Tachycardia, HR >180 bpm in cats3 and HR >150– 190 bpm for large and small dogs, respectively,44 during anesthesia deserves special mention, because it should prompt the anesthetist to run through a list of rule-outs and not simply assume it is a response to inadequate anesthetic depth. Tachycardia can be secondary to a noxious stimulus, hypoxemia, hypercarbia, and hypovolemia. It can also occur secondary to administration of drugs such as alfaxalone, ketamine, atropine, and dopamine.

These guidelines are supported by generous educational grants from IDEXX Laboratories, Inc., Midmark, and Zoetis Petcare.