User's Manual Part 2

6-22
6.3.8.1. Understanding the Agent Display
1. Measurement unit
2. Current gas label of detected gases
3. Current exhaled measurement of detected gases
4. Current inspired measurement of detected gases
6.3.8.2. MAC Values
Minimum alveolar concentration (MAC) is a standard for comparing the minimum concentration
of the inhalation agents in the alveoli. It is a basic index to indicate the depth of anesthesia. 1
MAC represents the end-tidal concentration of an agent (at sea level) that, in 50% of patients
will prevent movement in response to a painful stimulus.
Minimum alveolar concentration (MAC) coefficient values are listed below:
Agent
SEV
ISO
ENF
DES
HAL
N
2
O
1 MAC
2.05%
1.15%
1.7%
6.0%
0.75%
100%
NOTE
• Altitude, patient age and other individual factors are not considered in the formula below
The formula to calculate the MAC value from end tidal gas measurements is as follows:
MAC =
% Et(Agent 1)
+
% Et(Agent 2)
+
% Et(N20)
X (Agent 1)
X (Agent 2)
100
! WARNING
• MAC values are empirical, not absolute values. The MAC values correspond to those of
healthy adults. Age and other individual factors influencing the behavior of volatile
agents are not taken into account.
6.3.8.3. Scavenging
When administering anesthetic agents always connect the scavenge line, P/N 1846, per
hospital policy to the exhaust port of the 3880 monitor. The respiratory gas exhaust is on the
right side panel of the monitor unit. Use a vented scavenge P/N 1846 line with less than
30mBar suction.
6.3.8.4. Oxygen Sensor
The 3880 system utilizes para-magnetic technology for the oxygen sensor providing. This
technology provides breath by breath FiO2.
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