Postoperative Respiratory and Activity Monitoring

Investigators will study adults undergoing elective abdominal surgery with at least moderate risk for postoperative pulmonary complications. Participants will be monitored on their chest and thigh with devices that record their breathing pattern (breath volume and frequency) and body position and movements. These monitors will be placed on their skin in the Post-Anesthesia Care Unit (PACU) and will stay on for three days, or until the patient is able to ambulate freely or until their hospital discharge, whichever comes earlier. Investigators will analyze the association between the frequency, duration and intensity of various activities (e.g., sitting, walking) and breathing and other clinical complications, in combination with medications received and other hospital course events.