Placing the probe
Placing the probe
After measuring the distance from nose to the 10th inter costal space ( see video ) and marking the tube the probe is positioned in the esofagus with help of a nasal tube of 16 mm wide. The length of this nasal tube is approximately 170 cm. The nasal tube is sprayed internally with silicon spray. This will make it easier to push forward the tube with the balloon to the marked position.
The tube with the balloon is put inside the stomach tube, see pictures. The balloon should be just inside the stomach tube. The stomach tube is inserted in the esofagus. Checking the right position by sucking and blowing is not possible. When the tube is inside the trachea the resistance when pushing it up will be very low. Also in most horses the sliding up of the tube is visible on the outside. Push the stomach tube as far as possible in the esofagus. Then pull it out but push the measuring probe up to keep it in place. This is the reason that the stomach tube is shortened to app. 170 cm. If it is to long pushing up the measuring probe is not possible and it may come out with the stomach tube. Better to insert it to far and pull it out later tot he right position. Pushing up the measuring probe without the stomach tube is more difficult.
The balloon is now positioned between the heart and the cardia. To near to the heart the pressure decreases , just in front of the cardia gives the best results. When there is no curve visible pull the tube a little bit outward, the balloon might be inside the stomach. And that’s on the other side of the diaphragm.
Connecting the probe
Working with the Equivent 100 the polyethylene probe is connected to the pressure inlet of the Equivent 100. Two to four ml of air is put inside the probe and balloon. First blow up the balloon a little bit. Then drain the air from the system by sucking it out ( be sure to make no under pressure ) and close it by keeping pressure on the silicon tube. The pressure in the esofagus is slightly negative and the system might fill with air if it is not kept closed. After connecting the silicon tube to the 3-way stopcock adjust 2-4 ml of air inside the system. The stopcock is connected to the Equivent 100 , the syringe with 4 ml of air is connected to an other port of the stopcock and finally the measuring probe is connected to the third port. After connecting release the pressure on the silicon tube and insert the 2-4 ml of air.
In the Equivent 200 and 300 it is important that the polyethylene tube stays in place during working of the horse. Passing from inside the nose to the outside were the tube is taped tot he head polyethylene might easily close up internally because the angle is very small. For this reason a pvc tube is connected to the end of the polyethylene tube with help of a litte piece of silicon tube. PVC can make a more steep angle and not close internally. To make this possible the polyethylene tube has to end just inside the nose. Cut it there or be sure to have some polyethylene tubes of different length.
The tube is taped tot he nose with ductape. The Equivent 200 or 300 are taped to the bridle.