Intraluminal colon pressure dynamics with Valsalva maneuver during air enema study. 
To determine the effects of the Valsalva maneuver on intraluminal colon pressure during air enema studies.  Air enema studies were performed in four adult volunteers, and intraluminal colon pressure measurements were recorded with a high-speed electronic strip chart and aneroid gauge methods.  One hundred thirty-five Valsalva maneuvers were produced with open- and closed-glottis maneuvers, with varying degrees of straining, and during normal peristalsis.  Valsalva pressure waves are discrete waveforms that can be distinguished from baseline insufflation and normal peristaltic waves.  Valsalva waves are of both simple and complex types.  The range of peak Valsalva pressures was 12-148 mm Hg.  Average mild, moderate, and vigorous pressures with a closed glottis were 22, 38, and 90 mm Hg, respectively.  High pressures (120-130 mm Hg) were observed with open- and closed-glottis maneuvers.  Valsalva maneuvers increase intracolonic pressure 12-148 mm Hg above baseline pressure.  Valsalva pressure waves are discrete and can be accurately detected with both aneroid and electronic transducer systems.