Análisis del signo de Hoover en relación con parametros funcionales, radiologicos y de radio de curvatura en pacientes con enfermedad pulmonar obstructiva crónica / [Relationship between Hoover sign, functional and variables, and curvature radius in patients with obstructive pulmonary disease]

The purpose of the present study was: 1) to relate the Hoover sign -SH (+)- with several functional (spirometry and lung volumes) and radiographic (AP x-ray) parameters, 2) to characterize the changes in diaphragmatic curvature radius and the efficiency and to establish some relationships with the functional and radiographic parameters. Fifteen patients with COPD (SH (+), n: 8) were studied. The radius was determined in the right hemidiaphragm after maximal inspired and expired x-ray. The SH (+) was found in more severely obstructed patients (FEV1

) and with high degree of air trapping (RV/TLC

, p 0.01). The expiratory radius (Re) was higher (p 0.05), and their efficiency (1/Re), was minor (p 0.05). The FEV1

correlated with the degree of hyperinflation according to TLC

(r -0.58, p 0.022) and with air trapping according to RV

(r -0.77, p 0.0008). The patients with low FEV1

showed high Re (r -0.61, p 0.015) and decreased diaphragmatic efficiency during expiration (1/Re) according to 1/Re = 0.093 cm-1 + 0.0012 cm-1* FEV1

(r 0.688, p 0.0054). The FEV1 correlated with the diaphragmatic movement (r 0.71, p 0.003). The PaCO2 correlated with the TLC

(r 0.534, p 0.04), the RV

(r 0.62, p 0.014) and with the radiographic parameters of hyperinflation (r 0.546, p 0.035) and air trapping (r 0.528, p 0.043). The presence of Hoover sign suggest severe bronchial obstruction, diaphragmatic flattening, increase of curvature radius, decrease of mobility and efficiency.