Session will explore challenges associated 
with the ‘difficult to wean’ patient

Michelle Cao, DO, FCCP
Michelle Cao, DO, FCCP

Four experts will review the latest evidence-based guidelines on mechanical ventilation liberation, address the role of noninvasive ventilation in liberation from the ventilator, and discuss nonconventional methods for weaning in two highly challenging diseases during Tuesday’s session Ventilator Liberation: Challenges to Weaning the ‘Difficult to Wean’ Patient. The session starts at 3:45 pm in room 294. One of those experts and chair of the symposium, Michelle Cao, DO, FCCP, answered these questions from the Daily News.

Why is successful weaning from mechanical ventilation a challenge in acute-on-chronic respiratory failure syndromes?

→ Traditional weaning protocols are designed for patients with acute respiratory failure, and may not be applicable to all types of respiratory failure. Neuromuscular patients, for example presenting with acute-on-chronic respiratory failure, have limited “respiratory reserve” due to progressive neuromuscular respiratory weakness. Many patients are already dependent on nocturnal and/or daytime ventilatory support. Traditional weaning protocols do not take this into account and therefore patients are at high risk for failing extubation.

What are the current protocols for weaning?

→ Protocols for ventilator liberation are not standardized across ICUs. That being said, the 2017 clinical practice guidelines on ventilator liberation, a joint effort from ACCP/ATS, recommends performing a spontaneous breathing trial (SBT) with inspiratory pressure augmentation rather than without (T-piece or CPAP). For high- risk patients who have passed SBT, the guideline recommends extubation directly to noninvasive ventilation.

What are the different unconventional weaning methods for respiratory failure in COPD and neuromuscular disease?

→ “Unconventional” is the best term to describe ventilator liberation strategies for this high-risk group of patients. It would depend on the patient’s underlying medical condition, especially if the patient is dependent on home ventilatory support nocturnally or full time. For the neuromuscular patient or hypercapnic COPD patient, “weaning” protocols are not the best strategies to help the clinician determine a successful extubation. For example, extubation directly to noninvasive ventilatory support with high-pressure support (high inspiratory pressure, very low expiratory pressure) to augment ventilation and tidal volumes is probably the best approach for a neuromuscular patient whom is dependent on full-time home mechanical ventilation, noninvasively. Extubation directly to noninvasive ventilation is also recommended for the hypercapnic COPD patient. For neuromuscular patients, aggressive and scheduled implementation of mechanical in ex-sufflator (i.e. cough assist) pre- and post-extubation is also key to keeping the patient extubated.

How did these methods come about?

→ Previous studies have shown effectiveness of extubation directly to noninvasive ventilation to be successful in patients with hypercapnic respiratory failure. We are lacking robust clinical trials and clinical practice guidelines for the neuromuscular population specifically.

How does noninvasive ventilation come into play here?

→ Noninvasive ventilation is key to successful extubation for the hypercapnic respiratory failure patient. Dr. John Bach, who is considered to be a pioneer in respiratory care of neuromuscular patients, once quoted, “You do not wean from the ventilator; you wean from the endotracheal tube.” Many of our patients are already dependent on home ventilatory support noninvasively, so it does not make much sense to “wean” them from the ventilator, but rather, wean from the endotracheal tube, back to their baseline, which is dependence on home mechanical ventilation.

What other points/key takeaways do you want attendees to come away with? 

I hope that attendees will be more aware of the critical care management of acute-on-chronic hypercapnic respiratory failure, in particular neuromuscular disease and hypercapnic COPD. Clinical practice guidelines are needed for the critical care management of the acute on chronic respiratory failure patient, specifically those whom are dependent on home mechanical ventilatory support at baseline.