a nasopharyngeal airway is better tolerated when a gag reflex is present, unless basilar skull fracture or midface trauma is suspected.
- Confirm endotracheal tube placement with exhaled carbon dioxide plus bilateral breath sounds and a chest radiograph; the tip sits about 2-6 cm above the carina, roughly at the 21 cm (women) or 23 cm (men) lip mark.
- Maintain adult cuff pressure at 20-30 cmH2O (about 25 is typical) to seal the airway without exceeding tracheal capillary perfusion pressure.
- Limit each suction pass to 10-15 seconds with a catheter whose outer diameter is less than half the artificial-airway inner diameter, and stop for severe desaturation or bradycardia.
Choosing the Airway
An artificial airway maintains patency, supports ventilation, gives suction access, or bypasses an obstruction. TMC stems name the reason: depressed consciousness, upper-airway obstruction, ventilatory failure, secretion retention, trauma, or a long-term airway need. An oropharyngeal airway (OPA) is appropriate for an unconscious patient without a gag reflex and is sized from the corner of the mouth to the angle of the jaw. A nasopharyngeal airway (NPA) is better tolerated when a gag reflex is present, but avoid it with a suspected basilar skull fracture, severe midface trauma, or nasal obstruction.
Airway Decision Table
| Scenario clue | Airway direction | Safety point |
|---|---|---|
| Unconscious, no gag reflex | Oropharyngeal airway | Mouth-corner-to-jaw-angle sizing |
| Gag reflex present, no facial trauma | Nasopharyngeal airway | Lubricate, never force |
| Failure to oxygenate or ventilate | Endotracheal tube | Confirm placement immediately |
| Long-term ventilation or secretion access | Tracheostomy | Secure tube, humidify gas |
| Laryngectomy patient | Stoma access only | Oxygenate and suction through the stoma |
| New trach dislodged, in distress | Call for help, oxygenate | Avoid creating a false passage |
Confirming Endotracheal Tube Position
After intubation, use multiple methods: symmetric chest rise, bilateral breath sounds, absent epigastric sounds, exhaled carbon dioxide (the most important immediate confirmation of tracheal placement), improving oxygenation, and a chest radiograph. The adult tip target is 2-6 cm above the carina, which usually corresponds to about a 21 cm lip mark in women and 23 cm in men. If, after intubation, the left breath sounds are absent and the right are louder, suspect right mainstem intubation and withdraw the tube slightly per protocol while a carbon dioxide waveform confirms the tube is still tracheal.
Cuff Management, Humidification, and Speaking Valves
Keep adult cuff pressure at 20-30 cmH2O (about 25 cmH2O is typical). Too little allows leak and microaspiration; too much exceeds tracheal mucosal capillary pressure (about 25-30 mmHg) and risks ischemia, necrosis, or stenosis. A persistent leak despite acceptable pressure points to an undersized or malpositioned tube, a damaged cuff, or a faulty pilot balloon — not a reason to overinflate. Because the artificial airway bypasses the nose, inspired gas must be warmed and humidified by a heated humidifier or a heat-moisture exchanger sized to the secretion burden; thickening secretions signal inadequate humidification.
A speaking valve requires cuff deflation and a patent upper airway so the patient can exhale around the tube — applying it with the cuff inflated causes dangerous air trapping.
Suctioning: Indications and Technique
Suction for clinical need, not by schedule. Indications include visible secretions, coarse breath sounds, an ineffective cough, a rising peak pressure from secretions, a sawtooth flow waveform, or desaturation from mucus plugging.
- Catheter size: outer diameter less than half the artificial-airway inner diameter (a 7.0 mm tube allows roughly a 10-12 Fr catheter).
- Duration: limit each pass to 10-15 seconds; hyperoxygenate before and between passes.
- Suction pressure: roughly 100-150 mmHg in adults.
- Stop and oxygenate for severe desaturation, bradycardia (often vagal plus hypoxemic), arrhythmia, bleeding, or distress.
Troubleshooting and the DOPE Mnemonic
When oxygenation worsens after airway placement, verify the tube before touching ventilator settings. Sudden low exhaled volume suggests a leak, cuff failure, disconnection, or displacement; sudden high pressure suggests biting, kink, secretions, bronchospasm, or falling compliance. For any abrupt deterioration in an intubated patient, run DOPE: Displacement, Obstruction, Pneumothorax, Equipment failure.
Distinguish a mature tracheostomy tract (a dislodged mature tube can often be replaced by trained staff) from a fresh tract, where blind reinsertion risks a false passage — call for help, oxygenate over the stoma, and avoid forceful reinsertion. Remember the laryngectomy patient breathes only through the stoma, so direct oxygen, suction, and ventilation there.
Closed (In-Line) vs Open Suctioning
The exam distinguishes open suctioning (disconnect from the ventilator, sterile single-use catheter) from closed in-line suctioning (a sheathed catheter that stays attached to the circuit). Closed suctioning preserves positive end-expiratory pressure and FiO2 because the circuit is never opened, which matters for patients on high PEEP or high FiO2 in whom a disconnect causes derecruitment and rapid desaturation. It also limits aerosolization of secretions, which is preferred for patients with airborne-transmissible infections.
The trade-off is that the sheath can foul over time and the closed catheter is somewhat less effective for very thick plugs. When a stem describes a patient on PEEP of 12-15 who desaturates with every open suction pass, the targeted answer is to switch to closed suctioning rather than to suction less often.
Avoiding Suction-Induced Harm
Several suction complications are tested. Hypoxemia is prevented by hyperoxygenation before and between passes and by limiting each pass to 10-15 seconds. Bradycardia and arrhythmia arise from vagal stimulation compounded by hypoxemia, so the response is to stop suctioning, oxygenate, and ventilate. Mucosal trauma and bleeding follow excessive negative pressure or a catheter that is too large, so keep adult pressure near 100-150 mmHg and the catheter outer diameter under half the tube's inner diameter. Atelectasis results from prolonged suction evacuating lung volume; using closed suction and brief passes limits it.
Instilling saline routinely is no longer recommended because it can dislodge bacteria into the lower airway and cause desaturation without reliably thinning secretions.
Securement and Migration
Tube security is itself an intervention. Recheck depth markings after every transport, repositioning, coughing fit, or sudden cuff leak, because even a one- to two-centimeter migration changes which lung is ventilated, and the margin is tiny in children and short-necked adults. Document tube size, depth at the lip or teeth, cuff pressure, securement method, and patient response after any change so that gradual migration or a recurrent leak becomes visible across serial assessments — exactly the trend a later scenario may ask you to spot.
A semiconscious trauma patient has snoring respirations and an intact gag reflex. There is no facial injury and no sign of a basilar skull fracture. Which temporary airway adjunct is most appropriate?
After oral intubation, the patient has absent left breath sounds, louder right breath sounds, and a normal end-tidal CO2 waveform. What is the most likely problem?
An intubated patient has an audible cuff leak. Cuff pressure reads 28 cmH2O, but the pilot balloon slowly deflates after each reinflation. Which interpretation is most appropriate?