General considerations

You have all been taught the A,B,C's of CPR. In wildlife immobilization it is better spelled A,B,c

AIRWAY

It is virtually all about the airway. Nearly all of your problems will come from inadequate ventilation due to a compromised airway. If you are working in the field, they will be breathing through their nose. This alone will restrict the flow of air. Add to this some dirt or snow in one nostril, some respiratory secretions and poor body positioning, and you will have major problems. Now, you may not notice them until they are breathing problems or cardiac problems, but they started as airway problems. Remember the words of Dr. Larry Jackson, "the flow through a ridgid tube is directly proportional to it's radius to the fourth power." What you should gleen from that is that a small change in the radius of the airway, will result in a huge change in the flow of air. A small amount of dirt in the nares or saliva in the back of the throat can mean a huge differnce in the airflow. If you use an endotracheal tube don't cheat and choose one that you can place easily and think you can simply inflate the cuff to seal the leaks. You will seal the leaks but you will limit the amount of fresh gasses available to the animal. Keep the animal's head extended and tongue pulled forward to prevent the base of the tongue from blocking the airway.

Many animals have the nastey habit of falling asleep with their nose flat up against some object or the ground. This can lead to serious problems in a very short time. Watch them as the fall asleep and make sure that they do not occlude their airway.

Raccoon with nose against cage floor
Raccon after repostioning
Snow Leopard with muzzle against bench
Black Bear with flexed neck and muzzle in dirt
A different Black Bear asleep in perfect postition

BREATHING

If you notice slow respiratory rates or poor respiratory volumes on each breath, it is probably due to: 1) too much drug, 2) a build up of respiratory secrtetions, 3) the animal has pnuemonia, 4) has aspirated some stomach contents, or 5) has poor body positioning. If it is pneumonia, it is really an airway problem and you shouldn't have started the procedure. If it is aspiration or respiratory secretions, it is really an airway problem. Too much drug is a primary breathing problem and you can give DOXOPRAM at 1mg/lb IV and roll the animal from side to side every 2 minutes until breathing improves. This rolling will also give you a chance to reasses your body positioning.

CARDIAC

Almost every cardiac problem I have seem in wildlife immobilization has stemmed from the use of Xylazine. Why I don't like Xylazine The heart rate in an animals that has been given xylazine will be slow AND irregular. You will be able to get a sense that beats are being skipped one or two at a time. If you have a ventricluar dysrhythmia in an animal that has not had Xylazine, you are the unlucky recepient of a very rare situation. Bigeminy is the most frequent ventricluar dysrhythmia but it is nearly always due to hypoventilation. (And that is usually an airway problem!!) If you don't have a ECG machine, you can assume the animal is in bigeminy if the heart rate suddenly falls to half of what it had been yet the rhythm still sounds normal.
It goes from:lub,dublub,dublub,dublub,dublub,dublub,dub
To:(missed)lub,dub(missed)lub,dub(missed)lub,dub
To treat bigeminy, roll the animal from from side to side a few times, ventilate the animal by (in the office) bagging it or blowing into its endotracheal tube, or (in the field) grabbing the hide and lifting the chest wall several times, roll the animal over and repeat several times. For any other cardia problems you will need to have a hand-held ECG machine in the field with you. For bigemeny that does not respond to rolling and ventilation, and for premature ventricular contractions (diagnosed with the ECG) I treat with acepromazine 0.01 mg/kg IV.

POSITIONING LARGE IMMOBILIZED ANIMALS

The weight of the up lung and heart will compress the lower lung and compromise its circulation and aeration. The larger the animal the more significant the effect (because of the greater weight of the up lung and heart) It is very important to roll every immobilized animal to the opposite side every 5 - 10 minutes to prevent problems.

Secretions of saliva are increased in ruminants and felids with some immobilizing agents, i.e. Ketamine and Telazol. I have not seen this in black bears. Atropine can be used to reduce these secretions but animals should still be positioned in a way to prevent these from entering the airway. In animals with long necks, like deer and elk, I elevate the "Adam's Apple" (pharynx) by putting a rolled up jacket or backpack under the neck. The nose should then be allowed to rest slightly below the level of the pharynx. This allows saliva to flow out of the mouth not into the airway and makes it a little harder for stomach contents to be forced uphill, over the backpack, and if they do; they will hopefully run out the mouth or nose and not into the airway. Short necked animals like bison and bears, I position on a slight downhill angle in hopes of keeping the airway clear. DO NOT position any animal on too much of a downhill grade or the weight of the abdominal contents will prevent the proper movement of the diaphragm.

In ruminants, the fermentation of the rumen's contents continues to produce gas during immobilization. (up to 1 liter per minute in elk and bison) The only way for them to expel this gas is by belching (eructation). If the immobilization procedure will last more than 30 minutes you may have to pass a special floating stomach tube to suction off the gas. A regular stomach tube will get plugged with rumen contents. Even small amounts of this gas may force rumen contents up the esophagus and they may then gravitate into the airway. Inhalation pneumonia is very serious and frequently fatal. If very large amounts of gas builds up, the pressure in the rumen may even begin to prevent blood from flowing through the vessels in the rumen wall and other vessels in the abdomen. These animals are HUGELY distended and if you thump them like a melon on their left side they will ping like an inner tube. This is a grave situation. Give them the reversing agent right away intravenously. Get them onto their chest and lift their head. If you can get them to eructate soon enough and fast enough, they might live.

Again, in short necked animals, the chest should only be slightly (10 degrees) downhill from the abdomen. The weight of the abdominal contents will make it harder for the diaphragm to pull back. This will lessen ventilation.

During any immobilization:WORK QUICKLY, BE EFFICIENT. Use reversible agents when possible so you can get these animals onto their feet ASAP when you are done.Remember: Anesthesia is the controlled poisoning of an animal.

REPTILESGo To Reptile PageDo not immobilize reptiles by hypothermia (putting them in the refrigerator). This results in a high number of cases of pneumonia. I use a gas induction chamber for all but the largest snakes. When they are anesthetized, place an endotracheal tube and maintain them on gas. On the sankes too big for the induction chamber, I use telazol. DO NOT pick snakes up by their head without supporting the rest of their body's weight. They have only a single condyle at the A/O joint and this can be rather easily disarticulated. (breaking their neck) 

REVERSING AGENTS AND INTRAVENOUS INJECTIONS.

On small animals the cephalic vein is usually used as the injection site for reversal agents.

The jugular vein or lateral saphenous vein works well in large animals but in the winter when the hair is thick, or if you are not good at hitting veins, pull out the tongue and look for a big vein on the underside of the base of the tongue. See a picture of this vein It is nice because it is big and you can see it. If you use this vein, use as small a needle as possible (25 - 27 guage). It will bleed some after the injection so put your thumb over the injection site for a few seconds but be ready to get out of the way when the beast wakes up. Obviously, if you are reversing an agent on something like a grizzly bear, give the reversing agent and let the tongue bleed. Some of these animals wake up very quickly after the reversing agent has been given. Have all your gear packed. In brown bears, polar bears, and the big cats, be very careful if you are using reversing agents. Your vehicle should be very nearby and the engine running.

I do not like the commonly used mixture of Ketamine and Xylazine. Drug Page Xylazine has a very depressing effect on the heart and heart rates will be very low. This depressant effect is made worse in the presence of epinephrine (adrenaline). Since most immobilized animals have been stressed to some degree and some are very highly stressed, there is always some epinephrine in their system. Mix atropine Drug Page into your ketamine/xylazine cocktail and you will lessen this cardiac effect. Yohimbine (0.15 mg/kg intravenously) and tolazoline (3.0 mg/kg intravenously) are specific reversing agents for the xylazine portion of the cocktail and will end the depressant cardiac effects. This will, however, leave the animal immobilized with only the ketamine part of the cocktail, which can lead to muscle tremors or convulsions. For that reason, it is suggested that you not reverse the Xylazine for 45 minutes after the cocktail is given. By then, most of the ketamine will have worn off and the chances of seizures will be lessened.

Medetomidine (DORMITOR) Drug Page is in the same family as xylazine and has all the same shortcomings. It is very useful in young healthy animals that are only moderately stressed. It should be part of a cocktail, mixed with ketamine or telazol. Medetomidine can be reversed with atipamizole.

Some books talk about immobilization with straight Xylazine. I do not like this at all. Why I Don't Like Xylazine

During Anesthesia

Monitor the heart and respiratory rate every time you roll the animal. If they are positioned properly and rolled every 5 - 10 minutes there are usually no problems. Make sure there is no dirt or snow blocking the nose or mouth. Protect the eyes from the sunlight as they do not blink often and may have dilated pupils. Put an ophthalmic ointment in their eyes to prevent drying. The most common problems are slow heart rates and poor ventilation. Increase the heart rates with atropine given intravenously. This is usually given in the underside of the tongue because their blood pressure is low from the slow heart rate so other veins are hard to find. For poor ventilation, first check the airway for dirt or debris! Second, roll the animal and double check for proper positioning. You can manually ventilate them by grabbing the hide on the side of the chest and lifting up and pushing down. You can move a lot of air this way. Do this while someone draws up 1mg/lb of doxapram. This is also given intravenously.

Do not put a muzzle on immobilized animals. What is the purpose? Use the drugs properly and there is no need of a muzzle. Muzzles interfere with air movement and what if the animal gets light, rolls over and runs off????

Dart Guns

For close range work I like the Telinject or Daninject systems. Their darts only hold 3 ml so Telazol reconstituted with 2.7 mL of sterile water will give 166mg/ml. You can give all 500 mg (1 vial) in a 3 cc syringe that way. If reconstitued with 1.8mL it will give you 200mg/mL. Now you can give 600mg in a 3cc dart. For long distance shots I like the Palmer system or the Pneudart system. Telemetry darts are available for both of them so if the animal runs off you can track them. Use barbed needles so the dart stays in the animal while it runs away.

Induction Chambers

I also use the aquarium as an induction chamber for anesthetizing birds, rabbits, reptiles and venomous snakes. I have a wooden top that fits snugly over the top edges of the aquarium and a 7/8 inch hole drilled somewhere in the wood that fits the tubing of my anesthetic machine. I use it as a type of gas chamber and let the animal breath the gas until it is asleep. You can use it for anything that fits into the tank, birds, small mammals, nasty cats and small dog. Once they are asleep, you can pass an endotracheal tube or use a mask to maintain them on gas anesthetics. Small pets can be put inside a mask and use the mask as the induction chamber. Here a 2 liter pop bottle has been adapted to make a mini-induction chamber for a squirrel with a fractured femur.

BODY TEMPERATURE

Many people forget about this and it can lead to serious problems. Remember this rule:HEAT IS PRODUCED BY THE MASS AND LOST BY THE SURFACE AREA. The smaller the animal, the greater surface area is in comparison to the mass, therefore, it will lose body heat faster than it can produce it. Conversely, large animals will produce it faster than they can dissipate it. If you are dealing with a large animal like a bear or wolf in the summer and if it has been chased or trapped for any length of time, it may be hyperthermic, (temperature over 105). Pass a stomach tube and give cold water 10 - 20 mL/lb. Rubbing alcohol poured on the sparsley haired areas of the body will help as well. If you give cold water enemas, you won't be able to get an accurate temperature for a while so your monitoring is thrown off. Hyperthermia is a serious condition. Even after the body temperature is back to normal, it can drop too far, or there can be swelling of the brain. These animals should be watched closly. If swelling of the brain is seen, (mental dullness, loss of consciousness, seizures) mannitol, furosemide and dexamethasone should be administered intravenously. If your working with small species, babies, or sparsely haired animals,

hypothermia (temperature under 94) is very likely. Keep them inside a jacket, wrapped in a blanket and add handwarmers if you have them. If they are really cold, pass a stomach tube and give warmed sugar water, 10 - 20 mL/lb.

About the Media:

If you do a god job you may make the papers, if you do a bad job you will be on the 6:00 news

They like to get close and shoot lots of footage then edit it down to about 15 seconds on the news. Tell them that you will give them an opportunity to take some shots at a specific point and ask them not to get in your way before then. As long as they know they will get something to take back, they are usually receptive.

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