Tuesday, November 6, 2007

This presentation is part of : Critical Care Health Models
Measuring the Effects of Heated Humidification on Sputum Viscosity in the Tracheostomized Patient
Margaret M. Ecklund, MS, RN, CCRN, APRN-BC, Pulmonary Medicine, Rochester General Hospital, Rochester, NY, USA
Learning Objective #1: The learner will be able to identify airway alterations when tracheostomy tubes are present
Learning Objective #2: The learner will be able to list strategies for caregivers to optimize humidification for artificial airways

Purpose:The study was conducted to determine if there is a difference in sputum viscosity when heated humidification is used. Background:No standards exist for humidification of spontaneously breathing tracheostomy patients. There is evidence that suggests that air delivery with 100% relative humidity supports the normal airway mucosal function. Decreased humidity can negatively affect lung mechanics. Adverse effects of low humidity are proportional to duration of exposure.  Viscosity is resistance to flow.  Lowering viscosity of mucus improves clearance. A simulated cough machine is based on the premise of airflow dependent mucus clearance and measures the sputum recoil. A sample of mucus is placed at the base of the “trachea”. Different aliquots can be used for successive measures. Measurement variability with different aliquots in repeated measurements on the same sample is generally less than 10%. Method The pilot study included 10 hospitalized adult patients with tracheostomy tubes.  Each patient, serving as their own control, received humidification with or without a donut heater with the alternative condition for the following 3 days, with 24 hours between therapies. A total of 6 samples were collected for each subject.  The data collector was blinded to the application of heater to the circuit.  Samples were tested on the simulated cough machine to measure sputum viscosity, using 3 repeated measures of the same sample.  Data were analyzed using Repeated measures ANOVA. Results Consistent differences attributable to heating condition were detected in circuit relative humidity, circuit temperature, oxygen percent and oxygen flow. Average mucus viscosity was not affected by the heating condition. Conclusion: The study added evidence for humidification, but no standards can be written based on the findings. Additional measures would be useful in providing more data about the effect of heat on mucus viscosity.