Factors Determining Pressure Measurement Accuracy by Intraluminal Esophageal Manometry

Abstract

Measurement accuracy represents an important prob­ lem for all physicians using esophageal pressure determi­ nations for clinical or investigative assessment of esoph­ ageal motor function. Although intraluminal manometry is generally regarded as providing sophisticated quanti­ tative assessment of esophageal motility, the examina­ tion, as currently performed, often yields only semiquan­ titative information. Inaccurate esophageal pressure measurement causes two major problems: (1) measurement artifact, and (2) measurement insensitivity. In some circumstances, ap­ parent differences in esophageal pressure values between subject groups may represent measurement artifact rather than real physiological or pathological differ­ ences. In contrast, measurement insensitivity may ob­ scure real differences in esophageal pressures existing between subject populations, causing such differences to go unrecognized. Clearly, reduction or elimination of measurement inaccuracy is desirable. We believe that the instrumentation and methodology are now available to achieve accurate quantitation of esophageal pressure activity. Esophageal pressure values obtained by manometry are determined by several different factors, including: recording system perform­ ance fidelity, recording technique, scoring method, and conditions existent during manometry. All these factors must be dealt with satisfactorily in order to achieve precise esophageal pressure measurements. Instrumentation In the late nineteenth centrury esophageal pressure studies were first performed by Kronecker and Meltzer 1 using intraluminal balloons. The balloon method under­ went modification,2, a but remained the major technique for recording esophageal motor activity until the early 1950's. Because this cumbersome method featured am­ plitude lag at high frequencies, and sphincter pressure varied with different balloon diameters,4-6 investigators sought other recording methods. In the 1950's Ingelfinger's group in Boston,7, 8 Code