Low Flow Anesthesia

Low-flow anesthesia (LFA) is a technique in which at least 50% of the exhaled air, after carbon dioxide absorption, is mixed with a certain amount of fresh gas and returned to the patient during the next inspiration. In 1974, R. Virtue defined minimal flow anesthesia (MFA) as 0.5 L/min. In 1984, Baker and Simionescu classified LFA as 0.5-1 L/min and MFA as 0.25-0.5 L/min. The aim of this study is to investigate whether there are hemodynamic differences between open-heart surgery cases performed with LFA at different fresh gas flow rates.

This study aims to evaluate changes in perfusion index (PI) in pediatric patients undergoing elective surgery under low-flow anesthesia. PI will be monitored at multiple intraoperative and postoperative time points to assess its relationship with hemodynamic stability and depth of anesthesia. The study will also investigate whether low-flow anesthesia affects the incidence of emergence agitation (EA). Patients will be assigned to either low-flow or normal-flow anesthesia groups based on routine clinical practice. No intervention will be applied beyond standard care. The findings are expected to provide insight into the predictive value of PI in postoperative recovery and support safer anesthesia practices in pediatric populations.

The aim of this study is to investigate the relationship between low-flow and normal-flow anesthesia techniques and the development of postoperative delirium in elderly patients undergoing surgery for hip fracture.

Emergence agitation (EA) involves restlessness, disorientation, excitation, non-purposeful movement, inconsolability, thrashing, and incoherence during early recovery from general anesthesia. Sevoflurane and desflurane have increased the incidence of EA in children. A proposed explanation for this is that sevoflurane and desflurane cause differential recovery rates in brain function, due to differences in clearance of inhalational anesthetics from the central nervous system; whereas audition and locomotion recover first, cognitive function recovers later, resulting in EA. Low-flow anaesthesia (LFA) occurs when the fresh gas flow (FGF) is significantly lower than the patient's minute volume. In a low-flow system, the recirculated fraction should amount to at least 50% after carbon dioxide (CO2) absorption.In LFA using minimal FGF (250-500 mL/min), if the vaporizer is turned off 10-15 minutes before the end of the operation and the FGF is not changed, the inhaled anesthetic agent concentration gradually and slowly decreases to zero and the inhaled agent consumption decreases even more. In a study conducted on infants undergoing cleft lip-palate surgery, it was shown that the incidence of postoperative agitation were statistically lower in infants who administered 0.5 L/min FGF. Strabismus surgery is one of the most frequently performed ophthalmologic operations in children and is associated with moderate postoperative pain and a high incidence of EA (40-86%). The incidence of EA after strabismus surgery is high, especially due to visual disturbances; however, the pathogenesis of this condition remains unclear. In our study, the effects of different FGFs administered in children undergoing strabismus surgery on EA and anesthetic agent consumption will be investigated.

This study aims to compare the use of low fresh gas flow (1 L/min) desflurane anesthesia with minimum fresh gas flow (0.5 L/min) desflurane anesthesia in patients undergoing robotic-assisted abdominal surgery. The comparison will be based on hemodynamic and respiratory parameters. The secondary aim of our study is to compare the two different fresh gas flow methods in terms of inhalation agent consumption and soda lime consumption.