Pediatric postoperative patients are at increased risk for post-operative respiratory complications such as hypoventilation. There is no objective measure of early respiratory parameters that would predict respiratory compromise after surgery efficiently in pediatric patients. Current respiratory assessment in non-intubated patients relies on oximetry data, impendence respiratory rate monitor and subjective clinical assessment. Pulse oximetry has been extremely helpful in recognizing oxygen desaturations but it is a late indicator of respiratory decline. New advances in technology and digital signal processing have led to the development of an improved impedance based Respiratory Volume Monitor (RVM). The RVM (ExSpiron™, Respiratory Motion, Inc.; Waltham, MA) has been shown to provide accurate real-time, continuous, non-invasive measurements of tidal volume (TV), minute ventilation (MV) and respiratory rate (RR) mostly in adult patients. The investigators' primary hypothesis is that the non-invasive, impedance-based RVM monitor will accurately reflect TV, RR and MV in pediatric patients.

Inclusion Criteria:

• pediatric patients between the ages of 1 year and 17 years
• ASA status of 1-3
• scheduled to undergo a procedure with general anesthesia at Boston Children's Hospital

Exclusion Criteria:

• Patients undergoing an emergency procedure or a
• patients undergoing a procedure where the study monitor will interfere with the surgical procedure site or standard of care
• preexisting respiratory disease
• muscular disease affecting the respiratory system

Patients undergoing general anesthesia for surgical procedures at Boston Children's Hospital.