Cuffed tubes

Cuffed tubes have a soft balloon around the distal end of the tube which inflates to seal the airway (Figure 4.1). Cuffed tubes are necessary when positive pressure ventilation is required or in situations where airway protection is essential to minimise aspiration of oral or gastric secretions (although all cuffs are not an absolute barrier to secretions). If the tracheostomy tube lumen is occluded when the cuff is inflated, the patient will not be able to breathe around the tube, assuming the cuff is correctly positioned and inflated within the trachea.

Figure 4.1 Cuffed tracheostomy tubes.

Reproduced with permission of HEE eLfH.

Uncuffed tubes

Uncuffed tubes do not have a cuff that can be inflated inside the trachea and tend to be used in longer term patients who require ongoing suction to clear secretions. These tubes will not allow sustained effective positive pressure ventilation as the gas will escape above the tracheostomy tube. It is essential that patients have an effective cough and gag reflex to protect them from aspiration, as there is no cuff to ‘protect’ the airway. Uncuffed tubes are rarely used in acute care (Figure 4.2).

Figure 4.2 Uncuffed tracheostomy tubes.

Reproduced with permission of HEE eLfH.

Another type of uncuffed tube is the minitrach tube. These are typically 4 mm internal diameter and have no cuff. They are primarily designed to allow airway toilet (suction) but can facilitate delivery of oxygen. They are too small to provide any ventilation or removal of carbon dioxide and so can only be considered an emergency method of oxygenation. Minitrachs are sometimes used when preparing to decannulate a patient. The minitrach can remain in the stoma and keep it patent in case a tracheostomy tube needs to be reinserted. Minitrachs can also be inserted through the cricothyroid membrane. Specialised insertion kits are available for this, either electively or in an emergency (Figure 4.3).

Figure 4.3 Minitrach tubes.

Reproduced with permission of HEE eLfH.

Fenestrated tubes

Fenestrated tubes have an opening(s) on the outer cannula, which allows air to pass through the patient’s oral/nasal pharynx as well as the tracheal opening. The air movement allows the patient to speak and produces a more effective cough. However, the fenestrations increase the risk of oral or gastric contents entering the lungs. It is therefore essential that patients who are at high risk of aspiration or on positive pressure ventilation do not have a fenestrated tube, unless a non-fenestrated inner cannula is used to block off the fenestrations (see Figure 4.4).

Figure 4.4 Fenestrated tubes can be cuffed or uncuffed; the various inner tubes are shown.

Suctioning with a fenestrated tube should only be performed with the non-fenestrated inner cannula in situ, to ensure correct guidance of the suction catheter into the trachea.

The upper type of inner tube (Figure 4.4) has a fenestration in it, which lines up with the fenestration in the outer tube. Air can then flow through the tube as before, but, in addition, some air can flow through the holes and out through the patient’s mouth. This air flow to the upper airway allows the patient to talk. If positive pressure needs to be given to the patient to aid ventilation, for example, in the event of a cardiac arrest or worsening respiratory function, then the tracheostomy inner tube without the fenestrations should be fitted. This then allows positive pressure airflow to enter the lungs rather than escaping through the mouth.

The lower inner tube (right) has no hole (or fenestration) and so air flow is allowed straight through the tube from one open end to the other. When this is in situ, minimal amounts of air pass through the patient’s upper airway. This inner tube should be in place when the patient is suctioned as there is a small risk of a suction catheter passing through the fenestration and damaging the tracheal mucosa (Figure 4.4).

Figure 4.5 demonstrates different airflow patterns with different tubes inserted. There are video demonstrations available in the url present in the footnote.²

Figure 4.5 Different airflow patterns with different tubes inserted.

Reproduced with permission of HEE eLfH.

Single-cannula tubes

Single-cannula tubes were historically the first to be sited in a critical care area. The system is less complicated than a double-cannula tube and is usually for temporary use only. These tubes can be cuffed or uncuffed. The larger inner diameter of the single-cannula tube allows lower inflation pressures to be used when the patient is ventilated, as the larger diameter offers lower resistance to gas flow. The Intensive Care Society (ICS) in their 2008 guidance have recommended that these tubes are not used routinely in critical care, owing mainly to concerns about them becoming occluded with secretions and the difficulty in cleaning this type of tube. Indeed, without a removable inner cannula, if these tubes do become blocked, often the only way to unblock them is to change the whole tube. Depending on the nature of the stoma and the condition of the patient, this can clearly be hazardous.

Double-cannula tubes

Double-cannula tubes have an outer cannula to keep the airway open and an inner cannula that acts as a removable liner to facilitate cleaning of impacted secretions. Some inner cannulae are disposable; others must be cleaned and reinserted (Figure 4.6). Patients discharged from a specialist area with a tracheostomy should have a double-lumen, ideally uncuffed, cannula in place. This type of tube is the safest to use outside the specialist environment, although to reduce the incidence of tube occlusion, the inner cannula must be regularly cleaned. If an uncuffed tube becomes blocked, it is more likely that a patient can breathe past the tube via their upper airway, making these tubes inherently safer for non-specialist locations. If there is a high risk of aspiration or need for long-term ventilation, then a cuffed tube may be required long term.

Figure 4.6 Double-cannula tubes.