Mechanical Ventilation: Ventilator Specifics:

Modes of Mechanical Ventilation:

  • Patients should be on pressure control ventilation for at least the first 24 hours.
  • Patients can be switched to spontaneous ventilation when able, with high levels of PEEP.
  • Airway pressure release ventilation is another possible spontaneous ventilation mode, but this isn't typically used at TGH.

Pressure and Volume Settings:

  • "Ultra-protective" lung ventilation is recommended, keeping tidal volumes < 4ml/kg.
  • Driving pressures should be 10-15 cmH2O above the PEEP, while keeping the plateau pressure <25 cmH20.


  • The PEEP should initially be set at 10 cmH2O, and can be further increased for lung recruitment.
  • Patients with right-sided heart dysfunction may further decompensate with high levels of PEEP.
  • Patients with left-sided heart dysfunction may benefit hemodynamically from higher levels of PEEP.


  • The goal is to minimize the FiO2, ideally < 50%.
  • Remember, oxygenation of blood and tissues is determined by the flow and sweep gas settings.
  • " After optimizing the sweep and flow, the FiO2 should be adjusted to maintain an arterial O2 saturation of sbout 88-95%.

Respiratory Cycle:

  • The respiratory rate is typically set at 10 breaths per minute, and can be adjusted in consort with the sweep gas settings to maintain physiologic pH.
  • ELSO guidelines recommend an inverse ratio ventilation strategy (I:E ratio at 2:1).
  • At TGH we do not universally employ this strategy, we use it for patients with specific pathology.
  • At TGH we generally use a conventional I:E ratio.

Recruitment Manouvers:

  • The ELSO guidelines do not recommend performing recruitment maneuvers unless you have determined that the patient's lungs are contributing a significant amount to gas exchange
  • To determine if the lungs are contributing, the Cilley test is performed by increasing the FiO2 to 1.0; if the SaO2 rapidly increases to 100% then the test is positive.
  • The recommended recruitment maneuvers are.
    • Switch to CPAP at 25 cmH2O, or
    • PCV at 15/10, rate of 5, I:E at 3:1.

Summary of Ventilation Settings:

Summary of Ventilation Settings

Considerations for V-A ECMO:

  • Remember in V-A ECMO, some of the patient's still passes through the pulmonary circulation and relies on the lungs for oxygenation.
  • This blood is mixed with blood from the ECMO oxygenator in the patient's aorta.
  • At relatively low flows, the lungs play a significant role in tissue oxygen delivery.
  • Ventilation parameters may have to be adjusted to accommodate for this, and may require deviation from the recommended settings seen in Table 7-1.

Liberation from Mechanical Ventilation:

  • Just because a patient is on ECMO, it does NOT mean they need intubation or mechanical ventilation.
  • In some cases, patients benefit from being liberated from mechanical ventilation and extubated while on ECMO.
    • These are usually patients who are on ECMO as a bridge to recovery.
  • Patients on ECMO should have sedation reduced and switched to spontaneous ventilation as early as possible (if it is safe to do so).
  • Because native respiration is not required for gas exchange, patients may be extubated on ECMO without passing traditional criteria.
  • Extubating patients while on ECMO can help facilitate mobilization and rehabilitation.

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