BIPHASIC POSITIVE AIRWAY PRESSURE (BIPAP) - A NEW MODE OF VENTILATORYSUPPORT

Biphasic Positive Airway Pressure (BIPAP) can be described as pressure controlled ventilation in a system allowing unrestricted spontaneous breathing at any moment of the ventilatory cycle. It can also be descr ibed as a Continuous Positive Airway Pressure (CPAP) system with a tim e-cycled change of the applied CPAP level. As with a pressure controll ed, time-cycled mode, the duration of each phase (Thigh, Tlow) as well as the corresponding pressure levels (Phigh, Plow) can be adjusted in dependently. Depending on the spontaneous breathing activity, BIPAP ca n be subdivided into: no spontaneous breathing: CMV-BIPAP spontaneous breathing at the lower pressure level: IMV-BIPAP spontaneous breathing at the upper pressure level: APRV-BIPAP spontaneous breathing at both CPAP levels: genuine BIPAP Since it enables progressive transition fr om controlled to all levels of augmented mechanical ventilation, BIPAP appears to be a suitable mode for the entire period of mechanical ven tilation of the patient. There are difficulties neither in choosing th e correct moment for switching nor the further respiratory management of the ventilated patient under BIPAP. The necessary adaptation (venti lation, oxygenation) can be individualized on the basis of blood gas a nalyses. An increase or reduction of the invasivity of ventilation can be attained without any problems with BIPAP. Furthermore, spontaneous breathing of the patient does not necessitate any switching of the mo de of ventilation. The transition from controlled to augmented ventila tion is smooth. BIPAP enables the therapist to let the patient breathe freely even under the most invasive ventilation conditions. In this w ay, not only are the lung mechanics of the patient crucially improved but an important contribution is made to the prophylaxis of the develo pment of atelectases.