Cervical Spine Movements With Single-Handed Versus Bimanual Cricoid Pressure Under Simulated Cervical Immobilization: A Randomized Controlled Trial.

BACKGROUND

Cricoid pressure is applied during intubation of full-stomach patients or in emergency situations, including trauma, oftentimes after excluding cervical spine injury. Cervical spine movements under cricoid pressure are mainly studied in cadavers.

METHODS

This prospective, randomized, assessor-blind trial (CTRI/2022/05/042505, dated May 12, 2022) enrolled adult ASA I and II patients with normal spines undergoing neurointerventional procedures with simulated cervical spine immobilization. Patients were randomized to single-handed or bimanual cricoid pressure (one hand anterior, the other providing posterior support below midcervical level). Cinefluoroscopic lateral images from occiput (C0) to C6 were obtained at baseline and during cricoid pressure. Angular displacement between adjacent cervical vertebrae was measured by a blinded radiologist. The primary outcome was maximal angular displacement at C4-C5. Secondary outcomes included segmental motion from C1 to C6, laryngoscopic view, intubation time and attempts, and hemodynamic responses.

RESULTS

Fifty patients (25 per group) were analyzed. Bimanual cricoid pressure showed significantly reduced angular displacement at C4-C5 (4.34±3.98 vs. 0.71±1.92, P=0.001). Similar findings observed at C1-C2 (4.34±4.45 vs. 0.89±1.97, P=0.001), C2-C3 (5.46±4.14 vs. 1.27±2.66, P=0.001), C3-C4 (5.66±4.52 vs. 1.51±1.72, P=0.001), and C5-C6 (3.04±4.44 vs. 0.18±2.19, P=0.006). Other secondary outcomes were comparable.

CONCLUSIONS

During simulated cervical spine immobilization, bimanual cricoid pressure significantly reduces cervical spine movements without impairing intubation conditions. Posterior support likely counteracts spine movements caused by cricoid pressure.