Predictors of ineffective cough during a chest infection in patients with stable amyotrophic lateral sclerosis.
BACKGROUND
In patients with neuromuscular diseases, a chest infection is associated with a reduction in respiratory muscle function that may result in decreased cough effectiveness.


OBJECTIVE
To determine if a clinical or functional parameter in patients with amyotrophic lateral sclerosis (ALS) in a stable condition could predict spontaneous cough ineffectiveness during a respiratory tract infection.


METHODS
Forty consecutive patients with ALS referred to our Respiratory Care Unit were studied during a one-year follow-up.


RESULTS
FEV(1), FVC, FEV(1)/FVC, peak cough flow (PCF), peak velocity time (PVT), maximum inspiratory and expiratory pressures, and bulbar dysfunction evaluation using the Norris scale bulbar subscore (NBS). A total of 26 patients (65%) had spontaneous cough ineffectiveness during a respiratory tract infection. The best variables to predict nonassisted cough during a respiratory tract infection were NBS (p < 0.01) with a cutoff point of 29 (sensitivity, 0.89; specificity, 0.90; positive predicted value, 0.88; negative predictive value, 0.87), PCF (p < 0.001) with a cutoff point of 4.25 L/s (sensitivity, 0.74; specificity, 0.85; positive predictive value, 0.71; negative predictive value, 0.85), and PCF/PVT (p < 0.001) with a cutoff point of 28.88 L/s(2) (sensitivity, 0.77; specificity, 0.96; positive predictive value, 0.91; negative predictive value, 0.89).


CONCLUSIONS
In patients with stable ALS, bulbar dysfunction (NBS < 29), PCF (< 4.25 L/s), and PCF/PVT (< 28.88 L/s(2)) could predict the risk of ineffective spontaneous cough during a respiratory tract infection.
Sancho
Jesús
J
Respiratory Care Unit, Hospital Clínico Universitario, Avda. Blasco Ibáñez 17, E46010 Valencia, Spain.
Servera
Emilio
E
Díaz
Juan
J
Marín
Julio
J
D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000150:complications* / Q000503:physiopathology; D003371:Cough / Q000150:complications* / Q000503:physiopathology / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009093:Mucus; D015999:Multivariate Analysis; D012372:ROC Curve; D012131:Respiratory Insufficiency / Q000209:etiology; D012141:Respiratory Tract Infections / Q000150:complications*; D012680:Sensitivity and Specificity; D013147:Spirometry