02-14-2013 03:54 AM
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• Risk of damage to a Trachea during Anesthesia 1
My Apologies there were a couple of diagrams further down the page but for some reason have come out.sorry
So what physically happens when a trachea collapses? Well, the cartilage rings that surround the trachea become compressed and the muscle that lines the tracheal tube becomes weak and flimsy. Try to picture this. Imagine a water hose in its normal form. The hose is able to flow water freely with no restriction. Now if you step on a section of the hose to compress it slightly, less water is able to flow through the hose. The same thing happens in a collapsed trachea. The tracheal tube becomes compressed and breathing becomes harder to do.
Often, the results of a collapsed trachea involve heavy panting, rapid breathing, a course cough or wheezing. However, these are also signs of an upper respiratory infection, so always check with a vet to properly diagnose your dog. To make things even worse, the inflammation caused by the collapse from the muscles in the trachea creates an increase in secretions which in turn exacerbates the heavy panting and breathing. Adding on, a collapsed trachea that goes untreated will mostly likely end up getting worse, so you don’t want to drag your feet to the vet when you start seeing these symptoms in your dog.
There are several factors that also aggravate a collapsed trachea in your dog. Obesity, (your going to love this) cigarette smoke, respiratory infections and an enlarged heart can all be very detrimental to an already collapsed trachea. If your dog is over weight, you’ll want to get your dog some more exercise and possibly place them on a stricter diet. If you smoke, quit! It’ll be good for both you and your dog.
Treatment for a collapsed trachea may include antibiotics, cough suppressants, and certain steroidal medications. Just make sure you check with your vet on the proper treatments. There are also surgical procedures which can correct a collapsed trachea. Usually, this involves placing a rigid prosthetic tube within the trachea to provide more support and prevent any sort of constriction or collapsing of the cartilage rings. This is harsh but in my opinion if the trachea is that bad it would be best to euthanase the dog. This dog would only suffer continuously for the rest of it’s short life even after an operation.
Now if you know that your dog has a weak trachea or even hyperplasia a narrow trachea then a harness would be the only time I would recommend using one. Also keeping your dog calm and relaxed and if necessary use a pet calm pill to keep him or her relaxed. The summer months would be the most worrying time for any bulldog let alone one that has problems with the trachea. The vet is going to tell you this is hereditary and you should not breed from this dog and I would agree….but what if this dogs trachea had been damaged. Keep this last bit in your mind cos I will come back to this later.
Trachea size in bulldogs, any thing below a 7 is considered small. But during my research I have come across a few vets that have different opinions. Some say any thing below a 6 is considered small. I believe when a puppy is small then the trachea will be small and as the dog matures so should the trachea. Just as any part of the body grows so should all parts of the body including the trachea. So if your puppy had a procedure done when he she was a wee puppy and the trachea was small and the vet stated this. Then the trachea should all so grow with the pup. It would pay to check this out once the dog had matured.
Now these next two I want to get into and I want to make you aware of is:
• Endotracheal tubes
• Risk of damage to a Trachea during Anaesthesia
Endotracheal tube is the tube that is used when a dog is put under anaesthesia. This tube enables oxygen to be administered during an operation. When a tube is placed down a dogs windpipe / trachea it can get damaged. It can also be damaged when it is being removed. Of cause a vet is not going to admit to this and will sometimes tell you your dog has a narrow trachea or he had trouble getting the tube down the windpipe. The dog coughs after an operation and this damages the windpipe even more….And now your dog is put on antibiotics and then your dog can end up with mechanical pneumonia. You know your dog was just fine before the op so why is he/she having trouble coughing?
Remember I said keep in mind: "The trachea is also a semi-rigid tube that is pretty resilient to small amount of force" and “but what if this dogs trachea had been damaged”.
Well what if I told you that trachea damage is common during an operation because of rough treatment. And how the tube is used. Would you be surprised, upset or just accept that’s the way it is?
And did you know that this not only happens to dogs. It also happens to humans as well.
Below I have copied and pasted this from the British Journal of Anaesthesia.
The risk of aspiration was determined in 90 adult patients undergoing surgery during endotracheal anaesthesia. Twenty ml of contrast medium (a dye solution) was instilled on the back of the tongue in patients lying supine on the operating table after obtaining an airtight seal in the trachea by inflating the cuff of the endotracheal tube. In 18 patients contrast medium passed through the larynx and accumulated in the trachea above the inflated cuff and entered the lungs at the end of the operation when the cuff was deflated. This aspiration can be prevented by placement of the cuff just beyond the true vocal cords, or by tilting the operating table 10 degrees head down before deflating the cuff and applying SUCTION through the endotracheal tube.
Now back to the dogs:
Damage to the trachea produced in dogs by large and small residual volume cuffs during 6 h of IPPV was compared using a specially designed endotracheal tube. The cuffs under evaluation were adjusted to exert similar average pressures on the tracheal wall, so that many of the variables believed responsible for tracheal injury were controlled. The true compliance of the cuff was measured with the tube inside and outside the trachea of the anaesthetized dogs. The maximum estimated pressure transmitted to the tracheal wall, derived from these compliance curves, was found to equal the peak airway pressure in the presence of a small air leak past each cuff. At various tracheal wall pressures there were only very minor differences in tracheal damage between the large and small residual volume cuffs tested.
THE EFFECTS OF CUFFED ENDOTRACHEAL TUBES ON THE TRACHEAL WALL
Direct tracheoscopy was employed to assess tracheal damage following prolonged intubation. Comparison of conventional and low-pressure cuffs showed that there was less trauma from the low-pressure cuff. Comparison of tube sizes showed a reduction in injury with 8-mm diameter tubes compared with larger ones.
Then there is the fluid that has accumulated and if fluid has leaked passed the tube it can be aspirated and end up on the lung and can turn into mechanical pneumonia.
There can be too much pressure when inflating the cuff, which will damage the trachea. And if the inflated cuff is not deflated fully when it is being removed will most defiantly damage the trachea.
When I asked a vet this question “Do cuffed endotracheal tubes increase the risk of airway mucosal injury. Post-extubation... the answer was “yes in some cases and with some vets”.
So it’s a matter of what you don’t know may not hurt you, but it might hurt your dog.
I have gathered and read so much about the trachea. I’m so much more in control of what I can discuss with my vet prior to any of my dogs going under for an operation. I think when a vet realises you know some of the procedures they do, they are more likely to be a bit more careful in the way they treat our bulldogs.
Here are some photo’s and diagrams I have been collecting.
Human endotracheal tube with this inflated cuff:
Stretching of the tracheal wall may be caused by over-inflation of the cuff. This may lead to tracheitis, pressure necrosis of the tracheal wall, or tracheal rupture.
You can see how if they can do this to humans then it can easily happen to a dog.
Sorry couldn’t find any Bulldog ones.
So many different types of tubes here.
These tubes are commonly used on dogs, you can just see the the deflated cuff on some of them. Note the sizes!
X-ray of a endotracheal tube down the windpipe.
A survey we are doing in rescue right now for the Breed Council Health Committee (will be published next April) is showing the average trachea tube size is 7 which is small!!