Patent ID: 7775207

Claim:
An apparatus for providing re-breathing capability to a breathing circuit, the apparatus comprising: (a) a device for altering operation of the breathing circuit from a first mode permitting air flow through a first path in the breathing circuit to a second mode providing a re-breathing capability to the breathing circuit; (b) a CO2 sensor to detect CO2 concentration in the breathing circuit between the device and a patient; (c) a flow sensor to detect a rate of gas flow in the breathing circuit between the device and the patient; (d) a pressure sensor to detect a pressure of gas in the breathing circuit; and (e) a processor connected to the CO2, flow, and pressure sensors and adapted to: during at least one inspiration by the patient, receive at least one of the CO2, flow rate, pressure, and a selected gas within the breathing circuit between the device and the patient, generate a waveform based on the received detected flow rate, CO2 concentration, the pressure, or the selected gas, analyze the waveform to determine a condition of the device, including whether the device is in a mode selected from Leak, Re-breathing and Normal during the at least one inspiration by the patient, and trigger an alarm responsive to a determination that the device is not functioning properly.