Quantifying diaphragm perfusion in humans: A novel application of contrast-enhanced ultrasound

As oxygen demand increases (e.g., exercise), the availability of oxygen decreases (e.g., high altitude) or cardiopulmonary function is impaired (e.g., respiratory disease), our cardiopulmonary system works at a greater percentage of its maximal capacity to supply oxygenated blood to tissues. Currently, there is no reliable way of determining the blood flow to the respiratory muscles. The current technique (near-infrared spectroscopy with injectable dyes) has conflicting data and limitations which hinders our understanding of respiratory muscle blood flow.