The 50-millilitre syringe as an inexpensive training aid in the application of cricoid pressure

A recent study in our department demonstrated that depressing the plunger o f a 50-mL syringe was reliably and linearly related to the force applied be tween 20 N and 50 N. Using a 50-mL syringe we constructed a simple device t o help train anaesthetic assistants to apply cricoid pressure correctly. We then tested anaesthetists, operating department practitioners (non-physici ans) and nurses in our hospital to see if they could correctly apply forces of 20 and 40 N. All subjects were then trained using this apparatus and on ce confident were retested immediately afterwards, and again 1 week and 1 m onth later. The results show a wide variation in the force applied with onl y 30% of subjects applying appropriate force at 20 N, and 40% at 40 N. Trai ning leads to a significant improvement in performance (P < 0.005 at 20 N a nd P < 0.001 at 40 N) which is maintained for 1 week for both 20 N (P < 0.0 5) and 40 N (P < 0.05) but not for 1 month. Therefore training should be pr actised on a weekly basis. This is an inexpensive and simple device that we believe to be useful in helping anaesthetic assistants to apply effective cricoid pressure.