Suctioning an adult ICU patient: assessment

Clinical indications on the need for suction





Assessment of the patient to identify the need to suction a tracheal tube should be continuous with chest auscultation performed every two hours or more frequently as indicated by clinical signs such as those mentioned in recommendation 2.



The decision to suction a tracheal tube must be made on the basis of the clinical need to maintain the patency of the tracheobronchial tree. A tracheal tube should only be suctioned when clinically indicated by signs which could include:

  1. visible, palpable or audible secretions (such as sputum, gastric or upper airway contents or blood)
  2. respiratory: desaturation, rising peak inspiratory pressure (during volume-controlled mechanical ventilation/modes), decreasing tidal volume (during pressure-controlled ventilation/modes), increased respiratory rate, increased work of breathing or coarse breath sounds on auscultation
  3. cardiovascular: increased heart rate and blood pressure
  4. other: restless/agitated or diaphoretic patient
  5. a saw-tooth pattern on a flow-volume loop or expiratory flow-time waveform as illustrated on the ventilator graphics.



Prior to suctioning, consideration should be given to the potential complications and contraindications in individual patients (see Table: Hazards/complications of suctioning).



To reduce patient anxiety and to promote patient understanding of, and compliance with, the suctioning procedure patients should be given clear information regarding the suction procedure including: the need for suction, the consequences of not suctioning when it is required and the effects of suctioning. Furthermore, this information should be repeated with each suction procedure as some patients may not recall previous instructions.



Patient assessment before, during and post suction should include an evaluation of the effects on the patient’s pre-suction signs and symptoms. This should include monitoring of cardiac rate and rhythm, blood pressure, pulse oximetry, airway reactivity, tidal volumes, peak airway pressures, or intracranial pressure (See Table: Assessment pre/during/post suction/outcome measures).



Some patient groups require constant/continuous monitoring of electrocardiogram (ECG) and pulse oximetry before, during and post suctioning. (See Table: Assessment pre/during/post suction/outcome measures).



Documentation of the assessment and suction procedure must occur.


The evidence review for these recommendations was current to December 2012. Clinicians are advised to check the literature as research may have been published that change these recommendations

Suctioning is an uncomfortable and distressing procedure for the critically ill adult with an artificial airway. Nonetheless, tracheal tube suction may be necessary to clear secretions, maintain airway patency and to optimise oxygenation and ventilation. There are a number of potential adverse effects, however, on several body systems including:

  1. respiratory (e.g. reduction in lung volumes, hypoxia, and alveolar collapse, introduction of infection and trauma to the trachea)
  2. cardiovascular (e.g. bradycardia, hypotension, and hypertension)
  3. neurological (e.g. increase in intracranial pressure and reduction in cerebral blood flow).

Despite the relative frequency of this procedure the body of evidence is limited. Three systematic reviews (SRs) and a literature review (LR) consistently found evidence supporting suctioning only when clinically indicated because of the potential complications associated with the procedure (1-4) and this is congruent with local clinical practice. The recommendation is therefore to suction only when clinically indicated.

There have been seven new studies since 2006 investigating/reporting indications for suctioning, assessment pre/during/after suctioning events and minimisation of adverse effects. This includes four SRs, one LR, one interrupted time series (ITS), and one prospective observational study (OS) resulting in ‘C’ rating (LIII studies) (1, 2, 4-8).

Hazards/complications of suctioning



Patients at risk


  • Decrease in dynamic lung compliance and FRC
  • Atelectasis
  • Hypoxia/hypoxaemia
  • Tissue trauma to the tracheal and/or bronchial mucosa
  • Bronchoconstriction/bronchospasm
  • Acute pulmonary haemorrhage
  • ALI/PEEP dependent/high O2 requirements
  • Lack of cough reflex
  • High risk of bronchospasm/reactive airways


  • Hypertension
  • Hypotension
  • Cardiac dysrhythmias
  • Unstable CVS


  • Changes in cerebral blood flow and increased ICP
  • Unstable/high ICP
  • Spinal injury with autonomic dysreflexia


  • Coagulopathy i.e. platelets <20, INR>2.5

Infection Prevention

  • Increased microbial colonization of lower airways
  • Immunocompromised

Table adapted from AARC (2010) Clinical Practice Guidelines. (1)

ALI = acute lung injury, CVS = cardiovascular stability, FRC= functional residual capacity, ICP = Intracranial pressure INR = International normalised ratio, O2 = oxygen, PEEP = Positive end expiratory pressure


A prospective observational study examined the value of a number of clinical signs (including patient agitation, SpO2 fall, respiratory sounds, changes in respiratory pattern and a ‘saw-tooth’ pattern on the flow-volume loop) as indicators of retained secretions in a cohort of 66 consecutive ventilated patients (9). In this group, only a saw-tooth pattern and respiratory sounds appeared to be of value. However, for two-thirds of patients there was only one observer who was not blinded to outcomes, limiting the value of these findings. There have been no new studies since this landmark research. Two SRs (1, 2) and one LR (4) consistently support this recommendation. Identification of these clinical signs will require the use of flow-volume loop analysis and/or expiratory-flow time waveform for assessment when suctioning is indicated and the clinician to constantly review the patient and ventilator. The recommendation is to suction as indicated represented by a saw-tooth pattern on ventilator graphics.

Using mechanical ventilator waveforms to assist with patient assessment

Practice point - Assessment of the need for suctioning


  • saw-tooth pattern on flow-time waveform and flow/volume loop.

Possible causes

  • Secretion build-up in large airways, ETT/tracheostomy tube.
  • Condensate in ventilator circuit.

Practice point - Assessment of tube patency and large airway obstruction using the expiratory flow waveform

Basic things to know about the expiratory flow curve

  • Should be triangular in shape.
  • Expiratory flow should be complete between 1 to 2 seconds.

Obstruction to the small airways, large airways and endotracheal tube/ tracheostomy tube will result in changes to the expiratory flow curve. This practice point addresses the changes that may be seen with significant obstruction to large airways and endotracheal/tracheostomy tube.

Loose secretion build-up in endotracheal tube

Note saw-tooth pattern on the pressure, flow and flow/volume waveforms

Saw-tooth pattern on the pressure, flow and flow/volume waveforms indicating loose secretion build-up in endotracheal tube or condensate in tubing.

NOTE: This occurs on inspiration and expiration.

Severe fixed obstruction

Severe fixed obstruction caused by secretion build-up within tracheostomy tube inner cannula. Resolved by removal/replacement of inner cannula. Note fixed expiratory flow and prolonged expiratory flow. There is also evidence of failure to expire all the tidal volume i.e. gas trapping.

Evidence of gas trapping i.e. build-up of pressure indicating severe fixed obstruction e.g. secretion build-up in inner tracheostomy tube.

Prolonged expiratory flow indicating fixed obstruction. Flow never returning to zero, indicating next breath delivered before expiration is finished.

Partial occlusion of ETT caused by tube kinking.

Note prolonged expiration i.e. less than 80% of tidal volume expired in first one second of expiration.

Prolonged expiration (less than 80% expired in 1 second) indicating partial obstruction of tube caused by kinked tube.

Normal expiratory flow (80% expired in 1 second).

Considerations prior to suction

Prior to suctioning consideration should be given to the potential complications and contraindications in individual patients (see Table: Hazards/complications of suctioning). Monitoring of baseline physiological variables such as respiratory, ventilator, cardiovascular, and neurological parameters should be undertaken by the clinician. In a descriptive study, suctioning has been identified by patients as causing anxiety and discomfort (10). To reduce patient anxiety and to promote patient understanding of and compliance with suctioning, patients must be given clear information regarding the suction procedure including: need for suction, consequences of not suctioning when it is required and effects of suctioning. Explain that the procedure is likely to be uncomfortable, but will be brief and that the procedure may need to be done more than once. This information should be repeated because patients may not recall previous instructions (11). If the clinician’s perceive this procedure is causing undue discomfort or distress to the patient, then clinicians should align this procedure with sedation if prescribed.

Assessment pre/during/post suction/outcome measures

Physiological variablePre-suctionDuring suctionPost-suction outcome measures
Breath soundsNil added (I)
SpO2Improved (I) *
Respiratory rateImproved (I)
Pattern of breathingImproved (I)
Sputum colourDocument
Sputum amountDocument
Sputum viscosityDocument
Palpation  (I)
Arterial blood gases (ABGs) >20mins (D) #
Ventilator parameters
Saw-tooth pattern Absent (I)
Tidal volume Increased (I)
Peak airway pressure Decreased (I)
Compliance Increased (I)
ECG rate (HR)Baseline (D)
ECG rhythmBaseline (D)
Blood pressure (BP) Baseline (D)
Mean arterial pressure (MAP)Baseline (D)
Intracranial pressureAs indicatedAs indicatedAs indicated (I)

(D) delayed improvement >10mins, (I) immediate improvement <10mins, * may be delayed in patients with impaired circulation, # ABGs are not routinely required post suctioning.

Monitoring effects

The effects of the suction procedure on the patient must be evaluated before, during and after the procedure (see Table: Assessment pre/during/post suction/outcome measures). Patients most at risk of adverse events (see Table: Hazards/complications of suctioning) may require more diligent monitoring by the clinician and a lower threshold for terminating the procedure may be required because of the increased risk of adverse events. These changes can be transient or sustained and this may influence the clinician’s decision to continue or terminate the procedure. This recommendation is based on the clinical experience of the group members and achieved consensus.


Documentation should occur:

  1. following assessment of the patient, identifying the indication(s) for suctioning
  2. following suction.

The documentation at a minimum is to include:

  • physical assessment of the patient pre and post-suctioning (see recommendation 5)
  • patient tolerance of suctioning procedure
  • if pre-oxygenation was used
  • results/product of suctioning (including amount, colour and viscosity of secretions).

A thorough clinician’s assessment would be performed at the beginning of each shift, which may identify indications for a suction to be performed. Periodic assessment throughout the day may also identify the need for artificial airway suction, such as the performance of second hourly auscultation or ventilator observations. Documentation of adverse events during the suctioning procedure should also occur, particularly, sustained changes in physiological parameters. Some critical care areas may have respiratory assessment charts with documentation of the suction procedure; either paper or computerised, in which suction can be documented with mandatory fields and annotations concerning adverse events can be added.

A recommendation concerning the minimum time between suctions was deleted after internal validation and before external validation occurred. It was considered that it was contradictory to recommend a minimum time when the consensus of the group was to suction only when indicated. It was also felt that tube patency could be assessed in other ways, such as ventilator graphics, other than passing a suction catheter down an artificial airway.

Grading of recommendation taxonomy

Grade of recommendation



Body of evidence can be trusted to guide evidence


Body of evidence can be trusted to guide practice in most situations


Body of evidence provides some support for recommendation/s but care should be taken in its application


Body of evidence is weak and recommendation must be applied with caution


Consensus was set as a median of ≥ 7

Grades A–D are based on NHMRC grades (12)


  1. (AARC) AAfRC. AARC Clinical Practice Guidelines. Endotracheal suctioning of mechanically ventilated patients with artificial airways. Respiratory Care. 2010;Jun; 55(6):758-64.
  2. Overend TJ, Anderson CM, Brooks D, Cicutto L, Kein M, McAuslan D, et al. Updating the evidence base for suctioning adult patients: a systematic review. Canadian Respiratory Journal. 2009;16(3):e6-e17.
  3. Subirana M, Sola I, Benito S. Closed tracheal suction systems versus open tracheal suction systems for mechanically ventilated adult patients. Cochrane Database of Systematic Reviews. 2007 (4):CD004581. PubMed PMID: 17943823. English
  4. Pederson CM, Rosendahl-Nielsen M, Hjermind J, Egerod I. Endotracheal suctioning of the adult intubated patient - What is the evidence? Intensive and Critical Care Nursing. 2009;25:21-30.
  5. Jongerden IP, Kesecioglu J, Speelberg B, Buiting AG, Leverstein-van Hall MA, Bonten MJ. Changes in heart rate, mean arterial pressure, and oxygen saturation after open and closed endotracheal suctioning: A prospective observational study. Journal of Critical Care. 2012; Article in press.
  6. Jongerden IP, Rovers MM, Grypdonck MH, Bonten MJ. Open and closed endotracheal suction systems in mechanically ventilated intensive care patients: A meta-analysis. Critical Care Medicine. 2007;35(1):260-70.
  7. Lasocki S, Lu Q, Sartorious A, Fouillat D, Remerand F, Rouby J. Open versus closed-circuit endotracheal suctioning in acute lung injury. Anesthesiology. 2006;Jan(104):39-47.
  8. Subirana M, Sola I, Benito S. Closed tracheal suction systems versus open tracheal suction systems for mechanically ventilated adult patients. The Cochrane Collaboration. 2010;7:1-51.
  9. Guglielminotti J, Alzieu M, Maury E, Guidet B, Offenstadt G. Bedside detection of retained tracheobronchial secretions in patients receiving mechanical ventilation: It is time for Tracheal Suctioning? Chest. 2000;118:1095-9.
  10. Arroyo-Novoa CM, Figueroa-Ramos M, Puntillo KA, Stanik-Hutt J, Thompson CL, White C, et al. Pain related to tracheal suctioning and critically ill adults: A descriptive study Intensive and Critical Care Nursing. 2008;24(1):20-7.
  11. Rolls K. Care of Adult Patients in Acute Care Facilities with a Tracheostomy: Clinical Practice Guideline. North Sydney: ICCMU, 2012.
  12. NHMRC. NHMRC additional levels of evidence and grades for recommendations for developers of guidelines:PILOT PROGRAM 2005 - 2007. Australian Government; 2005.


The information on this page is general in nature and cannot reflect individual patient variation. It reflects Australian intensive care practice, which may differ from that in other countries. It is intended as a supplement to the more specific information provided by the doctors and nurses caring for your loved one. ICNSW attests to the accuracy of the information contained here but takes no responsibility for how it may apply to an individual patient. Please refer to the full disclaimer.