DefinePK

Abstract

Purpose
Saline load test is used to determine the presence or to estimate the degree of gastric retention. This test was first described by Goldstein & Boyle in 1965.1
Preparation
1. Patient should be fasting for 8 hours.
2. Patient should not be taking any medicine which prolongs gastric emptying.
3. A l000ml I/V bottle of normal saline may be used to prepare the solution. Solution is prepared by      removing 250mI of Saline from bottle.
4. Empty the stomach with a 32 french size Ewald tube or large bore Nasogastric tube. Emptying of the    stomach contents is initiated with the patient in sitting position. This is repeated with the patient lying     on left side, on stomach, on right side, and then on the back. Total aspirated fluid is pooled in a   beaker and its volume, pH and colour is recorded. An overnight gastric residual contents greater than  200ml. is consistent with outlet obstruction.2,3
Saline Load Test:
a) 16 F Nasogastric tube is inserted to about 65cm. from the nares.
b) An standard I/V tubing is attached to the bottle containing 750ml. of Saline solution.
c) Bottle is suspended from an 1/V pole.
d) Tip of the I/V tubing is attached to the female adaptor of patient’s nasogastric tube. Patient is still in     sitting position. Clamp is now fully open so that fluid may run freely from the bottle through the  tubing into the patient’s stomach, at this point time is noted. When all the saline runs out of the bottle   the tube is disconnected from the adaptor and nasôgastric tubing is clamped to prevent the reflux of   gastric contents. Patient remains in the sitting position for full 30 minutes. On completion of 30 minutes, aspiration of the gastric contents is begun with the patient sitting and then in each lying positions i.e. back, on stomach, on right and left sides.
Interpretation
The normal stomach can empty greater than 500ml. of normal saline in 30 minutes after instillation of 750ml. leaving no more than residual of 250ml. Normal average 30 minutes residual collection after Saline Load Test is 88ml. with the Standard deviation of 82ml. Average obstructed patients return 500m1. to 750ml. after 30 minutes.