Insertion forces and risk of complications during cricothyroid cannulation.

Our purpose was to determine the forces required to insert several different styles of cricothyroid cannulas and to relate the magnitude of these forces and cannula design features to the incidence of complications during insertion. Tests were done on unembalmed cadavers and anesthetized dogs. Samples of 4 different commercial cricothyroid cannulas were tested. Each cannula type was tested in 5 different cadavers and 10 different dogs. A lubricant was applied to the cannulas in half of the dogs tested. Major findings are 1) there is a linear correlation between insertion force and device diameter, 2) higher puncture force is associated with a greater incidence of complications, 3) posterior wall penetration occurs more frequently with a curved penetrating device, 4) using small pilot needles to guide insertion of large cannulas minimizes complications, and 5) lubricant is less effective for cannulas having abrupt diameter changes. These findings provide guidelines for design of safer cricothyroid cannulas.