Strategies for Success in One-lung Anesthesia

Abstract

One lung anesthesia is defined as a technique in which one lung is separated from the other in ventilation during surgery. Lung isolation techniques are primarily designed to facilitate OLV in patients undergoing cardiac, thoracic, mediastinal, vascular, osophageal, or orthopedic procedures involving the chest cavity. Pulmonary ventilation means the inflow and outflow of air between the atmosphere and the lung alveoli. Distribution of ventilation is different between each lung segment according to the position, pleural pressure and transpleural pressure. Pulmonary perfusion serves three purposes which are; delivering oxygen to the body, removing CO2 from the alveoli, and providing left heart preload to support systemic cardiac output. Lung perfusion can be affected by gravitational and non-gravitational factors. Hypoxic pulmonary vasoconstriction is the constriction of the small arterioles in response to alveolar hypoxia. There are various modifiers to HPV such as; inhalation anesthetics, intravenous anesthetics, other drugs, surgical retraction, and positioning of the patient. Thoracic surgery represents a unique set of physiological problems that require special considerations.