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→The Flow Rate graph---a detailed look
==The Flow Rate graph---a detailed look==
'''NOTE''': ''Only ResMed S9, Philips Respironics System One, and Fisher & Paykel Icon Not all machines record Flow Rate data; if you are a DeVilbiss IntelliPAP, you will not have a Flow Rate graph when you look at your data in SleepyHeadproduce detailed flow rate graphs.''
The Flow Rate graph is a visual record of each and every breath you took while using the machine. You are inhaling when the Flow Rate is positive and you are exhaling when the Flow Rate is negative. Stronger inhalations result in higher (positive) peaks and stronger exhalations result in lower (more negative) valleys in the Flow Rate graph. The events from the Event Table are superimposed on the Flow Rate graph with vertical lines of different colors.
The Flow Rate graph looks quite different depending on how far you have zoomed in on the data. All of the following Flow Rate graphs are from the same night's data:<br />
The Flow rate graph can be enhanced by showing a dotted line at zero flow by right-clicking on the left margin of the Flow Rate Graph and using the context menu to set a Dotted Lin at Zero. Everything above that line is inspiration (I) and everything below is expiration (E). This is a good example of normal I:E where in inspiration time is shorter than expiration. Normal breathing in this case, the inspiration quickly gains in flow rate (volume in mL/sec) and reaches a peak at which time the flow rapidly slows to zero, then expiration seamlessly beings. The expiration cycle is passive, meaning your chest simply relaxes and gravity does most of the work of collapsing the chest and causing air in the lungs to flow out. Expiration results in a fast flow rate at first which gradually slows to near zero resulting in the flattened line near zero flow. This is not holding your breath, but is the result of a relaxed normal exhale, as compared to a forced exhale. Take a look at your figure with the transitions from I to E marked. We can look at the transitions in the time scale (x-axis) and see that inspiration is approximately one breath every 5-seconds (12 BPM) with inspiration being about 2.2 seconds and expiration being 2.8 seconds. Notie the green line bisecting the graph during expiration below and showing -3.43 mL/sec flow. This shows the exact place where your cursor was located is indeed in expiration and there is expiratory flow. This would be textbook normal.
[[file:normal respiration markup.png]]
An interesting note here is that many of the machines will mistake the transition and count part of expiration as inhale, resulting in an incorrect I:E time or ratio. In the case of your overall statistics, we see a 14 BPM resp rate with Insp time of 1.88 and exp time of 2.10 which is both normal and correct.
[[File:fr-all_zpsf8767371.jpg]]
'''3)''' Glitches: Sometimes you run into a SleepyHead glitch and the y-axis for the Flow Rate graph is off: The middle part of the breathing cycle is not graphed at 0 L/min. It's a known problem. If this happens to you, the easiest thing to do is just to mentally draw the 0.0 L/min line half way between the peaks and valleys in the Flow Rate graph and use that to measure when you are inhaling and exhaling.<br />
==The Pressure graph---a detailed look==
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