ALS MODULE 7 Pharmacology

Transcription

1 ALS MODULE 7 Pharmacology Relates to HLT404C Apply Advanced Resuscitation Techniques

2 Introduction There are no studies that addressed the order of drug administration. There is inadequate evidence to define the optimal timing or order for drug administration. ARC Guideline 11.5 December 2010 page 2. The administration of drugs will almost certainly be used in cardiac arrests and should be prepared and given in accordance with the hospital guidelines and health care protocols whilst awaiting the orders and/or arrival of the doctor.

3 Introduction Drugs used in cardiac arrest can be categorised according to therapeutic objectives. To increase perfusion pressure and enhance contractility e.g. Adrenaline To correct arrhythmias e.g. Amiodarone Restore electrolyte balance e.g. Magnesium, Potassium Chloride, Calcium Chloride To correct acidosis e.g. Sodium Bicarbonate

4 Adrenaline Classification: Sympathomimetic Actions: Activates an adrenergic receptive mechanism on affected cells and imitates all actions of the sympathetic nervous system Fight or Flight Acts on both alpha and beta receptors and is the most potent alpha receptor activator causing peripheral vasoconstriction, increased heart rate & myocardial contractility

5 Adrenaline Dosage: 10ml of 1:10,000 solution = 1 mg 1ml of 1:1000 solution = 1mg add 9mls N/saline to make 1:10,000 Can repeat every 3-5 minutes No maximum dose Method of Administration: IV/IO/ETT

6 Adrenaline Indications: Ventricular Fibrillation/pulseless Ventricular Tachycardia after initial counter shocks have failed (after 2nd shock then after every second cycle). Asystole and electromechanical dissociation (pulseless electrical activity) in initial cycle (then every second cycle). Relief of hypersensitivity reactions to drugs and other allergens given either IM or SC

7 Adrenaline Adverse effects: Tachyarrhythmias Severe hypertension after resuscitation Tissue necrosis if extravasation occurs Other adverse effects such as arrhythmias, headache and increase in myocardial oxygen demand

8 Amiodarone Classification: Antiarrhythmic Actions: Suppresses SA node function Decreases speed of conduction through AV node, refractoriness of AV node Prolongs PR, QRS and QT intervals Increases the action potential of contractile fibres, e.g. effects Na, K and Ca channels to slow the speed of conduction system

9 Amiodarone Dosage: Specific Resuscitation Drugs 300mg Bolus Additional bolus of 150mg could be considered Maybe followed by an infusion refer to local protocols Method of Administration: Draw up gently/slowly to prevent froth Slow push into either IV or IO

10 Amiodarone Indications: Ventricular Fibrillation (VF) Pulseless Ventricular Tachycardia (VT) Conscious Ventricular Tachycardia - infusion Rapid Atrial Fibrillation and Flutter - infusion

11 Amiodarone Adverse effects: Hypotension Bradycardia Heart Block Torsades de Pointes GIT disturbances This is why we give it as a SLOW PUSH

12 Calcium Classification: Electrolyte Actions: Essential for normal muscle and nerve activity It transiently increases myocardial excitability and contractility and peripheral resistance. Dosage: 5-10mls of 10% calcium solution Suggest dilute (20mls N/Saline) to minimise extravasation effects. Please check your local protocols.

13 Calcium Method of Administration: Slow push into either IV or IO Indications: Hyperkalaemia Hypocalcaemia Overdose of calcium channel blocking drugs e.g. Verapamil, Nifedipine

14 Calcium Adverse effects: Increased myocardial and cerebral injury by mediating cell death Tissue necrosis with extravasation Rapid IV administration causes flushing, burning sensation and cardiac arrest

15 Lignocaine Classification Antiarrhythmic Actions: Suppresses discharge from ectopic foci by blocking sodium channel, inhibits re-entry arrhythmias that lead to VT/VF Reduces action potential production which results in slowed cardiac conduction

16 Lignocaine Dosage 1mg/kg body weight Bolus Can give additional bolus of 0.5mg/kg Method of Administration: IV /IO/ETT Indications VF and pulseless VT where Amiodarone cannot be used Prophylaxis in the setting of recurrent VF or VT

17 Lignocaine Adverse effects: Slurred speech Altered consciousness Muscle twitching Seizures Hypotension Bradycardia Heart block Asystole

18 Magnesium Classification: Electrolyte Antiarrhythmic Actions: Magnesium is an electrolyte essential for membrane stability. Hypomagnesaemia causes myocardial hyperexcitability particularly in the presence of hypokalaemia and digoxin. Anticonvulsant

19 Magnesium Dosage: Bolus of 5mmol. Suggest dilute (20mls N/Saline) to minimise extravasation effects. Infusion (20mmols over 4 hour) Please check your local protocols Method of Administration: Slow push into either IV or IO Infusion

20 Magnesium Indications: Torsades de Pointes VF/pulseless VT (usually administered when refractory to defibrillator shocks and a vasopressor) Known hypokalaemia Known hypomagnesium Cardiac arrest from Digoxin toxicity

21 Magnesium Adverse Effects: Hypotension Bradyarrhythmia Respiratory failure Muscle weakness Flushing

22 Potassium Chloride Classification: Electrolyte Actions: Potassium is an electrolyte essential for membrane stability. Low serum potassium, especially in conjunction with digoxin therapy and hypomagnesaemia, may lead to life threatening ventricular arrhythmias.

23 Potassium Chloride Dosage: Bolus of 5mmol Suggest dilute (20mls N/Saline) to minimise extravasation effects. Please check your local protocols Method of Administration: Slow push into either IV or IO Indications: Persistent VF due to documented or suspected hypokalaemia

24 Sodium Bicarbonate Use only with adequate ventilation and CPR Consider if arrest is over 15 minutes or in known metabolic acidosis - take an ABG/VBG for ph if no return of spontaneous circulation (ROSC) Prolonged arrest can result in lactic acid build up (acidosis), which can lead to depression of cardiac contractility.

25 Sodium Bicarbonate Dosage: 1mmol/kg infused over 2-3 minutes then guided by ABG s or VBG s Adverse Effects: Metabolic alkalosis, hypokalaemia, hypernatraemia and hyperosmolality. Sodium bicarbonate and adrenaline or calcium when mixed together may inactivate each other, precipitate and block the IV line.

26 Atropine Classification: Anticholinergic Actions: Parasympathetic antagonist that accelerates sinus or atrial pacemakers Increases atrioventricular conduction Increases heart rate, Conduction & cardiac output

27 Atropine Dosage: 600mcg 1mg Repeated as necessary every 3-5 min up to a total dose of 3 mg Method of Administration: IV/IO/ETT Indications: Symptomatic bradycardia (see guideline 11.9): - systolic BP < 90 mmhg heart rate < 40/min ventricular arrhythmia heart failure

28 Atropine Adverse effects: Tachycardia Rebound bradycardia if given too slowly or dose too small Blurred Vision Delirium Hyperthermia in large doses

29 Summary Asystole Adrenaline VT/VF - Defibrillation +/- Amiodarone Hyperkalaemic arrest Bicarbonate and Calcium Electrolytes Known/suspected U+E s imbalance Protracted arrest/acidosis - Sodium Bicarbonate Bradycardia - Atropine ALL FLUSHED WITH 20-30MLS OF NORMAL SALINE

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31 Pharmacology Further Reading/Resources ARC Guidelines December 2010 Guideline 11.5 and Australian Injectable Drug Handbook, 4 th Edition 2009, SHPA Australian Medicines Handbook 2009 Rapid ACLS, Barbara Aehlert, RN. Mosby Inc 2007 The Merck Manual Online Medical Library,

32 Next Steps Pharmacology Please now complete the online quiz by clicking on the exit button - top right hand of your screen. This will take you back to the Topic Outline page. Scroll down to 7 - Module Assessment and complete the online Final Assessment. Please complete the Evaluation form and print off your certificate.