LIQUID GASTRIC EMPTYING ASSESSED BY DIRECT AND INDIRECT TECHNIQUES: RADIONUCLIDE LABELLED LIQUID EMPTYING COMPARED WITH A SIMPLE PARACETAMOL MARKER METHOD

Radionuclide techniques have enabled direct quantitative measurements of gastric emptying for solid and liquid phases of a meal. Such a technique has been used to validate the use of plasma paracetamol levels as a means of indirect assessment of liquid gastric emptying and to confirm a useful correlation exists between plasma and saliva paracetamol concentrations. Ten healthy volunteers underwent a routine gastric emptying study. The meal comprised a 100g ‘hamburger’ and 150 ml of 10% dextrose in water containing ¹¹³In and 1 g of dissolved paracetamol. The time taken for 50% of the liquid marker (T50) to clear the gastric region was assessed. Time to peak concentration of paracetamol for both saliva (C max‐saliva) and plasma (C max‐plasma) was determined. A significant correlation was found between the time to C max‐plasma and T50 (r_s= 0.624, P < 0.05) and also time to C max‐saliva and T50 (r_s= 0.573, P < 0.05), confirming that paracetamol concentration in plasma and saliva reflect radionuclide assessed liquid emptying. A useful correlation also exists between time to C max‐plasma and time to C max‐saliva (r_s= 0.84, P < 0.01) permitting them to be used interchangeably. The use of time to C max‐saliva to assess liquid gastric emptying has a number of applications.