Suctioning an adult ICU patient: Clinical practice - Saline

Recommendations for practice





To prevent the occurrence of adverse events, bolus instillation of normal saline should not be routinely used prior to suctioning.


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

Some critical care areas still practice routine instillation of saline as part of the suctioning procedure. On reviewing two systematic reviews (SRs), one randomised controlled trial (RCT), one literature review, one interrupted time series, and one single case repeated measures design (SCRM), there continues to be little or no data to indicate that administration of saline during the suction procedure provides any benefit to suctioning, and some evidence that it may be detrimental (1-6). The administration of saline during the suctioning procedure was evaluated in terms of effect on: haemodynamics, oxygenation, tracheal aspirate yield, ventilator-associated pneumonia (VAP) rates and tracheal tube occlusion rates.

Three SRs and one SCRM design reviewed haemodynamic parameters following saline instillation and were consistently unable to identify a statistical significance between administration and non-administration and there appears to be little evidence of serious complications despite some minor changes in heart rate (3, 4, 6, 7). Likewise an SR and an RCT of tracheal tube occlusion rates did not differ between administration of saline and non-administration in adult patients undergoing the suction procedure (1, 4).

There is inconsistent and conflicting evidence in regard to oxygenation, as reported in three SRs and one SCRM design. While some have shown a significant decrease in oxygenation following saline administration during suction others have found no difference between saline administration and non-administration (3, 4, 6, 7).

An argument for the use of saline during the suction procedure is that it may facilitate increased removal of tracheal tube secretions. There is inconsistent evidence, documented in an SR and a literature review, to either support or refute this theory (4, 5).

In regards to VAP there are inconsistent results. An SR indicated no statistical difference in VAP rates in patients receiving saline administration during suctioning (4). One RCT did indicate a significant reduction in VAP rates in patients receiving saline administration as part of the suctioning procedure (1). Thus, there is inconsistent evidence in the use of saline to reduce VAP.

An SCRM study reported that adequate hydration, adequate humidification, use of mucolytic agents and effective mobilisation should be instituted prior to the consideration of saline instillation for patients with increased viscosity of their secretions (6).

The recommendation is: to prevent the occurrence of adverse events, bolus instillation of normal saline should not be routinely used prior to suctioning.

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 (8)


  1. Caruso P, Denari S, Ruiz S, Demarzo S, Deheinzelin D. Saline instillation before tracheal suctioning decreases the incidence of ventilator-associated pneumonia. Critical Care Medicine. 2009;37(1):32-8.
  2. Klockare M, Danielsson A, Hatherley R, Larsson S, Jacobsson H, Mure M. Comparison between direct humidification and nebulization of the respiratory tract at mechanical ventilation: distribution of saline solution studied by gamma camera. Journal of Clinical Nursing. 2006;15:301-7.
  3. 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.
  4. Paratz JD, Stockton KA. Efficacy and safety of normal saline instillation: A systematic review. Physiotherapy. 2009;95:241-50.
  5. 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.
  6. Zahran EM, Abd El-Razik AA. Tracheal suctioning with versus without saline instillation. Journal of American Science. 2011;7(8):23-32.
  7. (AARC) AAfRC. AARC Clinical Practice Guidelines.  Endotracheal suctioning of mechanically ventilated patients with artificial airways. Respiratory Care. 2010;Jun; 55(6):758-64.
  8. 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.