Quiz for Weeks 1 & 2 - Questions Question 1. [Mini Problem Based Exercise (PBE)] You come upon a semi-conscious, middle-aged female lying on the roadside near a pedestrian crossing outside a pub. a) Give four broad hypotheses to account for her state, and briefly indicate the

mechanisms involved. b) What should be your actions in such a situation? c) Explain the mechanisms leading to rapid pulse, reduced pulse amplitude,

pallor and sweating in a patient with hypovolemic shock. Question 2. Classify shock into three physiological categories and illustrate each category with 2 pathological causes. Question 3. List and define the four determinants of cardiac output. Question 4. Describe the sequence of clinically detectable changes to circulatory status that occurs during prolonged blood loss. Question 5. Describe the fate of an intravenously administered crystalloid, such as lactated Ringer’s solution, and comment on its usefulness in the management of hypovolaemia. Question 6. List the social circumstances that influence health outcomes. Question 7 a) Give an example to show that you understand whether my suburban

neighbour can also be my legal neighbour. b) Compose a coherent paragraph to show that you understand the relationships

between the following terms: negligence, liability, fault, compensation, reasonable care, industrial revolution.

c) What are the four fundamental requirements which need to be established by

a patient, who is claiming that they deserve compensation by a doctor?

d) Explain what is meant by the statement that the tort of negligence does not

include a general duty to rescue. Explain why this is the case. e) Give 5 aspects of practice, in which doctors are expected to conform to a

reasonable standard of care. f) Is this statement true or false? Briefly explain your answer.

“The Law Reform Act 1995 (Qld) states that, although doctors must render assistance at any emergency which they witness, their actions will not be subject to negligence suits unless they act with gross negligence.”

Question 8 a) What are the two main sources of law in Australia? b) Give three kinds of courts in which Australian doctors may find themselves,

and indicate the kind of case in which the doctor in each court would be involved.

c) True / False

1. The common law is uniform throughout the states of Australia 2. The High Court of Australia has been involved in a number of important

medical negligence cases in its history 3. It is necessary for a doctor to have intended to kill a patient for him/her to

be found to be criminally negligent in regard to the patient’s death 4. Medicare fraud is a disciplinary, not a criminal offence 5. Sexual relations between doctors and patients can be subject to inquiry

and prosecution through the criminal law, the common law, and disciplinary law.

6. Since physician impairment is a health matter, it cannot be made subject to any legal proceeding

7. Doctors must exercise skill and care at a standard which is more than just reasonable, as judged by their peers

d) Give three differences between the criminal and the civil law.

STOP! DON’T TURN THE PAGE UNTIL YOU HAVE WORKED ON THESE QUESTIONS IN MONDAY’S PBL TUTORIAL, OR ATTEMPTED WRITTEN ANSWERS YOURSELF.

Quiz for Weeks 1 & 2 – Answer Guide Question 1. You come upon a semi-conscious, middle-aged female lying on the roadside near a pedestrian crossing outside a pub. a) Give four broad hypotheses to account for her state, and briefly indicate the

mechanisms involved. Students should think of a hypothesis as a coherent explanation of a patient’s problem. That is, it should account for all of the patient’s signs and symptoms. In its detailed form, a hypothesis includes the mechanisms leading to these clinical features (e.g. semi-consciousness). Hypotheses may be so specific as to be diagnoses but usually they are broad statements rather than a disease label. So, the best answers will formulate true hypotheses rather than diagnoses, e.g.

• CNS depression due to alcohol or other drugs • Head injury from violence or motor vehicle accident • CNS depression due to reduced blood flow due to hypovolaemic shock from

trauma in MVA • CNS depression due to reduced blood flow due to cardiogenic shock from

coronary vessel occlusion • CNS dysfunction due to interruption of arterial supply to part of brain, i.e. stroke

This list is a lot better than, for example: drunk, stroke, myocardial infarct, MVA b) What should be your actions in such a situation? Answers should include the ABC First Aid protocol and standard precautions. c) Explain the mechanisms leading to rapid pulse, reduced pulse amplitude,

pallor and sweating in a patient with hypovolemic shock. • Rapid pulse: ↓BP → ↓stretch in carotid sinus → via baroceptor reflex →

↓parasympathetic drive to heart → ↑ heart rate. As the BP falls significantly, sympathetic system is activated.

• Weak pulse: the: ↓ blood volume → venous return → ↓ stroke volume → ↓ pulse wave (which is proportional to the stroke volume)

• Pallor: ↓BP → sympathetic activation → vasoconstriction in skin (also muscle, gut) • Sweating: sympathetic terminals also drive sweat glands: this is an overflow effect

when there is massive activation of the sympathetic nervous system.

Question 2. Classify shock into three physiological categories and illustrate each category with 2 pathological causes. • Hypovolemic – haemorrhage, dehydration, burns, losses into oedema of traumatic

or surgical wounds, severe vomiting and diarrhoea…

• Cardiogenic – myocardial infarct, myopathy, arrhythmia, valve dysfunction including ruptured cordae, tamponade in pericarditis or effusion or haemorrhage…

• Distributive – reduced peripheral resistance in anaphylactic shock, septic shock… Question 3. List and define the four determinants of cardiac output. 1. Preload = filling or end diastolic volume, determined by venous return (or venous

pressure)

2. Afterload = aortic blood pressure against which ventricle must deliver stroke volume

3. Heart Rate = number of stroke volumes delivered per unit time

4. Inotropic State = contractility or fourth variable which determines stroke volume at given values of preload and afterload. It is mediated by internal calcium stores in the sarcoplasmic reticulum and increased by sympathetic drive, certain drugs, and most things that increase heart rate.

Question 4. Describe the sequence of clinically detectable changes to circulatory status that occurs during prolonged blood loss. Initially, ♦ pulse rate rises and pulse pressure (reflecting stroke volume) falls, as cardiac output

and tissue perfusion are maintained by compensatory mechanisms.

♦ peripheral pallor develops as non-essential beds are shut down by sympathetically mediated vasoconstriction, but still the perfusion of vital organs is maintained and the systolic blood pressure is not substantially depressed.

♦ sweating may occur as a result of sympathetic nervous system overflow.

Later, as the limit of compensatory mechanisms is exceeded and the cardiac output falls seriously, the patient moves into decompensated shock in which perfusion of vital organs is compromised. Systolic blood pressure decreases and mental state is depressed with anxiety, air hunger and confusion. At this stage the patient is rapidly approaching irreversible shock and death.

Question 5. Describe the fate of an intravenously administered crystalloid, such as lactated Ringer’s solution, and comment on its usefulness in the management of hypovolaemia. Sodium lactate will be metabolised in the liver, heart and other aerobic tissues (assuming the patient’s circulatory status is compatible with aerobic metabolism in such tissues) to carbon dioxide and sodium bicarbonate. The carbon dioxide is excreted via the lungs, leaving the alkaline sodium bicarbonate remaining – this may contribute to correcting metabolic acidosis, or lead to a degree of actual metabolic alkalosis, depending on circumstances and the amount administered. The fluid is free from macromolecules (i.e. it is crystalloid not colloid) and so will partition out into the tissues according to the Starling forces at the capillary membrane. Depending on interstitial fluid pressure (i.e. degree of dehydration or hypovolemia versus pre-existing over hydration or oedema from cardiac or renal disease) only a modest fraction will remain intravascular after equilibrating over twenty minutes or so (say of the order of 15% typically). But, as they say, it is a “good start,” granted that more complex fluids, probably including blood in a patient with significant hypovolemia, are on their way. Question 6. List the social circumstances that influence health outcomes. • Stress, social isolation, job insecurity all lead directly to worse health by direct

pathogenic mechanisms through effects of stress on the limbic system and autonomic nervous system, to adverse health related behaviours and lifestyle factors, and reduced access to health care services.

• Childhood development leads to long-term effects on social development and

economic success. • Poor work environments, job related stress, low socio-economic status, and reduced

family and social support networks all predispose to abuse of nicotine, alcohol and other substances which have negative health effects.

Question 7 a) Give an example to show that you understand whether my suburban

neighbour can also be my legal neighbour. b) Compose a coherent paragraph to show that you understand the relationships

between the following terms: negligence, liability, fault, compensation, reasonable care, industrial revolution.

c) What are the four fundamental requirements which need to be established by

a patient, who is claiming that they deserve compensation by a doctor? d) Explain what is meant by the statement that the tort of negligence does not

include a general duty to rescue. Explain why this is the case.

e) Give 5 aspects of practice, in which doctors are expected to conform to a reasonable standard of care.

f) Is this statement true or false? Briefly explain your answer.

“The Law Reform Act 1995 (Qld) states that, although doctors must render assistance at any emergency which they witness, their actions will not be subject to negligence suits unless they act with gross negligence.”

Answers a) My neighbour recently re-landscaped his front yard. He hired a machine to move some large

boulders, but while doing this dropped one of the boulders over our fence. This damaged my garage. Because of the proximity of my property to where he was working, and the fact that he could reasonably foresee that any carelessness with the machine could damage it, he had a legal duty of care to me. I could have sued him for negligently damaging my garage.

b) It has long been the case in English law, that if someone is injured by the activities of another,

the injured party should be compensated financially by the other person. Originally this meant that in any circumstance where these were the facts, the other person was liable (strict liability). With the advent of the Industrial Revolution, it was recognised that claims for compensation would skyrocket to unmanageable proportions, so liability came to be limited to circumstances where it could be shown that the other person was at fault, even though the harm done was not intentional.

Thus commenced the legal tradition of negligence liability, whereby failure of a person or organisation to observe reasonable standards of care for the particular activity, could result in that person or organisation having to compensate the victim, but where liability was kept in check, or limited, by the need to demonstrate some fault.

c) The patient must establish that there was a duty of care on the part of the doctor to him/her,

that the doctor somehow breached the standard of care which was owed, and that he or she suffered damage which was caused by that breach. (These are the three fundamental requirements. It is sometimes said, in addition, that the damage must not be too remote, and that the damage was reasonably foreseeable. These two requirements are often understood as implied in the damage and duty of care elements).

d) Negligence may occur through a person’s omission to fulfil a recognised duty, as well as

through positive action. It is the law’s responsibility to strike a balance between various duties of care, and the imposition of too onerous a burden on citizens or people engaged in different activities. It has long been accepted that the tort of negligence does not include a general duty to rescue, since such a duty would be far too broad to be reasonably applied. A general duty to rescue would mean that in every situation where someone is in trouble, any other proximate person would be expected to assist. This expectation would interfere too much with everyone’s ability to carry on normally with their own activities.

e) Duties to diagnose, treat, follow-up, attend (eg when asked for a house call), disclose

information for decision-making, keep patient information confidential. f) False. (Doctors are not required by the Law Reform Act to render assistance at any

emergency which they witness).

Question 8 a) What are the two main sources of law in Australia? b) Give three kinds of courts in which Australian doctors may find themselves,

and indicate the kind of case in which the doctor in each court would be involved.

c) True / False

1. The common law is uniform throughout the states of Australia 2. The High Court of Australia has been involved in a number of important

medical negligence cases in its history 3. It is necessary for a doctor to have intended to kill a patient for him/her to

be found to be criminally negligent in regard to the patient’s death 4. Medicare fraud is a disciplinary, not a criminal offence 5. Sexual relations between doctors and patients can be subject to inquiry

and prosecution through the criminal law, the common law, and disciplinary law.

6. Since physician impairment is a health matter, it cannot be made subject to any legal proceeding

7. Doctors must exercise skill and care at a standard which is more than just reasonable, as judged by their peers

d) Give three differences between the criminal and the civil law.

Answers a) Statutes (legislation passed by the state or federal parliaments) and the common law (the

body of law developed by judges hearing cases and establishing principles by precedent). b)

• Federal Court: a hearing concerning over-servicing • District Court: a hearing concerning disciplinary matters, brought by a medical

registration board (in Qld, the District Court would constitute a Health Practitioners Tribunal)

• State Supreme Court: a hearing concerning a criminally negligent action or omission • High Court: an appeal, by doctor or patient, against a finding of a lower court, usually a

state Supreme Court, concerning medical negligence c) 1-F; 2-T; 3-F; 4-F; 5-T; 6-F; 7-F d)

• Action brought by state (criminal law) and by injured person (civil law • Standard of proof is beyond reasonable doubt (criminal law) and on the balance of

probabilities (civil law) • Penalty is fine or imprisonment, usually (criminal law) and payment of compensation,

usually (civil law)