Background: Secondary peristalsis is important for the clearance of retained refluxate or material from the oesophagus. Combined impedance and manometry can directly detect both oesophageal contraction and bolus transit.
Aim: To apply combined impedance and manometry to characterize oesophageal bolus transit and clearance by secondary peristalsis in healthy individuals.
Methods: Eleven healthy volunteers underwent combined impedance and manometry with a catheter containing seven impedance-measuring segments and eight water-perfusion pressure transducers. Saline and solid agar boluses of 5 ml were applied for primary peristalsis and secondary peristalsis was stimulated by rapid mid-oesophageal injections of saline.
Results: The rate for complete bolus clearance of secondary peristalsis with saline injections was less than that of primary peristalsis with saline swallows (69 vs. 95%, P=0.02). No statistical difference in bolus propagation time between primary and secondary peristalsis was observed (P=0.45). Bolus presence time of secondary peristalsis was significantly longer than that of primary peristalsis for all impedance-measuring segments (all P<0.05). Solid swallows differed from saline swallows with lower rate of complete bolus transit and longer bolus transit time.
Conclusion: Our data show that the impedance technique can successfully characterize oesophageal bolus transit and clearance by secondary peristalsis. These findings suggest that secondary peristalsis may be less effective than primary peristalsis regarding oesophageal transit and clearance of a liquid bolus.