Tidal volume, oxygen uptake, cardiac output, and body surface in the cat

Twenty-two cats were studied under chloralose anesthesia. When animals breathed pure oxygen in a closed circuit especially set for spirogram recording, respiratory rate, tidal volume, minute volume, and oxygen uptake of 19 cats averaged 15 breaths/min, 26 ml, 0.380 liter/min, and 18.5 ml/min, respectively. Cardiac output of 11 cats, determined by simultaneous measurements after Fick and Stewart-Hamilton methods, averaged 234 and 184 ml/min, respectively. Statistical analysis shows a high degree of individual variability partially dependent on body size. Body surface was directly measured in 12 animals and a coefficient for prediction of body surface on a body weight basis was calculated: m 2 = 0.087 kg 2/3 . When corrected per unit of body surface, the range of individual oxygen uptake in 19 cats was reduced and it averaged 113/ml min m 2 . Similar correction of cardiac output was not equally effective.