Stages & Planes of Anesthesia Flashcards
This stage:
- Immediately follows administration of an inhalation or induction agent
- Patient is conscious but disoriented and show reduced sensitivity to pain
- Normal or increased heart rate and respiratory rate
- May show sign of fear or anxiety
- All reflexes present
Stage 1 : Voluntary excitement
This stage:
- Begins with the loss of consciousness
- All reflexes present, may be exaggerated
- Animal may exhibit involuntary excitement in the form of rapid movement of the limbs, vocalization and struggling
- Breathing may be irregular or the animal may hold its breath or hyperventilate
Ideally, should be bypassed or avoided
Stage 2 : Involuntary excitement
This stage is subdivided into 4 planes, representing increasing anesthetic depth
Stage 3 : Surgical anesthesia / Anesthetic period
[Stage 3 Plane]
Depressed gagging and swallowing reflexes to allow endotracheal intubation
- may be adequate for minor surgeries
- patient will move and exhibit increased heart and respiratory rates, or react to painful stimulus
Plane 1 — Light anesthesia
[Stage 3 Plane]
Suitable for most surgical procedures
- the skeletal muscle tone becomes more relaxed, and many of the protective
- reflexes are diminished or lost
Plane 2 — Moderate anesthesia
[Stage 3 Plane]
There is significant depression of the cardiopulmonary system if often present and is therefore considered to be excessively deep for most surgical procedures.
May require ventilation assistance.
Plane 3 — Deep anesthesia
[Stage 3 Plane]
The patient is too deeply anesthetized for safety and is in danger of respiratory and cardiac arrest.
Recognized by the “rocking” ventilatory pattern in which the abdominal muscles are increasingly responsible for ventilation while the thoracic muscles become less active.
Plane 4 — Overdose
Stage where there is cessation of respiration which may be followed by circulatory collapse/death.
Stage 4 — Comatose or dying stage
