Table 3 Criteria to suspend the protocol and return to a controlled/supported mode of ventilation

(1) Surgery or invasive procedures requiring sedation

(2) Respiratory distress as defined by:

a) sustained hypoxemia (pulse oximetry oxygen saturation [SpO₂] < 90%) with an FiO₂ > 60% and PEEP > 10 cm H₂O or hypercapnia with pH < 7.30 OR clinical respiratory distress

b) repeated episodes (≥ 3 episodes within 1 h) wherein an inspiratory pressure (drive pressure + PEEP on pressure modes or plateau pressure on volume modes) of 35 cm H₂O or more is attained (despite suctioning, bronchodilation, etc.)

(3) Hemodynamic instability despite fluid boluses and requirement for high dose vasopressors: norepinephrine > 15 μg/min (0.2 μg/kg/min) or equivalent

(4) Suspected myocardial ischemia based on EKG and/or elevated Troponin I

(5) Neurologic deterioration with need to control PaCO₂ (e.g. raised intracranial pressure) or central hypoventilation

(6) Respiratory rate < 10 breaths/min related to need for increased sedation

(7) PEEP ≥ 13 cm H₂O

(8) FiO₂ ≥ 71%