Effect of Low-Flow Anesthesia in Single Lung Ventilation on Postoperative Respiratory Complications

Mechanical ventilation in thoracic surgery patients is often complicated because patients are usually in the lateral decubitus position and the operated lung is intermittently deflated to facilitate surgical exposure . Single-lung ventilation during thoracic surgery is prone to volutrauma, barotrauma, atelectrauma, and oxygen toxicity, which are important aspects of ventilator-associated lung injury (VILI) . In studies conducted on operated patients, the use of lung-protective ventilation, including low tidal volume (6-8 ml/kg), respiratory rate, driving pressure (DP), and positive end-expiratory pressure (PEEP) application, has been recommended in the perioperative period to reduce postoperative pulmonary complications. Optimum oxygenation should be provided to patients during the intraoperative period, avoiding the harmful effects of hypoxia and hyperoxia. This situation becomes even more important in single-lung ventilation. Fresh gas flow in anesthesia systems can be done with traditional high-flow, normal-flow, or low-flow strategies according to the clinician's preference. The interest in the anesthesia method with low fresh gas flow has increased all over the world and in our country. The development of the technology of the anesthesia devices used, the increase in knowledge about the content of inhaled gases, and the availability of monitors that continuously and thoroughly analyze the anesthetic gas composition have facilitated the use of low-flow anesthesia safely. When the literature is evaluated, it is defined as 4 lt/min and above as very high flow, 2-4 lt/min as high flow, 1-2 lt/min as medium flow, 0.5-1 lt/min as low flow, 0.25-0.5 lt/min as minimal flow, and \<0.25 lt/min as metabolic flow . High flow has now been abandoned due to both cost and environmental pollution. Low-flow anesthesia creates a breath air closer to physiological conditions during anesthesia by heating and humidifying the inhaled gases. In addition, it provides a cost advantage