Select an Initial Pressure Setting that is Just Slightly Higher than the Patient’s Peak Pressure When Attempting a Pressure Support Wean
Anthony D. Slonim MD, DrPH
Pressure-support ventilationis a flow-cycled mode of ventilation. During inspiration, inspiratory flow in this mode decreases as lung volumes reach full inhalation. This mode is also patient triggered, meaning that the patient is able to initiate the inspiratory cycle. This leads to increased patient comfort by enhancing patient-ventilator synchrony. Finally, pressure-support ventilation is considered to be pressure limited, whereby the pressure-support ventilation level is determined by the provider and programmed into the machine to assist the patient. The patient controls the rate and timing of respirations.
What to Do
As a mode to assist with weaning mechanical ventilation, the pressure-support level can be adjusted so that the patient is achieving an adequate tidal volume (6 to 10 cm3/kg) with a comfortable respiratory rate (10 to 14 breaths per minute). As a starting point, the pressure-support level can be placed 2 to 5 cm H2O above the peak pressure limit and adjusted as necessary to accomplish the previously recommended parameters. Of course, the assessment of acid-base balance and oxygenation by either arterial blood gas measurements or end-tidal CO2 and pulse oximetry will allow more definitive adjustments.