Classification of motor function in GERD using oesophageal high-resolution manometry
| Metrics | Description | |
| EGJ barrier function | ||
| Morphology | Separation between LES and CD | Type 1: superimposed LES and CD Type 2: axially separated LES and CD pressure signals separated by <3 cm Type 3a: ≥3 cm separation between the LES and CD pressure signatures with respiratory inversion point at the level of the CD Type 3b: ≥3 cm separation between the LES and CD pressure signatures with respiratory inversion point at the level of the LES |
| Vigour | EGJ-CI (mm Hg·cm) | DCI box set to encompass the LES and CD over a period of three complete respiratory cycles above a threshold pressure of the gastric baseline |
| Oesophageal body motor function | ||
| Distal contractile integral, DCI (mm Hg·cm·s) Defect (measure at 20 mm Hg isobaric contour) | Intact: ≥50% of contractions with DCI >450 mm Hg·cm·s and no defect Fragmented: ≥50% of contractions with DCI >450 mm Hg·cm·s and defect >5 cm Ineffective oesophageal motility: ≥50% of contractions with DCI <450 mm Hg·cm·s Absent peristalsis: 100% of contractions with DCI <100 mm Hg·cm·s | |
| Provocative tests | ||
| MRS (five liquid swallows—2 mL each—taken <4 s apart) | Contractile response Failure of contractile response | Post-MRS DCI augmentation Absent post-MRS contraction |
| RDC (free water drinking of 200 mL of water within 30 s) | Panoesophageal pressurisation LES relaxation Effective post-RDC contraction | |
CD, crural diaphragm; DCI, distal contractile integral; EGJ-CI, o esophagogastric junction contractile integral; LES, lower o esophageal sphincter; MRS, multiple rapid swallows; RDC, rapid drink challenge.