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!