Anesthesia Department
ELECTRICITY & ELECTRONICS
“For Anesthetist”
By
Prof. Gamal Elewa, MD
Faculty of Medicine, Ain Shams University
Intended Learning Outcomes
By the end of this lecture , the post-graduate student will be
able to:
1. Know types of electricity and clinical applications
2. Know General Electricity applications in
anesthesia
3. Understand Equipment: Defibrillators, Cardiac
Pace Makers, Electro-cautery (surgical
diathermy), Others: computer
4. Consider Electrical Safety and Avoid
Electrocaution
©
General Electricity
• Definitions
• Types of electricity: Static vs Dynamic. AC
vs DC. High vs low pressure lines
• SI units: currenr (A), electr. Potential (V),
resist (Ω), ..
• Classification of substances according to
their electrical conductivity: conductors,
semi- conductors, insulators
©
Types of electricity
• Static vs Dynamic
• Clinical importance of static electricity
• Direct vs AC current
©
Direct & Alternating Current
• DC: Flows in one direction
• AC: Periodically reverses its direction (sine
wave):
-Wavelength: distance between 2 waves
-Frequency: no. of waves/cycle
-Velocity: wave length X Frequency
©
ELECTRICAL SI UNITS
•
•
•
•
•
•
Frequency: Hertz (Hz)= cycle/sec
Power: Watt (W)
Electrical current: Ampere (A)
Electrical Potential (EMF): Volt (V)=W/A
Electrical Charge: Coulomb (C)=As
Electrical Resistance (Impedance,
Reactance): Ohm (Ω)=V/A (Ohm’s Law)
• Electrical Inductance: Farad (F)=As/V
• Electrical Capacitance: Henry (H) =Vs/A
©
Electrical Conductivity
• Conductors: Metals, e.g. cupper, lead,
platinum, gold, silver
• Insulators: glass, plastic, rubber, wood,
mica, porcelin, ceramic
• Semiconductors: Silicon, germanium,
selenium
- Used in: transistors, thermistors, diodes,
some transducers
- Affected by temperature, e.g. thermistors
General Electricity
• WHEAT STONE BRIDGE: R2/R1= R3/Rx
R2
R
2
Rx
y
x
R1
R3
Medical Equipment
•
•
•
•
Defibrillators
Cardiac Pace Makers
Electro-cautery (surgical diathermy)
Others: computer
Defibrillator
• Definition
• Physical and Clinical Principles
• Indications & uses: Cardioversion &
Defibrillation
• How applied?
• Precautions
• Automated types
Pace Maker
•
•
•
•
•
•
Definition
Principle
Uses (Indications)
Types
Terminology
Precautions
Pacemaker Identification
Chamber
paced
Chamber
sensed
Response
Programmable
of generator
to sensed P
or R waves
Multi-site
pacing (when
2 atria or
ventricles are
paced)
O
V
A
D
O
V
A
D
O(asynchro
nus)
T=triggered
I=inhibited
D=dual=T+I
O
A
V
D
O(fixed function)
P(rate/output)
M= multiprogram
C=communicatin
R=rate modulating
Electro-cautery (Diathermy)
• Def
• Principle
• Types: Unipolar vs Bipolar, coagulation vs
cutting
• Precautions: general, with pacemaker
Electrocution
• Types: Macro-shock
Micro-shock
• Why?
• Prevention
Summary of important points
Electricity
Definitions
Types & Applications
Equipment
Hazards & Their Prevention
©
Examples of questions to assess the ILOs
-Wheatstone bridge: principle and clinical applications
- Electrical cautery: precautions with pacemaker
-Physical principle of defibrillators & their types
- Hazards of defibrillators
-Difference(s) between:
* Direct & alternating currents,
* Monophasic & biphasic defibrillators,
* Static & dynamic electricity
©
• THANK YOU