APRV(Airway Pressure Reliese ventilation)
1. The concept and the purpose (Figure ; APRV)
It opens CPAP pressure intermittently (if making synchronize with the expiration) and it is APRV that helps expiration. Agreeing in 1-1.5 seconds about the (2) open assembly time which a spontaneous-respiration isn't stored in in the period which opens (1) and to differ with BIPAP is. It is possible to use in Drager Inc. Evita and VIASIS Inc. AVEA "NADO".
2. The component
(1) It is composed of CPAP aspect and (2) opening aspect.
3. The control system
1) The controlling mechanism
The MPU method is mainstream.
2) The operating principle
It is more desirable to have made the opening of the CPAP pressure synchronize with the ending of intake like BIPAP and to have made a recompression synchronize with the beginning of intake on the ventilation efficiency.
4. The modification element
1) The synchronization mechanism
Evita uses the condition (the trigger window, the condition of the recognition of the intake beginning and the end-of-suction end) of BIPAP. AVEA can set to the optional value by 5% of units in 0-50% of each of the high-pressure aspects and the low pressure aspects of ranges.
2) The CPAP pressure, the opening pressure
The appropriate CPAP pressure, the opening pressure are valid with the improvement of the oxygenation ability. However, if using what CPAP pressure, opening pressure on the ventilation efficiency, being best, it decides and it is in the difficulty.
3) The opening number of times
The maximum APRV frequency is to spontaneous-respiration number 1/2. The appropriate APRV frequency is unclear.
5. The advantage, the fault
In APRV, the point which can do ventilation help without what adding an airway pressure to is an advantage. When using high CPAP pressure, the improvement of the oxygenation ability can look forward to it and also the ventilation help can look forward to it by the expiration release. However, there is a fault which causes ventilation restraint during the CPAP period, too. Therefore, even if it increases a pressure difference, the ventilation help doesn't always increase sweepingly. In being "DURENISE", the existence of the spontaneous-respiration is a precondition and also the point which the ability of the ventilation help has a limit is an agreement in case of adaptation.