Evidence-based guidelines for weaning and discontinuation of ventilatory support

 

MAJOR RECOMMENDATIONS

Excerpted by the National Guideline Clearinghouse (NGC):

The grading scheme for the strength of the evidence for each recommendation (A-C) is defined at the end of the Major Recommendations.

Recommendation 1. In patients requiring mechanical ventilation for > 24 hours, a search for all the causes that may be contributing to ventilator dependence should be undertaken. This is particularly true in the patient who has failed attempts at withdrawing the mechanical ventilator. Reversing all possible ventilatory and nonventilatory issues should be an integral part of the ventilator discontinuation process. (Grade B)

Recommendation 2. Patients receiving mechanical ventilation for respiratory failure should undergo a formal assessment of discontinuation potential if the following criteria are satisfied:

1. Evidence for some reversal of the underlying cause of respiratory failure
2. Adequate oxygenation (eg, PaO₂/FIO₂ > 150-200; requiring positive end-expiratory pressure [PEEP] < 5-8 cm H₂O; FIO₂ < 0.4-0.5) and pH (e.g., > 7.25)
3. Hemodynamic stability as defined by the absence of active myocardial ischemia and the absence of clinically important hypotension (i.e., a condition requiring no vasopressor therapy or therapy with only low-dose vasopressors such as dopamine or dobutamine < 5 micrograms/kg/min)
4. The capability to initiate an inspiratory effort

The decision to use these criteria must be individualized. Some patients not satisfying all of the above the criteria (e.g., patients with chronic hypoxemia below the thresholds cited) may be ready for attempts at discontinuation of mechanical ventilation. (Grade B)

Recommendation 3. Formal discontinuation assessments for patients receiving mechanical ventilation for respiratory failure should be performed during spontaneous breathing rather than while the patient is still receiving substantial ventilatory support. An initial brief period of spontaneous breathing can be used to assess the capability of continuing onto a formal spontaneous breathing trial (SBT). The criteria with which to assess patient tolerance during SBTs are the respiratory pattern, adequacy of gas exchange, hemodynamic stability, and subjective comfort. The tolerance of SBTs lasting 30 to 120 min should prompt consideration for permanent ventilator discontinuation. (Grade A)

Recommendation 4. The removal of the artificial airway from a patient who has successfully been discontinued from ventilatory support should be based on assessments of airway patency and the ability of the patient to protect the airway. (Grade C)

Recommendation 5. Patients receiving mechanical ventilation for respiratory failure who fail an SBT should have the cause for the failed SBT determined. Once reversible causes for failure are corrected, and if the patient still meets the criteria listed in Table 3 of the original guideline document, subsequent SBTs should be performed every 24 h. (Grade A)

Recommendation 6. Patients receiving mechanical ventilation for respiratory failure who fail an SBT should receive a stable, nonfatiguing, comfortable form of ventilatory support. (Grade B)

Recommendation 7. Anesthesia/sedation strategies and ventilator management aimed at early extubation should be used in postsurgical patients. (Grade A)

Recommendation 8. Weaning/discontinuation protocols designed for nonphysician health care professionals (HCPs) should be developed and implemented by intensive care units (ICUs). Protocols aimed at optimizing sedation should also be developed and implemented. (Grade A)

Recommendation 9. Tracheotomy should be considered after an initial period of stabilization on the ventilator when it becomes apparent that the patient will require prolonged ventilator assistance. Tracheotomy should then be performed when the patient appears likely to gain one or more of the benefits ascribed to the procedure. Patients who may derive particular benefit from early tracheotomy are the following:

• Those requiring high levels of sedation to tolerate translaryngeal tubes
• Those with marginal respiratory mechanics (often manifested as tachypnea) in whom a tracheostomy tube having lower resistance might reduce the risk of muscle overload
• Those who may derive psychological benefit from the ability to eat orally, communicate by articulated speech, and experience enhanced mobility
• Those in whom enhanced mobility may assist physical therapy efforts

(Grade B)

Recommendation 10. Unless there is evidence for clearly irreversible disease (e.g., high spinal cord injury or advanced amyotrophic lateral sclerosis), a patient requiring prolonged mechanical ventilatory support for respiratory failure should not be considered permanently ventilator-dependent until 3 months of weaning attempts have failed. (Grade B)

Recommendation 11. Critical-care practitioners should familiarize themselves with facilities in their communities, or units in hospitals they staff, that specialize in managing patients who require prolonged dependence on mechanical ventilation. Such familiarization should include reviewing published peer-reviewed data from those units, if available. When medically stable for transfer, patients who have failed ventilator discontinuation attempts in the intensive care unit should be transferred to those facilities that have demonstrated success and safety in accomplishing ventilator discontinuation. (Grade C)

Recommendation 12. Weaning strategy in the prolonged mechanical ventilation (PMV) patient should be slow-paced and should include gradually lengthening self-breathing trials. (Grade C)

[ธารทิพน์ วิเศษธาร]

wean