Why should we perform open tracheal suction via an endotracheal tube

Evidence base

Tracheal suction involves the removal of pulmonary secretions from the respiratory tract using negative pressure under sterile conditions.

For open tracheal suction via an endotracheal tube, a sterile flexible suction catheter is attached via tubing to a portable or wall-mounted suction unit. Tracheal suction improves airway patency and oxygenation. Indications for tracheal suction include (Coombs et al 2013):

• Audible secretions.
• Reduced oxygen saturation levels.
• Reduced breath sounds or chest movements.
• Coarse crackles on chest auscultation.
• Deterioration in arterial blood gases such as a reduction in oxygen or an increase in carbon dioxide.
• Evidence of cyanosis.

Since endotracheal suction might cause hypoxia, which can predispose the patient to cardiac dysrhythmias, pre-oxygenating the patient with 100% oxygen before tracheal suction is recommended (American Association for Respiratory Care (AARC) 2010). The instillation of saline into endotracheal tubes to loosen secretions has little benefit and has not been recommended for some time (Thompson 2000).

It is important when undertaking tracheal suction that the appropriate suction pressure is used. It is appropriate to apply the minimal amount of negative pressure suction to achieve secretion clearance. This helps to prevent atelectasis (complete or partial collapse or closure of a lung), hypoxia and mucosal damage, which may be attributed to the application of excessive suction pressure (Pedersen et al 2009). To avoid these complications, suction pressures of 80-120mmHg are recommended (Pedersen et al 2009).

Suction using a large size suction catheter is associated with an increased risk of alveolar collapse and atelectasis (Pedersen et al2009). The external diameter of the suction catheter should be less than 50% of the internal diameter of the endotracheal tube, as represented by the equation: suction catheter size (French) = 2x (size of endotracheal tube (mm) -2). This allows air to enter the lung during suction and prevents hypoxia and atelectasis (Day et al 2002).

The suction catheter should be inserted into the patient’s endotracheal tube until resistance is felt. This resistance signals that the catheter has reached the carina of the trachea (the junction between the right and left main bronchi) (Figure 1). However, care should be taken in patients with a long-term tracheostomy as repeated suction over months or years could damage the carina. In non-ventilated tracheostomy patients who have a cough, the suction catheter can be inserted only as far as the end of the tracheostomy as this will ensure mobilisation of secretions and encourage a more normal physiological method of secretion removal.

The suction catheter should be withdrawn by 1-2cm to avoid damage to the mucosa when suction is applied (Pedersen et al 2009). Damage to the mucosa may result in inflammation and the potential for infection. Suction should only be applied when withdrawing the suction catheter to minimise mucosal damage in the respiratory tract (Wood 1998). The withdrawal process should take no longer than 15 seconds (Pedersen et al 2009). Lengthy suction attempts are associated with hypoxia and damage to the tracheal mucosa (Pedersen et al 2009).

The frequency of suction should be informed by the viscosity and purulence of the secretions, the status of the airway and any changes in respiratory parameters. It should not be determined by rigid or routine timescales because of the risk of adverse side effects (Van de Leur et al 2003, Chaseling et al 2014).

The removal of secretions via tracheal suction has associated risks, including (Pedersen et al 2009, AARC et al 2010):

• Bleeding.
• Hypoxia or hypoxaemia.
• Bronchoconstriction.
• Atelectasis.
• Ulceration and damage to the trachea.
• Haemodynamic instability.
• Increased intracranial pressure.

Tracheal suction can be unpleasant for the patient, causing discomfort and distress. This distress should be considered and time allowed to reassure and support the patient before and following the procedure.

Closed endotracheal suction involves suction via a sterile, sheathed catheter inserted into the ventilator system, which remains connected during suction (Pedersen et al 2009). Closed endotracheal suction is only performed when closed suction equipment is available, generally in intensive care units, by appropriately trained staff. It is used in ventilated patients and minimises the risk of infection while maintaining respiratory support.

Learning points

1. The external diameter of the suction catheter should be less than 50% of the internal diameter of the endotracheal tube, as represented by the equation: suction catheter size (French) = 2x (size of endotracheal tube (mm) -2).
2. The frequency of suction should be informed by the thickness and purulence of the secretions, the status of the airway and any changes in respiratory parameters.
3. The instillation of saline into endotracheal tubes to loosen secretions has little benefit and has not been recommended for some time (Thompson 2000).
4. Risks associated with tracheal suction include: bleeding; hypoxia or hypoxaemia; bronchoconstriction; collapse of the alveoli (atelectasis); ulceration and damage to the trachea; haemodynamic instability; increased intracranial pressure.
5. Tracheal suction can be unpleasant for the patient, causing discomfort and distress. It is important to make time to reassure and support the patient before and after the procedure.

Disclaimer: please note that the information provided by RCNi Learning is not sufficient to make the reader competent to perform the task. All clinical skills should be formally assessed at the bedside by a nurse educator or mentor. It is the nurse’s responsibility to ensure their practice remains up to date and reflects the latest evidence.

Useful resources

• Adam S, Osborne S, Welch J (Eds) (2017) Critical Care Nursing: Science and Practice. Third edition. Oxford, Oxford University Press.
• Hughes M, Black R, Grant I (2011) Advanced Respiratory Critical Care. Open University Press, Oxford.
• Mallett J, Albarran JW, Richardson A (Eds) (2013) Critical Care Manual of Clinical Competencies and Procedures. Wiley-Blackwell, Chichester.

References

American Association for Respiratory Care (2010) AARC Clinical Practice Guidelines. Endotracheal suctioning of mechanically ventilated patients with artificial airways. Respiratory Care. 55, 6, 758-764. 20507660 MEDLINE

Chaseling W, Bayliss S-L, Rose K et al (2014) Suctioning an Adult ICU Patient with an Artificial Airway: A Clinical Practice Guideline. NSW Government Version 2. Agency for Clinical Innovation, Chatswood NSW.

Coombs M, Dyos J, Waters D, Nesbitt I (2013) Assessment, monitoring and interventions for the respiratory system. In Mallett J, Albarran JW, Richardson A (Eds) Critical Care Manual of Clinical Procedures and Competencies. Wiley-Blackwell, Chichester, 63-171.

Day T, Farnell S, Wilson-Barnett J (2002) Suctioning: a review of current research recommendations. Intensive and Critical Care Nursing. 18, 2, 79-89. 12353655 10.1016/S0964-3397(02)00004-6 MEDLINE • CROSSREF

Pedersen CM, Rosendahl-Nielsen M, Hjermind J, Egerod I (2009) Endotracheal suctioning of the adult intubated patient – what is the evidence? Intensive and Critical Care Nursing. 25, 1, 21-30. 18632271 10.1016/j.iccn.2008.05.004 MEDLINE • CROSSREF

Thompson L (2000) Suctioning Adults with an Artificial Airway: A Systematic Review. Joanna Briggs Institute for Evidence Based Nursing and Midwifery, Adelaide, Australia.

Van de Leur JP, Zwaveling JH, Loef BG, Van der Schans CP (2003) Patient recollection of airway suctioning in the ICU: routine versus a minimally invasive procedure. Intensive Care Medicine. 29, 3, 433-436. 12577155 10.1007/s00134-003-1640-3 MEDLINE •CROSSREF