RESPIRATORY MUSCLES - FUNCTIONAL-EVALUATION

The respiratory muscles are essential components of the pump that move air in and out of the lungs. The function of the respiratory muscles is intimately linked with their anatomical arrangement and their histo logical and biochemical composition. Diseases that affect the respirat ory system invariably affect the muscles and their work. More often th e end result is a decrease in the force the muscles can generate, and in some extreme cases the development of muscle fatigue. Compromise in the function can be initially assessed by simple history, especially positional dyspnea, Determination of the respiratory rate, and observa tion of the thoraco-abdominal displacement in the upright and supine p osition complement the initial evaluation, Measurement of spirometry i n the sitting and the supine position, and determination of lung volum es and blood gases help direct attention to the respiratory muscles. D ecreased strength is confirmed by measuring inspiratory and expiratory forces, Decreased endurance can also be measured with relatively simp le stools. The addition of esophageal and gastric pressures, EMG and t horacoabdominal movements add certainty to the evaluation. The near fu ture incorporation of MRI to the dynamic evaluation of respiratory mus cle function will add a new dimension to our capacity to evaluate thei r function, This monograph systematically reviews these accepted conce pts and offers the readers a tool to enhance their knowledge in this i mportant area of respiration.