Table 2.

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.