[Equipment] ResMed S9 miscounts apneas

[Well Rested]

My ResMed S9 ST has missed about 15-20 apneas (lasting up to 50 seconds) for the last two nights. When I press the "info" button on my machine, the AHI registers as 0.0, but when I download the data and view flow rate in ResScan, I see significant events that were not counted. Has anyone experienced this before?

Is it possible to get a detailed description of the rules that the S9 uses to score an apnea event? I assume that a cessation of breathing for 10 seconds is not the only consideration?

[PaulaO2]

Doesn't the data on the screen reset itself at noon? Or what the machine says is noon? But the data on the card is, obviously, not reset.

[Well Rested]

Doesn't the data on the screen reset itself at noon? Or what the machine says is noon? But the data on the card is, obviously, not reset.

That is correct: the AHI index on the SD card registers 0 events, the AHI index on the CPAP machine registers 0 events, but it is obvious (by looking at flow data) that 0 is not the correct number.

[greatunclebill]

ResScan 3.7 Terms & Definitions


Usage = the time that a patient receives therapy from the device
Used days > X hours Y minutes = total number of days where daily usage exceeded the compliance threshold
% Used days > X hours Y minutes = calculates the percentage of used days out of the total number of days selected
Total hours used = total patient usage of a selected time range
Events = apneas, hypopneas, AHI
Apnea = 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
Hypopnea = an episode of shallow or slow breathing during sleep. A hypopnea is scored when there is a reduction in breathing by 50% of the baseline for 10 seconds or more. The event is scored after 10 seconds of the hypopnea.
AHI = apnea/hypopnea index = is calculated by adding together the total number of apnea and hypopnea events over a period of time. For statistics it is the total number of events divided by total daily usage. For graphs the AHI is incremented at the occurence of every event and reset every hour
Leak = an estimate of the total rate of air escaping due to mouth and mask leaks. It is derived by analyzing the inspriatory and expiratory air flows together with the expected mask vent flows. High or changing leak rates may affect the accuracy of other measurements
Tidal volume = the volume of air inspired or expired in one respiratory cycle (breath)
Respiratory rate = the frequency of breathing, expressed as the number of breaths per minute
Minute ventilation = the volume of air breathed in (or out) w/in any 60 second period
Flattening = a measurement of partial upper airway obstruction. This measurement is based on the shape of the inspiratory flow-time curve. A flat shape suggests upper airway obstruction.
Snore = Snore index is the measure of the amplitude of pressure wave generated by a patient's snoring
% Spontaneous cycled breaths = Spont C = the percentage of patient breaths that were spontaneously cycled (termination of IPAP and changing to EPAP)
% Spontaneous triggered breaths = Spont T = the percentage of patient breaths that were spontaneously triggered (initiation of IPAP).
Oxygen desaturation index = the mean value of the number of drops in oxygen saturation per hour
Flow = an estimate of the air flow entering the lungs. It is derived by taking the total flow and then removing the leak and the mask vent flow components.
95th percentile = the value exceeded during the selected range for 5% of the time
Median = the median value recorded during the selected range
Maximum = the maximum value recording during the selected range

ResScan 3.10 Terms & Definitions


Compliance

Usage = the time that a patient receives therapy from the device.

Used Days > X hours Y minutes = the total number of days where Daily Usage exceeded the compliance threshold (X hours Y minutes).

% Used Days > X hours Y minutes = % Used Days calculates the percentage of Used Days out of the total number of days selected.

Total Hours Used = the total patient Usage over a selected time range.

Events

Apnea = 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.

Obstructive Apnea = when there is a physical closing of the upper airway. Central Apnea = when the upper airway remains open.

Unknown Apnea = when accurate determination of whether the apnea is obstructive or central is not possible, due to the leak at any time during the apnea being higher than 30 L/min.

Hypopnea = episode of shallow or slow breathing during sleep. A hypopnea is scored when there is a reduction in breathing by 50% of baseline breathing for 10 seconds or more. The event is scored after 10 seconds of the hypopnea.

AHI = Apnea-Hypopnea Index (AHI) = calculated by adding together the total number of apnea and hypopnea events over a period of time. For statistics, it is the total number of events divided by total Daily Usage. For graphs, the AHI count is incremented at the occurrence of every event and reset every hour.

Key Respiratory Parameters

Leak = an estimate of the total rate of air escaping due to mouth and mask leaks. It is derived by analyzing the inspiratory and expiratory airflows, together with the expected mask vent flows. High or changing leak rates may affect the accuracy of other measurements.

Tidal Volume = the volume of air inspired or expired in one respiratory cycle (breath).

Respiratory Rate = the frequency of breathing, expressed as the number of breaths per minute.

Minute Ventilation = the volume of air breathed in (or out) within any 60 second period.

Flattening = a measurement of partial upper airway obstruction. This measurement is based on the shape of the inspiratory flow-time curve. A flat shape suggests upper airway obstruction.

Snore index = the measure of the amplitude of pressure wave generated by a patient's snoring.

% Spontaneous Triggered Breaths = the percentage of patient breaths that were spontaneously triggered (initiation of IPAP).

% Spontaneous Cycled Breaths = the percentage of patient breaths that were spontaneously cycled (termination of IPAP and changing to EPAP).

Oxygen Desaturation Index = the mean value of the number of drops in oxygen saturation per hour. Flow = an estimate of the airflow entering the lungs.It is derived by taking the total flow and then removing the leak and mask vent flow components.

Flow Limitation = a measurement of partial upper airway obstruction.

Statistics

95th Percentile = the value exceeded during the selected range for 5% of the time.

Median = the median value recorded during the selected range.

Maximum = the maximum value recorded during the selected range.

[zonk]

As Paula pointed out that the S9 day start from noon so you need to check the sleep quality report before noon as after noon it set to zero but you should see it in the advanced info menu (hold the two silver buttons for 3 sec and turn the push dial). Sometimes rebooting does help.
If haven't got the manual you can can ask for it
http://www.apneaboard.com/adjust-cpap-pr...tup-manual

[PaulaO2]

So you can see other data on the card, right? It says 0 events all across the board? Clear airway, apnea, etc? Yet the graphs indicate issues?

What are the leaks like?

[Well Rested]

So you can see other data on the card, right? It says 0 events all across the board? Clear airway, apnea, etc? Yet the graphs indicate issues?

What are the leaks like?

Thank you for your response. Yes, 0 events all across the board. Leaks are 3 L/min or less. I'm going to try to attach a photo of a 5 minute flow span (but I'm new to this so I hope it works). Attachment is the detail pane of ResScan. Bottom graph shows flow, top graph shows events (and none are registered). There are 4 events here that are clearly longer than 10 seconds.

[attachment]

[PaulaO2]

I wonder if those are snores and not actual apnea events?

While it is rare to get 0 events, it is possible.

How do you feel? Do you feel rested and alert in the morning?

[Well Rested]

I wonder if those are snores and not actual apnea events?

While it is rare to get 0 events, it is possible.

How do you feel? Do you feel rested and alert in the morning?

I wouldn't know how to recognize a snore if I saw one. What I identify is 0 flow for up to 50 seconds in one case.

I feel fine when I wake up the morning. I also felt fine before I got the CPAP machine 25 days ago. The only reason I have the machine is because my fiancee recognized breathing pauses -- I got a sleep study and they told me I had central apnea, AHI=58. I snore very rarely.

Thanks again for your help.

[PaulaO2]

Poking around on the 'net has so far shown nothing.

Has it always done this or is it new? The no event thing.