Appendix 2.1 Compliance and resistance
App.2-1
APPENDIX 2 METHODS OF DETERMINING PARAMETERS
Appendix 2.1 Compliance and resistance
The compliance is a characteristic of compliance (extensibility) of broncho-pulmonary system of
the patient. Resistance parameter is a measure of patient’s airway and the endotracheal (tra-
cheostomy) tube resistance.
The static compliance and resistance (Cst and Rst) are measured in all modes of ventilation
having hardware breaths by special hardware test breath. The measurement period in the range
of 0 - 10 minutes is set by the user in [Menu]
→
[Ventilation parameters]
→
[Compl. meas pe-
riod]. If necessary the user can measure the value of compliance and resistance at any time by
pressing the Cst/Rst window in the indication area of monitoring parameters.
Hardware test breath differs from the usual inspiration at operation in any mode of ventilation
because of the presence of inspiratory plateau. Test breaths in the CMV/VCV and SIMV/VC
modes always have rectangular flow waveform. Test breaths in the modes CMV/PCV and
SIMV/PC can have a little pressure dip during the formation of the plateau. For any test breaths
inspiratory time will be increased to the 0.5 - 2.0 s (for the formation of the plateau).
The device has also a second method for calculating of the compliance and resistance - dynam-
ic, i.e. at every inspiration without a special test inspiration by solving a system of differential
equations connecting the pressure and flow of gas in the breathing circuit. In the device’s inter-
face, the parameters obtained by this method are named as C and R and are displayed in sepa-
rate block of measurement parameters. The values of the parameters C and R vary on every
respiratory cycle.
At C and R parameters obtaining, a modern mathematical method for calculating lung mechan-
ics called the LSF (least square fitting) is used. The LSF method is based on the analysis of the
mathematical model of the lungs mechanical activity in real time during the whole respiratory
cycle.
Leakage in the circuit, depending on its value, can cause significant error in the compliance and
resistance measurement.
Appendix 2.2 AutoPEEP
AutoPEEP occurs when the ventilator settings (frequency, volume and inspiratory time) does
not correspond to the patient’s capabilities. In this case the patient before the start of the new
inspiration does not have enough time to exhale the air of the previous breath. Accordingly, the
end expiratory pressure is higher than the specified by ventilator setting.
AutoPEEP measurement is realized only for inactive patients in the mandatory breath cycles.
Measurement is carried out by creating an expiration delay (expiration hold) by the command of
operator or periodically (after the time specified in software).
For measurement by the operator's command, select "autoPEEP" in any block through [Menu]
[Display settings] [Choose measured par.blocks]. To measure click on the autoPEEP block,
then the block will change color from white to blue (indicating the beginning of the measure-
ment), and after the end of inspiration, the measured value will be displayed on it. To re-
measure, press the autoPEEP block again.
For periodic measurement using graphical button “Monitoring” select RESP2 window, where
measured autoPEEP value will be displayed.
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Страница 25: ...2 3 Front panel 2 9 2 3 Front panel Figure 2 1 Front view of the electronic unit ...
Страница 124: ...4 21 Open valve function 4 76 For your notes ...
Страница 158: ...6 11 Check and calibration of mainstream CO2 sensor 6 8 For your notes ...
Страница 160: ...7 Troubleshooting 7 2 For your notes ...
Страница 162: ...8 Transportation 9 Storage 10 Disposal 10 2 For your notes ...
Страница 166: ...13 commission date mark 12 2 For your notes ...
Страница 168: ...14 Maintenance and repair data 14 2 For your notes ...
Страница 196: ...Appendix 2 9 Ideal body weight of the patient IBW App 2 10 For your notes ...
Страница 200: ...Appendix 3 Electromagnetic environment App 3 4 For your notes ...
Страница 201: ...Appendix 4 Pneumatic scheme of ventilator App 4 1 APPENDIX 4 PNEUMATIC SCHEME OF VENTILATOR ...
Страница 202: ...Appendix 4 Pneumatic scheme of ventilator App 4 2 For your notes ...