Mindray A8 Operating Instructions

Operator’s Manual of Anesthesia System 7 - 3
Anesthetic Gases and O
2
Concentration Monitoring MAC Values
7.2 MAC Values
The minimum alveolar concentration (hereinafter referred to as MAC) can be displayed on the screen
when the anesthesia system is configured with external AG module.
MAC is a basic index indicating the depth of inhaled anesthesia. The ISO 80601-2-55 defines MAC as
follows: alveolar concentration of an inhaled anesthetic agent that, in the absence of other anesthetic
agents and at equilibrium, prevents 50% of subjects from moving in response to a standard surgical
stimulus.
The following table lists 1 MAC of various inhaled anesthetic agents.
NOTE: The data shown in this table are from ISO 80601-2-55, which are
published by the U.S.Food and Drug Administration for a healthy
40-year-old male patient.
NOTE: In actual applications, although the gas module accounts for patient
age, the effects of weight and other factors on the inhaled anesthetic
agent should be considered.
When one or more anesthetic agents are used, the formula for calculating MAC is as follow:
Where, N stands for the number of all anesthetic agents (including N
2
O) which the AG module can
measure, EtAgent
i
stands for the end-tidal concentration of each kind of inhaled anesthetic agent,
and AgentVol
age
i stands for the 1 MAC value corresponding to each kind of inhaled anesthetic agent
after age correction.
The formula for calculating age correction of 1MAC is as follow:
NOTE: The formula above is only available for patients who are older than one
year old. If the patient is less than one year old, the system will use one
year old to do age correction.
For example, for a 60-year-old patient, if the AG module detects 0.9% Iso and 50% N
2
O in the patient
end-tidal mixed gas, the 1MAC of Iso is 1.01% and 1MAC of N
2
O is 92.7% of the 60-year-old patient
based on the above age correction formula. The MAC value is calculated as follows::
anesthetic agent Des Iso Enf Sev Hal N
2
O
1 MAC 6.0% 1.15% 1.70% 2.10% 0.77% 105%*
* 1 MAC of nitrous oxide can only be reached in a hyperbaric chamber.
Table 7-1 1 MAC of various inhaled anesthetic agents

−
=
=
1
0
N
i
age
i
iAgentVol
EtAgent
MAC
))40(00269.0(
40
10
−×−
×=
age
age
MACMAC
4.1
%7.92
%50
%01.1
%9.0
=+=MAC

Mindray A8 Specifications

General

Brand	Mindray
Model	A8
Category	Medical Equipment
Language	English