Amyotrophic lateral sclerosis: prospective study on respiratory parameters.

Objective: To verify how efficient respiratory parameters are in the follow-up of subjects with amyotrophic lateral sclerosis (ALS) and to observe possible correlations between respiratory and nutritional functions.

Method: Sixteen patients with probable or defined ALS were selected and evaluated over eight months using the following respiratory parameters: spirometry, maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), arterial gasometry and pulse oximetry; and nutritional parameters such as body mass index (BMI) and percentage weight loss.

Results: P(a)CO(2) was a significant parameter to follow up disease evolution (p=0.051). There was significant correlation between MIP and MEP (r: 0.83); BMI and MIP (r: 0.70); BMI and MEP (r: 0.72); pulse oximetry and forced vital capacity (r: 0.57).

Conclusion: P(a)CO(2) was shown to be an efficient and significant parameter in the measurement of respiratory impairment; the correlations among MIP, MEP and BMI indicated that these are significant parameters for periodic clinical evaluation.