Electrical Safety

Is this statement true or false? The safe use of medical electrical equipment for cardiac type procedures can only be assured if: (i) The equipment complies with AS 3551 and is appropriate for the procedure. (ii) The environment in which the procedure is to be carried out is wired in accordance to AS 3003. (iii) The procedure is carried out under an appropriate set of rules that links the equipment with the type of procedure and the type of wiring in the area. Select one: True False

True

Electrical Safety: SUPPLY SYSTEMS. In a hospital setting, which electrical supply conductor is attached to 'earth' at the substation? Select one: active neutral earth none of the above

neutral

In Australia, which mark on an item of medical equipment indicates that the supplier claims that the device complies with the requirements imposed by the Australian federal government? Select one:

'Triangle with a circle with a tick in it'

Place numbers in against the Acceptance tests shown below to indicate the order in which the tests should be undertaken. The first test to be undertaken should be number 1. Protective earthing resistance test Patient leakage current test Touch current test Earth leakage current test Insulation resistance test

1) Protective earthing resistance test 2) Insulation resistance test 3) Touch current test 4) Earth leakage current test 5) Patient leakage current test

Electroporation is: Select one: Cell damage due to electrically induced holes forming in the cell wall A reaction to excessive electrical current flowing adjacent to cells Reversible if current levels are not excessive All of the above

All of the above

Which of the following is false? Body-type procedures, using equipment with any class of 'applied part', may safely be undertaken: Select one: in body protected areas. in cardiac protected areas. in areas where all equipment used is powered via a medical safety switch. when equipment used is SELV type equipment. All answers above are true, none is false.

All answers above are true, none is false.

Which of the following is not a registrable therapeutic device? Select one: An electrically powered infusion device. A heart valve. A defibrillator. An implantable cardiac pace-maker. All here listed are registrable, none is not registrable.

All here listed are registrable, none is not registrable.

Electrical Safety: MACRO SHOCK. Which of the following is true? Select one: a) Macro shock is the most common type of electric shock. b) Macro shock occurs when the body becomes a conductor of electric current passing by means other than by direct contact with the heart. c) Answers a) and b) d) Macro shock is always apparent to the subject. e) Macro shock will eventually 'blow' a fuse or trigger the circuit‑breaker.

Answers a) and b) "Micro-electrocution" is the term that should be used whenever a micro-shock causes death. "Macro-shock" is when a much larger current is passed through the body, usually via a skin to skin pathway the current is not applied directly through the heart muscle.

How does Cardiac Muscle differ from Skeletal Muscle? Select one: The metabolism process of cardiac muscle depends on aerobic respiration. Cardiac muscle cells are electrically insulated from adjoining cardiac muscle cells Cardiac muscle does not have the regular striations of skeletal muscle Cardiac muscle is self-exciting. None of the above.

Cardiac muscle is self-exciting.

Eletrical Safety: MICRO SHOCK. Which of the following is false? Select one: Micro shock occurs below the threshold of perception. A micro shock as low as 200 micro Amperes may cause ventricular fibrillation. When micro shock occurs, the heart becomes a conductor of minute electrical currents. Micro shock cannot occur if the earth wire is intact.

Micro shock cannot occur if the earth wire is intact. - it is electric shock risk that is present for hospital patients with externally protruding intracardiac electrical conductors, such as external pacemaker electrodes

Which organisation checks that a laboratory, undertaking type testing to Australian Standards specification, performs satisfactorily? Select one: C-Tick Standards Australia National Association of Testing Authorities (NATA) International Electrotechnical Commiesion (IEC)

National Association of Testing Authorities (NATA)

Which body part is the better conductor of electrical current? Select one: Skin Nerve Muscle Fat Bone

Nerve

RESPIRATION: What is the function of a pneumotachograph? Select one: Pneumotachographs measure blood flow according to the Venturi effect. The Venturi effect is the phenomenon that occurs when a flowing fluid is forced through a narrow section, resulting in a pressure decrease and velocity increase. These instruments measure the blood pressure drop when a patient blows into the device. Pneumotachographs measure air flow according to the Venturi effect. The Venturi effect is the phenomenon that occurs when a flowing fluid is forced through a narrow section, resulting in a pressure decrease and velocity increase. These spirometers measure the air pressure drop when a patient blows into the device. There are two types: Fleisch and Lilly. Pneumotachographs measure heart rate according to the Doppler effect. These spirometers measure the heart rate drop when a patient blows into the device. There are two types: Taylor and Francis. Pneumotachographs measure reaction times according to the Doppler effect. These spirometers measure the reaction of the patient when an electrical stimulus is given via two electrodes placed on the skin. There are two types: Taylor and Francis

Pneumotachographs measure air flow according to the Venturi effect. The Venturi effect is the phenomenon that occurs when a flowing fluid is forced through a narrow section, resulting in a pressure decrease and velocity increase. These spirometers measure the air pressure drop when a patient blows into the device. There are two types: Fleisch and Lilly.

Which of the following devices must conform to Australian Standards under Australian federal or state legislation, before they can be sold in Australia? Select one: Prescribed class electrical products. Registrable therapeutic goods. Listable therapeutic goods. Equipment used for the diagnosis of patients.

Prescribed class electrical products.

RESPIRATORY FUNCTION: CALCULATION. When spirometry is performed by a patient, we compare the observed values to values predicted by studies of the general population. Several factors are put into an equation to generate an ideal or predicted value for FVC, FEV1, and FEF25-75. Age, gender, height, and race are important predictors of lung function. Weight is generally not important. The questions which follow compare observed lung function to predicted values. A 35 year old woman presents with a history of progressive shortness of breath on exercise. She denies increased phlegm, but does complain of a dry cough. She is a non-smoker. Her spirometry is as follows: Observed Predicted FVC 2.20 3.67 FEV1 1.75 3.02 a) Which type of lung disease does she have (obstructive, restrictive, mixed)? b) What would you predict that her FEF25-75 would be (increased, decreased or normal)? Select one: She has obstructive lung disease (answer to a); therefore the FEF25-75 would also be increased in range (answer to b). She has obstructive lung disease (answer to a); therefore her FEF25-75 would also be normal (answer to b). She has restrictive lung disease (answer to a); therefore the FEF25-75 would also be decreased in range, almost normal (answer to b). She has mixed lung disease (answer to a); therefore the FEF25-75 would be normal in range (answer to b). She has mixed lung disease (answer to a); therefore the FEF25-75 would be increased in range (answer to b).

She has restrictive lung disease (answer to a); therefore the FEF25-75 would also be decreased in range, almost normal (answer to b).

Which Australian organisation produces Approval and Test Specifications for the design of Medical Technology? Select one: Standards Australia Electricity Trust of South Australia Therapeutic Goods Administration All of the above

Standards Australia

CARDIAC PACEMAKER: What is the function of a cardiac pacemaker? Select one: The cardiac pacemaker is a magnetic stimulator, producing periodic magnetic pulses conducted to magnets located on the surface of the heart (epicardium), within the heart muscle (myocardium), or within the cavity of the heart or the lining of the heart (the endocardium). The stimulus conducted to the heart causes it to contract. This can be used prosthetically in disease states in which the heart is not stimulated at a proper rate on its own. The cardiac pacemaker is an electric stimulator, producing periodic electric pulses conducted to electrodes located on the surface of the heart (epicardium), within the heart muscle (myocardium), or within the cavity of the heart or the lining of the heart (the endocardium). The stimulus conducted to the heart causes it to contract. This can be used prosthetically in disease states in which the heart is not stimulated at a proper rate on its own. The cardiac pacemaker is a wearable device, that has the function to maintain low heart rate for athletes. For example joggers and swimmers, particularly in endurance races. The cardiac pacemaker measures blood flow and stimulates a higher blood flow when needed, by giving small electric shocks to the heart muscle through its electrodes implanted within the heart muscle. All of the above.

The cardiac pacemaker is an electric stimulator, producing periodic electric pulses conducted to electrodes located on the surface of the heart (epicardium), within the heart muscle (myocardium), or within the cavity of the heart or the lining of the heart (the endocardium). The stimulus conducted to the heart causes it to contract. This can be used prosthetically in disease states in which the heart is not stimulated at a proper rate on its own.

The natural pumping rhythm of the heart is initiated by: Select one: The sympathetic and parasympathetic nerve signals sent from the brain. The self excitability of cardiac muscle cells situated at the sinoatrial node. The timing of impulses conducted along the Bundle of HIS. Delays in conduction between muscles cells due to the structure of intercalated discs. All of the above.

The self excitability of cardiac muscle cells situated at the sinoatrial node.

Which of the following outcomes of electrocution is most likely to result in death? Select one: Atrial fibrillation. Respiratory paralysis. Ventricular fibrillation. Muscle Spasms.

Ventricular fibrillation: rapid heartbeat, fast, regular beating of the heart is caused by abnormal electrical impulses that start in the ventricles.

The T-wave of an electrocardiogram results from which cardiac activity? Select one: Atrial depolarisation. Atrial diastole. Ventricular repolarisation. Ventricular systole. None of the above.

Ventricular repolarisation.

Electrical Safety: EARTH CONDUCTOR. The earth conductor in class 1 equipment is important so as to minimise the risk of: Select one: a) micro shock electrocution from leakage current. b) macro shock electrocution from faulty equipment. c) faulty fuses and circuit breakers not working. a) and b) all of the answers

a) and b) Earth conductor: reference point in an electrical circuit from which voltages are measured, a common return path for electric current, or a direct physical connection to the Earth

Electrical Safety: EQUIPMENT SAFETY. Electrical devices are constructed to prevent electrical hazards, by: Select one: providing a separate earth conductor attached to all exposed metal parts. providing an insulated case. providing internal power which is not referenced to earth (eg., batteries). all of the above.

all of the above.

Electrical Safety: FUSES AND CIRCUIT-BREAKERS. Fuses and circuit-breakers do not guarantee protection of personnel from electric shock because: Select one: the earth wire in the flexible cord may not be correctly wired. the amount of current required to make them to work is far greater than that required to cause macro shock. the time required for a fuse or circuit breaker to break the circuit may be too long. all of the above.

all of the above.

Which of the following is false? An 'applied part' is a part, which in normal use: Select one: necessarily comes into physical contact with the patient for the equipment to perform its function. can reasonably be expected to be brought into contact with the patient. needs to be contacted by the patient. is likely to be contacted following unnecessary action by the patient.

is likely to be contacted following unnecessary action by the patient. -Medical Electrical Equipment that in normal use unecessarily comes into physical contact with the patient for Medical Electrical Equipment or a Medical Electrical System to perform its function.

Which of the following is false? A line isolation transformer protects the patient against: Select one: macro shock between active and neutral supply conductors. macro shock between active and earth supply conductors. the loss of electrical supply during an active to earth fault. the undetected connection of class 1 equipment with a broken earth wire fault.

macro shock between active and neutral supply conductors. Line isolation 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 reasons Neutral: is a circuit conductor that normally carries current back to the source

Which of the following is false? If a medical procedure includes the possibility of an intra-cardiac conductor, Select one: then unprotected patient circuits that may make intra-cardiac connection, may be used in a cardiac protected area. then all mains powered equipment must be connected in the same equipotential earthed area. then all applied parts that may make intra-cardiac connection, should be identified with the heart in a box symbol. then the procedure must be undertaken in a cardiac protected area.

then unprotected patient circuits that may make intra-cardiac connection, may be used in a cardiac protected area.