2000 OPEN FORUM Abstracts
LUNG RECRUTIMENT MANEUVERS UTILIZING AIRWAY PRESSURE RELEASE VENTILATION
Lori Hand, BSc. RRT. CHT; Maureen Meade, MD, FRCPC, MSc; McMaster University, Hamilton Health Sciences Corporation, Hamilton, Ontario, Canada
BACKGROUND: Patients with acute lung injury are prone to further lung injury from alveolar collapse and cyclic lung reopening. Lung recruitment maneuvers (LRMs) may prevent this ventilator-induced lung injury. Traditionally, LRMs are conducted using continuous positive airway pressure (CPAP) in the range of 30 to 45 cm H2O, for 20 to 40 seconds. Newest generation mechanical ventilators may not allow CPAP levels as high as 45 cmH2O. The purpose of this exercise was to explore the use of APRV mode for conducting LRMs. METHOD: We conducted LRMs in 20 patients using APRV as follows. We set the high pressure to the desired inflation pressure for the LRM; low pressure to maximum (not exceeding high pressure); high pressure time was maximized (30 secs) and low pressure time minimized (0.1sec). To initiate the LRM we switched to APRV mode and clocked the desired duration manually, then returning to the previous mode of ventilation. We monitored ventilatory and hemodynamic parameters. Patients were given no additional sedation for the LRM. RESULTS and EXPERIENCE: LRMs conducted using APRV mode were similar to those using CPAP mode with respect to hemodynamics and gas exchange variables. Respiratory therapists performing the LRM found the APRV procedure simple to perform. Patients tolerated the procedure very well; no LRMs were aborted due to patient discomfort. CONCLUSION: LRMs via APRV appear to be equal to that delivered via the CPAP mode, as pressure delivered in APRV is technically achieved in the same manner as CPAP pressure. This allows no increase in manpower (having to change ventilators) when a patient is ventilated with a newer generation ventilator that does not allow CPAP levels as high as 45 cmH2O. A more in depth comparison needs to be followed out to adequately assess this issue.