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What and Why on Low Flow

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Low-flow anesthesia: The clinical, economic, ecological and patient safety benefits

Modern anesthesia machines have circle rebreathing systems that can significantly reduce fresh gas flow (FGF). The real benefits appear only when the FGF is reduced to less than half the minute ventilation of the patient, usually less than 3.0 L/min. Low FGF affect the gas kinetics in the circle system, especially when FGF is less than 1.0 L/min. Monitoring of inspiratory and expiratory gas concentrations is essential to ensure patient safety and facilitates precise gas administration.

This paper describes the general principles of low-flow anesthesia and presents the clinical benefits of low-flow anesthesia delivery, especially with FGF below 1.0 L/min. Those benefits include:

Cost reduction, Over 80% of the anesthetic gases are wasted when at FGF of 5.0 L/min. Typically, reduction of FGF from 3.0 L/min to 1.0 L/min saves about half the total consumption of any volatile anesthetic agent.

Environmental protection. Reduced FGF releases less anesthetic agent into the air, resulting in lower greenhouse gas and pollutant emissions.

Quality of care. Lower FGF keeps recirculating gases more warm and humid helping maintain patients’ body temperature; prevention, prevent post-operative shivering, and prevent airway and bronchial drying during endotracheal intubation.