الفهرس 
1- Introduction and Historical ReviewOnly 14 pages are availabe for public view
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Abstract
Low flow anesthesia is the minimum flow required to ensure adequate carbon dioxide elimination during spontaneous or controlled ventilation with the most efficient breathing system.
In low flow anesthesia the fresh gas flow rate is reduced to 1 L/min and in minimal flow anesthesia to 0.5 L/min. In closed system anesthesia, the fresh gas flow just meets the gas volume taken up by the patient, which can be only achieved by frequent adjustments of the gas flow controls. Both, the pressure within the breathing system and the circulating gas volume are maintained, and the ventilation pattern remains completely unchanged
The cost of inhaled agents is relatedto more than the amount taken up; it also depends on their market prices, their relativepotencies, the amount of vapor released per millilitre of liquid, and last but not least the freshgasflow rate (FGF) delivered to the vaporizer, which is the most important factor determining the costof anesthesia.
Several studies also proved that use of low and minimal flow anesthesia techniques can dramatically reduce the annual costs of volatile anesthetics. Anesthesia is estimated to account for 3 – 12% of global nitrous oxide release, and this could be reduced considerably with low fresh gas flow rates and reduction of waste. The use of low fresh gas flow rate in patients provides relative humidity equivalent to circuit humidifiers.
Low flow anesthesia reduces the costs of anesthesia, decrease atmospheric pollution with inhalation anesthetics and improve the anesthetic gas climate. Although there are potential risks associated with low flow anesthesia, modern anesthesia machines meet all technical requirements for safe use of low flow techniques if they are used in conjunction with equipment for monitoring inhaled and exhaled gas concentration.
However, due to the development of modern anesthetic apparatus, the availability of comprehensive gas monitoring, an increasing environmental awareness, the introduction of new advantageous but expensive inhalational anesthetics and the world wide restriction of economical resources in medical care, an increasingly strong recollection towards low flow techniques can be observed and should be encouraged.
The monitoring facilities present on modern anesthesia machines should convince clinicians that low- or even minimal-flow anesthesia would not jeopardize the safety of their patients.