Suction Frequency as a Criterion for Tracheostomy Tube (TT) Removal (Decannulation)

Adults (ICU / general patients)

• A 2017 systematic review on tracheostomy decannulation (Journal of Intensive Care) states: "frequency of suctioning should be less than 4 in the previous 24 hours" as part of the decannulation screening checklist.
• Some protocols phrase this as suction frequency less than once every 4 hours (i.e., no more than 6 times/day), with the stricter cutoff of <4/day being preferred.

Pediatric patients

Full Decannulation Criteria (suction is just one component)

Key takeaway

<4 suctions in 24 hours is the accepted threshold for adult patients being considered for TT removal. If a patient still requires suctioning 4 or more times per day, it suggests they cannot independently manage secretions, and decannulation is premature.

How to Measure Cough Strength

1. Peak Cough Flow (PCF) - Gold Standard

• A standard asthma peak flow meter connected to a face mask (most practical, low-cost, portable)
• OR a pneumotachograph (more accurate, used in respiratory labs)
• OR a digital/electronic peak flow meter

1. Seat the patient upright in a comfortable position
2. Apply the face mask firmly over nose and mouth (ensure a tight seal)
3. Instruct the patient to take a deep breath in (as deep as possible)
4. Then cough hard - "as if something went down the wrong pipe"
5. Record the highest value from 4-7 trials; the best result is used

2. Interpreting PCF Values

• For TT decannulation: PCF >160 L/min is the accepted minimum threshold (Pulmonology, 2015)
• Cough support (e.g., MI-E) should be considered when PCF <270 L/min in patients with neuromuscular disease - Murray & Nadel's Textbook of Respiratory Medicine

3. Surrogate / Pressure-Based Methods

• Patient exhales forcefully against a briefly occluded mouthpiece from near TLC
• Reflects expiratory muscle strength - a surrogate for cough strength
• Normal: typically >80 cmH₂O in adults; MEP >50 cmH₂O used as a decannulation/weaning criterion in some protocols
• Measured with a respiratory pressure meter (RMS device)

• Simpler and more widely available than PCF
• PEFR >160 L/min is commonly used as a decannulation criterion
• Less specific than PCF because it measures normal exhalation, not cough effort

• Bedside subjective grading (weak/moderate/strong) by the clinician
• Used when instruments are unavailable
• Harrison's Principles notes: "Cough strength is generally assessed qualitatively; peak expiratory flow or maximal expiratory pressure at the mouth can be used as a surrogate marker for cough strength" - Harrison's Principles of Internal Medicine, 22nd Ed.

4. Assisted Cough PCF (Augmented PCF)

• Stack breaths using a manual resuscitation bag (breath stacking) to maximize inspiratory volume
• Then cough - the resulting "assisted PCF" or "LVR-PCF" gives a better estimate of potential cough efficacy with mechanical assistance
• This helps decide if MI-E (mechanical insufflation-exsufflation) would benefit the patient

Summary Table

Patient Coughing Out Secretions Through the TT with Cuff Deflated - Clinical Significance

What is Happening Physiologically?

• Air can now flow past the tube and up through the upper airway (larynx, pharynx, nose/mouth)
• During a cough, the expiratory airflow is restored to a more normal path
• If the patient generates enough force to expel secretions out through the TT, it shows the lower airway secretions are being propelled upward and out

What Does This Sign Tell You?

Where Does This Fit in Decannulation Readiness?

1. Cough strength is present - the patient can generate expulsive force
2. Secretion management is adequate - patient can clear secretions without suctioning

• Patent upper airway
• Ability to clear secretions (cuff deflation trial + active cough)
• Adequate consciousness
• Adequate spontaneous ventilation

Why Cuff Deflation is Necessary for This Assessment

• Air is trapped below the cuff - no upper airway flow
• Even a strong cough only expels air out the TT opening
• Secretions above the cuff accumulate (subglottic pooling) - aspiration risk
• Cough cannot be properly assessed

• Airflow is restored through the upper airway
• Cough can move secretions upward and out
• Glottic function and laryngeal sensation can be assessed
• Voice returns (air through vocal cords)
• This is a necessary step before any decannulation attempt

What to Do Next After This Finding

1. Continue cuff-deflated trials - extend duration progressively (hours to days)
2. Monitor suctioning frequency - aim for <4 suctions/24 hours
3. Assess swallowing - speech pathology evaluation (FEES or bedside swallow assessment) to rule out aspiration
4. Capping trial - place a cap/speaking valve over the TT with cuff fully deflated; ensure SpO₂ stays >92%
5. Confirm upper airway patency - laryngoscopy to visualize the airway above the tube
6. Proceed to decannulation if all criteria are met (conscious, no respiratory distress, cough adequate, swallowing safe)

Key Point

A patient who coughs secretions out spontaneously through the TT with the cuff deflated is demonstrating active secretion management. This is a green flag for progressing the decannulation protocol - it means the patient is doing the work of clearance themselves, which is exactly what is required after the tube is removed.

Excessive Coughing/Secretions with Cuff Deflated + Speaking Valve (PMV) - Why It Happens & What to Do

Why Does This Happen? (The Mechanism)

1. Release of Pooled Subglottic Secretions ("Above-Cuff Secretions")

• Secretions pool above the cuff (in the subglottis and pharynx)
• They cannot go up (blocked by the larynx) or down (blocked by the inflated cuff)
• They just accumulate silently

• The pooled secretions suddenly drop into the trachea
• This triggers an immediate, vigorous cough reflex
• The patient coughs out large amounts of secretions - which looks alarming but is actually the airway protecting itself

2. PMV Restores Subglottic Pressure = Stronger Cough

• All expired air is redirected up through the upper airway (larynx, mouth, nose)
• This rebuilds subglottic pressure - the pressure needed to generate an effective cough
• Subglottic pressure was zero (or near zero) with an open/uncapped TT
• Now restored, the patient can generate a stronger, more effective cough - and expels secretions that were previously stuck

Is This Dangerous or a Problem?

Why the PMV Should NOT Be Used in Truly Copious Secretions

Do NOT place the PMV when: increased or copious secretions are present, or sub-optimal humidification exists.

What to Do - Step-by-Step Management

1. Suction through the TT to clear lower airway secretions
2. Suction the mouth/pharynx to clear above-cuff secretions before deflating
3. Deflate the cuff slowly while suctioning (not all at once) - this minimizes the sudden dump of pooled secretions
4. Suction again after cuff deflation
5. Then place PMV

• Allow the coughing - it is productive and clears the airway
• Reassure the patient
• Provide suction if needed
• Monitor SpO2, respiratory rate, work of breathing
• If distress or O2 desaturation: remove PMV immediately

Key Clinical Principle

Coughing during speaking valve use is the airway doing its job. The PMV restores the normal cough mechanism. Excessive secretions on first use are usually a sign of how much had accumulated during prolonged cuff inflation - not a sign that the valve should be stopped. With consistent use, secretion burden decreases over time as laryngeal and pharyngeal sensation recovers, swallowing improves, and the patient clears secretions more efficiently.