Chapter 12: Respiratory care, CPR and blood transfusion
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Tracheostomy: suctioning
Evidence‐based approaches
Rationale
An effective cough requires closure then reopening of the glottis once an adequate intrathoracic pressure has been achieved. The mechanism of closing the glottis is compromised in patients with a tracheostomy tube, and so these patients are unable to generate the high flows required for coughing (Barnett [14]). In addition, the lack of natural warmth and humidification usually provided by the upper airways can increase sputum load or make secretions tenacious and difficult to expectorate (McNulty and Eyre [154]). Thick and dry secretions can block the tracheostomy tube and cause airway obstruction. Tracheal suction is therefore a critical part of tracheostomy care and all professionals caring for patients with altered airways should be competent in the procedure (Wilkinson et al. [286]).
Indications
Suctioning can cause significant patient distress and is associated with airway changes and cardiovascular instability. It should therefore only be performed when indicated and not at fixed intervals (Barnett [14]). Frequency should be determined on an individual patient basis with the aim of clearing airway secretions when the patient is not able to do so themselves, ensuring airway patency. A careful assessment of the patient should be carried out to determine the following:
- whether the patient is able to clear their own secretions through the use of a good, strong cough
- the location of any secretions
- whether these secretions could be reached by the suction catheter
- how detrimental these secretions might be for the patient.
Contraindications
While there are no absolute contraindications, suctioning may be painful and distressing for the patient and can be complicated by (Bonvento et al. [28], ICS [116], Pathmanathan et al. [216]):
- hypoxaemia
- bradycardia and cardiovascular compromise
- alveolar collapse and atelectasis (incomplete lung inflation)
- tracheal mucosal damage
- bleeding
- possible introduction of infection.
Infection risk
Standard precautions must be used at all times when suctioning; this includes wearing an apron, gloves and eye protection (NICE [193]). As with all procedures, hands should be decontaminated with soap and water or an alcohol‐based handrub before and after contact with the patient, and all equipment disposed of in the clinical waste. All disposable equipment used for suctioning (e.g. suction tubing and canister) presents an infection control risk due to the presence of bacteria. Equipment should therefore be dated and changed regularly, as per the manufacturer's recommendations or local policy (Wilkinson et al. [286]).
Method of suctioning
Suctioning should be performed with an inner tube (non‐fenestrated) in place (Morris et al. [167]) using a fine‐bore suction catheter of the appropriate size (Figure 12.49). Instillation of 0.9% sodium chloride to ‘aid’ suctioning is not recommended (Pathmanathan et al. [216]). The routine use of ‘deep suctioning’ is also discouraged due to the risk of hypoxia, mucosal damage, inflammation, bleeding and airway occlusion (Barnett [14], Greenwood and Winters [95], NTSP [206]). If deep suctioning is required, the patient should be pre‐oxygenated (see the section on specific patient preparation below) and the whole procedure should take no longer than 10 seconds to prevent hypoxia and patient distress (NTSP [206]).
Figure 12.49 Tracheal suction using a fine‐bore suction catheter.
Shallow suctioning, where the catheter is inserted no further than the distal end of the tracheostomy tube, is preferred (Dawson [58]). Patients should be encouraged to cough secretions up to the tracheostomy tube if they are able, and these are then cleared through the use of shallow suctioning (ICS [116]). Any difficulty in passing the suction catheter should prompt further investigation as it may be that the tube is blocked or misplaced and requires immediate attention (Cosgrove and Carrie [52], ICS [116], NTSP [206]). Oral suctioning may also be required; this can be achieved by using a rigid Yankauer suction catheter tip (Figure 12.50).
Figure 12.50 Oral suction using a Yankauer suction tip.
Anticipated patient outcomes
The patient's airway will remain patent through the use of suction to help clear excess secretions that the patient is not able to expectorate. Suctioning should be performed in a manner that causes the least possible amount of distress for the patient.
Clinical governance
Competencies
All staff caring for patients with an altered airway should be aware of the indications and risks of suctioning. They should be trained and assessed as competent in doing so safely before performing the procedure unsupervised (Wilkinson et al. [286]). They should also be aware of the different types of suction device available, and be able to assemble, maintain and use them safely.
Pre‐procedural considerations
Equipment
Suction unit
A low‐volume, high‐pressure suction unit should be used for tracheal suctioning, with the pressure set between 13 and 20 kPa (100–150 mmHg) (NTSP [206]). The lowest possible suction pressure should be used to prevent hypoxia, mucosal trauma and atelectasis. Prior to the procedure being performed, the suction unit should be turned on at the correct suction pressure and the system checked to ensure the suction is working prior to use.
A suction canister should be placed in between the suction unit and the suction tubing to collect the fluid and secretions suctioned. After the procedure, a small amount of sterile water should be suctioned to clear the tubing of secretions. The canister, tubing and bottle of sterile water should be changed every 24 hours to prevent bacterial growth and contamination, and all equipment should be dated and checked daily, even when not in regular use.
Suction catheters
Choosing the correct suction catheter size depends on the size of the tracheostomy tube. As a guide, the diameter of the suction catheter should not exceed half of the internal diameter of the tracheostomy tube. The formula in Box 12.8 can be used to determine the correct size catheter.
Most suction catheters are single use and should be disposed of immediately after each use in the clinical waste. However, within a critical care setting, a closed‐circuit suction system may be used for patients being mechanically ventilated. In a closed‐circuit system, the catheter is sealed in a protective plastic sleeve (Figure 12.51) and is connected to the ventilator circuit, and can remain within the circuit unit until it requires changing. A closed‐circuit system helps to reduce the risk of infection caused by bacterial contamination of the catheter (Pathmanathan et al. [216]). In addition, it reduces the risk of hypoxia and the loss of positive end‐expiratory pressure (PEEP) by removing the need to break or disconnect the ventilator circuit. These circuits are usually changed every 72 hours or as per the manufacturer's recommendation (NTSP [206]).
Figure 12.51 Components of a closed‐circuit catheter. The control valve locks the vacuum on or off. The catheter is protected inside an airtight sleeve. A T‐piece connects the device to the tracheal tube.
Specific patient preparation
Patients who are mechanically ventilated and are receiving high concentrations of oxygen may benefit from being pre‐oxygenated prior to the procedure (Greenwood and Winters [95], NTSP [206]). This involves the delivery of 100% FiO2 to the patient for 1 minute prior to passing the suction catheter.
The procedure should always be explained to the patient and verbal consent gained (if the patient is conscious). If required, the patient should be repositioned to ensure their comfort and allow easy access to the tracheostomy tube.
Procedure guideline 12.9
Tracheostomy: suctioning a patient (single‐use suction catheter)
Complications
Hypoxia
The act of suctioning reduces vital volume from the lungs and upper airways. Each suctioning procedure should last no longer than 10 seconds to decrease the risk of tracheal damage and hypoxia (NTSP [206]). Ventilator disconnection or removal of the oxygen supply will also add to the risk of hypoxia prior to suctioning. This risk can be reduced by pre‐oxygenating the lungs with 100% oxygen, either manually or via a ventilator (Greenwood and Winters [95]).
Cardiac arrhythmias
Arrhythmias may be brought about by the onset of hypoxaemia, or a vagal reflex due to tracheal stimulation by the suction catheter (Bonvento et al. [28]).
Raised intracranial pressure
This may occur if the suction catheter causes excessive tracheal stimulation and results in coughing and an increase in the patient's intrathoracic pressure, both of which can compromise cerebral venous drainage (Greenwood and Winters [95]).
Tracheal mucosal damage
Damage may be caused by using a catheter that is too big, using too high a suction pressure or passing a suction catheter down through a fenestrated inner tube (NTSP [206]). Unnecessary ‘deep’ suctioning may also contribute to mucosal damage.
