[Influences of respiratory frequency on breathing mechanics during artificial ventilation in man and animal].

Effects of respiratory frequency on breathing mechanics were examined on 11 surgical patients during artificial ventilation with inhalation of nitrous oxide, oxygen and halothane (GOF). When the respiratory frequency was increased stepwise from 10 to 30/min, the total compliance was significantly reduced stepwise (from 55.42 +/- 9.55 ml/cmH2O to 47.38 +/- 9.31, p less than 0.01). In animal experiment, the respiratory frequency was similarly increased from 10 to 30/min in 11 mongrel dogs under sodium thiamylal anesthesia with air breathing. The total pulmonary compliance decreased significantly from a control level of 13.62 +/- 5.04 ml/cmH2O to a value of 10.96 +/- 3.00 ml/cmH2O which was obtained under the administration of synthetic histamine (betazole hydrochloride) (p less than 0.01). However, the decreases in compliance with histamine were parallel with the control values without the drug treatment. From these results it was assumed that the reduction of the total pulmonary compliance under increased respiratory frequency was due not to changes in small airway but to those in large airway.