A system and method are provided to monitor a patient's respiration during and after medical/surgical procedures, as well as in clinical situations wherein the patient is at increased risk for developing central or obstructive respiratory depression and/or apnea. A sensor attached to the patient's face, which monitors nasal and oral air-flows. An electronic monitor analyzes patient respiratory patterns and initiates bedside and/or remote nursing station alarms in real time if and when a clinically significant respiratory event is detected. Respiration is measured by monitoring changes in the acoustic signature of the patient's breath passing over a corrugated or uneven surface, changes in the pressure of an inflatable closed volume of a sensor caused by the changes in temperature of the interior volume caused by the patient breathing over the sensor, or both.