The specific aim of this study is to evaluate the intermittent non-invasive measurements of pulmonary function: pulmonary blood flow (PBF), functional residual capacity (FRC), shunt fraction index (Qsi) and airway dead space measured by the VQm PHM™ compared to known clinical standards. PBF will be compared to continuous and intermittent bolus thermodilution cardiac output as measured through a Swan-Ganz catheter. FRC will be compared to an FRC measurement provided by a standard nitrogen washout method. Qsi will be compared to shunt fraction calculated through mixed venous and arterial blood gas values (VBGs/ABGs). Airway dead space will be compared to an airway dead space measurement provided by a ventilator.
