811 WHETHER 10 WATER SWALLOWS NECESSARY TO OBTAIN REPRODUCIBLE RESULTS OF HIGH-RESOLUTION OESOPHAGEAL MANOMETRY?

Abstract

Abstract Not less than ten wet swallows assessment in the primary test position is recommended by Chicago classification 4.0 for high-resolution oesophageal manometry (HREM); however, the required number of measurements are not sufficiently supported. Aim to evaluate the number of wet swallows necessary for correct interpretation of the results of lower esophageal sphincter integrated relaxation pressure (IRP) with low probability of type I and II errors. Methods Patients referred to perform HREM were enrolled. Solid-state 10Fr catheter and Solar (Laborie) software were used. Minimum 10 swallows by 5 mL water were obtained. These were analysed for cumulative means of IRP after 1…9 measurements. Conclusion made at each moment was compared with one based on 10 measurements. The results were characterized as true/false positive/negative for calculation of diagnostic accuracy. To exclude sample influence, Monte-Carlo simulation of sequential decision-making was performed with the use of sequential probability ratio test. Association of the diagnostic accuracy from recall was studied with the use of receiver operating characteristic curve (ROC) analysis. Results One hundred subjects were enrolled (25 with disorders of EGJ outflow). During the simulation, the probability of matching the decisions based on the 10 measurements and lower number of them was high. ROC analysis showed that actual probability to obtain false-positive results was twice as lower then ‘allowed’ rate of 5%. The probability to make false-negative results did not exceed 10% in any number of measurements. The probability that the conclusions made after 2 and after 10 measurements match was 0.9584 in those with disorders of EGJ outflow and 0.9652 in those without (figure 1). Conclusion The standard number of measurements required to support the presence of disorders of EGJ outflow during evaluation of 5 mL wet swallows in the primary position is excessive. Values of the IRP after 2 swallows allows to make similar decision to that after 10 swallows with >95% probability. This allows to reduce the number of wet swallows to assess in the primary position and save time for assessments in alternative position or perform provocation tests.