Thermal compensation algorithm in ManoScan™ high resolution esophageal manometry: does it really affect manometry metrics and final diagnosis?

Background/aim: The accuracy of pressure measurements with ManoScan™ high-resolution manometry (HRM) catheters decreases due to the development of pressure drift (PD) resulting from variations between room and body temperature. The corrective algorithm called thermal compensation (TC), added to the manometry software program by the manufacturer is used to prevent the development of PD. To date, no studies have demonstrated that PD leads to changes in manometry metrics and/or clinical diagnosis. The present study aims to demonstrate the impact of the TC algorithm on HRM metrics and final diagnosis. Materials and methods: Records of 124 consecutive esophageal HRM studies with ManoScan™ HRM catheters were retrospectively reviewed. Manometry metrics and final diagnoses were compared by applying formal TC as recommended by the manufacturer (fTC group), without TC (nonTC group), and by performing TC at the 1st s (TC1 group), 5th s (TC5 group), and 10th s (TC10 group), respectively. Results: Significant differences were observed in values of integrated relaxation pressure (IRP) and distal contractile integral (DCI), and the percentage of weak and intact peristalsis between the fTC group versus the TC1 and TC5 groups. In 28 of 85 studies in which IRP was normal and in 25 of 39 studies in which IRP > 15 mmHg, contrary IRP values were detected when TC was not performed or performed at a different time point than recommended. In the comparison of diagnoses, fewer esophagogastric junction outflow obstruction (EGJ-OO) and more normal esophageal motility (NEM) were diagnosed in the fTC group than in the nonTC group. Conclusion: The omission of the TC or its application at an incorrect time point on esophageal manometry studies using the ManoScan™ HRM system can lead to inaccurate IRP measurements and diagnostic errors between NEM and EGJ-OO diagnoses.