Shenzhen PM-9000 Express Manual del operador descargar pdf (Pagina 248)

18.3 MAC

Minimum alveolar concentration (MAC) is the minimum concentration of the agent in the

alveoli. It is a basic index to indicate the depth of anesthesia. MAC is defined as this: alveolar

concentration of an inhaled anesthetic agent that, in the absence of other anesthetic agents

and at equilibrium, prevents 50% of patients from moving in response to a standard surgical

stimulus.

Minimum alveolar concentration (MAC) values are listed below:

Agent Des Iso Enf Sev Hal N2O

1 MAC 7.3% 1.15% 1.7% 2.1% 0.77% 105%*

* indicates 1 MAC nitrous oxide can only be reached in hyperbaric chamber.

NOTE

•

The MAC values shown in the table above are those published by the U.S. Food

and Drug Administration for a healthy 40-year-old adult male patient.

•

In actual applications, the MAC value may be affected by age, weight and other

factors.

The formula to calculate the MAC value is as follows:

-1

EtAgenti

MAC

i=0 AgentVoli

Where N is the number of all agents (including N2O) that the AG module can measure,

EtAgenti is the concentration of each agent and AgentVoli is the concentration of each agent

at 1 MAC.

For example, the AG module measures there are 4% of Des, 0.5% of Hal and 50% of N2O in

the patient’s end-tidal gas:

4.0% 0.5% 50%

MAC

+=1.67

7.3% 0.77% 105%

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Shenzhen PM-9000 Express Manual del operador Pagina 248