Stylet bend angles and tracheal tube passage using a straight-to-cuff shape

Area of Science:

• Medical Devices
• Anesthesiology
• Airway Management

Background:

• Malleable stylets enhance tracheal tube maneuverability but can cause impingement on tracheal rings after vocal cord passage.
• Stiffened tracheal tubes may impede passage due to their rigidity post-insertion.

Purpose of the Study:

• To evaluate the impact of different bend angles in styletted tracheal tubes on insertion difficulty.
• To determine the optimal bend angle for facilitating tracheal tube passage.

Main Methods:

• Four bend angles (25, 35, 45, 60 degrees) of straight-to-cuff tracheal tubes were tested.
• Thirty-two operators performed random insertions into 16 cadaveric airways.
• Ease of passage was subjectively graded as no resistance, some resistance, or impossible.

Main Results:

• No resistance was reported in 69.1% of insertions at 25 degrees, decreasing with higher angles.
• Impossible passage occurred in 2.3% at 25 degrees, rising to 53.9% at 60 degrees.
• Odds of impossible passage increased significantly with angles >35 degrees.

Conclusions:

• Bend angles exceeding 35 degrees in styletted tracheal tubes elevate the risk of difficult and impossible tracheal intubation.
• Further research is needed to explore other variables like stylet stopping points and tube tip designs.