Monitoring the lower oesophageal sphincter: sphinctometer or sleeve?

Two methods have been used to study lower oesophageal sphincter (LOS) funct ion in gastro-oesophageal reflux disease: the sleeve sensor and the sphinct ometer. Our aim was to directly compare the sleeve and sphinctometer in viv o. Ten asymptomatic volunteers were intubated with a perfused assembly inco rporating a sleeve sensor, a solid-state assembly incorporating a sphinctom eter and a pH probe. LOS function was recorded pre- and post-prandially. Du ring basal periods sleeve and sphinctometer readings correlated well both w ithin and between subjects (r(2) = 0.89 (P < 0.0001)). However, the sphinct ometer relaxed less during swallows (median 42 (interquartile range 27-55)% vs 73 (62-81)% (P < 0.001)), transient LOS relaxations (TLOSR) (50 (40-70) % vs 94 (88-100)% (P < 0.001)) and reflux episodes (67 (59-75)% vs 97 (91-1 00)% (P = 0.02)). Using criteria derived from 10 dry swallows, the expected relaxation of the sphinctometer during TLOSR was defined. The sphinctomete r had an overall sensitivity ranging from 43 to 71% for the detection of TL OSR with 11-22 false positive relaxations, depending on the criteria employ ed. Sensitivity was particularly poor in those with low basal LOS pressure. The sphinctometer has a lower capacity to register LOS relaxations than th e sleeve sensor, which limits its value in studying the pathophysiology of reflux disease.