Effect of salicylate on respiratory mechanics and postinspiratory muscle pressure.
In 5 spontaneously breathing anesthetized dogs, sodium salicylate (250 mg/kg) was administered. Air flow, volume, and tracheal pressure were measured. The passive mechanical properties of the respiratory system, control of breathing parameters, and the postinspiratory pressure generated by the inspiratory muscles (PmusI) were computed both before and during progressive salicylate-induced hyperventilation. Resistance fell, whereas elastance and time constant were not altered with increased ventilation (VE). The relationship between PmusI and expiratory duration (TE) presented a sigmoidal decay rate, which did not vary with hyperventilation. PmusI at TE = 0 (PmusI, 0); the times for PmusI to decay to 50 (T50), 25 (T25), and 0 percent (TZ) of PmusI, 0; inspiratory (TI), expiratory (TE) and total cycle duration (TT) decreased with increasing VE. As expiration shortened more than inspiration and TI fell more than VT rose, TI/TT and VT/TI increased during hyperventilation. In conclusion, in the face of salicylic intoxication: Rrs diminished, TI and TE decreased markedly, yielding higher values of TI/TT and VT/TI, and although T50, T25, and TZ fell, the relative time profile of PmusI remained unaltered.
Zin
W A
WA
Laboratory of Respiration Physiology, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Brazil.
Rocco
P R
PR
Pereira
H S
HS
Fonseca-Costa
A
A
D000818:Animals; D001784:Blood Gas Analysis; D001831:Body Temperature; D004285:Dogs; D011312:Pressure; D012123:Pulmonary Ventilation / Q000187:drug effects / Q000502:physiology; D012119:Respiration / Q000187:drug effects / Q000502:physiology; D015656:Respiratory Mechanics / Q000187:drug effects / Q000502:physiology*; D012132:Respiratory Muscles / Q000187:drug effects* / Q000502:physiology; D012459:Salicylates / Q000494:pharmacology*; D020156:Salicylic Acid; D013990:Tidal Volume
D012459:Salicylates; D020156:Salicylic Acid