Nasal inspiratory pressure: An alternative for the assessment of inspiratory muscle strength?

Abstract

Introduction: The strength of inspiratory muscles is assessed thorough the determination of the static mouth pressure (MIP). However, since this manoeuvre has some problems, alternative techniques have been developed in the last few years. One of the most promising is determination of sniff nasal inspiratory pressure (SNIP). Aim: To evaluate SNIP assessment as an alternative for the evaluation of the maximal inspiratory muscle strength. Methods: Subjects were consecutively included and assigned to one of three different groups: control (8), COPD patients (23) and patients with neuromuscular disorders (21). Different maximal inspiratory pressures were determined: (a) dynamic at the esophagus (sniffPesmáx, reference variable), (b) MIP, and (c) SNIP. Results: Both SNIP and MIP showed an excellent correlation with the reference variable, sniffPesmáx (r=0.835 and 0.752, respectively, P<0.05 for both). SNIP/. sniffPesmáx intra-class correlation coefficients were 0.585 (CI 95%: -0.097 to 0.901) in controls, 0.569 (CI 95%: -0.048 to 0.836) in COPD patients, and 0.840 (CI 95%: 0.459 to 0.943) in neuromuscular disorders, respectively. For MIP/. sniffPesmáx these values were 0.602 CI 95%: -0.108 to 0.933), 0.418 (CI 95%: -0.108 to 0.761), and 0.712 (CI 95%:, 0.378 a 0.882). Moreover, both SNIP and MIP showed 100% sensitivity in the three groups of subjects, although specificities were 100%, 69% and 75% for SNIP, and 83%, 54% and 75% for MIP, respectively. Conclusions: SNIP is a good physiological marker of inspiratory muscle strength. Its role is likely to complement that of MIP. © 2010 SEPAR.