Chassard D, Berrada K R, Tournadre J P, Boulétreau P
Service d'Anesthésie-Réanimation, Hôpital de l'Hôtel-Dieu, Lyon, France.
Anesth Analg. 1996 Feb;82(2):374-6. doi: 10.1097/00000539-199602000-00028.
The lower esophageal sphincter is composed of smooth muscles and is the main barrier against regurgitation during anesthesia. As smooth muscles are usually sensitive to CO2, we investigated the response of lower esophageal sphincter pressure to varying concentrations of CO2 in six anesthetized pigs using a manometric method. CO2 was increased by increasing the dead space at the Y piece of the ventilator. Basal values for ETCO2 were 35 +/- 2 mm Hg, reaching 62 +/- 1 mm Hg at the end of the study (P < 0.03). In response to the increase in ETCO2, no change in lower esophageal sphincter pressure was noted (12 +/- 3 mm Hg vs 13 +/- 4 mm Hg). These findings indicate that the lower esophageal sphincter is not affected by CO2 in the range usually encountered in clinical practice.
食管下括约肌由平滑肌组成，是麻醉期间防止反流的主要屏障。由于平滑肌通常对二氧化碳敏感，我们采用测压法研究了六只麻醉猪食管下括约肌压力对不同浓度二氧化碳的反应。通过增加呼吸机Y形管处的死腔来增加二氧化碳。呼气末二氧化碳分压（ETCO2）的基础值为35±2毫米汞柱，研究结束时达到62±1毫米汞柱（P<0.03）。随着ETCO2的增加，食管下括约肌压力未出现变化（12±3毫米汞柱对13±4毫米汞柱）。这些发现表明，在临床实践中通常遇到的二氧化碳浓度范围内，食管下括约肌不受其影响。
