Pain Control
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Transcript of Pain Control
Pain Control.
Pain Control Methods.
• Pharmacological methods.– How to decide where to start.– Individual drugs.
• Non-pharmacological methods.– Physical methods.– Psychological methods.
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What is pain?
• “An unpleasant sensory and emotional experience associated with actual or potential tissue damage. Each individual learns the application of the word through experiences related to injury in early life.”
• “Pain is what the patient says it is.”
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Pharmacological Methods of Pain Control.
• Paracetamol
• NSAIDS
• Opiates
• Local Anaesthetics
• Nitrous Oxide
• Medications aimed at treating the underlying pathology e.g. GTN for Angina
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WHO Pain Ladder.
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Paracetamol.
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Paracetamol.
• Weak inhibitor of prostaglandin synthesis.
• However no anti-inflammatory effect.
• Is there another mechanism of action?
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Paracetamol.
Side effects.
• Rashes
• Renal Impairment
• Increased risk of hepato-toxicity in liver failure.
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Aspirin.
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Meadowsweet.
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NSAIDs
Mechanism of action
• Inhibition of cyclo-oxygenase enzyme that converts Platelet Activating Factor into Prostaglandins.
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NSAIDs
Cautions and Contraindications.
• Hypersensitivity to Aspirin or NSAIDs
• Active Peptic Ulceration.
• Pregnancy – premature closure of Ductus Arteriosus.
• Renal Impairment.
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NSAIDs
Side effects.
• Hypersensitivity.
• GI Bleeding – less common with Ibuprofen
• Bronchospasm.
• Renal failure.
• Fluid retention.
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Opiates.
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Opiates.
Mechanism of action –
• Agonists/Partial Agonists at mu type Opiate Receptors.
• These are mainly in CNS, but also found in other tissues.
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Opiates.
Side effects.Type A – Related to opiate receptors inside CNS.
Hallucinations.Dysphoria.Respiratory depression.Vomiting.
Related to opiate receptors outside CNS.Constipation.Urinary retention.Hypotension.
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Opiates.
Type B - Non opiate receptor mediated histamine release.
Urticaria
Anaphylaxis
ARDS
These usually respond to anti-histamines not naloxone.
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Local Anaesthetics.
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Novocaine.
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Local Anaesthetics.
Mechanism of action.
• Defuse into axons in non ionised form.
• Ionised form blocks fast sodium channels from the inside.
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Local Anaesthetics.
Side effects - CNS.
• Circumoral numbness.
• Lightheadedness.
• Tinnitus.
• Convulsions.
• Coma.
• Respiratory arrest.
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Local Anaesthetics.
Side effects - CVS.Bradydysrhythmias.Loss of vasomotor tone.Ventricular tachydysrhythmias.
Also, Allergic reactions.Nerve injuries.Infarction of appendages with adrenaline.Pain at injection site.
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Local Anaesthetics.
• Lignocaine 3mg/kg
(double mixed with 1:200 000 adrenaline)
• Bupivucaine 2mg/kg
• Prilocaine 5mg/kg
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Entonox.
Mixture of 50% Oxygen and 50% Nitrous Oxide.
Unknown mechanism of action.
Doesn’t cause respiratory depression.
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Entonox.
• Cautions and Contraindications.
Nitrous oxide defuses out of the blood
faster than Nitrogen dissolves into it.
Entonox should not be given in any situation where expansion of a gas filled space may have an adverse effect on the patient.
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Entonox.
• Cautions and Contraindications.• Pneumothorax
• Intestinal Obstruction/Grossly distended abdomen.
• Diving injuries.
• Severe head injuries (maybe pneumocephalus)
• Middle ear surgery.
• Unconscious patients.
• Severe facial trauma.
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Other drugs.
• Amitryptaline.
• Gabapentin.
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Non Pharmacologicalmethods of pain control.
• Physical.
• Psychological.
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Stabilisation.
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“Rubbing it better”
• Gate theory of pain
• Topical preparations
• Acupressure?
Kober A, Scheck T, Greher M, Lieba F, Fleischhackl R, Fleischhackl S, Randunsky F, Hoerauf K (2002).
Prehospital analgesia with acupressure in victims of minor trauma: a prospective, randomised, double blinded trial.
Anaesth Analg 95(3) 723-727.
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Non-pharmacological methodsof Pain Control.
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Remember a time when you were alone and afraid?
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Remember a time when you werehappy?
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“children tolerate pain well”
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Distraction.
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Any questions?
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Summary.
• How to choose which drugs to use for pain control based on;– Aetiology of pain.– Amount of pain.– Individual drugs.
• Physical methods of pain control.
• Psychological methods of pain control.
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Thank You.