Lower esophageal sphincter integrity is maintained during succinylcholine-induced fasciculations in dogs with "full" stomachs.

During succinylcholine-induced muscle fasciculations, gastroesophageal barrier pressure in fasted adult dogs (n = 10) was compared by esophageal manometry with that in the same dogs with full stomachs. After fasting, fasciculations did not increase significantly either mean intragastric pressure (4.7 +/- 1.3 mm Hg before; 5.2 +/- 1.7 mm Hg during) or lower esophageal sphincter pressure (35.4 +/- 21.4 mm Hg before; 40.6 +/- 17.5 mm Hg during). Filling the dogs' stomachs with 300 mL of saline significantly increased both mean intragastric pressure (from 3.8 +/- 2.2 to 7.4 +/- 1.4 mm Hg) and mean lower esophageal sphincter pressure (from 20.2 +/- 6.8 to 28.6 +/- 14.8 mm Hg). Fasciculations did not produce a further increase in either mean intragastric or mean lower esophageal sphincter pressure. Most importantly, in all animals, under all conditions, gastroesophageal barrier pressure remained positive (range, 6.0-65.5 mm Hg) and therefore served as a barrier to passive regurgitation.