Question

A patient's chest radiograph indicates scattered patchy infiltrates. The following parameters are observed while the patient receives VC A/C ventilation:

Height 168 cm (5 ft 6 in)
Temperature 38.1 deg C (100.5 deg F)
Pressure (peak) 52 cm H₂O
Pressure (plat) 38 cm H₂O
VT (set) 500 mL
Mandatory rate 16
FIO2 1.0
PEEP 10 cm H₂O

Which of the following changes in mechanical ventilation should the respiratory therapist recommend?
1) decrease mandatory rate
2) increase PEEP
3) increase inspiratory flow
4) decrease set VT

Answer 1

Given the high peak pressures, the respiratory therapist should consider strategies to reduce the risk of ventilator-induced lung injury. Therefore, the best option is to decrease the set tidal volume to potentially lower peak pressures and minimize barotrauma, in line with lung-protective ventilation practices. The correct option is 4.

Step-by-step explanation:

A patient receiving VC A/C ventilation, whose chest radiograph indicates scattered patchy infiltrates suggestive of pneumonia, and has the following parameters: a preset tidal volume (VT) of 500 mL, a mandatory rate of 16 breaths per minute, an FiO2 of 1.0, and PEEP at 10 cm H2O.

The peak pressure is observed at 52 cm H2O and the plateau pressure at 38 cm H2O. Given that these pressures are relatively high, particularly the peak pressure, the respiratory therapist should consider strategies to reduce the risk of ventilator-induced lung injury (VILI).

While increasing PEEP might be a consideration for improving oxygenation and preventing alveolar collapse, the high peak pressure suggests there is already a significant amount of pressure being applied to the lungs. Therefore, option 2 (increase PEEP) might not be advisable without further assessment.

Options 1 (decrease mandatory rate) and 3 (increase inspiratory flow) could potentially increase the peak pressure or not affect it at all, respectively. However, option 4 (decrease set VT) might be the best choice. Reducing the VT could lead to lower peak pressures, decrease the risk of VILI, and still allow adequate ventilation. This would be in line with strategies of lung-protective ventilation, which often involve using lower VT to minimize barotrauma from high pressures.