A novel method of measuring cricoid force

The application of cricoid pressure is an effective means of preventing regurgitation of gastric contents when correctly applied. A force of 30 N (3 kg) is recommended for an unconscious patient. This study assesses the validity of using floor scales to measure cricoid force applied by anaesthetic assistants and compares their use to an established training technique. Forty subjects applied pressure to a cricoid model in a blinded manner, on three test occasions. For each test, cricoid pressure was maintained for 1 min and the highest and lowest forces recorded on the model were noted. The first test was before any instruction. The second test followed a period of practice on the cricoid model. For the final test, subjects stood upon a set of floor scales and noted their weight. Force was applied to the cricoid model until the weight on the floor scales reduced by 3 kg. Performance improved both following practice on the model and using the floor scales. Applying cricoid force while standing on floor scales and using the change in weight as a guide resulted in a predictable force on the cricoid model. The use of floor scales is a useful method of demonstrating the forces needed for effective cricoid pressure.