Prevention of kinking of a percutaneous transtracheal intravenous catheter.
BACKGROUND
Transtracheal jet ventilation (TTJV) through a percutaneously inserted intravenous/TTJV catheter, using a high-pressure oxygen source and noncompliant tubing is a simple and quick method of effective ventilation, especially in a patient in whom the lungs cannot be ventilated via mask and/or whose trachea cannot be intubated. TTJV becomes impossible if any part of the plastic portion of the TTJV catheter kinks; although the incidence of this problem is not known, kinking of the catheter is most likely to occur as the catheter turns from a predominantly posterior to a predominantly caudad direction. These experiments tested the hypothesis that a small-angle bend in the tip of the TTJV catheter would reduce the requirement to aim the entire TTJV catheter in a caudad-directed orientation.


METHODS
A model of the trachea was designed using polyvinylchloride tubing to observe TTJV catheter insertion and plastic catheter kinking. The TTJV catheters were inserted at 0, 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, and 30 degrees angles in trials of 15 times each. Small-angle bends, placed at 2.5 cm from the distal end of the TTJV catheter, of 0, 5 degrees, 10 degrees, 15 degrees, and 20 degrees were used, and each bent TTJV catheter was inserted at each of the above insertion angles 15 times.


RESULTS
Increasing the angle of insertion decreased the incidence of kinking of the TTJV catheter at every small-angle bend in the tip of the TTJV catheter. Increasing the small-angle bend in the tip of the TTJV catheter decreased the incidence of kinking with every angle of insertion. A small-angle bend in the tip of the TTJV catheter and the angle of insertion often were complementary in their ability to decrease the incidence of kinking. With a cumulative angle of 10 degrees, 98% of the plastic catheters kinked, compared to 0 in trials involving a cumulative angle of 30 degrees or more. Analysis via the chi-squared test yielded a P value of < 0.0001 when comparing incidence of kinking for cumulative angles of 10-30 degrees.


CONCLUSIONS
A modest bend in the tip of the TTJV catheter greatly reduces the sharpness of the angle of insertion required to eliminate kinking of the plastic catheter. Because the risk/benefit ratio is so low, we suggest that a small-angle bend of 15 degrees should always be created and, combined with a 15 degrees angle of insertion, should result in a rare incidence of kinking.
Department of Anesthesiology, University of California, San Diego Medical School.
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L
Sdrales
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JL
Benumof
D002406:Catheterization, Peripheral / Q000295:instrumentation*; D004867:Equipment Design; D004868:Equipment Failure; D006612:High-Frequency Ventilation / Q000295:instrumentation*; D006801:Humans; D014132:Trachea