[The effects of different patterns of mechanical ventilation on the respiratory mechanics and gas exchange in dogs severely injured by steam inhalation].
OBJECTIVE
To study the effects of conventional mechanical ventilation (CMV), high-frequency jet ventilation (HFJV) and high-frequency bidirectional jet ventilation (HFTJV) on the respiratory mechanics and gas exchange in dogs inflicted severely by steam inhalation injury.


METHODS
Nine mongrel dogs inflicted by steam inhalation to severe inhalation injury were served as the model. Indices of respiratory mechanics, hemodynamics and blood gas analysis were monitored respectively with the above three patterns of mechanical ventilation.


RESULTS
(1) Total respiratory resistance (Rrs) and resistance of lungs (R(L)) were evidently higher with the ventilations than those in control (P < 0.01). And total respiratory compliance (Crs) and compliance of lungs (C(L)) were obviously lower with the ventilations than those in control (P < 0.05) but with no significant differences among the changes of Rrs, R(L), Crs and C(L). (2) Carbon dioxide (CO(2)) retention could be induced by CMV and HFJV. HFTJV was much more effective than HFJV in enhancing the expiration of CO(2) (P < 0.01). (3) There was no remarkable difference in functional residual capacity (FRC) and PaO2 between dogs with three patterns of ventilations.


CONCLUSIONS
All these three patterns of ventilations could overcome the respiratory resistance and help respiration, but they couldn't restore the high airway resistance and low compliance of lungs already established postburn. The efficiency of CMV was similar to that by HFJV, but that of HFTJV was much better than that of HFJV.
Li
G
G
The first affiliated hospital Jiangxi Medical College, Nanchang 33006, P.R. China.
Guo
G
G
Xu
C
C
D000818:Animals; D002059:Burns, Inhalation / Q000503:physiopathology*; D004285:Dogs; D005260:Female; D008297:Male; D011659:Pulmonary Gas Exchange; D012119:Respiration; D012121:Respiration, Artificial