8-20 
Message 
Alarm 
Priority 
Cause  Solution 
BIS R Over 
Range  Low 
The monitored value of 
BIS R exceeds the 
measurable range. 
Replace the BIS module.   
BIS High 
Imped. 
Low 
The sensor is not properly 
attached to the skin of the 
patient, resulting in a high 
impedance. 
1. Check whether the BIS sensor is 
in proper contact with the skin. 
2. Replace the BIS sensor. 
BIS Sensor Off  Low 
The sensor is detached 
from the patient. 
1. Check whether the BIS sensor is 
in proper contact with the skin. 
2. Replace the BIS sensor. 
BIS Electrode 
1 High Imped. 
Low 
The impedance of BIS 
electrode 1 is too high. 
1. Check whether BIS electrode 1 is 
in proper contact with the skin. 
2. Replace the BIS sensor. 
BIS Electrode 
1 Lead Off 
Low 
BIS electrode 1 is 
detached from the patient.   
1. Check whether BIS electrode 1 is 
in proper contact with the skin. 
2. Replace the BIS sensor. 
BIS Electrode 
2 High Imped. 
Low 
The impedance of BIS 
electrode 2 is too high. 
1. Check whether BIS electrode 2 is 
in proper contact with the skin. 
2. Replace the BIS sensor. 
BIS Electrode 
2 Lead Off 
Low 
BIS electrode 2 is 
detached from the patient.   
1. Check whether BIS electrode 2 is 
in proper contact with the skin. 
2. Replace the BIS sensor. 
BIS Electrode 
3 High Imped. 
Low 
The impedance of BIS 
electrode 3 is too high. 
1. Check whether BIS electrode 3 is 
in proper contact with the skin. 
2. Replace the BIS sensor. 
BIS Electrode 
3 Lead Off 
Low 
BIS electrode 3 is 
detached from the patient.   
1. Check whether BIS electrode 3 is 
in proper contact with the skin. 
2. Replace the BIS sensor. 
BIS Electrode 
4 High Imped. 
Low 
The impedance of BIS 
electrode 4 is too high. 
1. Check whether BIS electrode 4 is 
in proper contact with the skin. 
2. Replace the BIS sensor. 
BIS Electrode 
4 Lead Off 
Low 
BIS electrode 4 is 
detached from the patient.   
1. Check whether BIS electrode 4 is 
in proper contact with the skin. 
2. Replace the BIS sensor. 
BIS Electrode 
G High Imped. 
Low 
The impedance of BIS 
electrode G is too high. 
1. Check whether BIS electrode G is 
in proper contact with the skin. 
2. Replace the BIS sensor. 
BIS Electrode 
G Lead Off 
Low 
BIS electrode G is 
detached from the patient.   
1. Check whether BIS electrode G is 
in proper contact with the skin. 
2. Replace the BIS sensor. 
BIS Electrode 
Low 
The impedance of BIS  1. Check whether BIS electrode C is