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Prevention of kinking of a percutaneous transtracheal intravenous catheter
1Department of Anesthesiology, University of California, San Diego Medical School.
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.