Dogs were anesthetized and randomly mechanically ventilated with VT of 6, 8, 10, 12, and 15 mL/kg while maintaining a constant minute volume.
Arterial blood gases and pulmonary mechanics were collected after 15 minutes of equilibration at each VT.
Repeated measures ANOVA was used to determine the effect of VT with a P-value of <0.05 considered significant, and a Pearson product moment was used to determine correlation between VT and pH and PaCO2.
VT had a significant effect on PaCO2 (P < 0.001) and on pH (P < 0.001) with lower VT being associated with higher PaCO2 and lower pH.
There was a strong correlation between VT and PaCO2 (r = –0.87) and VT and pH (r = 0.83). Increased airway pressures and pulmonary compliance were associated with increasing VT.
Conclusions: There is a predictable decrease in the pH, decrease in airway pressure, decrease in compliance, and increase in the PaCO2 associated with lower VT.
Low VT ventilation is well tolerated in healthy dogs; the role of low VT ventilation in dogs with acute lung injury/acute respiratory distress syndrome as well as the influence of positive end expiratory pressure requires further evaluation.
Source: Oura, T., Rozanski, E. A., Buckley, G. and Bedenice, D. (2012), Low tidal volume ventilation in healthy dogs. Journal of Veterinary Emergency and Critical Care, 22: 368–371. doi: 10.1111/j.1476-4431.2012.00749.x
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