Introduction

Based on the Chicago classification, HREM diagnosis is classically based on metrics obtained with wet swallows carried out in the supine position. However, both patients and physicians often feel that this is not a physiological position to conduct the test as it may not translate to the real world experience. With the patient in the upright/sitting position, the test would more closely simulate real-life behaviour and may be safer for elderly patients at risk of aspiration.

Aims & Methods

In an Asian tertiary centre, a total of 104 patients had undergone high resolution esophageal manometry (HREM) with retrospective data analysis comparing both conventional supine position with the upright position. The latter is generally favoured by all patients as this represents the physiological posture during meals.

Results

Using 2-tailed paired sample T-test, comparison across all cases showed a consistently lower median Integrated Relaxation Pressure (IRP) [6.0 mmHg vs to 8.7 mmHg; p <0.01] and lower mean Distal Contractile Integral (DCI) [1463 mmHg/cm/sec vs 1864 mmHg/cm/sec; p =0.014] in the upright posture compared to supine position although the mean Distal Latency (DL) difference was not significant [6.21secs vs 6.27 secs; p =0.491]. During upright and supine position comparison respectively, subgroup analysis on subjects with normal HREM diagnosis showed even lower median IRP [4.9 mmHg vs 7.5 mmHg; p <0.01] and lower mean DCI results [1436 mmHg/cm/sec vs 1695 mmHg/cm/sec; p <0.01] with mean DL in this subgroup showing no significant statistical difference [6.29 secs vs 6.38secs; p=0.545]. The final HREM diagnosis in upright position is concordant with the conventional supine position up to 81.7% and showed an even higher concordance in terms of management similarity up to 98.1%. Only 2 cases (2/104) showed a significant discordance between supine and upright HREM diagnosis [normal HREM vs esophagogastric juntion –outflow obstruction(EGJ-OO) and hypercontractile esophagus vs normal HREM]. Minor diagnostic discordance [normal HREM vs ineffective esophageal motility (IEM)] was noted in 17/104 cases which had no major clinical impact on patients and may be overcome by adopting a lower cut-off for mean DCI for upright group.

Conclusion

In patients who are unable to perform HREM in supine position, adopting the upright position shows a high clinical concordance and may be considered a more physiological approach in the HREM protocol.

References

Riva CG, Siboni S, Ferrari D, Sozzi M, Capuzzo M, Asti E, Ogliari C, Bonavina L. Effect of Body Position on High-resolution Esophageal Manometry Variables and Final Manometric Diagnosis. J Neurogastroenterol Motil. 2020 Jul 30;26(3):335-343. doi: 10.5056/jnm20010. PMID: 32606256; PMCID: PMC7329148.