Normal lower esophageal sphincter pressure: a comparison of rapid vs. slow pull-through techniques.

This study simultaneously compared radially oriented normal lower esophageal sphincter pressure in 18 volunteers measured by motorized rapid pull through, hand withdrawn slow pull through, and motorized slow pull through. Slow pull-through pressures were scored four ways: peak pressure, mean pressure, highest minimum pressure, and pressure at respiratory phase reversal. Motorized and hand withdrawn slow pull-through methods gave identical average pressures, but the motorized method was slightly less variable except for the peak pressure scoring method where minimum variability did not require motorized withdrawal (average coefficient of variation=18%). Rapid pull through pressures varied significantly more than all other methods (average coefficient of variation=38%). Radial pressure asymmetry occurred with all methods with leftward pressures ranging from 62% greater for rapid pull through to 21% greater for respiratory reversal scored slow pull through. The peak, mean respiratory reversal and minimum slow pull-through methods correlated very well with each other (r ranged from 0.89 to 0.98) but not with rapid pull through (r ranged from 0.45 to 0.58). The interobserver correlation coefficient was poorest with respiratory reversal slow pull through (0.86), and excellent for all other pull-through methods (0.96-0.99). In conclusion, the method and recording orifice orientation chosen to record lower esophageal sphincter pressure markedly influenced the magnitude and variability of recorded pressure. Slow pull through is more reliable than rapid pull through and the peak method appears to be the easiest way to score slow pull through pressures.