A side-stream respiration monitoring system includes a sensor, a monitor, and a display. The sensor is constructed to engage respiration flows having a variable flow amounts and acquire a respiration sample from the flow. The monitor is connected to the sensor and configured to determine the amount of respiration flow as well as the amount of several constituents of the respiration flow such as oxygen, carbon dioxide, water, and nitrous oxide. The monitor is also configured to adjust the determined values for ambient environment variations and is self-calibrating with respect to the ambient conditions. The monitor temporally aligns the acquired data to account for dead-space respiration events and physiological respiration modifications such as cardiac events. Information generated by the monitor is communicated to an operator via a display configured to display the real-time respiration performance.