Concurrent Validity of the Static and Dynamic Measures of Inspiratory Muscle Strength: Comparison between Maximal Inspiratory Pressure and S-Index

• Autor(a) principal: Areias,Guilherme de Souza
• Data de Publicação: 2020
• Outros Autores: Santiago,Luan Rodrigues, Teixeira,Daniel Sobral, Reis,Michel Silva
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Brazilian Journal of Cardiovascular Surgery (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0102-76382020000400011
• topic: Residual Volume; Maximal Respiratory Pressures; Linear Models; Total Lung Capacity; Muscle Strength; Muscle Contraction

Abstract Objective: To verify the concurrent validity between the inspiratory muscle strength (IMS) values obtained in static (maximal inspiratory pressure [MIP]) and dynamic (S-Index) assessments. Methods: Healthy individuals were submitted to two periods of evaluation: i) MIP, static maneuver to obtain IMS, determined by the Mueller’s maneuver from residual volume (RV) until total lung capacity (TLC); ii) and S-Index, inspiration against open airway starting from RV until TLC. Both measures were performed by the same evaluator and the subjects received the same instructions. Isolated maneuvers with differences < 10% were considered as reproducible measures. Results: Data from 45 subjects (21 males) were analyzed and that showed statistical difference between MIP and S-Index values (133.5 ± 33.3 and 125.6 ± 32.2 in cmH2O, respectively), with P=0.014. Linear regression showed r2=0.54 and S-Index prediction formula = 39.8+(0.75×MIP). Pearson’s correlation demonstrated a strong and significant association between the measures with r=0.74. The measurements showed good concordance evidenced by the Bland-Altman test. Conclusion: S-Index and MIP do not present similar values since they are evaluations of different events of the muscular contraction. However, they have a strong correlation and good agreement, which indicate that both are able to evaluate the IMS of healthy individuals.