Cricoid Pressure Training: How Useful are Descriptions of Force?

Abstract

Cricoid pressure has been used for over 200 years. During that time, training in the technique has not changed greatly, despite the well-documented potential for complications if performed improperly. Typically, training relies on quantitative or qualitative descriptions such as "firm" pressure, a number of Newtons of force or equivalent force to that causing pain while pressing on the nose. This study tests the value of these descriptive methods in training to apply cricoid pressure. Fifty subjects were asked to apply cricoid pressure after receiving a description of the force required and again after having tested how much finger pressure on the bridge of their nose was required to cause discomfort. Initial force, force at 45 seconds, minimum force, and maximum force was recorded. The results were analysed using the Wilcoxon signed ranks test, which showed no significant difference in performance between the two types of training. One subject maintained pressure in the range of 25 to 35 Newtons for the entire 45 seconds of the first attempt but no subject performed this well on the second attempt. The use of qualitative and quantitative descriptors of the appropriate pressure does not appear useful in the training of the technique of cricoid pressure. Training incorporating force feedback is recommended.

Rapid Sequence Induction and Intubation

“…None of the patients experienced regurgitation or vomiting when the pressure was applied, and 3 patients had immediate reflux into the pharynx upon release of the pressure after tracheal intubation. 81,82 In his report, Sellick described the use of "firm" pressure but did not quantify the actual force needed to occlude the esophagus or how this force could be reproduced in the clinical setting. 3 Since then, CP has been considered the lynchpin of RSII and the expected standard of care during anesthesia induction for patients at high risk of aspiration.…”

“…Whereas some authors strongly endorse the technique and believe in its effectiveness, 99 others believe that CP should be abandoned because it adds to patients' risks with no evidence of any gained benefit. 22,82 22,82 …”

Analysis of the Application of Cricoid Pressure: Implications for the Clinician

“…Many authors accept the value of 1 kg being equivalent to 9.81 N. A simple approximation is 1 kg 5 10 N. Furthermore, a consensus has been made that application of cricoid cartilage pressure to the conscious patient should be 1 kg to 2 kg or 10 N to 20 N. Once the patient becomes unconscious, pressure should increase to 3 kg to 4 kg or 30 N to 40 N. Forty-four N should reasonably protect patients from aspiration. 4,9,[23][24][25][26][27][28][29] Controversial Aspects of Cricoid Pressure…”

Practice makes perfect? Evaluation of cricoid pressure task training for use within the algorithm for rapid sequence induction in critical care

“…It has been shown among anaesthetic staff that commonly used descriptors of cricoid force are inadequate, knowledge of the prescribed force is poor, as few as 20% are able to achieve the prescribed range, and furthermore, that despite effective training in its application, cricoid force remains a skill that is poorly retained. 4,[6][7][8][9][10][11][12][13] To achieve its purpose in preventing gastropharyngeal regurgitation and aspiration applied cricoid force must occlude the oesophageus at the level of the cricoid cartilage, maintaining an effective upper oesophageal pressure in excess of intragastric pressure. It has been demonstrated that the upper oesophagus can be occluded by the correct application of cricoid force at or in excess of 30 newtons (N).…”