During stage III anesthesia, which species has a tachycardia threshold of greater than 60 bpm?

During stage III anesthesia, which species has a tachycardia threshold of greater than 60 bpm?

• A. Large Dog
• B. Small Dog
• C. Cat
• D. Horse

Answer: (D)

During stage III anesthesia, tachycardia is judged relative to what is normal for that species under anesthesia. The heart rate that signals tachycardia isn’t the same across species; it depends on how the animal’s cardiovascular system typically behaves with anesthetic depth. For horses, the anesthetized heart rate tends to stay relatively low, so a heart rate rising above about 60 beats per minute is considered tachycardia. That makes a threshold greater than 60 bpm a characteristic finding for this species in this context. In contrast, dogs and cats often tolerate higher heart rates under anesthesia before tachycardia is noted, so their tachycardia thresholds aren’t described as simply “greater than 60.” Therefore, among the choices, the horse is the one with a tachycardia threshold >60 bpm.

During stage III anesthesia, tachycardia is judged relative to what is normal for that species under anesthesia. The heart rate that signals tachycardia isn’t the same across species; it depends on how the animal’s cardiovascular system typically behaves with anesthetic depth.

For horses, the anesthetized heart rate tends to stay relatively low, so a heart rate rising above about 60 beats per minute is considered tachycardia. That makes a threshold greater than 60 bpm a characteristic finding for this species in this context.

In contrast, dogs and cats often tolerate higher heart rates under anesthesia before tachycardia is noted, so their tachycardia thresholds aren’t described as simply “greater than 60.” Therefore, among the choices, the horse is the one with a tachycardia threshold >60 bpm.