A patient receiving mechanical ventilation has an exhaled tidal volume (VT) of 500 mL and a positive end expiratory pressure setting (PEEP) of 5 cm H2O. Patient-ventilator system checks reveal the following data:

Question

Time PIP (cm H2O) Pplateau (cm H2O)
0600 27 15
0800 29 15
1000 36 13

The respiratory therapist should recommend which of the following for this patient?
1. Tracheobronchial suctioning
2. Increase in the set tidal volume
3. Beta adrenergic bronchodilator therapy
4. Increase positive end expiratory pressure
a. 1 and 3 only
b. 2 and 4 only
c. 1, 2, and 3 only
d. 2, 3, and 4 only

Answer 1

ANS: A
Calculate the transairway pressure (PTA) by subtracting the plateau pressure from the peak inspir-atory pressure. Analyzing the PTA will show any changes in the pressure needed to overcome air-way resistance. Analyzing the Pplateau will demonstrate any changes in compliance. The Pplateau re-mained the same for the first two checks and then actually dropped at the 1000-hour check. An-alyzing the PTA, however, shows a slight increase between 0600 and 0800 (from 12 to 14 cm H2O) and then a sharp increase to 23 cm H2O at 1000. Increases in PTA signify increases in airway resistance. Airway resistance may be caused by secretion buildup, bronchospasm, mucosal ede-ma, and mucosal inflammation. Tracheobronchial suctioning will remove any secretion buildup, and a beta adrenergic bronchodilator will reverse bronchospasm. Increasing the tidal volume will add to the airway resistance according to Poiseuille's law. Increasing the PEEP will not address the root of this patient's problem; the patient's compliance is normal.