Electrical safety for anesthesia personnel in operation room.

1. Dr. Pallavi
Dr. Sanjay
Dr. Suresh
Dr. Setuvarun
Dr. Yamini
Seth G.S.M.C. & K.E.M.H.
ELETRICAL SAFETY IN
OPEARTING ROOM

4. CURRENT (I) – amperes (A)
VOLTAGE DIFFERENCE (V) - volts
RESISTANCE (R)- ohms
I

5. George Simon Ohm
(1789-1854)
- German Physicist

6. OHM’ LAW

7. CONDUCTOR AND INSULATOR

9. HOW CAN ELECTRICITY FLOW THROUGH BODY?
Two ways:
 Resistive coupling
 Capacitive coupling

10. RESISTIVE COUPLING
When the body makes a
direct physical connection
with the electrical circuit, its
due to resistive coupling.
• Faulty equipments
• Leakage current

11. CAPACITIVE COUPLING
Body acts like a capacitor, which
stores the electrical charge.
In case of direct current, current
flows for a brief period until the
source and receiver are at same
potential.
In case of alternating current,
body would continuously charge
and discharge, and current will
continuously flow.

12. ELECTRICAL CURRENT EXISTS IN 2 FORMS :
 Direct Current (DC)- Electrons flow in only one
direction.
Used in certain medical equipment: defibrillators,
pacemakers, electrical scalpels.
 Alternating Current (AC)- Electrons flow back
and forth through a conductor in a cyclic fashion
It is used in household and offices and is standardized to a
frequency of 60 cycles/sec (60 Hz)
AC is far more efficient and also more dangerous than DC (~ 3 times):
tetanic muscle contractions that prolong the contact of victim with source

13. DETERMINANTS OF ELECTRICAL INJURIES
 Current density
 Current intensity
 Tissue resistance

14. The pathway that current takes through the body will
determine which tissues are damaged.
The effect of the size of current and current pathway can
be considered together as current density. This is the
amount of current flowing per unit area.
Macroshock current is
distributed somewhat evenly
through body parts.
Microshock current path is
through a single point,
usually the heart
Term used to describe the
very low level shocks that go
undetected

15. For example, a 50 Hz alternating current flowing between each hand
the current has passed through the whole of the trunk with only a
small part of it passing through the heart, i.e. the myocardial current density is
relatively low. However, if the current flows directly into the myocardium (or in
very close proximity to it), for any given current, the current density will be much
greater. In these circumstances, a substantially smaller current (50 μA at 50 Hz)
can cause ventricular fibrillation.

16. MICROSHOCK
 Dangerous to an “electrically sensitive” patient - with breaks in skin like
abrasions, wet dressings, pacemakers, or monitoring lines connected to a
transducer.
Examples of equipment that may allow
microshock include central venous catheters, intracardiac
pacemakers with an external lead and, to a lesser extent, a
temperature probe placed in the oesophagus immediately
behind the left atrium.

18.  Nerves and blood vessels are the best conductors: path of least
resistance for current after it enters the body
 The least resistance is found in nerves, blood, mucous
membranes and muscles
 The highest resistance is found in bones, fat and tendons
 Skin’s resistance ranging between 40,000 and 100,000 Ω
depending on thickness
 Moist mucus membranes: significant orofacial injury to infants
and toddlers
Exposure of different parts of the body to the same
voltage >> same current >> different degree of damage
because resistance varies.

19. ELECTRICAL INJURY TO SPECIFIC TISSUES
& ORGANS
Cardiovascular System-
 Direct necrosis of the myocardium- Focal or diffuse
Widespread, discrete, patchy contraction band necrosis
involving the myocardium, nodal tissue, conduction pathways
and coronary arteries
 Cardiac dysrhythmias- AC > 50-100 mA with hand-to-hand or
hand-to-foot transmission >
ventricular fibrillation
High-voltage current (AC or DC) >
ventricular asystole

20. Possible mechanisms:
1) Arrythmogenic foci due to myocardial
necrosis (esp. SA Node injury)
2) Alterations in the Na+ - K+ adenosine triphosphatase
concentration
3) Changes in the permeability of myocyte membranes
4) Anoxic injury (respiratory arrest precedes the injury to
the heart)

21.  Large arteries not acutely affected because their rapid
flow dissipate heat.
Medial necrosis: aneurysm formation and rupture
 Smaller vessels acutely affected due to coagulation necrosis
 compartment syndrome

22. NERVOUS SYSTEM
 Loss of conciousness, confusion & impaired recall
 Peripheral motor & sensory nerves >
motor & sensory deficits
 Seizures, visual disturbances & deafness
 Hemiplegia, quadriplegia, spinal cord injury
 Transient paralysis, autonomic instability > hypertension,
peripheral vasospasm due to lightning from massive
release of catecholamines

23. RESPIRATORY SYSTEM
 Direct injury to the respiratory control center >> cessation of
respiration or suffocation secondary to tetanic contractions
of the respiratory muscles
 Acute respiratory dysfunction syndrome secondary to
ischemia, aggressive fluid resuscitation,
ventilator-associated pneumonia

24. OTHER SYSTEMS
 Kidneys susceptible to anoxic/ischemic injury
 Release of myoglobin & creatinine phosphokinase >
renal tubular damage > renal failure
 Fractures
 Transient autonomic disturbances > fixed pupils may
be perceived as severe brain injury or even death
 Temporary sensorineural hearing loss

25. Better Safe
Than Sorry

26. PREVENTION OF
ELECTRICAL HAZARDS

27. PREVENTING ELECTRICAL HAZARDS
Electrical accidents appear to be
caused by a combination of three
possible factors:
1. unsafe equipment and/or installation,
2.unsafe by environment,
3. and unsafe work practices.

28. PREVENTING ELECTRICAL HAZARDS
These include:
 Insulation
 Guarding
 Grounding
 Electrical protective devices:
 Fuses & circuit breakers
 Ground fault circuit interrupter
 Isolation transformer & Line isolation monitor
 Safe work practices

29. INSULATION
 One way to safeguard
individuals from
electrically energized
wires and parts is
through insulation.
 An insulator is any
material with high
resistance to electric
current.

30.  Insulators such as glass, mica, rubber, and plastic,
 Before you prepare to work with electric equipment,
it is imperative to check the insulation
 The insulation of flexible cords, such as extension
cords, is particularly vulnerable to damage.

31.  Electrical Power can exist in two forms-
 GROUNDED
 UNGROUNDED

32. GROUNDING
 The "ground" refers to a conductive body, usually the earth,
and means a conductive connection, whether intentional or
accidental, by which an electric circuit or equipment is
connected to earth or the ground plane.
 Method of protecting from electric shock.
 Secondary protective measure.
 By "grounding" a tool or electrical system, a low-
resistance path to the earth is intentionally created.

33. UNGROUNDED
GROUNDED

34. GROUNDING
 Think about your house:
 2 prong outlets = no ground
 3 prong outlets = grounded
 Modern homes have a ground
to reduce amount of shock

35. TWO PRONGED PLUG

36. THREE PRONGED PLUG

37.  Low resistance and has sufficient
current carrying capacity to
prevent the buildup of voltages
that may result in a personnel
hazard.
 This does not guarantee that no
one will receive a shock, be
injured, or be killed.
 It will, however, substantially
reduce the possibility of such
accidents.

38. One of these is called
the "service or system
ground."
This type of ground is
primarily designed to
protect machines, tools,
and insulation against
damage.
There are 2 types of grounding required -

39. To offer enhanced protection, an
additional ground, called the
"equipment ground"
This additional ground
safeguards the electric
equipment operator in the event
that a malfunction causes any
metal on the tool to become
accidentally energized.
The resulting heavy surge of
current will then activate the
circuit protection devices and
open the circuit.

40. EXTREMELY IMPORTANT
 Never remove a grounding
device from any electrical source,
tool, or equipment.
 Never remove the ground prong
from an electrical cord or device
of any kind.
 Never by-pass grounding or
circuit breaker protection as any
time.
 If you find any of the above
have occurred, repair and / or
report immediately.

41. CIRCUIT PROTECTION DEVICES
 Circuit protection devices are designed to
automatically limit or shut off the flow of electricity
in the event of a ground-fault,
overload, or short circuit in the wiring system.
 Fuses, circuit breakers, ground-fault circuit
interrupters, isolation transformer and line isolation
monitor

42. CIRCUIT PROTECTION DEVICES
Fuses & circuit breakers-
monitor the amount of current
that the circuit will carry.
 Fuses are designed to melt when too
much current flows through them.
 Circuit breakers, on the other
hand, are designed to trip open the
circuit by electro-mechanical means.

43. They prevent over-heating of
wires and components that
might otherwise create hazards
for operators.
They also open the circuit
under certain hazardous
ground-fault conditions.
Fuses & circuit breakers-

44. GUARDING
Live parts of electric equipment
operating at 50 volts or more must
be guarded against accidental
contact. This is accomplished by:
 Location in a room, vault, or similar
enclosure accessible only to
qualified persons
 Use of permanent, substantial
partitions or screens to exclude
unqualified persons
 Elevation of 8 feet (2.44 meters) or
more above the floor.

45. GROUND FAULT CIRCUIT INTERRUPTER
 The ground-fault circuit interrupter, or GFCI, is designed to
shutoff electric power within as little as 1/40 of a second.
 It works by comparing the amount of current going to electric
equipment against the amount of current returning from the
equipment along the circuit conductors.
 If the current difference exceeds 6 milliamperes, the GFCI
interrupts the current quickly enough to prevent electrocution.

46. GROUND FAULT CIRCUIT INTERRUPTER

47. UNGROUNDING
 The OR has many perils that make
grounding impracticle.
 Saline puddles
 Power cords with tears in their
insulation (colored part of cord)
 Numerous electronic devices
that  risk

48. UNGROUNDING – ISOLATED POWER
 Isolated Power System provides protection from
Macroshock.
 Faulty equipment plugged into an isolated power system
does not present a shock hazard.

49. ISOLATION TRANSFORMER
An isolation transformer is a transformer used to transfer
electrical power from a source of alternating current (AC)
power to some equipment or device while isolating the
powered device from the power source, usually for safety.

50. ISOLATED AND UNGROUNDED

51. LINE ISOLATION MONITOR
Continuously monitors the
potential for current flow from
the isolated power supply to
ground.
Determines the degree of
isolation bw 2 power wires and
the ground.
Predicts the current flow

52. Alarm is activated if 2mA-5mA of current is
detected.
Line isolation monitor

54. STANDARDS OF SAFETY OF MEDICAL EQUIPMENTS

55. British Standard symbols used on medical equipments-

65. SAFE WORK PRACTICES
While working with electric equipment need to use safe
work practices.
These include:
 Switch off electric equipment before inspecting or
making repairs
 Using electric tools that are in good condition
 Using appropriate protective equipment

66. CARE OF CORDS & EQUIPMENTS
 Power tools and extension cords must be inspected
each time they are used.
 They must be taken out of service immediately upon
discovery of worn or broken insulation.

72. DON’T
 Don’t plug in equipment
with wet hands
 Don’t plug in equipment
when cord is wet
 Don’t drape cords over hot or sharp
objects
 Don’t run cords where they cause
tripping hazard
 Don’t use extension cords unless
authorized

73. MANAGEMENT OF ELECTRICAL
HAZARDS

74. PERSONS AT RISK -
o PATIENT
o DOCTORS
o NURSING STAFF
o OTHER PERSONES PRESENT IN OPERATING
ROOM

75. PATIENT MOST IMPORTANT BECAUSE-
Wet surface
Metal tables
Can’t move
Direct contact with electrosurgical equipments

76. GUPTA K, PREM KUMAR GV, BANSAL A, MEHTA Y
BURN INJURY BY DISPLACEMENT OF ELECTROCAUTERY PLATE.
INDIAN J ANAESTH [SERIAL ONLINE] 2011 [CITED 2013 FEB 2];55:634-5.
AVAILABLE
FROM: HTTP://WWW.IJAWEB.ORG/TEXT.ASP?2011/55/6/634/90636

77. ELECTROCAUTERY

78. PRINCIPLE
 High current enters body through small surface
area electrode i.e. cutting tool producing high
resistance R, small area, causes local tissue
heating which leads to cutting and coagulation.
 Operate at frequency approximately 300 kHz
to 2 MHz, to prevent cardiac arrhythmias.

79. UNIPOLAR VS BIPOLAR
 UNIPOLAR-
Electric current that enters in body travels
through the body and collected outside
surgical field by grounding pad.
 BIPOLAR-
Current enters in body through one electrode
collected millimeters away from second
identical electrode .

80. PRECAUTIONS
GROUNDING PAD - Wide area, well jelled
and with good contact with body.
Unipolar cautery should be avoided in
neurosurgery patient and patient with AICD.

81. Remove all metal
ornaments such as ear
rings and bangles.
 IF present, keep the
grounding pad on
same side of surgery
NOT on OPPOSITE
side.
 RECONCENTRATION

82. ELECTRO-QUATERY WITH LARGE CONTACT

83. ELECTRO-QUATERY WITH POOR CONTACT

84. ELECTROCAUTERY WITH AICD-
RESPONSE TO CAUTERY—
Inhibition of pacing.
Asynchronous pacing.
Reset to backup mode.
Ventricular fibrillation .
Myocardial burns rare.

85. PRECAUTIONS TO BE TAKEN-
 Use bipolar cautery.
 Limit use to minimal.
 Use grounding pad close to operative site and
away from pacemaker site.
 Do not use cautery within 15 cm of pacemaker
site .

86.  Frequency of cautery should be limited for 1 sec
burst every 10 sec.
 Pacemaker should be changed to asynchronous
mode by magnet or by programmer before using
cautery.
 Provision of alternate temporary pacing should be
there in operative room.
 Drugs like ISOPROTERENOL , ATROPINE should
be available.
 Defibrillation – paddles should be kept as far as
possible from pulse generator , if possible antero
posterior.
 Pacemaker devise should be rechecked after
procedure.

87. Abdelmalak B, Jagannathan
N, Arain FD, Cymbor S,
McLain R, Tetzlaff JE
Electromagnetic interference
in a pacemaker during
cauterization with the
coagulating, not cutting
mode.
J Anaesthesiol Clin
Pharmacol [serial online]
2011 [cited 2013 Feb
2];27:527-30. Available
from: http://www.joacp.org/te
xt.asp?2011/27/4/527/86600

88. ABSTRACT
 Electromagnetic interference in pacemakers has almost always been
reported in association with the cutting mode of monopolar
electrocautery and rarely in association with the coagulation mode.
 We report a case of electrocautery-induced electromagnetic
interference with a DDDR pacemaker (dual-chamber paced, dual-
chamber sensed, dual response to sensing, and rate modulated) in the
coagulating and not cutting mode during a spine procedure. We also
discuss the factors affecting intraoperative electromagnetic interference.
 A 74-year-old man experienced intraoperative electromagnetic
interference that resulted in asystole caused by surgical electrocautery
in the coagulation mode while the electrodispersive pad was placed at
different locations and distances from the operating site (This
electromagnetic interference did not occur during the use of the cutting
mode). However, because of careful management, the outcome was
favorable. Clinicians should be aware that the coagulation mode of
electrocautery can cause electromagnetic interference and
hemodynamic instability. Heightened vigilance and preparedness can
ensure a favorable outcome.

89. Figure 1: Patient's electrocardiogram (EKG) tracing and arterial line
wave form showing normal sinus rhythm with good perfusion prior to
the application of electrocautery

90. Patient's electrocardiogram (EKG) tracing and arterial line wave
form showing bradycardia evolving to asystole as a result of EMI
during electrocauterization with coagulation mode while the
electrodispersive pad was on the opposite shoulder of the
pacemaker. A similar response was seen when the electrodispersive
pad was moved to the contralateral thigh

91. Patient's electrocardiogram (EKG) tracing and arterial line wave
form showing minimal EMI not affecting arterial line tracing during
electrocauterization with cutting mode while the electrodispersive
pad was on the contralateral thigh

92. DEFIBRILLATORS-
 Defibrillators are one of the most important thing in operating
room.
 If improperly used it may lead to electrical injuries
COMMON MISTAKES –
 Insufficient force is applied to paddles and contact is poor.
 paddles applied to irregular surface or bony prominences.
 Insufficient or wrong kind of jell is used.
 Another conductive medium between paddles.

93. PREVENTION-
 Defibrillator should be checked daily.
 Adequate jelly should be applied.
 Skin contact should be good as indicated by
indicator on pads.
 Ensure there is no other conductive medium .
 Before delivering shock check and say clearly and
loudly
“ I CLEAR, YOU CLEAR, EVERYBODY CLEAR”.

94. MRI ROOM-
 One of potential space for electrical accidents.
 Routine equipments cant be used.
 Magnetic field can induce changes in ECG along with
heating and thermal injuries at the site of ECG
electrode and pulse oxymeter- ANTENNA EFFECT.
 Cardio scope and pulse oxymeter wire should be
kept straight , avoid loops and multiple contacts with
patient.

95.  Use MRI compatible pulse oxymeter with fiber optic
signal linking between sensor and monitor.
 Temperature probe with RF filter should be used.
 Absolute exclusion of ferromagnetic material .

96. SAFETY MEASURES-
 Regular check of all electrical equipments.
 Team work- Involvement of surgeon, anaesthetist,
nursing staff along with biomedical engineering
department.
 Proper checklist before every procedure.
 Proper grounding.
 Fire plans.

97. GENERAL PRECAUTIONS-
 Multiple plugs extension boxes should not be placed
on floors as they may come in contact with fluid and
electrolyte solutions.
 Ceiling mounted tracks can be used to bring
electrical outlet close to operating table.
 Power chords that come down the wall should not
cross traffic lines.
 Power taps in operating room should have water tight
or flip covers so that water should not enter in it

98.  Electrosurgical and laser units may interfere with
operation of other equipments , so should be away from
monitors.
 Electrosurgical equipments and monitors should be
attached in separate circuit.
 Electrosurgical equipments and monitors should be
periodically inspected by biomedical engineering
department.
 This equipments should be regularly calibrated.

99.  Wear and tear of chords should be regularly checked
and replaced.
 Monitors should be handled with respect.
 Infusion pump should be draped with watertight
covers .
 Care should be taken while moving equipments.

100. Work shouldn’t be

101. THANK YOU