Saline Instillation: Helpful or Harmful?

In an era of evidence-based practice, it is no longer acceptable to continue a practice because “that’s the way it’s always been done.” One such practice is the instillation of saline into an advanced airway such as an endotracheal tube or tracheostomy prior to or during suctioning.

At the Regional Spinal Cord Injury Center of the Delaware Valley at Thomas Jefferson University Hospital, Phildelphia, in an attempt to stay current with evidence-based practice for the care of individuals with spinal cord injury (SCI) and have standardized practice guidelines, we reviewed the literature on the installation of saline prior to and during suctioning. What we found was interesting, not only for the SCI population but the non-SCI population as well.

Reviewing the Research

Throughout our years of clinical practice, we often instilled small unit-dose vials of saline into an open tracheostomy to elicit a more productive cough or loosen secretions in patients with SCI, or so we thought. Even though the patients gagged and gagged, we never imagined we could be inflicting harm, just temporary discomfort for the greater result of airway clearance.

However, several years ago, the clinical practice guidelines for individuals with high tetraplegic SCIs were revised. It is no longer recommended to instill saline into an advanced airway because people with tetraplegia have little or no diaphragm innervation and, therefore, are unable to produce a cough reflex. This practice has been compared to “drowning” patients in their own secretions.

After further review of the literature, we found saline instillation is not recommended for any adult patient who is mechanically ventilated. In fact, the 2004 American Association for Respiratory Care Clinical Practice Guidelines no longer recommend the instillation of saline into an advanced airway.



1. Celik, S.A., & Kanan, N. (2006). A current conflict: Use of isotonic sodium chloride solution on endotracheal suctioning in critically ill patients. Dimensions of Critical Care Nursing, 25(1), 11-14.

2. Demers, R.R., & Saklad, M. (1973). Minimizing the harmful effects of mechanical aspiration. Heart & Lung, 2(4), 542-545.

3. Gray, J.E., MacIntyre, N.R., & Kronenberger, W.G. (1990). The effects of bolus normal-saline instillation in conjunction with endotracheal suctioning. Respiratory Care, 35(8), 785-90.

4. Ackerman, M.H., & Mick, D.J. (1998). Instillation of normal saline before suctioning in patients with pulmonary infections: A prospective randomized controlled trial. American Journal of Critical Care, 7(4), 261-266.

5. Kinloch, D. (1999). Instillation of normal saline during endotracheal suctioning: Effects on mixed venous oxygen saturation. American Journal of Critical Care, 8(4), 231-240.

6. Akgul, S & Akyolcu, N. (2002). Effects of normal saline on endotracheal suctioning. Journal of Clinical Nursing, 11(6), 826-930.

7. Klockare, M., et al. (2006). 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, 15(3), 301-307.

8. O’Neal, P.V., et al. (2001). Level of dypsnea experienced in mechanically ventilated adults with and without saline instillation prior to endotracheal suctioning. Intensive & Critical Care Nursing, 17(6), 356-363.

9. Hagler, D.A., & Traver, G.A. (1994). Endotracheal saline and suction catheters: Sources of lower airway contamination. American Journal of Critical Care, 3(6), 444-447.

10. Freytag, C.C., et al. (2003). Prolonged application of closed in-line suction catheters increases microbial colonization of the lower respiratory tract and bacterial growth on catheter surface. Infection, 31(1), 31-37.

11. Halm, M. & Krisko-Hagel, K. (2008). Instilling normal saline with suctioning: Beneficial technique or potentially sacred cow? American Journal of Critical Care,17(5), 469-472.

Catharine Farnan is clinical nurse specialist and Mary Patrick is project coordinator of the Regional Spinal Cord Injury Center of the Delaware Valley, both at Thomas Jefferson University Hospital, Philadelphia.

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