BIPAP(Bi-phasic Positive Airway Pressure),Bi-Level, Bi-Vent,BiPhasic
1. The concept and the purpose (Figure ; BIPAP, figure ; Experimental BIPAP equipment : Of the experimental equipment like the figure however, BIPAP is possible if it doesn't think of the synchronization with the spontaneous-respiration)
It was had in Evita of the Drager Inc., being the first time. The mode to be called Bi-Vent(Servo i), and Bi-Level(Bennett840), BiPhasic(AVEA), and so on, too, is the concept which is near following narrow sense BIPAP.
CPAP can improve the oxygenation ability of the lung by the low airway pressure compared with the active-ventilation but has the defect which adaptation is limited to without most in the ability of the ventilation help. It added ability of the ventilation help to CPAP in changing two CPAP levels alternately(, making side with the spontaneous-respiration) and it is the starting point of BIPAP (Narrow sense BIPAP). At first, it was defined as containing equal to or more than 2-3 spontaneous-respirations in one CPAP aspect. Under present condition, however, there was a limit in the ability of the ventilation help and clinical application, too, was limited. The Drager Inc. called the general term of the ventilation mode which is created by the mechanism (the BIPAP system) which it changes alternately by becoming recently and making two CPAP levels side with the spontaneous-respiration BIPAP and it got to include the concept of PCV and the SIMV(PCV) mode, too. At the this manual, this is called BIPAP of the wide sense. For example, the ventilation mode which the Drager Inc. calls BIPAP+ASB is the mode to add PSV in the period of the low pressure aspect, meaning SIMV(PCV)+PSV by the BIPAP system. BIPAP Assist becomes A/C(Pressure) similarity mode. In 変法 of narrow sense BIPAP, the condition only of one piece of expiration is called APRV to the low pressure aspect. This Akira describes narrow sense BIPAP.
2. The component
(1) It is composed by the low pressure aspect and the (2) high-pressure aspect. Of each aspect however, the spontaneous-respiration is possible.
3. The control system
1) The controlling mechanism
It changes two pieces of CPAP pressure at "the optional pressure and the number of times" using the demand flow system and electronic type exhalation-valve C-system of the fast-operate type by the MPU control.
2) The operation theory
(1) The change processing of each aspect
A trigger window is provided for the change of each aspect, it synchronizes with breathing when meeting an end-of-suction end recognition condition from the high-pressure aspect to the low pressure aspect in the intake beginning recognition condition and is switched from the low pressure aspect to the high-pressure aspect. For the details, refer to the explanation of the specialized study.
(2) The trigger window
In Evita, it is provided for 25% of ends of each aspect. The one which the change of the spontaneous-respiration and the aspect synchronized with increases an air quantity of ventilation more. However, improvement is demanded from the control method like SIMV because it doesn't synchronize and it sometimes changes, too. 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.
(3) PSV about the high-pressure aspect and the low pressure aspect
Evita4, Evita XL can add PSV only about the low pressure aspect. On the other hand, Bi-Vent of Servo i can add PSV with value to the high-pressure aspect and the low pressure aspect according to each. BiPhasic of AVEA can choose only both or the low pressure aspect of the high-pressure aspect and the low pressure aspect.
4. The modification element
(1) The pressure difference of the high-pressure aspect, the low pressure aspect (The BIPAP pressure)
It becomes the ventilation (narrow sense BIPAP) of the CPAP style which admits a spontaneous-respiration to both aspects if the pressure differences with BIPAP pressure are few but it is entrusted with the character of PCV and SIMV(Pressure) if setting a difference roughly (BIPAP of the wide sense).
(2) The time of the BIPAP frequency, each aspect
When making operate by the category of narrow sense BIPAP, even if it increases the BIPAP number of times above the constant value, the air quantity of ventilation doesn't increase and rather declines. Also, the frequency which doesn't synchronize with the spontaneous-respiration becomes high because the trigger window, too, becomes narrow. The ability of the ventilation help increases when increasing BIPAP pressure and the BIPAP number of times and copying the ventilation of PCV. But, in the time of the high-pressure aspect, it is necessary to set to the spontaneous-respiration 1 intake time.
(3) The hypoventilation back-up
The anaerosis back-up is available.
(4) PSV about the high-pressure aspect and the low pressure aspect
As for the setting of the PSV pressure and the BIPAP pressure when adding PSV to each aspect, there is not rational theory. In the first place (BIPAP which added PSV "NIOITE"), it is necessary to reevaluate about the meaning to change CPAP pressure.
5. The advantage and the fault
Of what tense however, the spontaneous-respiration is possible theoretically. Therefore, there is little Fighting. Also, because the setting possible range is wide, when combining optional pressure and the number of times, it is possible to create a mode of the ventilation of most ironhand type. Therefore, it is possible to apply clinically to the patient of all the clinical condition. However, because it is 変法 of CPAP persistently in the category of narrow sense BIPAP, it presupposes that the stable voluntary ventilation exists. Also, as for the maximum BIPAP number of times, agree in spontaneous-respiration number 1/4-1/3. Voluntary air quantity of ventilation with the high-pressure aspect has decreased when doing a pressure gap roughly when it let's increase ventilation help ability. The limit occurs to the ability of the ventilation help consequently. It will should compare the evaluation of the oxygenation ability with PCV/IRV specifically. However, because the fundamental ventilation thought is different from PCV/IRV which doesn't admit a spontaneous-respiration, being general, there is not a meaning in these simple comparison.
As for the meaning to add PSV to BIPAP, the possibility that it is possible to create a various mode can understand therefore but there is not theory which anyone can consent to about the advantage on being clinical.
On the other hand, in BIPAP (PCV and SIMV(Pressure) by the BIPAP system) of the wide sense, the existence of the spontaneous-respiration isn't indispensable, but as for the time of the high-pressure aspect, it is different from narrow sense BIPAP and agree commonly in the 1 intake time. of the capacity (brought) of the compliance (which is brought about by the lung and breathing circuit) in usual PCV There is an advantage which can maintain a set-pressure correctly because the provided case (the overshoot), too, has the pressure which is higher than the set-pressure according to the vibration system which has resistance but there is pressure relieving by the exhalation-valve whatever vibration system is loaded in the BIPAP system. Also, because of what tense however, it is possible to ventilate a patient freely because it is CPAP basically, Fighting can not happen theoretically.