Abstract
Background: Current AARC clinical practice guidelines (CPGs) recommend a suction catheter to endotracheal tube (SC:ETT) ratio based on a comparison between the external diameter of the suction catheter and the internal diameter (ID) of the ETT. A SC:ETT ratio of less than 50% is consistent with the current recommendation. We theorized that a more satisfactory assessment of SC:ETT ratio could be accomplished using volume or area formulas and expansion of diameter recommendations. Some respiratory care texts recommend a SC:ETT ratio that exceeds the CPG standard.
Methods: This research project was granted exemption status by the institutional review board at Texas State University-San Marcos. The project involved calculating the internal volume and area of a variety of ETT sizes, calculating the external volume and area of a variety of SC sizes and comparing the ETT and SC calculations to achieve a final ratio. In addition, we assessed negative pressures using vacuum suction and a lung model during multiple suction maneuvers.
Results: Our results indicate volume and area calculations provide an alternative method to determining SC:ETT ratio. We found that a volume or area ratio of 50% corresponds to a diameter ratio of 70%. We demonstrated that negative pressures during suctioning remain low at the new ratios. This indicates that use of a larger suction catheter than current clinical practice guidelines is possible while continuing to allow air entrainment between the suction catheter and endotracheal tube.
Conclusion: Our investigation determined the ETT internal volume and area, SC external volume and area and SC:ETT ratios based on volume, area and diameter for a variety of ETTs and SCs. Our results support an alternative ratio when pairing suction catheters and endotracheal tubes.
- Suction catheter size
- endotracheal tube size
- suction catheter
- endotracheal tube ratio
- tube diameter
- endotracheal suctioning
- airway clearance
Footnotes
- Mr. Christopher J. Russian; cr23{at}txstate.edu, Texas State University-San Marcos, 601 University Drive, San Marcos, Texas, United States, 78666; 512-245-3794, 512-245-7978
The authors report no financial or other conflict of interest in conducting this study.
The endotracheal tubes were purchased through funding from a Texas State University Research Enhancement Grant. The suction catheters were donated to our department by Kimberly-Clark at no charge. Kimberly-Clark had no other involvement in this project.
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