Level of dyspnoea experienced in mechanically ventilated adults with and without saline instillation prior to endotracheal suctioning.

The purpose of this study was to compare the level of dyspnoea with and without the use of 5-cc saline instillation prior to endotracheal suctioning of mechanically ventilated adults. A crossover, quasi-experimental design was used. Seventeen alert, mechanically ventilated adults were asked to rank their level of dyspnoea using the vertical visual analogue scale at specific time intervals surrounding two suctioning events. Saline was randomly assigned to be instilled prior to one of two suctioning episodes. Dyspnoea was ranked immediately after suctioning, and at 10-, 20-, and 30-minute intervals. Data were analyzed using repeated measures analysis of variance with time of measure (immediately after suctioning, 10-, 20-, and 30-minute intervals) and treatment type (with saline versus without saline instillation). The level of dyspnoea based on treatment type (with or without saline) was non-significant. Treatment type by age group interaction was significant (F(1, 15) = 5.41, P = 0.034). The nature of the interaction revealed that older patients (<60 years of age) experienced less dyspnoea without saline prior to suctioning and greater dyspnoea with saline instillation as compared to the younger subjects (<60 years of age). This study documented no beneficial effects of saline. However, it did demonstrate that saline instillation might precipitate a significantly increased level of dyspnoea for up to 10 minutes after suctioning in patients older than 60 years of age. Recommendations based on the results of this study would be to avoid the use of saline instillation prior to suctioning