Maximal Dynamic Inspiratory Pressure Evaluation in Heart Failure: A Comprehensive Reliability and Agreement Study

Abstract

Objective The purpose of this study was to analyze the reliability (interrater and intrarater) and agreement (repeatability and reproducibility) properties of tapered flow resistive loading (TFRL) measures in patients with heart failure. Methods For this cross-sectional study, participants were recruited from the cardiopulmonary rehabilitation program at the University of Brasilia from July 2015 to July 2016. All patients participated in the study, and 10 were randomly chosen for intrarater and interrater reliability testing. The 124 participants with heart failure (75% men) were 57.6 (SD = 1.81) years old and had a mean left ventricular ejection fraction of 38.9% (SD = 15%) and a peak oxygen consumption of 13.05 (SD = 5.3) mL·kg·min−1. The main outcome measures were the maximal inspiratory pressure (MIP) measured with a standard manovacuometer (SM) and the MIP and maximal dynamic inspiratory pressure (S-Index) obtained with TFRL. The S-Index reliability (interrater and intrarater) was examined by 2 evaluators, the S-Index repeatability was examined with 10 repetitions, and the reproducibility of the MIP and S-Index was measured with SM and TFRL, respectively. Results The reliability analysis revealed high S-Index interrater and intrarater reliability values (ICCs of 0.89 [95% CI = 0.58–0.98] and 0.97 [95% CI = 0.89–0.99], respectively). Repeatability analyses revealed that 8 maneuvers were required to reach the maximum S-Index in 75.81% (95% CI = 68.27–83.34) of the population. The reproducibility of TFRL measures (S-Index = 68.8 [SD = 32.8] cm H2O; MIP = 66 [SD = 32.3] cm H2O) was slightly lower than that of the SM measurement (MIP = 70.1 [SD = 35.9] cm H2O). Conclusions The TFRL device provided a reliable intrarater and interrater S-Index measure in patients with heart failure and had acceptable repeatability, requiring 8 maneuvers to produce a stable S-Index measure. The reproducibilities of the S-Index, MIP obtained with SM, and MIP obtained with TRFL were similar. Impact TRFL is a feasible method to assess both MIP and the S-index as measures of inspiratory muscle strength in patients with heart failure and can be used for inspiratory muscle training making the combined testing and training capabilities important in both clinical research and in the management of patients with heart failure.

Inspiratory muscle endurance is similarly reduced in the early and late stages of chronic Chagas heart disease

“…In the same way, the constant load test, where the individual ventilates with a pre-determined load until extreme tiredness, results in a time variable called TLim, in seconds [21]. This pre-determined load differs from the protocols already described, where some authors use the percentage of Pthmax of the incremental load test [23,25,27] or the percentage of MIP [34]. Despite having types of evaluation well described the protocols for global IME testing still need standardisation [25].…”

“…Two tests to determine IME were performed using an electronic inspiratory resistor (PowerBreatheK5, IMT Technologies Ltd., Birmingham, UK) and a nose clip. Using a flow-dependent valve, this device modifies its diameter based on the generated inspiratory flow and dynamically prints load, with the airway not occluded [23]. The protocol of incremental load in steps and the protocol of constant load [22] were applied with 15 min of rest between them.…”

Diaphragm thickness and mobility elicited by two different modalities of inspiratory muscle loading in heart failure participants: A randomized crossover study

“…Porto Alegre, Brazil) previously calibrated with a measurement range of -300 to + 300 cmH 2 O, with a smooth plastic mouthpiece connected to the device and the use of a nose clip to avoid air escape [7]. The S-Index, which is a dynamic assessment of inspiratory pressure [15,16,24], was measured using the POWERBreathe 1 KH2 device (International, Ltd., Warwickshire, United Kingdom). For the MIP and S-Index, both inspiratory muscle tests, participants were seated and instructed to perform a maximal voluntary exhalation at residual volume, followed by a maximal inspiratory effort, according to ATS/ERS standards [8].…”