Optimizing the high-resolution manometry (HRM) study protocol

Background: Intolerance of the esophageal manometry catheter may prolong high-resolution manometry (HRM) studies and increase patient distress. We assessed the impact of obtaining the landmark phase at the end of the study when the patient has acclimatized to the HRM catheter. Methods: 366 patients (mean age 55.4 ± 0.8 years, 62.0% female) undergoing esophageal HRM over a 1-year period were studied. The standard protocol consisted of the landmark phase, 10 5 mL water swallows 20-30 s apart, and multiple rapid swallows where 4-6 2 mL swallows were administered in rapid succession. The modified protocol consisted of the landmark phase at the end of the study after test swallows. Study duration, technical characteristics, indications, and motor findings were compared between standard and modified protocols. Key Results: Of the 366 patients, 89.6% underwent the standard protocol (study duration 12.9 ± 0.3 min). In 10.4% with poor catheter tolerance undergoing the modified protocol, study duration was significantly longer (15.6 ± 1.0 min, p = 0.004) despite similar duration of study maneuvers. Only elevated upper esophageal sphincter basal pressures at the beginning of the study segregated modified protocol patients. The 95th percentile time to landmark phase in the standard protocol patients was 6.1 min; as many as 31.4% of modified protocol patients could not obtain their first study maneuver within this period (p = 0.0003). Interpretation was not impacted by shifting the landmark phase to the end of the study. Conclusions & Inferences: Modification of the HRM study protocol with the landmark phase obtained at the end of the study optimizes study duration without compromising quality. When patients are intolerant of an esophageal high-resolution manometry catheter from repetitive swallowing or gagging, the study protocol can be modified such that test swallows are obtained first and the landmark phase obtained at the end of the study, when the patient has acclimatized to the catheter. Elevated upper esophageal sphincter basal pressures at the start of the study may identify patients who could benefit from this modification. Inability to obtain a swallow- or artifiact-free interval over the first 5-6 min of the study can be an indication for modification of the study protocol.