Tidal volume (TV) in dogs—the amount of air inhaled or exhaled during a normal breath—varies based on body size and breed, but a general rule of thumb used in veterinary medicine is:
Tidal Volume ≈ 10–20 mL/kg of body weight
Here’s a rough breakdown by breed size categories:
| Breed Size | Weight Range | Tidal Volume Range |
| Toy Breeds (e.g., Chihuahua, Yorkie) | ~2–5 kg | 20–100 mL |
| Small Breeds (e.g., Beagle, Shih Tzu) | ~5–10 kg | 50–200 mL |
| Medium Breeds (e.g., Border Collie, Cocker Spaniel) | ~10–25 kg | 100–500 mL |
| Large Breeds (e.g., Labrador, Golden Retriever) | ~25–40 kg | 250–800 mL |
| Giant Breeds (e.g., Great Dane, Mastiff) | >40 kg | 400–1,200+ mL |
Notes:
- Tidal volume increases with body weight.
- During anesthesia, TV is often set closer to 10–15 mL/kg for safety.
- Brachycephalic breeds (like Bulldogs or Pugs) may have lower effective TV due to airway obstructions or anatomical limitations.
Tidal volume (TV) in cats is generally more consistent than in dogs due to their narrower size range. In healthy cats, the average tidal volume is about 10–15 mL/kg of body weight.
Here’s a general breakdown by common breed sizes:
| Breed Category | Examples | Weight Range | Tidal Volume Range |
| Small Cats | Singapura, Cornish Rex | 2–3 kg | 20–45 mL |
| Average-Sized Cats | Domestic Shorthair, Siamese | 3–5 kg | 30–75 mL |
| Large Cats | Maine Coon, Ragdoll | 5–8+ kg | 50–120 mL |
Notes:
- Brachycephalic cats (e.g., Persians) may have altered airflow or breathing patterns, affecting ventilation but not significantly altering TV.
- During anesthesia, TV is usually set around 10–12 mL/kg to avoid barotrauma.
- Cats are obligate nose breathers, which can influence ventilation during upper respiratory diseases, but again doesn’t drastically alter TV.
