CRICOID PRESSURE DECREASES LOWER ESOPHAGEAL SPHINCTER TONE IN ANESTHETIZED PIGS

Purpose: Previous studies have shown a decrease of lower oesophageal s phincter (LOS) tone during stimulation of the upper oesophageal sphinc ter. Therefore, we hypothesized that during anaesthesia, cricoid press ure could result in a decrease in LOS pressure. Methods: The LOS and o esophageal barrier pressures (BrP = LOSP minus gastric pressure) were obtained in 11 anaesthetized pigs with intraabdominal pressure of 15 m mHg using a manometric method (perfused catheters) before and during f irm application of cricoid pressure. Reflux was assessed with concomit tant recording of the lower oesophageal pH. Results: Cricoid pressure decreased LOSP from 31.0 +/- 14.5 mmHg to 26.1 +/- 12.7 mmHg (P < 0.00 1) leading to a 35% reduction of oesophageal barrier pressure (9 +/- 1 0.3 mmHg vs 13.7 +/- 12.4 mmHg; P < 0.001). No episodes of reflux were recorded. Conclusions: This study shows that cricoid pressure decreas es LOS tone in anaesthetized pigs. Although no gastrooesophageal reflu x was recorded, this study suggests that, if cricoid pressure does not completely occlude the oesophagus, the decrease of oesophageal barrie r pressure induced could favour the appearance of pulmonary aspiration .