Gastric emptying of solids: Estimates of lag phase and constant emptying times

There is no consensus regarding the best way to estimate the lag phase time (Tlag) and the constant emptying time (T-RE) Of the gastric emptying of so lids. Furthermore, biphasic gastric emptying is usually described by the mo dified power exponential function of either Elashoff or Siegel. In an attem pt to test the validity of the power exponential functions and to identify relevant parameters of biphasic gastric emptying, we followed an approach w hich consists of describing the power exponential function by two straight lines. The first line is horizontal and represents Tlag. The second line is tangential to the constant emptying [tangent at the maximum slope (MS) or at the half-emptying value]. Scintigraphic data of 132 patients and 15 cont rols were fitted by both power exponential functions. Each corresponding ha lf-emptying time, nag and T-RE estimated from the Elashof and Siegel power exponential functions were strongly correlated (0.93 <r<1, P< 0.0001). The Bland and Altman statistical method demonstrated good agreement (<5% outlie rs). The half-emptying tangent method sometimes gave negative nag and shoul d be abandoned. Tlag(MS) and T-RE(MS) did not correlate and therefore were independent parameters. We conclude that the Elashoff and Siegel functions are equivalent and that the maximum slope tangent method allows a reliable description of the two independent phases of gastric emptying. ((C) 2000 Li ppincott Williams & Wilkins).