The Role of Non-invasive Ventilation and Factors Predicting Extubation Outcome in Myasthenic Crisis

Abstract

NIV may be applied to those patients with a low APACHE II score and a lesser degree of metabolic compensation for respiratory acidosis. For patients undergoing invasive mechanical ventilation, extubation failure is associated with significant in-hospital morbidity in myasthenic crisis. Adequate levels of Pemax and cough strength correlate significantly with extubation success.

Respiratory Care for Myasthenic Crisis

“…Patients are typically extubated if VC and PImax are ≥ 15 mL/kg and ≤_-20 cm H 2 O, respectively, and tidal volume ≥ 5 mL/kg (Kirmani et al, 2004;Meriggioli, 2009). In our study, a PEmax of > 40 cm H 2 O was a good predictor of extubation success in these patients (Wu et al, 2009). If the patient complains of fatigue or shortness of breath, extubation should not be performed even if the criteria of these indices are met and blood gases are normal (Berrouschot et al, 1997;Gracey et al, 1983;.…”

“…In addition, patients who had passed SBT but presented cough PEF of 60 L/min or less were nearly 5 times more likely to fail extubation compared with those with cough PEF higher than 60 L/min (Salam et al, 2004). In myasthenics, our data indicate that extubation failure is most commonly associated with a weak cough and inadequate airway clearance, and Pemax is useful in predicting cough strength after extubation (Wu et al, 2009). …”

“…If the patient complains of fatigue or shortness of breath, extubation should not be performed even if the criteria of these indices are met and blood gases are normal (Berrouschot et al, 1997;Gracey et al, 1983;. Our experience also indicates that the rapid shallow breathing index (breathing frequency divided by tidal volume) is a poor predictor for extubation outcome in patients with neuromuscular diseases (Kuo et al, 1996;Wu et al, 2009). …”

“…Tracheostomy placement ranges from 14 to 40% (Thomas et al, 1997;Rabinstein and Mueller-Kronast, 2005). In our retrospective analysis of 41 episodes, tracheostomy was performed in four (9.8 %) patients after being ventilated for a median duration of 26 days (range: 20 to 30 days) (Wu et al, 2009). All these four patients were finally liberated from mechanical ventilation (Wu et al, 2009).…”

“…Reintubaton is a significant event because these patients have significantly longer ICU and hospital stays (Rabinstein and Mueller-Kronast, 2005). Extubation failure is also associated with a higher incidence of ventilator-associated pneumonia (VAP) (Wu et al, 2009). Atelectasis is the most important risk factor for extubation failure in myasthenic crisis.…”