Cricoid pressure decreases ease of tracheal intubation using fibreoptic laryngoscopy (WuScope System

Cricoid pressure is commonly used during rapid sequence induction and intubation to minimize the risk of aspiration. The objective of the study was to evaluate the ease of fibreoptic (WuScope System(TM)) intubation in anesthetized adults receiving cricoid pressure.

The intubation difficulty scale (IDS) was used to measure tracheal intubation difficulties in 33 patients undergoing elective surgery with general anesthesia and complete neuromuscular blockade. Each patient had their trachea intubated under two conditions: with and without cricoid pressure. The order of conditions was determined randomly. Cricoid pressure was applied by an experienced anesthesia provider.

An IDS value of 0 (ideal intubation, that is one performed by the first operator on the first attempt, using the first technique with full visualization of the glottis and no vocal cord compression) occurred in 30 of 33 patients (91%) without cricoid pressure and in 22 of 33 patients (67%) with cricoid pressure (P < 0.05). Cricoid pressure compressed the vocal cords in nine patients (27%) and impeded tracheal tube placement in five (15%). In three patients (9%), pressure had to be released in order to successfully intubate.

Cricoid pressure may impede or even prevent fibreoptic laryngoscopic intubation with the WuScope System(TM).