Effect of Left Paratracheal Pressure on Cerebral Oxygenation During General Anesthesia

Pulmonary aspiration of gastric contents remains a potentially serious complication ofgeneral anesthesia. Cricoid pressure has traditionally been used during induction ofanesthesia to reduce the risk of regurgitation, although its effectiveness and itspotential effects on airway management remain debated.Left paratracheal pressure (LPP) has been proposed as an alternative technique based onthe frequent left‐sided position of the cervical esophagus. Anatomical and clinicalstudies have suggested that LPP may provide effective esophageal compression whilepreserving airway management conditions. Previous work from the investigators also showedthat application of LPP at 30 N did not significantly decrease left carotid blood flow.However, carotid blood flow is an indirect marker of cerebral perfusion, and the effectof LPP on cerebral oxygenation remains unknown.PARANIRS is a prospective, single‐center, randomized, controlled crossover study designedto evaluate the effect of LPP on regional cerebral oxygen saturation during generalanesthesia. Each participant will serve as their own control.After induction of general anesthesia, neuromuscular blockade, tracheal intubation, andhemodynamic stabilization, bilateral regional cerebral oxygen saturation will becontinuously monitored using near‐infrared spectroscopy. Measurements will be obtainedduring a baseline period without cervical pressure and during application of two cervicalpressure maneuvers: left paratracheal pressure at 30 N and cricoid pressure at 30 N.The order of the two cervical pressure maneuvers will be randomized. Each maneuver willbe applied for 60 seconds using a calibrated force‐measuring device to ensure a constantforce of 30 N, with a 60‐second washout period between interventions.Hemodynamic and respiratory variables, including mean arterial pressure, heart rate,peripheral oxygen saturation, and end‐tidal carbon dioxide, will also be continuouslyrecorded. The study is intended to determine whether LPP produces a clinically relevantchange in regional cerebral oxygenation and to compare its physiological effects withthose of conventional cricoid pressure.