Bulbar impairment score predicts noninvasive volume-cycled ventilation failure during an acute lower respiratory tract infection in ALS

Abstract

Amyotrophic lateral sclerosis (ALS) patients can suffer episodes of lower respiratory tract infections (LRTI) leading to an acute respiratory failure (ARF) requiring noninvasive ventilation (NIV).

Aim: To determine whether clinical or functional parameters can predict noninvasive management failure during LRTI causing ARF in ALS.

Material and method: A prospective study involving all ALS patients with ARF requiring NIV in a Respiratory Care Unit. NIV was provided with volume-cycled ventilators.

Results: 63 ALS patients were included (APACHE II: 14.93±3.56, Norris bulbar subscore (NBS): 18.78±9.68, ALSFRS-R: 19.90±6.98, %FVC: 40.01±18.07%, MIC: 1.62±0.74L, PCF 2.51±1.15L/s, PImax -34.90±19.44cmH2O, PEmax 51.20±28.84cmH2O). In 73.0% of patients NIV was successful in averting death or endotracheal intubation. Differences were found between the success and failure in the NBS (22.08±6.15 vs 8.66±3.39, p<0.001), ALSFRS (22.08±6.11 vs 12.71±4.39, p<0.001), PCFMI-E (3.85±0.77 vs 2.81±0.91L/s, p=0.007) and ALS onset (spinal/bulbar 33/13 vs 7/10, p=0.03). The predictor of NIV failure was the NBS (OR 0.53, 95% CI 0.31-0.92, p 0.002) with a cut-off point of 12 (S 0.93; E 0.97; PPV 0.76; NPV 0.97).

Conclusions: NBS can predict noninvasive management failure during LRTI in ALS.

Keywords: Amyotrophic lateral sclerosis; Assisted coughing; Bulbar dysfunction; Neuromuscular disease; Noninvasive ventilation; Respiratory failure; Respiratory infection.