Introduction of low-flow anesthesia. 麻醉科 R2 楊美惠 2004/11/08. The suggestion of Simionescu as: Metabolic flow = 250ml/min Minimal flow = 250-500 ml/min Low flow = 500-1000 ml/min Medium flow = 1-2 L/min High flow = 2-4 L/min Super-high flow = >4 L/min.
Introduction of low-flow anesthesia
The suggestion of Simionescu as:Metabolic flow = 250ml/minMinimal flow = 250-500 ml/minLow flow = 500-1000 ml/minMedium flow = 1-2 L/minHigh flow = 2-4 L/minSuper-high flow = >4 L/min
Fraction of uptake = 1-FA/FI
The beauty of closed circuit anesthesia is: with fixed amounts of anesthetic supply and a large circuit volume, the inspired concentration does not change much, but, after surgical stimulation, self-feed-back control by the patient will take hold to a certain extent, providing a prompt and effective defense mechanism.
2) Reduced consumption of anaesthetic gases and vapours
3) Cost savings
4) Reduced environmental pollution
5) Improved “climate” of anesthetic gases The humidity of anesthetic gases is significantly higher in low-flow than in high-flow anesthesia, and although the specific heat of gas is low, significant reductions in heat loss by the patient can be achieved by delivering humidified gas. appropriate humidification and warming of anesthetic gases have a significant influence on the function and the morphological integrity of the ciliated epithelium of the respiratory tract.
3) 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.<Gonsowski CT, Toxicity of compound A in rats: effect of increasing duration of administration. Anesthesiology 1994; 80:566-75>
4) Difficulty in changing the inspired anesthetic concentration rapidly due to the limited dial settings.