Philips V200 - Manual (Page 286)

Chapter 13
13-122 Respironics V200 Ventilator Operator’s Manual REF 1057983 A
Options and Accessories
• For adult patients: Bias flow = Pt Leak + 5 LPM.
• For pediatric patients: Bias flow= Pt Leak + 3 LPM.
Patient flow is estimated as the delivered flow (Bias flow during exhalation)
minus the estimated Leak Flow, minus the measured expiratory flow (flow
through the exhalation valve):
• Patient flow = Delivered flow - Leak flow measured expiratory flow
The estimated Leak Flow value in the above equation differs from the Patient
Leak value defined earlier. Leak Flow is the estimated leak at a given moment
in time and is dependent upon pressure (the higher the pressure, the higher
the leak flow) and the physical characteristics of the leak itself. The Patient
Leak value is the average Leak Flow over an entire breath.
When Auto-Trak is selected in NPPV mode, the estimated exhaled tidal volume
includes compensation for the estimated leak volume lost during exhalation.
Therefore, all other parameters that depend on exhaled tidal volume also
include this compensation (for example, minute ventilation and rapid-shallow
breathing index, F/Vt).
If the Graphics Option is enabled, waveforms and loops displayed in NPPV
mode will show estimated flows and volumes that include compensation for
the estimated leak.
Exhaled tidal volume is leak-compensated only in NPPV. Leaks that may occur
during invasive ventilation are intentionally not compensated for, allowing
them to be more easily detected.