* Methods: Five sheep, under anesthesia and on mechanical ventilation, were monitored using different tidal volume levels (6, 10, 15, 20 ml/kg) in bi-level positive airway pressure (BiPAP) mode versus synchronized intermittent mandatory ventilation (SIMV) mode.
* Results: Increasing tidal volumes resulted in decreased cardiac index and intrathoracic blood volume index, with significant differences noted at 15 ml/kg and 20 ml/kg compared to 6 ml/kg, along with changes in systemic vascular resistance index and mean