Preventing Noise in the Operating Room
Preventing noise in the operating room
Challenges we face
Basic fundamentals of the way we amplify the physiologic signal
EKG ~1-2 millivolts
EEG 3-40 microvolts
EP ~10 microvolts sensory, ~1-5 millivolts motor
EMG 3 millivolts (EDB)
Line voltage 120 Volts RMS
Bipolar (Electrocautery) Less than 1000 volts
Bovie (ESU) Up to 10 kilovolts
Voltage source (the brain) drives a current through the recording circuit
The current builds up a voltage on each of the impedances in the circuit
The amplifier rejects common signals and amplifies differences between the signals it sees from electrode 1 and electrode 2
Challenges we face
Basic fundamentals of the way we amplify the physiologic signal
EKG ~1-2 millivolts
EEG 3-40 microvolts
EP ~10 microvolts sensory, ~1-5 millivolts motor
EMG 3 millivolts (EDB)
Line voltage 120 Volts RMS
Bipolar (Electrocautery) Less than 1000 volts
Bovie (ESU) Up to 10 kilovolts
Voltage source (the brain) drives a current through the recording circuit
The current builds up a voltage on each of the impedances in the circuit
The amplifier rejects common signals and amplifies differences between the signals it sees from electrode 1 and electrode 2