The Science Journal of the American Association for Respiratory Care

2011 OPEN FORUM Abstracts


Chris Russian, Joshua F. Gonzales, Kevin Collins, Amanda Martinez; Respiratory Care, Texas State University-San Marcos, San Marcos, TX

Background: Current clinical practice guidelines (CPGs) recommend a suction catheter to endotracheal tube (SC:ETT) ratio of 50% or less to minimize the adverse effects of suctioning. This ratio is based on a comparison of external diameter of the SC to the internal diameter of the ETT. We theorized that a more accurate assessment of SC:ETT ratio would involve measuring the ETT total internal volume with and without the insertion of a SC. Current clinical practice and some respiratory care texts recommend a SC:ETT ratio that exceeds the CPG standard. Research Question: Does measuring endotracheal tube total volume with and without the insertion of a suction catheter provide a more consistent assessment of SC:ETT ratio based on current clinical practice? Methods: The current research project was granted IRB exemption (EXP2011P480) status by the institutional review board at Texas State University-San Marcos. ETT sizes of 10.0mm to 6.0mm will be examined with suction catheter sizes ranging from 6 to 16 Fr. Total ETT volume was established by filling each tube with fluid to the entire length of the tube. Next, researchers inserted a variety of suction catheters into each ETT and refilled the tube with fluid. Volume measurements were made with each suction catheter insertion. Only one catheter was inserted at a time. A comparison was made between the total volume held by each ETT and the volume held by each tube with a SC inserted. A SC:ETT ratio of less than 50%, based on volume measurements, was recorded at the conclusion of all measurements. Results: Total internal volume measurements were collected for each ETT size prior to SC insertion. After examining the SC:ETT ratio measurements, we determined that larger SC sizes could be used with some ETT compared to current CPG recommendations. Table 1. outlines our recommendations versus current CPG guidelines. Conclusion: We examined suction catheter size and volume displacement in relation to endotracheal tube total internal volume. Our results indicate the ability to use a larger suction catheter for elected ETTs while still maintaining a SC:ETT ratio of 50% or less based on volume measurements. We compared our findings with current respiratory CPG recommendations for SC:ETT ratio based on internal diameter measurement. Anecdotally, we believe our recommendations for suction catheter size based on ETT size is more consistent with current clinical practice.
Sponsored Research - None
All suction catheter and ETT length 305mm unless indicated otherwise.
* Suction catheter and ETT lengths changed to 290mm
t Suction catheter and ETT lengths changed to 270mm

± Volume of a 16Fr suction catheter with length of 305mm equals 6.81mL