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Planet-friendly low flow anesthesia!!!


What and why of low flow anesthesia...





Flow rates can be categorized into:
Metabolic flow: 250 ml/mn
Minimal flow: 250-500 ml/mn
Low flow: 500-1000 ml/mn
Medium flow: 1-2 L/mn
High flow: 2-4 L/mn
Super-high flow >4 L/mn

Advantages of low flow anesthesia:
-Anesthetic gases delivered using high FGF are usually dry and cold. Reducing FGF makes gases recirculating in the circle system more humid and warmer. This has A significant influence on the function and the integrity of the ciliated epithelium of the respiratory tract, prevent airway and bronchial drying during ETT use. It also helps maintain body heat and prevent postoperative shivering.
-Several studies prove that the use of low and minimal flow anesthesia techniques can dramatically reduce the (annual) costs of volatile anesthetics. Typically, the reduction of FGF from 3 L/min to 1 L/min results in savings of about 50% of the total consumption of any volatile agent. Reduced FGF releases a lower amount of anesthetic agents into the environment, resulting in less pollution. All gases delivered from the anesthesia machines are lost to the atmosphere. Halothane, Enflurane, Isoflurane contain chlorine. They are believed to have significant Ozone (O3) depletion potential.
-Relatively stable hemodynamic conditions during the process of surgery with closed-circuit anesthesia.
-Low expense.

Disadvantages of low flow anesthesia:
-Accidental hypoxia
-Hypercapnia
-Inadequate depth of anesthesia (Difficulty in changing the inspired anesthetic concentration rapidly due to the limited dial settings).
-Accumulation of potentially toxic trace gases
*Carbon monoxide accumulation: CO production comes from the contact of anesthetics with dry soda lime and gradual accumulation is due to difficult elimination under low flow. However, this is of no risk to the patient
*Accumulation of compound A: Compound A is derived from the contact of sevoflurane with soda lime. However, the highest value lies within the range determined to cause histological renal tubular damage in rats.
*Accumulation of methane
*Accumulation of acetone



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