The investigators aimed to evaluate the effects of cardiomegaly associated with inspiratory muscle weakness on tricompartmental distribution of chest wall volumes, on the thickness of the right hemidiaphragm and on the contraction speed of the respiratory muscles. As method of the present research, a pilot cross-sectional study was conducted with fourteen (14) patients with heart failure, functional class II and III, clinically stable, with cardiomegaly. Two groups were formed: one group with inspiratory muscle weakness (WG) (maximal inspiratory pressure - MIP \<70% predicted MIP) and a control group without weakness (CG). The pulmonary and respiratory muscle functions were assessed by spirometry and manometer, respectively. Before and after maximal exercise test, optoelectronic plethysmography was performed to evaluate the distribution of volumes, the kinematics and the contraction speed of chest wall muscles. The high-resolution ultrasonography was also used before and after the maximum test for obtaining diaphragmatic thickness
Study Type
OBSERVATIONAL
Enrollment
14
The maximal exercise ramp test, symptom-limited, performed by all patients in the study was performed based on treadmill ramp protocol through ErgoPC Elite® software associated with 12-channels electrocardiogram. Respiratory variables were obtained in standard conditions of temperature, pressure and humidity (StPD), breath-by-breath, with the patient breathing through a face mask without leaks coupled to gas analyzer (Cortex - Metamax 3B, Germany).To ensure that patients reached maximum effort during the examination, only the tests which patients obtain a respiratory exchange ratio (RR) ≥1.1 were accepted .
Laboratório de Fisiologia e Fisioterapia Cardiopulmonar
Recife, Pernambuco, Brazil
RECRUITINGDiaphragmatic thickness
A high-definition ultrasound in the the B mode with linear transducer of 7.5 megahertz was used to measure diaphragmatic thickness. In the lateral decubitus position, the transducer was positioned perpendicular to the chest, between the eighth and ninth intercostal spaces between the right anterior and medium axillary lines. Diaphragm was identified by two hyperechoic (bright) lines parallel to the pleural and parietal membranes respectively. The measurement of diaphragm thickness was held from the middle of the pleural line to the middle of peritoneal. The average of 3 final measures taken at the apposition zone obtained: at functional residual capacity (thickness of the relaxed diaphragm - Erel) at the end of the total lung capacity (thickness of the diaphragm contracted - Econt) and during a maximal inspiratory pressure maneuver from functional residual capacity.
Time frame: 30 minutes
Chest Wall tricompartmental volumes
The images generated by the triangulation of the infra-red light reflected by 89 markers placed over volunteers' chest walls and captured by 8 cameras allows the visualization of the same thoraxes as entire structure and in its own tricompartmental division: pulmonary rib cage (RCp), abdominal rib age (RCab) and abdomen (AB). Each compartment can be evaluated in terms of their volume variation across the recorded respiratory cycle.
Time frame: 30 minutes
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