Reliability of the time to maximal [13CO2] excretion and the half-[13CO 2] excretion time as a gastric emptying parameter: Assessments using the Wagner-Nelson method

• Published in: Journal of Smooth Muscle Research 2007, Vol.43(5), pp.201-209
• Main Authors: Sanaka, Masaki, Yamamoto, Takatsugu, Nakayama, Shin, Nagasawa, Kunitaka, Kuyama, Yasushi
• Format: Article
• Language: English
• Subjects: Adult; breath test; Breath Tests; Caprylates - administration & dosage; Carbon Dioxide - analysis; Carbon Isotopes - analysis; gastric emptying; Gastric Emptying - physiology; Humans; Male; Reproducibility of Results; Stomach - physiology; Wagner-Nelson method
• ISSN: 0916-8737; 1884-8796
• DOI: 10.1540/jsmr.43.201

In the [13C]-octanoate breath test, two popular parameters have been used to quantify gastric emptying rates, namely the time to the maximal [13CO2] excretion (Tmax) and the time to the half-[13CO2] recovery (T1/2b). Although each of Tmax and T1/2b is closely correlated with the scintigraphic half-emptying time, the two parameters occasionally indicate different judgments on a gastric emptying rate. In this study, to clarify which of the two parameters is more reliable, Tmax and T1/2b were compared to the "reference" parameters calculated using the Wagner-Nelson method, which allows accurate estimation of a time-course of gastric emptying from breath data. Ten healthy male volunteers underwent the breath test after ingestion of a muffin meal (320 kcal) containing 100 mg [13C]-octanoate. Breath samples were collected at 15-min intervals for 6 h. According to the conventional analytical algorithm, Tmax and T1/2b were mathematically calculated. By applying Wagner-Nelson analysis to the breath test, the time-percent gastric retention curve was generated and the half-emptying time (T1/2WN) was determined. T1/2WN was more closely correlated with Tmax (r=0.954, P