Breathing Easier: Evolving Strategies in Ventilator Liberation Guidelines

Before liberating a patient from mechanical ventilation, a weaning process is used to determine whether the artificial airway can safely be removed. Weaning methods include intermittent mandatory ventilation, synchronized intermittent ventilation, and pressure support ventilation. A spontaneous breathing trial (SBT) is a period of spontaneous breathing typically lasting 30 to 120 minutes with little to no positive pressure ventilatory assistance.
 
Studies have found that clinicians are slow to recognize readiness for extubation in nearly 75% of patients.¹ One study reported that only 55% of patients who pass an SBT are liberated from the ventilator before an additional SBT is performed.² Therefore, current guidelines have been fine-tuned to allow for earlier extubation without increasing the risk of complications. In 2017, the American Thoracic Society published guidelines on performing SBTs using post-extubation noninvasive ventilation, sedation management during SBT, and a cuff leak test.³ In this Concise Critical Appraisal, we highlight the key takeaways from the latest American Association for Respiratory Care mechanical ventilation liberation guidelines.⁴
 
Similarities to the 2017 Ventilator Weaning/Discontinuation Guidelines³:

• Clinicians should evaluate, address, and attempt to reverse all causes contributing to ventilator dependence.
• Assessments for airway patency and ability to protect the airway should be performed before removing the artificial airway.
• Any patient who fails an SBT should have a causal investigation and, once reversed, a repeat SBT should be performed every 24 hours.
• Post-surgical patients should have sedation and ventilator strategies aimed at early extubation.
• The appropriateness of extubating a patient should be determined by the multiprofessional intensive care unit (ICU) team, including physicians, respiratory therapists, and nurses.
• A patient without a clearly irreversible disease should not be considered permanently ventilator dependent until three months of repeated weaning attempts have failed.
• In patients whose ventilation has been prolonged, weaning should include slow-paced and gradually lengthened SBTs.
• For patients at risk of extubation failure who pass an SBT, preventive noninvasive ventilation should be used after extubation.
• A cuff leak test should be performed in mechanically ventilated patients deemed at high risk for post-extubation stridor. If a patient fails a cuff leak test, systemic steroids should be administered for at least four hours before extubation. A repeat cuff leak test is not required.
• After extubation, continuous monitoring and serial assessments are essential to promptly detect any signs of respiratory compromise.

 
Changes from the 2017 Ventilator Weaning/Discontinuation Guidelines:

• For patients ventilated longer than 24 hours, an SBT can be conducted with or without low-level pressure support ventilation (inspiratory pressure augmentation of < 8 cm H₂O).
• A rapid shallow breathing index is no longer needed to determine readiness for an SBT.
• To improve the rate of successful liberation, an SBT should be completed before noon each day.
• During the SBT process, the fraction of inspired oxygen should not be increased.

 
The decision to extubate a patient continues to depend on several factors, including overall respiratory status and condition, ability to protect their airway, and level of consciousness. It is critical that clinicians follow established extubation protocols and guidelines to ensure safe extubation with minimal risk of complications (e.g., reintubation, respiratory distress, cardiac arrest).
 
The updated guidelines have not altered the assessments for readiness to extubate, sedation protocols, and monitoring and managing the patient after extubation. Instead, the updated guidelines have changed some of the extubation criteria and weaning protocols. With advancements in ICU care, perhaps including artificial intelligence, the ventilator weaning and liberation process will continue to be augmented to reduce mechanical ventilation days and improve patient outcome.
 
 
References:

1. Esteban A, Frutos F, Tobin MJ, et al. A comparison of four methods of weaning patients from mechanical ventilation. Spanish Lung Failure Collaborative Group. N Engl J Med. 1995 Feb 9;332(6):345-350.
2. Robertson TE, Mann HJ, Hyzy R, Rogers A, et al; Partnership for Excellence in Critical Care. Multicenter implementation of a consensus-developed, evidence-based, spontaneous breathing trial protocol. Crit Care Med. 2008 Oct;36(10):2753-2762.
3. Ouellette DR, Patel S, Girard TD, et al. Liberation from mechanical ventilation in critically ill adults: an official American College of Chest Physicians/American Thoracic Society clinical practice guideline: inspiratory pressure augmentation during spontaneous breathing trials, protocols minimizing sedation, and noninvasive ventilation immediately after extubation. Chest. 2017 Jan;151(1):166-180.
4. Roberts KJ, Goodfellow LT, Battey-Muse CM, et al. AARC clinical practice guideline: spontaneous breathing trials for liberation from adult mechanical ventilation. Respir Care. 2024 Apr 24:respcare.11735. Online ahead of print.