Non-Responding Event Index (NRI)


Definition - What does Non-Responding Event Index (NRI) mean?

A non-responding event index (NRI) is a number indicating the average occurrences per hour of certain respiratory events detected by a respiratory therapy device. Specifically, the NRI tracks all respiratory events that are detected by a device such as an automatic positive airway pressure (APAP) machine but do not trigger the APAP's auto-adjust function.

WorkplaceTesting explains Non-Responding Event Index (NRI)

Positive airway pressure (PAP) machines are used to treat obstructive sleep apnea and related conditions. These devices deliver varying degrees of air pressure via a hose to a mask worn by the sleeping user. Some PAP machines collect data regarding the wearer's breathing patterns and other information throughout the night.

APAP machines are designed not to respond with adjusted air pressure in specific instances. For example, if a user's mask has slipped and is leaking, increased air pressure will only increase the volume of air leakage. An increase in CO2 caused by a non-obstructive breathing disorder will also not be aided by an increase in air pressure. Nonetheless, it is important for a patient's physician to be aware of these events. The NRI allows these incidents to be tracked and evaluated mathematically rather than subjectively.

The number of non-responding events (NRI) that occur per hour is one type of information that can be collected by these data capable PAP devices. Using this information, a person's physician can evaluate the effectiveness of various treatments and make necessary adjustments. In particular, non-responding events may be an indication that a patient has some type of complex sleep disordered breathing (CSDB) in addition to obstructive sleep apnea.

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