Discontinuation of Mechanical Ventilation

A simple daily assessment screen can identify patients who may be considered for successful tracheal extubation. This includes:

• Adequate gas exchange (e.g. PaO2/FiO2 greater than 150 to 200; level of positive end expiratory pressure (PEEP) less than 5 to 8 cm H2O; FiO2 less than 0.4 to 0.5; and pH greater than 7.25);
• Hemodynamic stability as defined by the absence of active myocardial ischemia and the absence of clinically significant hypotension (i.e., a condition requiring no vasopressor therapy or therapy with only low-dose vasopressors such as dopamine or dobutamine, less than 5 mcg/kg/min); and
• Appropriate neurological and muscular status allowing the capability to initiate an inspiratory effort.

Indicators of failure of spontaneous breathing trials

Inadequate gas exchange

• Arterial oxygenation saturation less than 85-90 %
• PaO2 less than 50-60 mmHg
• pH less than 7.32
• Increase in PaCO2 greater than 10 mmHg

Unstable ventilatory pattern

• Respiratory rate greater than 30-35 breaths/minute
• Respiratory rate change over 50%

Hemodynamic instability

• Heart rate greater than 120-140 beats/minute
• Heart rate change over 20%
• SBP greater than 180 mmHg, or
• SBP less than 90 mmHg
• Blood pressure change greater than 20%
• Vasopressors required

Change in mental status

• (e.g. somnolence coma, agitation, anxiety)

Signs of increased work of breathing

• (e.g. use of accessory respiratory muscles, nasal flaring, paradoxical breathing movements)

Onset or worsening of discomfort, diaphoresis

More here.