Critical Care Medicine-Pulmonary Disorders>>>>>Respiratory Diagnostic Modalities and Monitoring
Question 8#

A previously healthy 28-year-old man presents to the emergency department with severe respiratory distress, flu-like symptoms, and cough. The emergency physician intubates the patient for hypoxic respiratory failure. His postintubation chest x-ray shows diffuse, bilateral pulmonary infiltrations, and appropriate endotracheal tube position. The initial mechanical ventilation settings are FiO2 50%, PEEP 18 cm H2O, and tidal volume (TV) 6 mL/kg ideal body weight (IBW). The patient is transferred to the ICU, and 6 hours later you are informed that the patient is hypoxic on FiO2 100%, PEEP 24 cm H2O, and tidal volume (TV) 8 mL/kg ideal body weight (IBW). His plateau pressure is 42 cm H2O, and his ABG shows PaO2 of 54. You decided to place the patient on venovenous extracorporeal membrane oxygenation (V-V ECMO).

Which of the following mechanical ventilation settings are BEST after VV ECMO initiation?

A. Pressure controlled 25 cm H2O, rate 5, PEEP 15 cm H2O, FiO2 50%
B. Pressure controlled 30 cm H2O, rate 14, PEEP 10 cm H2O, FiO2 50%
C. Volume controlled, TV 5 mL/kg IBW, rate 14 PEEP 10 cm H2O, FiO2 50%
D. Volume controlled, TV 8 mL/kg IBW, rate 5, PEEP 10 cm H2O, FiO2 50%

Correct Answer is A

Comment:

Correct Answer: A

Venovenous ECMO can be used as salvage therapy in severe acute respiratory distress syndrome (ARDS). The ECMO circuit membrane lung (often called the oxygenator) can provide full gas exchange without relying on the patient lungs. It improves oxygenation by providing prepulmonary oxygen-rich blood and ventilation by removing CO2 with the sweep gas in the membrane lung. When a patient is on full V-V ECMO support, mechanical ventilation strategy should focus on preventing ventilatorinduced lung injuries. High PEEP during the early course of V-V ECMO (10- 14 cm H2O) is associated with decreased mortality in ARDS patients. The Extracorporeal Life Support Organization (ESLO) recommends placing the patient on pressure controlled ventilation at 25/15, I:E 2:1, rate 5, and FiO2 50% for the first 24 hours (answer A). After 24 to 48 hours, ELSO recommends reducing the pressure to 20/10, but keeping I:E ratio at 2:1, FiO2 20% to 40%, rate at 5 and allow for spontaneous breathing.

References

  1. Schmidt M, Stewart C, Bailey M, et al. Mechanical ventilation management during extracorporeal membrane oxygenation for acute respiratory distress syndrome: a retrospective international multicenter study. Crit Care Med. 2015;43(3):654-664. doi:10.1097/CCM.0000000000000753.
  2. Extracorporeal Life Support Organization. ELSO Guidelines for Adult Respiratory Failure v1.4. Available at https://www.elso.org/Portals/0/ELSO%20Guidelines%20For%20Adult%20Resp Accessed October 24, 2018.