Patient-ventilator asynchrony with nocturnal noninvasive ventilation in ALS

Area of Science:

• Neurology
• Pulmonology
• Biomedical Engineering

Background:

• Amyotrophic lateral sclerosis (ALS) management guidelines from the American Academy of Neurology (AAN) recommend noninvasive positive pressure ventilation (NIV) for patients with forced vital capacity (FVC) ≤50% predicted.
• Despite NIV's role, patient-ventilator asynchrony during nocturnal use in ALS patients has not been systematically investigated.

Purpose of the Study:

• To systematically evaluate the extent of nocturnal patient-ventilator asynchrony in ALS patients using NIV as prescribed by current AAN guidelines.
• To determine if demographic, disease severity, or NIV settings predict the degree of asynchrony.

Main Methods:

• Nocturnal polysomnography (PSG) was conducted on 23 ALS patients consistently using nocturnal NIV (nNIV) for FVC ≤50% or orthopnea.
• PSG recorded airflow, NIV pressures, respiratory effort, and oxygen saturation (SpO2).
• Patient-ventilator asynchrony was quantified using an asynchrony index (AI) per hour of recording time.

Main Results:

• Nineteen patients provided adequate PSG data; the mean AI was 69 ± 46/hour, with asynchrony time averaging 17% of recording time.
• Mean nadir SpO2 was 85% ± 7%.
• No significant predictors of asynchrony were identified among demographic, functional severity (FVC, ALSFRS-R), or NIV parameters.

Conclusions:

• Frequent nocturnal patient-ventilator asynchrony is documented in ALS patients using nNIV according to AAN guidelines.
• Current NIV prescription practices based on AAN guidelines may not provide optimal nocturnal ventilatory support for ALS patients.
• Further research is needed to optimize NIV settings and strategies for ALS patients.