Process the source file and calculate spirometric parameters
OverviewThe analysis results of respiratory parameters depends on the measurement settings and assumptions.
The respiratory parameters are calculated as continuous signals and can be converted into breath triggered results in a next step. The calculated spirometric parameters are volume parameters, see "Respiratory volume parameters", temporal parameters, see "Temporal respiratory parameters", pressure parameters, see "Respiratory pressure parameters" and flow parameters, see "Respiratory flow parameters".
Before the analysis is conducted, the measurement settings have to be set.
1) PEEP (positive end-expiratory pressure) detection parameter
The PEEP detection value (cmH2O) is a threshold parameter of the PEEP detection algorithm, see "Respiratory pressure parameters". The default value is 5%. The smaller the value, the more sensitive is the detection. In older SPIRO versions, too small threshold values could also lead to the detection of an onset of a pressure increase in the plateau of an inspiration. If the threshold value is chosen too large, the pressure increase is detected too late.
2) Patient information
The assumed body weight (kg) is needed to normalize spirometric parameters to the body weight. For example the tidal volume is calculated in mL/kg.
3) Measurement information
The measurement information include the measurement conditions and assumptions.
-A Leak threshold needs to be specified in %. Only leak values greater than that threshold will be considered in the analysis.
-The assumed ambient temperature needs to be provided in °C. This temperature is used as the temperature of the inhaled gas in the ATPS (ambient temperature and pressure saturated) setting, and as temperature of the inhaled and expired gas in the ATP (ambient temperature and pressure) setting. The default ambient temperature is 20°C. For more information on the different measurement settings see "Gas volume temperature relation".
-The best corresponding setting according to the assumed conditions should be selected from the following options:
a) Inhaled gas has ambient temp.
b) Inhaled gas has body temp.
c) Calibration syringe used
d) Inhaled gas is ambient temp.°C, expired gas is 37°C
After adapting these settings and conditions, the preprocessing test run results can be previewed in the Signal processing monitor, the Flow/Volume Loop monitor and the value viewer panel below. The calculated spirometric parameters are presented in more detail, see "Respiratory volume parameters", "Temporal respiratory parameters", "Respiratory pressure parameters" and "Respiratory flow parameters".
Signal processing monitor:
In this viewer the given signals, the inspiratory- and expiratory markers, the flow, Pmean, PIP, PEEP and Vt are previewed.
Additionally the signals can be scaled and zoomed by clicking the respective buttons below this previewer (from left to right).
1. button: automatic zeroing of the offsets of all signals.
2. button: automatic adaption of all signal offsets (shifting up and down)
3. button: automatic scaling of all signals (adaptation of the shown signal ranges according to the value range of the signals) If a signal is indicated in the reviewer and it is not visible, this might be due to an inappropriate value range.
4. button: zoom out
5. button: zoom in
This monitor previews Flow/Volume loops.
Each new loop starts with an inspiration, a positive flow (above Vt-axis) (red curve), and ends with an expiration, a negative flow (below Vt-axis) (blue curve). The previous two Flow/Vt loops are displayed in gray. All loops, respectively each axis can be scaled separately with the zoom buttons below the monitor.
Note: The Flow/Vt loops of mechanically ventilated patients are upside down of classical spirometric loops, where exhalation is forced.
Variable viewer showing the results of the current breath:
The variable viewers show different spirometric results of the current breath (breath rate, leak, tidal volume, PEEP, PIP, Pmean, Cdyn, PIFR, PEFR, MIFR, MEFR).
Rewind and run:
This button starts a preprocessing test run with the current setting. The results are previewed in the Signal processing monitor. By default the preview is done in real-time (1x), but it can be slowed down or speed up via the respective speed buttons.
By choosing different speeds (1/10x, 1/2x, 1x, 5x) the calculation and preview can be slowed down or speed up. By default the calculations are run at real-time (1x).
This button stops the current calculations and the respective preview.
Not recording!/ Recording!
By default the preprocessing results are not recorded. If these results are satisfactory, the button needs to be set to Recording! and the analysis has to be run again by clicking Rewind and run:. The results are stored in two files called "...SPIRO N.csv" and "... SPIRO N all.Poly5", where "N" is the number of the current analysis.
This button leads to a review of the previously stored results ("Store results of FLOW/PRES analysis per breath").
In this panel the path and the name of the stored result files is displayed.
Directs back to the start screen ("Initialization of the SPIRO APP").