What criteria are used to determine whether extubation will be successful?

After several days in the SICU, the patient’s respira-tory status has improved. What criteria are used to determine whether extubation will be successful?

Several criteria should be met to consider extubation:

·  The patient should be alert and cooperative on no sedation.

·  Muscular strength should be adequate, with a negative inspiratory force (NIF) ≤ –25 cm H₂O and/or a forced vital capacity (FVC) ≥15 mL/kg.

·  The hemodynamics should be stable, with no or minimal vasoactive infusions.

·  The PaO₂ should be ≥60 mmHg on a FiO₂ ≤0.5 and PEEP ≤5 cm H₂O.

·  The PaCO₂ should be ≤50 torr, or near the patient’s baseline.

·        The patient should tolerate a trial of spontaneous venti-lation, either on the respirator with a PS of 5–10 cm H₂O or on a T-piece. No tachypnea, dyspnea, tachycardia, hypertension, dysrhythmias, signs of myocardial ischemia, or desaturation should be observed. Obtaining an ABG after 30 minutes of such a trial does not add any further information to the clinical examination and the pulse oximeter data.

Protocols driven by non-physician staff, such as nurses or res-piratory therapists, have been shown to lead to significantly earlier discontinuation of mechanical ventilation and should probably be the rule.

Numerous criteria have been proposed to predict successful extubation, but the most helpful may be the “rapid shallow breathing index” or RSBI, calculated in a patient breathing spontaneously with a low PS.

RR is the respiratory rate in breaths per minute and V_T is the tidal volume in liters. A value below 105 suggests that extubation will be successful.