Instructions

Reposition the tube and blade to try to get the tube to make contact with the glottis. Drag above the upper teeth to rotate the tube. Drag above the lower teeth to rotate and advance the blade. Drag the lower teeth to simulate lifting forces. Alternatively, you can use the sliders.

FAQ

Why this page?

This page aims to help those seeking to learn or teach tracheal intubation understand some of the geometry.

It does this by illustrating the adverse impact of bending an endotracheal tube over the upper incisors while attempting tracheal intubation.

What do I do?

Slide the Tube Angle slider back and forth watching the impact on tube tip positions.

What am I looking at?

Above is a simplified diagram showing the upper and lower incisors (white triangles), the laryngoscope blade (grey arc) and a tracheal tube. A red bar is placed at the level of the blade tip to provide a approximate reference for the glottic opening between the vocal cords.

Why does the tip go backwards when the tube is rotated back?

Ah, this is the interesting point. As the tube is tilted back over the teeth the tube-blade contact point (shown with a red dot) migrates upwards. Because of the curve of the blade the tube is deflected posteriorly in an unintuitive manner.

But if bending over the teeth is not the answer, what is?

Applying more lift and flattening the blade helps a lot. You can simulate this by dragging below the teeth and then readjusting the blade positions.

There's a slideshow!

As I showed in earlier work, optimal tracheal tube orientation is to pull the tube laterally at the level of the mouth (to the right), so that you can rotate the tube backwards without bending it or shifting the blade-tube contact point. Avoid rolling the tube over. It's complicated. You may need to read the paper.

What is tracheal intubation?

Tracheal intubation is a vital skill for paramedics and emergency doctors, but training opportunities are scarce. The challenges in gaining experience requires innovative training methods to maximimise the chances healthcare workers can intubate in emergency situations.

In an emergency successful intubation can save a life, prevent brain damage or prevent fatal aspiration of gastric acid into the lungs.

However, even if when aided modern video laryngoscops the first time success rate for intubation by trained hospital doctors in the Emergency or Critical Care departments is only 85% (Prekker et al, 2023).

Notes

• The model assumes that the deflection angle when the tube reflects off the teeth will be matched by the deflection angle over the teeth themselves.
• The model will break if you put in extreme values, eg a tube radius that is less than the blade radius.
• The glottic marker tracks the blade tip height but can be moved further or close to the blade tip with Glottic Plane X slider. This behaviour approximates a Cormack and Lehane grade of 2b. See Cormack-Lehane grading system for more information.
• If you would like to take measurements, you can do so simply with the little fiducial.

Todo

• Help mode
• hide tube when invalid position (indicate why)
• Have a mode where the tube tracks the glottis
• Indicate approximate line of sight.
• Show successful orientation

Keyboard Shortcuts

• Arrow Up/Down: Adjust tube angle
• Arrow Left/Right: Adjust blade insertion
• R: Reset to defaults
• Ctrl+S: Save configuration
• Ctrl+L: Load configuration
• 1-4: Load preset configurations