Subglottic secretion viscosity and evacuation efficiency

Pamela V. O'Neal, Cindy L. Munro, Mary Jo Grap, Sarah M. Rausch

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Ventilator-associated pneumonia (VAP) is a common nosocomial pneumonia that occurs in critically ill patients and results in mortality rates as high as 71%. Subglottic secretions (SSs) are a known risk factor. Several clinical trials have shown that continuous aspiration of subglottic secretions (CASS) reduces the risk of VAP by nearly half. Optimal suction pressure levels needed to efficiently evacuate viscous SSs are unknown. The purpose of this study was to describe SSs and the effective suction pressure (20 mmHg, 30 mmHg, 40 mmHg, and 50 mmHg) needed to maximize evacuation efficiency based on SS volume (2 ml, 4 ml, and 6 ml) and viscosity (watery, thick, and gel-like). A laboratory model was designed to replicate a human trachea. Thick secretions had the highest percentage of mean recovery representative of evacuation efficiency of SSs (mean recovery of 86%). The suction pressure of 30 mmHg had the highest overall mean of secretion recovery (83%) across all viscosity types and amounts. This study demonstrated that higher viscosity secretions were easier to evacuate than lower viscosity secretions when 30-mmHg suction pressure was applied. Management of secretion viscosity may assist in secretion removal and delay VAP development. With increased understanding of the molecular structure of SSs, there is the potential that clinicians will be able to manipulate secretion viscoelastic properties to maximize evacuation efficiency of the secretions. Further research is needed to identify safe suction pressures for optimal evacuation of SSs in human subjects. copyright

Original languageEnglish (US)
Pages (from-to)202-209
Number of pages8
JournalBiological Research For Nursing
Issue number3
StatePublished - Jan 2007
Externally publishedYes


  • Intubation
  • Mechanical ventilation
  • Subglottic secretions
  • Ventilator-associated pneumonia

ASJC Scopus subject areas

  • Research and Theory


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