PURPOSE: Assessment of respiratory muscle strength is important to quantify the impact of chronic disease and the effects of respiratory muscle training.Maximal mouth and nasal inspiratory pressure tests (PIMax and SNIP) are currently applied to evaluate respiratory muscle strength.Its relationship was previously established; however, chest wall compartmental displacement during the maneuvers was not assessed. The aim of this study is to measure chest wall kinematics during maximal mouth and nasal inspiratory pressure in young healthy subjects.
METHODS: Optoelectronic Plethysmography was used to determine total and regional chest walldisplacement in 7 healthy males subjects(age 25.4 5.8 years,BMI 25 2.6kg/m2) during PImax and SNIPtests. Mouth and nasal inspiratory pressure were measured by a manometer.Displacement of chest wall compartments were normalized to total lung capacity(TLC) of each compartment(represented as % of TLC) toestablish an expansion index of total chest wall, pulmonary rib cage, abdominal rib cage and abdominal compartments.
RESULTS: Chest wall Kinematics during PImax and SNIP reveals the following compartmentaldisplacement in %TLC: chest wall 5±2.2% vs 2.4±1.7%, pulmonary rib cage 4.3±2% vs 1.8±1.2% (P=0.009,CI95% 0.87 to 4.1), abdominal rib cage 7.5 3.9 vs 3.8 2.1 and abdominal 5.4±4.1 vs 2.6±2.1%.All compartments expand further during PImax when compared to SNIP. PImax, PEmax and SNIP values (in cmH2O) were 148.3±40.0, 192±46.3 and 174.7±12; respectively.
CONCLUSION:Chest wall displacement tends to be higher during PImax maneuvers compared to SNIP especially at the rib cage pulmonary compartment,probably, due to higher and sustained accessory inspiratory muscle recruitment.
CLINICAL IMPLICATIONS: Results of respiratory muscle training depend of training schedule, intensities, frequency and type of training. Nevertheless training must to be effective to assess results of training is important. PImax and SNIP appears to assess inspiratory muscle strengths in different ways.
DISCLOSURE: Guilherme de Freitas Fregonezi, No Financial Disclosure Information; No Product/Research Disclosure Information