SMILE - General Anesthesia and Monitoring

We are almost ready to clean your pet's teeth.  Now, it is time to administer the general anesthesia so that intubation can be performed and the cleaning can commence.

Most commonly, a pet is induced (knocked-out) with an injectable anesthetic.  At the hospital where I take my dogs, they use a combination of ketamine and diazepam (Valium).  This is very quick-acting since it is injected directly into the vein.  Almost immediately the drugs take effect.  About half is given IV, then the technician will wait a minute to estimate how much more the animal might need to make sure the animal can be intubated.  A little more is given if needed.

Once the animal is asleep enough to allow intubation, the endo-tracheal tube is placed in the trachea to allow administration of an inhaled anesthetic (like isoflurane).  There is usually a cuff at the end of the trach tube (the part inside the trachea) which, when blown up, keeps fluids from entering the lungs.

In the above picture, you can see the endo-tracheal tube as it exits Heidi's mouth.  It is kept in place by a rubber band around the upper part of her mouth (snout or muzzle).  The little tube running alongside the larger one attaches to the cuff; this tube allows the cuff to be inflated once it is in place.  Once the cuff on the tube has been inflated, it is best to keep the tube from jiggling too much or pulling on it as this can damage the trachea.

(You can also see in this picture, above, Heidi's dirty teeth - she did not want me to show you this because she is embarrassed.  Her teeth are not terribly dirty since she has her teeth cleaned fairly often.)

Heidi has been attached to the anesthesia machine by her trach tube and is now asleep and ready for her teeth cleaning - almost.  The next step is very important!  The LVT will now attach monitoring equipment to keep track of her vital signs throughout the anesthetic episode (while she's asleep).  In my vet's hopsital, EKG leads are attached to three limbs (to monitor her heart rate), a pulse oximeter probe is placed on a toe (to monitor how well she is receiving and using oxygen), and an apnea alarm is placed on the end of the trach tube (to keep track of how often she is breathing).  Sometimes a tech might use a stethoscope or an esophageal stethoscope (placed in the esophagus near the heart) to monitor the heart rate.  

The top two rows of squiggly lines are her EKG.  Her pulse, shown as BPM or PR, is shown in big green numbers as 108.  Her pulse-ox reading, shown as a percentage and also called SpO2, is 98%.  Her respiratory rate, shown as RPM with the little lung symbol, is shown in large yellow numbers as 27.  All of these vital signs look really good.  108 is a normal heart rate for a small to medium sized dog.  98% is 98 out of 100, so that is great.  27 is a normal respiratory rate for a dog.  

Heidi's trip to la-la land is looking good so far.

Finally, the dental cleaning can begin!

SMILE - Pre-anesthetic Physical and Pre-Medication

The bloodwork is finished, the vet has perused it, and everything is ok to go full steam ahead.  This is when the vet gives a quick once over to make sure there is nothing else going on before the pre-med and anesthesia is given.

(Imagine taking your dog in to have their teeth cleaned and then goes home with an ear infection that no one noticed?  That is why your vet will perform a quick physical.)

After this, a "pre-med" is given.  This is usually a combination of a sedative and/or tranquilizer, possibly an analgesic, and an anticholinergic.  The sedative helps calm any jittery nerves and makes animals a little sleepy.  The analgesic will help with any pain that might occur during the procedure.  The anticholinergic reduces secretions (such as saliva in the mouth that could be aspirated) and prevents a slow heart rate that could occur from the general anesthesia.  All of this, mixed in one syringe, is injected under the skin (subcutaneously) about 20 minutes or so before the general anesthesia is started.

Heidi has had her pre-med and can barely hold her head up!  She is so sleepy.  I came back a minute later to find that her head had become too heavy to hold up any longer.

Once the sedation has started working, Heidi got to escape from the cage to have an intravenous catheter placed in her cephalic vein (her forearm).  She could barely sit upright (which was rather amusing)!

One of the LVT's is supporting her head so she doesn't flopple over.  The other one is feeling for the vein in her arm.  The purpose of an IV catheter is to provide fluids and electrolytes during the anesthesia (helps flush out the drugs and keep your pet hydrated since they are not drinking most of the day) and it gives IV access in case of an emergency (most emergency drugs need to be given IV since that is directly into the blood stream).

Heidi's vein was difficult to find that day.

So, to recap, Heidi has been checked in, assigned a cage, had blood drawn, been checked over by the vet, given a nice drug cocktail (the pre-med), and finally had an IV catheter placed.  And the actual dental cleaning hasn't even started yet!

Next up: General Anesthesia and Monitoring.

SMILE - Pre-Anesthesia for a Dental Cleaning

Dental Day commences:

Heidi and the boys have been checked in and are on their way back to the treatment area.  They all get weighed and have their temperature taken.  Blood is drawn from the jugular vein in the neck or the cephalic vein in the forearm.  Usually about 3ml of blood is drawn into two different kinds of tubes.  A CBC (complete blood count) and serum chemistry are performed usually.

Heidi getting her blood drawn from
her jugular vein in her neck.

A CBC looks at the numbers of red and white blood cells and platelets found in the sample.  The hematocrit (HCT) or packed cell volume gives an indication of the amount of red blood cells in the blood as a percentage.  This helps the veterinarian determine if an animal is anemic or dehydrated.  Heidi's hematocrit is always on the high end which can show that she is slightly dehydrated.  She has her bloodwork done every time she has anesthesia, so we are able to see that this high hematocrit is considered normal for her.  The blood chemistry panel can vary as to which chemistries are tested.  Usually there a few tests that look at the kidneys and a few at the liver.

The CBC results.

The serum chemistry results.

Heidi does not like being in a cage!  She is barking at me as I stand there and look at her imprisoned.  She calms down and is fine if I am not around.  As soon as I reappear though, she starts barking at me again.

You can see her cage card on the outside of the cage.  This is important to have on every animal's cage.  It not only identifies the name of the pet, but the sex, the date of arrival and departure, the veterinarian, and the reason for the visit.  DAP is our veterinarian's initials.  F,S means female, spayed.   The little blue squares indicate that she is not to be given water or food.

So, while Heidi's blood goes to the lab to be performed, she gets to lie in her cage and watch the mayhem that is a veterinary office in the morning.

Next up: Pre-anesthetic physical and Pre-medication.