Computer determination of lower esophageal sphincter relaxation (LESR) parameters studied during wet and dry swallows, orifice vs dent sleeve, and cholinergic stimulation and inhibition

Abstract

COMPUTER DETERMINATION OF LOWER ESOPHAGEAL SPHINCTER RELAXATION (LESR) PARAMETERS STUDIED DURING WET AND DRY SWALLOWS, ORIFICE VS DENT SLEEVE, AND CHOLINERGIC STIMULATION AND INHIBITION. JA Castell, CB Dalton, DO Castell. Bownan Gray School of Medlcme, Winston-Salem, NC. LESR interpretation is a subjective, mostly qualitative analysis. We studied LESR in humans using on-line computer analysis to provide objective measures of gastric pressure, resting lower esophageal sphincter pressure (LESP), %LESR, residual pressure (RP) during LESR, duration (LESR/D) and area (LESR/A) of LESR. The program was validated by comparing computer analysis to manual readings by 5 individuals. Excellent correlation was obtained for all parameters (LESP: r=95 , % LESR: x-=.87, LES.R/D r=.96). LESR parameters and peristaltic velocity (VEL) were studied in 10 volunteers. Using pneumohydraulic perfusion gastric baseline pressure was obtained, LES located, and LESR parameters measured during 5 dry and 5 wet swallows at baseline and after atropine (lOpgm/kg; iv) and bethanechol (40pgm/kg;subQ). Results be10 LESP %LESR LESR/D RP LESR/A VEL __-___ Wet Swallow 14.9 93.9 10.8 1-r 30052-x Dry Swallow 13.9* 89.2* 9.3* 1.8* 2252* 3.8* Atropine a.7* 91.3 9.4 0.8 1623 3.8* Bethanechol 25.7* 96.8* 13.8 0.7 5475 2.2* * = ~~0.05 compared to baseline wet swallow There as excellent correlation VEL vs T.ESR/D (r=-.80) and LESP vs % LESR (r=+.92) but poor correlation LESP vs RP (r=+.29). %LESR changed significantly with resting LESP while RP as uneffected. Cholinergicstimulationand inhibition caused apparent changes in LESR, but these are explained by their effects on peristaltic VEL (hence LESR/D) and resting LESP (hence % LESR). Differences in LESR between wet and dry swallows were confirmed by repeating studies in 5 volunteers using Dent sleeve. Values for %LESR and LESR/D were lower and et and dry swallow differences more pronounced. CONCLUSIONS: l)LESR is affected by type of swallow (dry vs et). 2)% LESR may not be the best measure of LESR since it is too dependent on resting LESP. 3)RP is not dependent on baseline LESP and may better define LESR. 4)Duration of the LESR is dependent on the velocity of the peristaltic ave. 5) Cholinergic regulation of human LESR is minimal.