Respiratory mechanical impedance in the rat.
The forced oscillatory impedance of the total respiratory system (Zrs) was measured in seven anaesthetized, paralysed rats weighing 351 +/- 55 g. Tracheotomy was performed, and the animals were placed in the supine position in a body box. Pseudo-random pressure variations between 0.5 and 10 Hz were applied around the chest. Central airflow was measured with a heated screen pneumotachograph. Total respiratory resistance (Rrs) and elastance (Ers), corrected for the impedance of the tracheal cannula, were markedly frequency-dependent: Rrs fell from 37.3 +/- 19.1 kPa.l-1.s at 0.5 Hz to 17.6 +/- 4.4 at 2 Hz and 10.3 +/- 3.3 at 10 Hz; the corresponding Ers values were 453 +/- 14, 594 +/- 90 and 713 +/- 104 kPa.l-1, respectively. This indicates that in the frequency range encompassing spontaneous breathing rates the classical resistance-intertance-compliance model provides an inadequate description of the respiratory mechanics in the rat.
Hantos
Z
Z
Kalmár Laboratory of Cybernetics, József Attila University, Szeged, Hungary.
Daróczy
B
B
Suki
B
B
Nagy
S
S
Debreczeni
L A
LA
D000403:Airway Resistance; D015113:Androstane-3,17-diol / Q000031:analogs & derivatives; D000818:Animals; D008170:Lung Compliance; D008297:Male; D017300:Pipecuronium; D010879:Piperazines; D051381:Rats; D012119:Respiration
D010879:Piperazines; D017300:Pipecuronium; D015113:Androstane-3,17-diol