Comparison of assisted and controlled mechanical ventilation in anesthetized swine.

We compared assisted mechanical ventilation with controlled mechanical ventilation with and without PEEP in 10 anesthetized swine. Catheters were placed to measure airway, intrapleural, and blood pressure; PaO2 and PaCO2; arterial pH; total minute ventilation; and mixed exhaled oxygen and carbon dioxide tensions. We calculated the ratio of physiological dead space to tidal volume, alveolar minute ventilation, CO2 production, VO2, and RQ. We found no clinically or statistically significant difference between assisted and controlled ventilation.