The trial will be a randomized crossover design. The study cohort will be randomized (50/50) to begin with either low Vt or high Vt ventilation. After achieving steady state, initial cardiac output measurements will be made using a measured oxygen consumption (VO2) and the Fick principle, per routine clinical protocol. Following baseline assessment of cardiac output and hemodynamics (which is standard of care for all catheterization procedures), participants will be transitioned to the alternative ventilation modality (high Vt or low Vt). After a 5-minute equilibration period, oxygen saturations and VO2 measurements will be re-acquired, to determine cardiac output and hemodynamics in this second state.
This study will investigate the different tidal volume (Vt) strategies during a cardiac catheterization procedure to determine whether or not low or high Vt have an impact on cardiac output.~Research question: While maintaining the same minute ventilation/PaCO2, does higher Vt (10 cc/kg)/lower rate vs. lower Vt (6 cc/kg)/higher rate (maintaining consistent PEEP) result in improved cardiac output?