A 47-year-old, 6'1" male patient is admitted to the hospital due to trauma from a motor vehicle accident. Forty-eight hours post admission, the patient is suffering from respiratory distress with severe hypoxemia and is intubated

Question

A chest X-ray, done prior to intubation, reveals a ground glass appearance bilaterally. The physi-cian requests the volume-controlled continuous mandatory ventilation (VC-CMV) mode for this patient. The initial settings for the ventilator should be which of the following?
a. VT = 450 mL, rate = 18 breaths/min, PEEP = 8 cm H2O
b. VT = 600 mL, rate = 10 breaths/min, PEEP = 5 cm H2O
c. VT = 750 mL, rate = 15 breaths/min, PEEP = 10 cm H2O
d. VT = 900 mL, rate = 12 breaths/min, PEEP = 5 cm H2O

Answer 1

ANS: A
First calculate ideal body weight (IBW) for a male, using the formula 106 + 6(ht – 60). This pa-tient's IBW is 84 kg. Minute ventilation is about 100 mL/kg IBW, which would be 8.4 L/min. Since the patient appears to have acute respiratory distress syndrome (ARDS) the tidal volume should be set to between 4 and 6 mL/kg. This would make the appropriate tidal volume range 336-504 mL. This eliminates all of the choices except "A." Dividing the tidal volume range into 8.4 L/min gives the set rate range at 17-25 breaths/min. This also eliminates all but choice "A."