SK DEM 16 - Lecture notes 1-31 PDF

Preview

Summary

Summary of all lectures from this module...

Description

L03 Tuesday, 10 January 2017

10:42

L03 - Who is Worthy of Moral Concern? What is Moral concern? It governs how we treat people and how we think about them. In medicine it is concerned with duties (and types of duties) towards patients and the interests patients have in receiving/continuing to be kept alive.

1) 2) 3) 4) 5) 6)

Criteria for Moral Concern Sentience Human Autonomy Personhood Potentiality Patient

Sentience - Ability to feel painful/pleasurable stimuli - If we can feel pain – assumption that we don’t want to, therefore interest in not feeling pain - Assumptions are always made that the patient is sentient - One issue is what if they are unconscious? It should be considered even if we don’t know whether or not they feel pain - Clinical application: moral reason to give pain relief, especially for foetus over 20 weeks gestation (nervous system intact enough to feel pain at this point) and this includes termination. Evidence suggests that the foetus can feel pain but we are not sure so we give pain relief anyway.

-

-

Human The belief in the sanctity of human life – something special about being human Some believe humans have a soul and there is something sacred or holy about life and can be the basis of many religious arguments. Or is it just a biological process? Religious and professional support Clinical application: prohibits abortion, euthanasia and often withdrawal of lifesaving treatment, do-not-resuscitate orders etc.

Autonomy - To respect autonomous wishes – wrong to frustrate autonomy because patient can make decisions/be responsible - Clinical application: have to accept autonomous decisions, but a non-autonomous patient needs others to decide for them (but on what grounds?) - Psychiatric patients, the young/elderly and the confused are the most vulnerable

DEM Page 1

Personhood - Being a person is not just a biological matter – it is the ability to have certain continuous mental states, like desires for the future, rational thoughts, memory o These provide a right to life - If mental states are no longer possible, the patient may no longer be a person - Personhood is developed from around 2 years - Clinical application: how should we diagnose and treat patients who are no longer persons? - Would rule out very young (foetus) and those with mental illnesses Potentiality - Although the person’s present state lacks a criteria for moral concern, they are likely to develop in the future - The opposite would be futility where it makes no difference whether or not treatment is administered - Clinical application: provides reasons for not harming the foetus (e.g. abortion), and justification for continuing treatment with life-supportive therapies until clinical improvement or futility reached

-

-

Patient Doctors have duties to all their patients, irrespective of the philosophical status of a patient Doctors are grounded in professional duties and obligations The law expects treatment in the best interests of the patient; futile care is considered battery Clinical application: provides justification for continuing care when other grounds are missing but is not against the law

When is a patient dead? - Moral concern (having rights, duties, obligations) changes when a patient dies - Conventionally, death declared when cardiopulmonary arrest is irreversible = cardiopulmonary death - 2 clinical states challenge this: o Persistent vegetative state = biographical death o Brainstem death = biological death Brain stem death – biological death - Death of the vital biological functions of the brain – respiration, thermoregulation, fluid balance - Everything remains perfused except for the brainstem - Heart continues to beat if oxygen is delivered – must be on ventilator as there are no impulses to the intercostal muscles so no breathing - This is termed biological death and is a legally recognised diagnosis - Patients suitable as organ donors - The patients do not look dead - they only look asleep and hence may not be accepted as death particularly for believers in the sanctity of life

DEM Page 2

Testing - In brainstem dead patients there will be no response: → Optic Nerve - cold water and cotton wool on cornea → Vestibulocochlear Nerve - cold water in ear → Hypoglossal Nerve - move endotracheal tube → Oculomotor Nerve - pupils will be fixed and dilated → Inflict pain at the extremities and look for a response → Stop ventilation to increase the PaCO2 to induce respiration

-

PVS – biographical death Death of upper brain (cortex) due to loss of perfusion – brainstem intact Irreversible loss of consciousness and all higher mental states Vital biological functions continue Death of the ‘person’ – experiential life has finished so is termed biographical death

Case Study: Tony Bland - Cannot have interests in staying alive as he has no conscious thoughts - Could have waited for next infection - no treatment and hence death by sepsis - Only other option is to stop feeding and hyperkalaemia will occur in 10-14 days Diagnosis of PVS - Exclude all other causes of persistent coma e.g. no toxins or drowning - Observe the following lack of clinical signs for 6-12 months o No awareness of self or environment o No response to visual, auditory, tactile or noxious stimulus o No evidence of language comprehension o Sleep/wake cycles maintained How do we know PVS is permanent unconsciousness - PET scanning - In one case of a young woman who fulfilled the criteria for PVS, the CT imagery showed significant brain activity in areas when she was asked to imagine certain things indicating that this was indeed not PVS but was more likely to be minimal awareness syndrome - Up to a quarter of patients with a confirmed diagnosis of PVS show some response What else might present as PVS? 1) Minimal awareness state o Although there is a spectrum as the patient may have some consciousness but cannot show it via communication o Severe minimal awareness may present as PVS as in the example above 2) Locked in syndrome 3) Guillain Barre syndrome – virus attacks CNS, presents as locked-in syndrome, recover in 6-12 months How should we treat these patients? Does the diagnosis matter? We need to think morally about how we treat these people.

DEM Page 3

L04 Tuesday, 10 January 2017

10:42

L04 - Learning and Memory Why Study Learning in Medicine? - If we understand how behaviour is learned then we may be able to change it - We need to understand how learning may contribute to psychological/psychiatric illnesses Classical (Pavlovian) Conditioning - Associated Learning A neutral stimulus becomes associated with an involuntary response by its association with a previously unconditioned stimulus. Preconditioning (unconditioned responses) Medical treatment → fear Chemotherapy → nausea Neutral responses White coat → no response Sight of hospital → no response Post conditioning (conditioned responses) White coat → fear Sight of hospital → nausea Over time the learned response can be weakened as the subject no longer associates the stimulus with the response. 3 Stages 1) Before conditioning  The unconditioned stimulus (UCS) produces an unconditioned response or UCR (a natural response that has not been taught)  Also involves a neutral stimulus (NS) – has no effect on a person; this does not produce a response until it is paired with the UCS 2) During conditioning  NS is associated with the UCS at which point it now becomes known as the conditioned stimulus (CS) 3) After conditioning o CS has been associated with the UCS to create a new conditioned response (CR)

Generalisation - Fearing things with similar characteristics - A fear of rats may generalise to other furry animals and white hair/beards

DEM Page 4

Phobias A phobia is an unreasonable fear of specific objects or situations, due (in part) to classical conditioning. It may be treated by ‘systematic desensitisation’ which is graded exposure to the object/situation, with the aim of getting rid of the association. The patient will begin associating the stimuli with relaxation as opposed to fear. Phobias can also be treated by ‘flooding’ which is facing the phobia directly. Operant (Instrumental) Conditioning The likelihood of a response occurring again is controlled by its consequences. Developed by BF Skinner in 1938 and involves response-outcome associations. The operant is an intentional action that has an effect on the surrounding environment. The process results in the changing of behaviour or development of new behaviours by the use of REINFORCEMENT which is given after the desired response and is a consequence that causes a behaviour to occur with increasing frequency. Principles of Operant Conditioning - Positive reinforcement: verbal praise in rehab, taking psychostimulant - Negative reinforcement: taking away the adverse stimulant e.g. adjusting gait to avoid pain, reassurance removes anxiety - Punishment: trying to quit smoking (craving, weight gain), uncomfortable cervical smear Behaviour Shaping - Successive approximations of required behaviours are reinforced - Token economies – rewards e.g. certificates - Particularly effective in children and animals

Social (Observational) Learning Learning by watching other people’s behaviour and its consequences is known as social learning. It includes aspects of imitation and modelling. Doctors are powerful models of this type of learning, as patients can quickly pick up embarrassment and anxiety from doctors. Some behaviours are difficult to learn without observation e.g. clinical skills. This type of learning was demonstrated by an experiment by Bandura utilising children and BoBo dolls. LEARNING AND MEMORY

DEM Page 5

-

Learning = acquisition of knowledge Memory = retaining knowledge Learning and memory are inextricably linked Ability to learn depends on ability to remember Ability to remember depends on prior learning

MEMORY - 3 stages: 1) Encoding: put information into store 2) Storage: preserve information over time 3) Retrieval: recover information when required Simple Model of Memory

- External stimuli → sensory memory → short-term memory → long-term memory Sensory Memory - Brief impression of a sensory stimulus – still in memory for a few seconds when it disappears, pre-processing

-

Short-term Memory – now replaced by working memory Limited capacity ( 7 +/- 2 objects) Short duration (several seconds) Maintenance via rehearsal – working memory Forgetting via displacement - replaced by new information Working memory consists of a central executive which controls and coordinates the allocation of data to different subsystems (see end)

Chunking - Information is simplified by rules which make it easily remembered once the rules have been learnt - Increases capacity of short term memory - Demonstrates how information stored in LTM can be related to information in STM

DEM Page 6

-

-

Long-term Memory Unlimited capacity Variable duration Forgetting via interference and decay Cues (mnemonics) and context (e.g. learning and exam in same location) aid retrieval Mood affects memories - low mood will result in sad memories Digital Span Test of STM Have to remember sequence of numbers that appear on screen If correctly remember, sequence will get longer If make mistake, sequence will get shorter and you lose a life (3 lives in total) Shows that STM has limited capacity of approximately 7 things Can be suppressed by articulatory suppression task e.g. stop rehearsal by asking for a phone number → can only process 1 stream at a time

Free Recall Task - Participants study a list of items on each trial, and then are prompted to recall the items in any order - Demonstrates: o Primacy effect: info presented early is more likely to be remembered – increased rehearsal o Recency effect: info later in list is more likely to be recalled – not yet replaced from STM Memory and Medical Consultations - Patients remember approx. 50% of info – less if anxious/elderly - Simple rules for consulting in order to aid the patient what you told them: o Don't give too much information - limited capacity of STM o Give the most important information first - primacy o Repeat important information - rehearsal o Use explicit categorisations - chunking o Make advice specific and concrete rather than general and abstract - easier to visualise

-

-

Causes of Memory Impairment Diffuse brain disease – dementias Focal brain disease – amnesias o Retrograde amnesia = cannot remember events PRIOR to brain damage o Anterograde amnesia = cannot later remember events that occur AFTER brain damage  Symptoms: difficulty learning new info, disorientation, confusion, personality/intelligence/judgement unaffected,  generally have good memory, trouble holding a job Physiological disturbance – delirium Psychiatric illness – schizophrenia, depression, anxiety, dissociative disease Working Memory

DEM Page 7

- It is actively processing memory as STM is too simplistic - The central executive is a flexible system responsible for the control and regulation of cognitive processes - It can be thought of as a supervisory attentional system that control cognitive processes and intervenes when they go astray - It decides which information is ongoing o Programming o Initiation o Regulation o Monitoring - Failures of the central executive can be analysed using the cognitive failures questionnaire in order to separate them from everyday slips and lapses

-

Phineas Gage Damage to frontal lobes Motor control, perception and language intact QoL deteriorated General impairments in control - disinhibited, impulsive, antisocial, profane, changes in mood and personality Dysexecutive syndrome/frontal lobe syndrome/pseudopsychopathy Deficits of central executive function

DEM Page 8

L05 Tuesday, 10 January 2017

10:42

L05 - Pain Early Views of Pain – Biomedical View - Pain is a response to external factors - Link between source of pain and the brain is direct, causal and automatic - Tissue damage causes the sensation of pain – amount of tissue damage is proportional to the amount of pain Classifying Pain - Patients with little tissue damage but lots of pain are making a fuss - Patients with lots of tissue damage but no pain are brave - When no physical cause can be found, the pain is all in the patient’s mind psychogenic - When a clear physical cause can be found, it is real pain – organic Psychological Aspects - Psychological processes were not thought to play a role in how patients experienced and expressed their pain o Pain is an automatic response – the person is passive o There is no role for interpretation or appraisal

-

-

Problems with this view Patients with the same degree of tissue damage reported different levels of pain – patients interpret and appraise their pain differently; some can manage, some cannot Phantom limb pain Most common form of pain is a headache, yet there is no tissue damage How do athletes continue with severe pain? Gross injuries occur without much pain e.g. severely wounded WW2 soldiers complained of little pain, perhaps because they were just happy to be going home and perceived their wounds as a sign of something good and courageous

Gate Control Theory of Pain - Pain is a multidimensional process that is mediated by other factors and is controlled by a gate at the spinal cord level - Pain is a perception and an experience Input to the gate: - Peripheral nerve fibres – injury sends info about pain, pressure or heat to the gate - Descending central influences from the brain – brain sends info about psychological state of the individual to the gate e.g. past experiences, fear, confidence, mood, expectations - Large and small fibres are part of the physiological input to pain perception

DEM Page 9

o Small diameter nerve fibres (bad) carry pain stimuli to the gate o Large diameter nerve fibres (good) inhibit transmission of small fibres Output from the gate: - Gate integrates information from sources - Sends to an action system, resulting in a perception of pain Factors Affecting Pain Perception - Factors that close the gate – reduce perception of pain o Physical – medication, stimulation of large fibres (massage, ice) o Emotional – happiness, relaxation o Behavioural – intense distraction - Factors that open the gate – increase perception of pain o Physical – activation of small fibres o Emotional – anxiety, worry o Behavioural – boredom, focusing on pain

-

Tolerance of pain can be affected by: Emotional and psychological state Memories of past pain experiences Upbringing Gender - females present more often; testosterone = buffer Beliefs and values Social and cultural influences Attitudes and expectations

-

Chronic Pain Long-lasting, intensive pain 6 months used as a cut-off Often reliant on large amounts of medication for a long period of time Medication often becomes ineffective over time May be constant or come-and-go May be due to a chronic condition e.g. arthritis Depression and anxiety are linked with increased chronic pain

-

Managing Chronic Pain – Psychological Interventions Clinical trials have shown psychological interventions can lead to significant improvements Interventions might include a combination of treatments Pain clinics are likely to be multidisciplinary – pharmacology, clinician, physiotherapy, clinical psychology Cognitive interventions – distraction, imagery, hypnosis, counselling Behavioural interventions – relaxation exercises, biofeedback, physical activity

DEM Page 10

Measurement of Pain - Difficult as pain is subjective o We cannot feel someone else’s pain o Can male doctors understand menstrual cramps, childbirth etc.? - Have to rely on indirect measures: 1) VAS (visual analogue scale) 2) MPQ (McGill Pain Questionnaire) 3) Pain diaries 4) Pain behaviours via observation VAS and MPQ frequently measured Visual Analogue Scale (VAS) Frequently used, usually 10cm line Used for pain severity and treatment effects Easily administered Use with kids over 5y/o Sensitive to small changes Quite simplistic as it only measures pain intensity, and does not assess quality of the sensation (what does the pain feel like) or its emotional impact - No pain → worst possible pain - No pain relief → complete pain relief -

McGill Pain Questionnaire - Examines different components of the pain experience – questions and body map  Sensory – sickening, pulsing, throbbing, pounding  Affective – tiring, fearful  Evaluative – annoying, troublesome

Pain Diaries - Used to analyse what things make pain worse during the day - Pros  Help doctor understand causes of the pain by observing its exacerbating and relieving factors  Provide detailed daily picture of pain experience  Help patient to see changes in pain and the impact of their behaviours on the pain - Cons

DEM Page 11

 Permanent record of pain may be demoralising  Patients can be lazy or forget, resulting in incomplete information  Inconvenient – just give me painkillers

-

Observation Patients can be asked to perform simple tasks to assess extent of pain e.g. walking Can record and rate how often patient expresses pain More useful with chronic than acute pain Examples of behaviours include groaning, grimacing, rubbing, stopping to rest, holding part of the body, distorted posture, irritability

Children and pain measurement - Can be difficult to understand children’s pain because they are pre-literate or have limited vocab - Therefore, likely to rely on observations - What is being measured - pain or distress? - Questionnaires might work - Visual accounts useful e.g. teddy and ...