ELECTRICITY & ELECTRONICS “ For Anesthetist” By Prof. Gamal Elewa, MD Faculty of Medicine, Ain Shams University Anesthesia Department

© I L O 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 x R2R2 R1 R3 Rx R2 y WHEAT STONE BRIDGE: R2/R1= R3/Rx

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 Multi-site pacing (when 2 atria or ventricles are paced) ProgrammableResponse of generator to sensed P or R waves Chamber sensed Chamber paced OAVDOAVD O(fixed function) P(rate/output) M= multiprogram C=communicatin R=rate modulating O(asynchro nus) T=triggered I=inhibited D=dual=T+I OVADOVAD OVADOVAD

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

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