In gavage feeding, which one comes first? The introduction of 20 ml of water or aspirate to check gastric pH?

Question

I read it somewhere that introducing 20 ml of water is done to check for the tube's patency. And checking for pH is done to check for placement. Both are assessments so which one comes first? Thanks!!!

Answer 1

I would aspirate first. My rationales are:

1. If the tube is not patent, it will be difficult to aspirate much of anything because the vacuum needed for suction will be compromised, so a poor aspiration return would be a sign that patency is in question.

2. Introducing water into the tube before aspirating may falsely increase the pH of any aspirate you retrieve, making it seem more basic than it really is, and perhaps lead to removing an NG that is in fact in the right spot

3. If the tube is  coiled, kinked, or placed into the trachea, the last thing we want to do is introduce fluid in before we know where it is. If we put water in first, we'll know that it's patent, but we won't discover that it is misplaced until it's too late and the fluid is in the lungs.

Remember, the only surefire way to know that an NG is in the right spot is to do an X-ray. Another way to check for placement that is less accurate but safer (in my opinion) is the introduce a small amount of air (maybe 10mL of empty syringe) into the tube while auscultating for bubbling in the upper quadrants. This is the technique that I see being used most often, despite it having fallen out of favor with some nursing schools.