S8 and S9 hypopnoea differences

[fiberfan]

I have wondered about the significant drop in HI many see when going from a S8 to a S9. I had seen a hypopnea definition in the S9 Data Management Guide and wondered if I could find a definition for the S8. All I had to do was was look in the S8 Clinical Guide.

A hypopnea is defined as a 50 to 75% drop in ventilation. A hypopnea is scored if the 8-second moving average ventilation drops below 50%, but not below 25%, of the recent average for 10 consecutive seconds.

A hypopnoea is an episode of shallow breathing during sleep. A hypopnoea is scored when there is a reduction in breathing by 50% of baseline breathing with partial upper airway obstruction for 10 seconds or more. The event is scored after 10 seconds of the hypopnoea.

My HI was 6.3 for the 16 nights I used the S8 and is 0 for 8 nights on the S9. I didn't note the AI for each machine but it is low on both. My doc wasn't happy with the AHI at my 2 week follow up, I think I will take both definitions when I see him for a 6 week follow up next month.

I thought others might find the 2 definitions interesting.

[Slinky]

ResScan 3.7 definition of an hypopnea:

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.

ResScan 3.7 is NOT compatible w/the new Resmed S9 devices.

[pzac]

Here are all the definitions rom ResScan 3.10:

• Definitions
  
  Compliance
  
  Usage
  Usage is the time that a patient receives therapy from the device.
  
  Used Days > X hours Y minutes
  Used Days is 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
  Total Hours Used is the total patient Usage over a selected time range.
  
  
  Events
  
  Apnea
  An apnea is 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
  An obstructive apnea is when there is a physical closing of the upper airway.
  
  Central Apnea
  A central apnea is when the upper airway remains open.
  
  Unknown Apnea
  An unknown apnea is 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
  A hypopnea is an 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
  The Apnea-Hypopnea Index (AHI) 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 count is incremented at the occurrence of every event and reset every hour.
  
  
  Key Respiratory Parameters
  
  Leak
  Leak is 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
  Tidal Volume is the volume of air inspired or expired in one respiratory cycle (breath).
  
  Respiratory Rate
  Respiratory Rate is the frequency of breathing, expressed as the number of breaths per minute.
  
  Minute Ventilation
  Minute Ventilation is the volume of air breathed in (or out) within any 60 second period.
  
  Flattening
  Flattening is 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 Triggered Breaths
  % Spontaneous Triggered Breaths is the percentage of patient breaths that were spontaneously triggered (initiation of IPAP).
  
  % Spontaneous Cycled Breaths
  % Spontaneous Cycled Breaths is 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
  Flow is 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
  Flow limitation is 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.

[/list]

[dsm]

I have wondered about the significant drop in HI many see when going from a S8 to a S9. I had seen a hypopnea definition in the S9 Data Management Guide and wondered if I could find a definition for the S8. All I had to do was was look in the S8 Clinical Guide.

A hypopnea is defined as a 50 to 75% drop in ventilation. A hypopnea is scored if the 8-second moving average ventilation drops below 50%, but not below 25%, of the recent average for 10 consecutive seconds.

A hypopnoea is an episode of shallow breathing during sleep. A hypopnoea is scored when there is a reduction in breathing by 50% of baseline breathing with partial upper airway obstruction for 10 seconds or more. The event is scored after 10 seconds of the hypopnoea.

My HI was 6.3 for the 16 nights I used the S8 and is 0 for 8 nights on the S9. I didn't note the AI for each machine but it is low on both. My doc wasn't happy with the AHI at my 2 week follow up, I think I will take both definitions when I see him for a 6 week follow up next month.

I thought others might find the 2 definitions interesting.

My humerous reply is that Resmed got fed up to the back teeth with the constant & repetitive carry-on about how Resmed machines did not produce the low AHI (esp HI results that other brands did !. So Resmed merely adopted the same level playing field

DSM

[bigk]

My humerous reply is that Resmed got fed up to the back teeth with the constant & repetitive carry-on about how Resmed machines did not produce the low AHI (esp HI results that other brands did !. So Resmed merely adopted the same level playing field

Yeah - I know you meant it as a joke but it wouldn't surprise me if this is actually the reason.

Same as the Aussie version of the S8II didn't have EPR in APAP mode but the US version did - I always thought that was for "me too" reasons rather than anything else. I find the EasyBreathe technology negates any need for EPR and don't intend on enabling it on my new S9 when it arrives this week. Including EPR in APAP mode just shut up the detractors rather than providing anything really useful IMO.

[Slinky]

In the North American version of the Resmed VPAP Auto and VPAP Auto 25 the EasyBreathe technology is not even engaged in Spontaneous (straight bi-level) mode, only in VAuto mode. Consequently many are experiencing too abrupt a pressure transition between inhalation and exhalation in Spontaneous mode. But by changing to VAuto mode w/the same IPAP and EPAP the pressure transition is smooth and easy as can be. There is no S9 bi-level or auto bi-level PAP