title: Triggering for submaximal exercise level in gastric exercise tonometry: serial lactate, heart rate, or respiratory quotient?
abstract: Gastric exercise tonometry is a functional diagnostic test in chronic gastrointestinal ischemia. As maximal exercise can cause false-positive tests, exercise buildup should be controlled to remain submaximal. We evaluated three parameters for monitoring and adjusting exercise levels (heart rate [HR], respiratory quotient [RQ], and serial lactate measurements) in 178 tests in both healthy volunteers and patients suspected of gastrointestinal ischemia. Exercise levels above submaximal occurred in 20% of HR-, 2% of RQ-, and 5% of lactate-monitored tests (P<0.05 for HR vs. RQ and lactate). Low levels were seen in 5% of HR-, 10% of RQ-, and 41% of lactate-monitored tests (P<0.01 for lactate vs. HR and RQ). High levels resulted in 43% false-positive tonometry results compared to 19% of all tests (P<0.001); low levels did not result in more false negatives (5% vs. 6%). Although RQ monitoring yielded the greatest proportion of optimal exercise tests, serial lactate monitoring is our method of choice, combining optimal diagnostic accuracy, low cost, and simplicity.
authors: Department of Internal Medicine, Medisch Spectrum Twente, Enschede, The Netherlands. jaotte@zeelandnet.nl
authors: Johannes A
authors: JA
authors: Otte
authors: Ellie
authors: E
authors: Oostveen
authors: Peter B F
authors: PB
authors: Mensink
authors: Robert H
authors: RH
authors: Geelkerken
authors: Jeroen J
authors: JJ
authors: Kolkman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001639:Bicarbonates / Q000097:blood; D004784:Environmental Monitoring / Q000379:methods; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006801:Humans; D007511:Ischemia; D007773:Lactates / Q000097:blood*; D008297:Male; D008365:Manometry; D008875:Middle Aged; D012143:Respiratory Physiological Phenomena; D013270:Stomach / Q000098:blood supply*
chemical_list: D001639:Bicarbonates; D007773:Lactates