What are the AASM recommendations for pressure and thermal airflow?
The AASM has recommended that an oronasal thermal sensor be used to detect the absence of airflow for identification of apnea. As an alternative, the recommendations state that when the thermal signal is unreliable, technicians may use a nasal air pressure transducer. Also, the recommended sensor for detection of airflow for identification of hypopnea is a nasal air pressure transducer, with or without square root transformation of the signal. The AASM is recommending one sensor for apnea detection and another sensor for hypopneas. The reasoning behind the recommendation for using two different types of airflow sensors is that nasal pressure transducers are more sensitive to slight changes in airflow (hypopneas), but may result in overestimating apneas, while thermal sensors are less sensitive to minor breathing changes, but are more reliable for identifying apnea. In the past, practitioners have generally used one or the other sensor, often based on personal preference. Thermocouples
