Table    1 .

Criteria of readiness for weaning trial

Criteria
Subjective assessment
Adequate cough
No neuromuscular blocking agents
Absence of excessive trachea-bronchial secretion
Reversal of the underlying cause for respiratory failure
No continuous sedation infusion or adequate mentation on sedation
Objective measurements
Stable cardiovascular status
Heart rate ≤ 140 beat/minute
No active myocardial ischemia
Adequate hemoglobin level ( ≥ 8 g/dl)
Systolic blood pressure 90–160 mmHg
Afebrile (36° C < temperature < 38° C)
No or minimal vasopressor or inotrope (< 5 µg/kg/minute dopamine or dobutamine)
Adequate oxygenation
Tidal volume > 5 mL/kg
Vital capacity >10 mL/kg
Proper inspiratory effort
Respiratory rate ≤ 35/minute
PaO2 ≥ 60 and PaCO2 ≤ 60 mmHg
Positive end expiratory pressure ≤  8 cmH2O
No significant respiratory acidosis (pH ≥ 7.30)
Maximal inspiratory pressure (MIP) ≤ -20 – -25 cmH2O
O2 saturation > 90% on FIO2 ≤ 0.4 (or PaO2/FIO2 ≥ 200)
Rapid Shallow Breathing Index (respiratory Frequency/Tidal Volume) < 105