see "ResScan guide for glossary (page 78) and graph interpretation
The temporary absence or cessation of breathing.
An apnea is scored when there is reduction in breathing by 75% of the baseline breathing for at least 10 seconds.
ResScan shows three types of apneas:
An apnea during which the upper airway remains open.
An apnea during which there is a physical closing of the upper airway.
An apnea during which a leak higher than 30 L/min occurs, precluding accurate determination of whether the apnea is obstructive or central.
For all indices, the value shown for Statistics is the total number of events divided by the Daily Usage.
AHI (Apnea–Hypopnea Index)
The total number of events is calculated by adding the number of apneas and hypopneas events.
For the AHI graph, the AHI count is incremented whenever an event occurs and reset every hour
AI: Apnea Index
HI: Hypopnea Index
CAI: Central Apnea Index
OAI: Obstructive Apnea Index
UAI: Unknown Apnea Index
A calculated value of a set of numbers computed by adding the total number of values and dividing by the number of values. Average for usage (therapy) hours is calculated over total calendar days.
Daily Usage is the total usage in a single session (a session starts at midday and finishes 24 hours later).
Average Daily Usage
Average daily usage is the result of the sum of Daily Usage divided by Used Days, over a selected time period.
The middle number in a sorted list of numbers. Half the numbers in the list are less, and half the numbers are greater (Example: 3, 3, 4, 5, 5, 5, 6, 9, 12, 23, 48: median = 5). Median for usage (therapy) hours is calculated over days used.
Median Daily Usage
The middle value for daily usage, where values for Daily Usage are listed from low to high, over a selected time period. While a few exceptionally
high or low values can have a significant influence on an average measure, the median is typically more reflective of the true central tendency.
The occurrence of an apnea or a hypopnea. Events are recorded as they occur. The maximum number of events stored per session is 500. After 500th event, 501 replaces 500, 502 replaces 501, etc.
An estimate of the patient’s airflow during inspiration and expiration. It is derived by taking the total flow and removing the leak and mask vent flow components.
A measure of partial upper airway obstruction. This measure is based on the shape of the inspiratory flow–time curve.
A flattening of the inspiratory flow–time curve suggests upper airway obstruction.
A normal inspiratory curve would be round shaped
Data Management Guide