1998 OPEN FORUM Abstracts
PREDICTING SUCCESS WITH A VENTILATOR SPEAKING VALVE
Thomas R. Nielson BA, RRT, Wendy C. Marshall MA, CCC-SLP, Hospital for Special Care, New Britain, CT.
Background: A ventilator patient with a cuffed artificial airway in place is at risk of significant resistance to airflow when attempting to exhale around a deflated cuff. Placement of an in-line speaking valve requires 100% of the exhaled gas to pass around the deflated tracheotomy tube. The literature encourages the consideration of tracheotomy tube size as a factor in determining candidacy but we hypothesized that if more than 50% of the gas exited through the upper airway during cuff deflation, the patient would not experience significant increase in the work of breathing when required to push 100% of the gas through the upper airway. In order to prevent undue distress to the patient during an in-line valve trial and to maintain cost effective practice in issuing in-line valves to patients we chose to quantify the gas exhaled through the upper airway versus through the ventilator circuit during cuff deflation and use that figure (percent leak) as a predictor of success. Method: Seventeen patients using a variety of trach tube sizes from 6 to 9 participated in the study. The method used was spirometric measurement of exhaled gas during full cuff deflation to be followed with monitored trials of placement of an in-line speaking valve. Gas measured by spirometry was compared to the set tidal volume of the patient and percent leak was calculated. A protocol was established and measurements of magnitude of leak as well as patient perception of comfort, SpO2, heartrate and quality and length of sustained phonation were taken. A 30 minute trial with an in-line valve in place with no signs of distress was considered to be successful. Results: There was significant difference (p < .03) between the percent leak through the upper airway during the initial cuff deflation trial among those who were eventually successful during speaking valve trial (mean=69%) and those who failed the speaking valve trial (mean=41%). There was no significant correlation between the magnitude of leak observed during cuff deflation and the size of the tracheotomy tube. Conclusion: Our facility has elected to designate 50% leak through the upper airway as the lower limit in selecting a patient for an in-line trial. Predicting success in placement of a one-way speaking valve in a ventilator dependent patient using an easily obtainable airflow indicator is a useful and inexpensive patient assessment tool.
The 44th International Respiratory Congress Abstracts-On-Disk®, November 7 - 10, 1998, Atlanta, Georgia.