My Supervisor said to use around 8 liters of air bleed-in at the mask, to help increase the patient's tidal volume.This addition of air did increase the pt.'s tidal volume and it did keep the variations in tidal volume readings from happening.But my guestion is,can this tidal volume reading be trusted, and why did the respronics people not mention a word about this to us in our inservice.Please let me know if this technique is used or is this a isolated situation.

This seems really bizarre to me. The additon of the flow may have caused the tidal volume READOUT to increase, but is there any evidence the patient actually got a bigger tidal volume?
Indeed the variations (and what is wrong with VT variation in PS breathing?!) may be because the set flow is being measured.

If you want a bigger VT why not increase the Pressure Support level?

You really should check with the Respironics people as to the wisdom of all this. In addition the Esprit is designed for non-invasive ventilation....one could almostexcuse this logic if one was using a CPAP device, though that would still be stretching it. But an Esprit? I'm sure the Respironics folks will not look kindly on such bizarre suggestions.