1.4 Tracheostomy Tubes & Cuff Care

Tracheostomy Tubes & Cuff Care

Tracheostomy is a surgical procedure that creates an opening in the trachea (stoma) for airway access. It is a vital intervention in critical care, but it requires diligent monitoring of cuff pressures, tube patency, and weaning protocols to prevent catastrophic airway complications.

Indications for Tracheostomy

A tracheostomy is typically indicated in the ICU for:

• Prolonged Mechanical Ventilation: Transferred from an ETT, usually after 10 to 14 days of mechanical ventilation, to reduce laryngeal and vocal cord injury, improve patient comfort, allow oral hygiene, and facilitate physical rehabilitation.
• Upper Airway Obstruction: Secondary to laryngeal tumors, bilateral vocal cord paralysis, severe maxillofacial trauma, or angioedema.
• Secretions: Inability to clear secretions due to severe neuromuscular disease (e.g., ALS).

Types of Tracheostomy Tubes and Components

A standard tracheostomy tube consists of an outer cannula, a removable inner cannula, and an obturator.

• Inner Cannula: Must be cleaned or replaced regularly to prevent mucous plugging.
• Obturator: A guide with a blunt tip used only during the insertion of the outer cannula. It must be removed immediately after the tube is placed to allow the patient to breathe.
• Fenestrated Tracheostomy Tubes: These tubes have one or more holes (fenestrations) in the posterior wall of the outer cannula. When the inner cannula is removed, the cuff is deflated, and the proximal opening is capped, air flows through the fenestrations, up through the larynx and vocal cords, allowing the patient to speak and breathe normally.
• Bivona Foam Cuff (Fome-Cuf): This specialized cuff is filled with self-expanding foam rather than air. The pilot balloon is left open to atmospheric pressure, allowing the foam to expand and conform to the trachea. Safety Rule: To insert or remove the tube, the foam must be fully collapsed by drawing air out with a syringe. Never inject air into a foam cuff, as this can cause tracheal rupture.

Cuff Pressure Monitoring and Regulation

Proper cuff pressure is critical to balance airway protection and tissue perfusion:

• Target Cuff Pressure: 20 to 30 cm H2O (equivalent to 15 to 22 mmHg).
• Physiological Rationale: The capillary perfusion pressure of the tracheal mucosal vessels is approximately 30 cm H2O. If cuff pressure exceeds 30 cm H2O, mucosal blood flow is obstructed, leading to tissue ischemia, necrosis, tracheomalacia, and tracheal stenosis. Conversely, if cuff pressure is less than 20 cm H2O, the seal is insufficient. This results in tidal volume loss during mechanical ventilation and allows subglottic secretions to leak past the cuff (microaspiration), which significantly increases the risk of Ventilator-Associated Pneumonia (VAP).
• Measurement: Cuff pressure should be monitored at least once per shift using a calibrated handheld cuff manometer.

Phonation and Weaning: Speaking Valves & Capping

The Passy-Muir Speaking Valve (PMV) is a one-way valve placed on the 15 mm hub of the tracheostomy tube. It opens during inspiration, allowing the patient to draw air through the tube. During exhalation, the valve closes, forcing air to travel around the tracheostomy tube, up through the larynx, and out of the nose and mouth, enabling speech and improving swallowing function.

• CRITICAL SAFETY RULE: The cuff must be completely deflated before placing a Passy-Muir valve. If the cuff remains inflated, the patient will be able to inhale through the valve but will be completely unable to exhale, leading to immediate air trapping, severe bar trauma, asphyxiation, and death.
• Capping Trials: Decannulation represents the ultimate goal of weaning. During a capping trial, the cuff is fully deflated, and a plug is placed on the tube opening, forcing the patient to breathe entirely through their upper airway. The trial must last 24 to 48 hours consecutively (including sleep). The patient must demonstrate adequate ventilation (normal PaCO2), oxygenation, secretion tolerance, and a strong, effective cough before decannulation can safely proceed.

Troubleshooting Tracheostomy Emergencies

Accidental Decannulation

• Immature Stoma (< 7 to 10 days old): If the tracheostomy tube is dislodged before the tract has matured, the clinician must never attempt a blind reinsertion. The stoma tract can easily collapse, and reinsertion attempts can lead to placing the tube in a 'false tract' (subcutaneous tissue), causing severe surgical emphysema and total airway obstruction.
  • Immediate Action: Cover the stoma with sterile gauze and initiate bag-mask ventilation over the upper airway while calling the surgical team immediately.
• Mature Stoma (> 10 to 14 days old): A new, lubricated tracheostomy tube with the obturator in place can be gently inserted into the stoma. The obturator must be removed immediately after insertion, followed by cuff inflation and confirmation of breath sounds.

Tube Obstruction (Mucous Plug)

• If a patient develops sudden respiratory distress, high ventilator peak pressures, and a suction catheter cannot be passed:
  1. Remove the inner cannula immediately. If a mucous plug is lodged within, this action will instantly clear the airway.
  2. If the obstruction persists, deflate the cuff to rule out cuff herniation over the end of the tube.
  3. If still obstructed, initiate bag-mask ventilation and prepare for immediate tube replacement.

ACCS Exam Traps

• Trap 1: Attempting to reinsert a dislodged tracheostomy tube in a patient whose trach is only 3 days old. The NBRC answer is always to bag-mask ventilate the patient from the upper airway and call surgery.
• Trap 2: Placing a speaking valve or capping a trach tube while the cuff is still inflated. This is a fatal error. Always deflate the cuff first.