Remifentanil alters sensory neuromodulation of swallowing in healthy volunteers: quantification by a novel pressure-impedance analysis

Exposure to remifentanil contributes to an increased risk of pulmonary aspiration, likely through reduced pharyngeal contractile vigor and diminished bolus propulsion during swallowing. We employed a novel high-resolution pressure-flow analysis to quantify the biomechanical changes across the upper esophageal sphincter (UES). Eleven healthy young (23.3 ± 3.1 yr old) participants (7 men and 4 women) received remifentanil via intravenous target-controlled infusion with an effect-site concentration of 3 ng/ml. Before and 30 min following commencement of remifentanil administration, participants performed ten 10-ml saline swallows while pharyngoesophageal manometry and electrical impedance data were recorded using a 4.2-mm-diameter catheter housing 36 circumferential pressure sensors. Remifentanil significantly shortened the duration of UES opening (P < 0.001) and increased residual UES pressure (P = 0.003). At the level of the hypopharynx, remifentanil significantly shortened the latency from maximum bolus d...