The Study Device The ExSpiron Respiratory Volume Monitor (Respiratory Motion, Inc., Waltham MA) has FDA 501(k) clearance to be used for patient care. It consists of a proprietary PadSet that is placed on the chest in the mid-axillary line and connected to a free standing monitor. This monitor measures and analyzes the changes in thoracic electrical impedance that occur during the respiratory duty cycle. It is able to quantify respiratory rate and also determine tidal volume and minute ventilation as well as graphically display changes in lung volumes. It has been shown to accurately measure the effect of interventions (medications, airway maneuvers) in endoscopy patients.5 Preliminary work has determined optimal lead placement demonstrated excellent correlation to spirometry with an R value of 0.94-0.98 and excellent accuracy and precision.6