New technologies in the gastrointestinal clinic and research: Impedance and high-resolution manometry

Table 1 Classification of individual swallows based on pressure topography criteria

Classification	Criteria
EGJ Deglutitive Relaxation (referenced to gastric pressure)
Normal relaxation	4 s Integrated Relaxation Pressure (IRP) < 15 mmHg
Impaired relaxation	4 s IRP >= 15 mmHg
Distal Segment Contraction (referenced to gastric pressure)
Normal	<= 2 cm defect in the 30 mmHg isobaric contour, Contractile Front Velocity (CFV) < 8 cm/s, Intrabolus Pressure (IBP) < 15 mmHg, and Distal Contractile Integral (DCI) < 5000 mmHg × s × cm
Mild peristaltic defect	Normal appearing wavefront propagation with a 2-5 cm defect in the 30 mmHg isobaric contour
Severe peristaltic defect	Evidence of wavefront propagation with a >= 5 cm defect in the 30 mmHg isobaric contour
Absent peristalsis	No propagating contractile wavefront and minimal (< 3 cm) contractile activity or pressurization greater than the 30 mmHg IBC
Nutcracker	DCI > 5000 and < 8000 mmHg × s × cm
Spastic nutcracker	DCI > 8000 mmHg × s × cm
Spasm	Simultaneous contraction (CFV > 7.5 cm/s)
Elevated intrabolus pressure	IBP > 15 mmHg compartmentalized between the EGJ and the peristaltic wavefront
Panesophageal pressurization	Esophageal pressurization UES to EGJ with > 30 mmHg IBP