Frequency dependence of CO2 elimination and respiratory resistance in monkeys.
In dogs, respiratory system resistance (Rrs) is frequency independent, and during high-frequency oscillatory ventilation (HFO) the relationship between CO2 elimination (VCO2) and frequency is linear. In contrast, we found in rabbits a large frequency-dependent decrease in Rrs with increasing frequency along with a nonlinear relationship between frequency and VCO2 (J. Appl. Physiol. 57: 354-359, 1984). We proposed that frequency dependent mechanical properties of the lung account for inter-species differences in the frequency dependence of gas exchange during HFO. In the current study we tested this hypothesis further by measuring VCO2 and Rrs as a function of frequency in a species of monkey (Macaca radiata). In these monkeys, Rrs decreased minimally between 4 and 8 Hz and in general increased at higher frequencies, whereas VCO2 was linearly related to frequency. This is further evidence supporting the hypothesis that nonlinear frequency-VCO2 behavior during HFO is related to frequency-dependent behavior in Rrs.
D000403:Airway Resistance; D000818:Animals; D002245:Carbon Dioxide / Q000502:physiology; D008253:Macaca mulatta; D011659:Pulmonary Gas Exchange; D012121:Respiration, Artificial; D013314:Stress, Mechanical; D013990:Tidal Volume
D002245:Carbon Dioxide