This ASG video tip is brought to you by an educational grant from Braintree, a part of Cibela Pharmaceuticals, makers of SUTAB. So going on to the impedance testing, a couple of things to remember is the impedance when there is a liquid, when there is a liquid bolus passing through, that leads to reduction in impedance. When there is a gas bolus passing through, there is an increase in impedance. So this helps us to figure out whether we are dealing with belching or acid reflux. And then we are also looking if there is anti-grade movement or retrograde movement. So retrograde movement of liquid is acid reflux or gastric reflux. Anti-grade movement of a liquid bolus is with swallowing. Retrograde movement of a gas bolus is belching. So here is an impedance test of an acid reflux episode. On the left-hand side, you're looking at the pH tracing. You see that the pH drops below four. So this is an acid reflux going down. Now the impedance catheter has multiple sensors throughout. And when you look at here, here is a reflux starting first. So there is a decrease in the impedance first happening in the distal sensor and then moving up as it goes proximally. So this is an acid reflux episode happening. Here is an example of a non-acid reflux episode. The pH is about four. So you don't see if you just do a pH testing, you may not notice this, that there is any reflux going on. And here is the impedance with a non-acid reflux. And here you see the decrease in the impedance starting first in the distal sensor and then it going approximately a fall in the impedance as it goes proximally. So this is a non-acid reflux episode. And here is an example of the gas reflux pH stays the same, no change in the pH. As I mentioned before, when there is a gas bolus passing through, there is an increase in the impedance as opposed to a decrease in the impedance that we see with liquid bolus passing through. So it is starting in the distal sensor and moving up proximally. So it starts in the distal sensor first and you see there is a gradual increase in the impedance as it goes proximally. So this is an example of a gas reflux or a belching. Thanks for watching!

impedance testing

belching

acid reflux

liquid bolus

gas reflux