2001 OPEN FORUM Abstracts
ASSESSMENTOF EXPIRATORY TRACHEAL PRESSURE WITH USE OF A SPEAKING VALVE.
Christopher PiccuitoRRT, Daniel Chipman RRT, Douglas Johnson MD, Robert Kacmarek PhD RRT FAARC,Dean Hess PhD RRT FAARC. Massachusetts General Hospital and Harvard MedicalSchool
Speaking valves (SV) are commonlyused to promote exhalation through the upper airway for patients with tracheostomy.We have been concerned that patients occasionally experience expiratory resistancewhen the SV is placed. Therefore, we assessed the utility of measuring expiratorytracheal pressure as an objective indicator of expiratory resistance when aSV is placed.
Method: Before placing theSV, an assessment of the appropriateness of placing it was made by a respiratorytherapist. If present, the cuff was deflated. In the case of a fenestrated tube,the inner cannula was removed. Secretions were cleared as needed. The set-upshown in the figure was then used to measure expiratory tracheal pressure withthe SV in place during relaxed breathing. After the pressure measurements, themanometer was removed and the SV attached directly to the tracheostomy tube.
Results: Assessments weremade in 37 patients. The expiratory pressure was 5 cm H2O in 75%of cases and 10 cm H2O in 90% of cases. Pressures >10 cm H2Owere associated with clinical evidence of respiratory distress and the SV wasimmediately removed. There was no difference in expiratory pressures for fenestratedtubes (n=18, 5.9±7.0 cm H2O) and nonfenestrated tubes (n=19, 5.7±4.5cm H2O)(P=0.94). Expiratory pressures were greater for larger tubes(ID 7 and 8 mm, n=21, 7.0±6.8 cm H2O) than smaller tubes ( 6 mm ID,n=16, 4.3±3.8 cm H2O), but this was not statistically significant(P=0.13).
Conclusions: Tracheal pressuremeasurements are a useful objective measure of expiratory resistance when aSV is used. Expiratory tracheal pressures 5 cm H2O are common withthe SV in place and seem to be well tolerated. We did not identify immediateclinical symptoms with pressures 10 cm H2O. Pressures >10 cm H2Oare not tolerated. With high pressures, the SV should be promptly removed, andcauses of expiratory resistance should be investigated such as a large tracheostomytube or upper airway pathology. Downsizing to a tube with a smaller outer diametershould be considered. It is interesting to note that we found no differencein expiratory tracheal pressures with fenestrated or nonfenestrated tracheostomytubes and a SV in place.