Chapter 12 - Hyaluronan in Ventilator-Induced Lung Injury

Abstract

This chapter presents the changes in the properties of hyaluronan caused by ventilator-induced lung injury (VILI). Treatment of patients with acute lung injury (ALI) or the more severe form, termed acute respiratory distress syndrome (ARDS), often requires the use of mechanical ventilation with high levels of oxygen to adequately oxygenate the brain and other vital organs. ALI is a general term that refers to damage to the lungs that occurs in a number of different situations, including infection of the blood, lungs or abdomen, aspiration of stomach contents into the lungs, pancreatitis, multiple blood transfusions, trauma, drug overdose, or near-drowning. Mechanical ventilation with large tidal volumes is used in order to recruit diseased areas of the lung with low compliance. This unfortunately leads to overdistension of normal areas of lung that display normal compliance. In severely damaged lungs, in which air space is reduced by up to 60%, the use of even low tidal volumes, calculated on the basis of the patient's size, may lead to the overdistension of the remaining normal lung. The damage to the normal areas of the lung by overdistension in ALI/ARDS has become known as VILI. Hyaluronan has been shown to be increased and to play a possible role in many forms of lung disease, including cystic fibrosis, asthma, alveolar proteinosis, sarcoidosis, farmer's lung, idiopathic pulmonary fibrosis bleomycin-induced lung injury, smoke-inhalation injury, lung injury from diesel fuel and emphysema. Hyaluronan has both structural and inflammatory properties in the lung. LMW HA may have an important role in inflammation as found in forms of ALI, including ARDS and VILI.