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Drug Therapy. Haemodynamic. in. Support. Kitty Chan School of Nursing,The Hong Kong Polytechnic University Email: hskittyc@inet.polyu.edu.hk Date: 2004. Objectives. Upon completion of the module, the students should have:

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  1. Drug Therapy Haemodynamic in Support Kitty Chan School of Nursing,The Hong Kong Polytechnic University Email:hskittyc@inet.polyu.edu.hk Date: 2004

  2. Objectives Upon completion of the module, the students should have: • developed a basic understanding of anatomy and a basic understanding of the clinical application of drugs for haemodynamic support as well as for advanced cardiac life support (ACLS)

  3. Indicative Readings Darovic G O 2002 Haemodynamic Monitoring: Invasive and Noninvasive Clinical Application. 3rd ed. Philadelphia: W B Saunders Company. Chapter 14 Pharmacologic Influences on Haemodynamic Parameters

  4. Introduction The correction of underlying causes or the control of precipitating factors in heart failure is always the first line of treatment. Pharmacological therapy may modify or reverse adverse consequences to improve the symptoms and promote a beneficial outcome of the clients. Multiple drug therapies are used to manage the haemodynamic status of the clients in critical care settings. Understanding the mechanism of the action of the drugs and primary effect in relation to the patient’s condition and haemodynamic parameters may enhance evaluations of the efficacy of drugs and determine their therapeutic end point.

  5. Introduction In this module, cardiovascular medications that are commonly used in critical care areas and the principles of administering drugs are highlighted. Rapid and ever-changing advances in drug therapies occur in the field of pharmacology. Recommended regimes of medication may be revised from time to time. Healthcare givers are advised to regularly verify the latest changes. It is our responsibility to update and broaden our knowledge and take appropriate precautions when administering drugs.

  6. Contractility Preload Afterload Blood Volume Aortic Impedance Venous Return Ventricular Compliance Peripheral Vascular Resistance (PVR) Cardiac Output Stroke Volume Heart Rate Basic Concept of Cardiac Output

  7. Desired Pharmacological Cardiovascular Effect Circulatory dysfunction & a decrease in cardiac output are common urgencies in critical care settings. Drugs with a rapid effect are required for haemodynamic support to maintain stability & accommodate physiologic changes. Goal: Optimization of Cardiac Output • Enhancing Stroke Volume • Antiarrhythmia

  8. Drugs Therapy: Optimization of CO [1] 1. Inotropes (Contractility) • Beta-adrenergic • Alpha-adrenergic • Digitalis • e.g., Adrenaline, Nor-adrenaline, Dopamine & Dobutamine • Disadvantages: These agents are arhythmogenic, and cause the heart rate increase, thereby affecting the cardiac workload and oxygen consumption 2. Diuretics (Preload) • Angiotensin-Converting Enzyme (ACE) Inhibitors: e.g. Lisinopril, enalapril • Loop diuretics: e.g., Lasix • Potassium-sparing diuretics: e.g. spironolactone or amiloride • Thiazide: e.g., hydrochlorthiazide • These agents relieve symptoms caused by peripheral & pulmonary oedema

  9. Drugs Therapy: Optimization of CO [2] 3. Vasodilators ( Afterload) • Nitrates: e.g., Nitroglycerin, nitroprusside • -Antagonists: Minipress, Cardura, Hytrin • Beta-Blocking Agents (-blockers): e.g. Betaloc, Carvedilol • Angiotensin-Converting Enzyme (ACE) Inhibitors: e.g., Captopril • Calcium Channel Blockers (Ca Antagonists): e.g., Verapamil, Nifedipine, Diltiazem • Hydrallazine 4. Vasopressors ( SVR) • -Agonists: e.g., Phenylephrine, Nor-adrenaline 5. Volume Expanders ( Preload) • Blood Transfusion • Colloids & Crystalloids

  10. Pharmacologic Effect on Haemodynamic Parameters Many of the cardiovascular drugs have multiple actions and can be classified in various categories. Vasoactive medications should be infused parenterally via the central line to assure their bioavailability and employed as precautionary measures of extravasation in the peripheral line. Since the coexisting ventricular dysfunction affects the effect of the medication, a haemodynamic status that is of normal value may not acheive optimal cardiac output. The drugs efficacy are usually titrated according to the haemodynamic parameters & to the clinical manifestations of the clients.

  11. Pharmacologic Effect on Haemodynamic Parameters Points to Note: The Effect of Dopamine is Dose-dependent

  12. Functional Classification of Adrenergic Receptor Sites

  13. Vasoactive Drugs

  14. Vasoactive Drugs: Inotropes & Vasopressors DOBUTAMINE 1 > 2 >   1(2) Inotropic Peripheral Vasodilation DA1 DA2 DA1 Inotropic 1 (2) High Dose  1  Renal Blood Flow Vasoconstriction Inotropic NOREPINEPHRINE 1 >  > 2 EPINEPHRINE 1 = 2 >  DOPAMINE 1 (2)  DA * Adrenergic Receptor Stimulation: Receptor-specific Effects of Physiologic & Pharmacologic Catecholamines Opie L H & Gersh B J 2001 Drugs for the Heart 5th ed Philadelphia: W B Saunders.

  15. Vasodilators

  16. Vasodilators: Anti-Anginals 2+ Ca Blockers Ischaemic Zone REDUCED AFTERLOAD SYSTEMIC CIRCULATION Ca2+ Blockers β- Blockers Nitrates Beta-Blockers -ve Chronotropic Inotropic SA PERIPHERAL ARTERIOLES Nitrates Vasodilation VENOUS CAPACITANCE REDUCED PRELOAD REDUCED VENOUS RETURN Opie L H & Gersh B J 2001 Drugs for the Heart 5th ed Philadelphia: W B Saunders.

  17. SYSTEMIC CIRCULATION REDUCED AFTERLOAD REDUCED PRELOAD PERIPHERAL ARTERIOLES Ischaemic Zone Nitrates Renin Angiotension II Tolerance Vasodilation VENOUS CAPACITANCE REDUCED VENOUS RETURN Blood Volume ↑ Tolerance Opie L H & Gersh B J 2001 Drugs for the Heart 5th ed Philadelphia: W B Saunders. Vasodilator:NitratesEffect on Circulation

  18. β-Blocking Agents (β-adrenergic Antagonists) • Indications: • Hypertensive crisis • SVT • Ventricular Arrhythmias(especially those associated with digitalis toxicity or catecholamine excess) • Absolute Cardiac Contraindications: • Severe bradycardia • Preexisting High Degree Heart Block • LV failure • Pulmonary Contraindiations: • Asthma • Severe Bronchospasm

  19. β-Blocking Agents (β-adrenergic Antagonists)

  20. Calcium Channel Blocking Agents • Actions: • Inhibits the influx of transmembrane Ca++ ions, arterial smooth muscles and myocardium •  Refractoriness & Slows the conduction of AV Node • Vasodilator ( SVR/Afterload) & Coronary Vasodilatation • Negative inotrope & negative chronotrope • Indications: • Antihypertensive • Terminates reentrant tachyarrhythmias • Controls HR in AF & A flutters • Chronic stable angina

  21. Calcium Channel Blocking Agents

  22. Contraindicated ∵ it causes bronchospasms ++ SA AV Ca Channel Blockers Decrease Coronary Tone Inhibits contraction of heart muscles β-Blockers & Calcium Channel Blockers: Haemodynamics β-Blockers -ve Chronotropic  CO = HR x SV  PVR → BP Initially PVR then or  β-Blockers Opie L H & Gersh B J 2001 Drugs for the Heart 5th ed Philadelphia: W B Saunders

  23. Amiloride Na+ Hypotonic triamterene H+ Thiazides K+ Spironolactone Na+ Cl- Na+ Isotonic Carbonic Loop Diuretics Anhydrase H2O with ADH Na+ H2O Inhibitors Na+ K+ 2Cl- Na+ Pump Impermeable to H2O Dopamine Hypotonic H2O DA1 Agonists Osmotics Diuretics: Preload ReductionDiuretic Sites of Action Opie L H & Gersh B J 2001 Drugs for the Heart 5th ed Philadelphia: W B Saunders

  24. Shock Classification: • Hypovolemic Shock - inadequate vascular volume • Cardiogenic Shock -  CO due to impaired ventricular function • Distributive Shock - massive vasodilation caused by the abnormal distribution of intravascular volume • Septic - severe systemic infection • Neurogenic - loss of sympathetic tone • Anaphylactic - severe hypersensitive reactions

  25. Acute Pulmonary Oedema, Hypotension & Shock Differentiate & determine the source of the problem: • Volume • Pump • Rate • Pulmonary Oedema Hypotension & Acute Pulmonary Oedema are indicators of Cardiogenic Shock

  26. Acute Pulmonary Edema, Hypotension & Shock Clinical Signs: Shock, Hypoperfusion, CHF, APO? Volume Problem Rate Problem Acute Pulmonary Oedema Pump Problem Bradycardia or Tachycardia Algorithms 1st line - APO • Frusemide IV 0.5-1.0MG/Kg • Morphine IV 2-4mg • Nitroglycerin S.L. • Oxygen/Intubation as needed Administer • Fluids • Blood Transfusions • Cause-specific interventions • ✼Consider vasopressors BLOOD PRESSURE ? Systolic BP 70- 100 mmHg NO S/S of Shock Systolic BP BP defines 2nd line of action Systolic BP 70- 100 mmHg S/S of Shock Systolic BP > 100mmHg Systolic BP < 70mmHg S/S of Shock Nitroglycerin 10-20 g/min IV Dobutamine 2-20 g/Kg/min IV Dopamine 5-15 g/Kg/min IV Norepinephrine 0.5-30 g/min IV 2nd line - APO • Nigroglycerin/Nitroprusside if BP > 100mmHg • Dopamine if BP = 70-100mmHg; S/S of shock • Dobutamine if BP >100mmHg; NO S/S of shock Further diagnostic/therapeutic considerations: • Pulmonary artery catheter • Intra-aortic Balloon Pump • Angiography for AMI/Ischaemia • Additional diagnostic studies

  27. Inotropes or Vasodilators 3 Diuresis NORMAL Volume 2 Cardiac Index(L/min/m2) HEART FAILURE 1 30 20 10 Pulmonary Capillary Wedge Pressure(mmHg) Haemodynamic Changes & Interventions PULMONARY OEDEMA OPTIMAL FILLING PRESSURE Marino, P. L. (1998) The ICU Book. (2nd ed) Philadelphia: Lippincott Williams & Wilkins. P248 fig.16.5

  28. Haemodynamic Changes & Interventions Leach, R. (2004). Crticial Care Medicine at a Glance. UK: Blackwell Publishing.

  29. Haemodynamic Changes & Interventions From Cardiovascular compensatory mechanisms and the detrimental positive feedback effects they exert in heart failure. The location of action of key drugs, by Leach, R. (2004). Critical Care Medicine at a Glance. p. 48. UK: Blackwell Publishing.

  30. Dysrhythmias Resuscitation Algorithms 1. Ventricular Tachycardia (VT)/Ventricular Fibrillation (VF) 2. Asystole 3. Pulseless Electrical Activity (PEA) • Electromechanical Dissociation (EMD) • Pseudo-EMD • Idoventricular Rhythms • Ventricular Escape Rhythms • Bradyasystolic Rhythms • Post-defibrillation Idoventricular rhythms VT & VF are the most common rhythms in cardiac arrest: *aim to reestablish cardiac rhythm *early defibrillation improves the outcome

  31. Dysrhythmias Resuscitation Algorithms 4. Tachydysrhythmias • Atrial Fibrillation/Atrial Flutter • Narrow-complex tachycardias • Stable Wide-complex tachycardias: • monomorphic • polymorphic 5. Bradycardia

  32. Antiarrhythmic Drug Therapy: Class & Action Hudak C M, Gallo B M & Morton P G (ed) 2002

  33. Combination of Antiarrhythmic Drug • A combination of drugs is favoured: • When a single medication fails • Reduce the dose to diminish side effects • DO NOT combine agents of the same class or subclasses: • Has potentially additive side-effects •  risk of dysrhythmias

  34. Use of Adenosine • Adenosine Triphosphate (ATP) • Actions: • Depresses sinus automaticity • Changes atrial tissue repolarizaton • Slow AV node conduction • Indications: • DRUG OF CHOICE FOR SYMPTOMATIC PSVT (RE-ENTRY PATHWAYS) • NOT for chaotic Atrial Flutter or Atrial Fibrillation • DIAGNOSTIC for Tachycardia with wide QRS complexes

  35. Adenosine Diagnostic Use of Adenosine  Onset of Atriaoventricular Block  Atrial Flutter Revealed  PSVT with Wide QRS Complexes The onset of ATP action takes only a few seconds. The underlying dysrhythmia is due to atrial flutter/fibrillation or a ventricular origin is revealed. *Caution must be taken against the serious tachycardia due to the risk of atrial flutter with a 1:1 AV block. Opie L H & Gersh B J 2001 Drugs for the Heart 5th ed Philadelphia: W B Saunders

  36. Diagnostic Use of Adenosine

  37. Amiodarone Amiodarone: • Powerful antiarrhythmic agents: • arrhythmias in congestive heart failure • prophylaxis & treatment for recurrent atrial fibrillation or VT • cardiac arrest in non-clinical settings • Risk of hypotension (IV) • multisystem side-effects: • serious pulmonary infiltration & fibrosis • Toxicity screening required for long-term use

  38. Sotalol Sotalol: • Effective in sinus tachycardia, PSVT, WPW, AF, VT & VF • Contraindicated in bradycardia, heart blocks & SSS • greater risk of torsades de pointes Opie L H & Gersh B J 2001 Drugs for the Heart 5th ed Philadelphia: W B Saunders.

  39. Effect of Amiodarone & Sotalol Generally, Amiodarone is more powerful than Sotalol: A> S S > A Atrial Ectopies WPW Negative Effect Negative Effect PSVT Sustained VT Post-Infarction Prophylaxis Arrhythmia of CHF A>> S ONLY Amiodarone Opie L H & Gersh B J 2001 Drugs for the Heart 5th ed Philadelphia: W B Saunders

  40. Lidocaine • Lidocaine: • Suppression of serious ventricular arrhythmias in AMI or post-cardiac surgery ( ∴correct hypoK+) • NOT for chronic recurrent ventricular arrhythmias • Free of haemodynamic effects

  41. Quinidine Quinidines: • Conversion of atrial flutter & atrial fibrillation • Monitor widened QRS ∵ serious conduction delay Toxicity  idiosyncrasy • Contraindicated in VT & predisposed to Torsades de pointes

  42. Emergency Treatment of Hyperkalemia 3 Principles: • Antaganize: Calcium Chloride • Shift into Cells: • Sodium Bicarbonate • Dextrose Insulin Infusion • Albuterol Nebulizer • Remove from Body: • Diuresis with Lasix • Cation-exchange Resin (Kayexalate) • Peritoneal Dialysis • Hemodialysis

  43. Electrolytes Disturbance Indications of Sodium Bicarbonate in resuscitation: • Class I: known pre-existing  K+ • Class IIa: pre-existing H2CO3- responsive acidosis • Class IIb: • prolonged resuscitation with effective ventilation • spontaneous circulation after a long arrest interval • Class III: hypercarbic acidosis e.g., DKA, tricyclic antidepressant overdose such as cocaine e.g., CPR without intubation In cardiac arrest patients: Misconception: Bicarbonate is the buffering agent CPR & Adequate Ventilation is the Key to eliminating acidosis

  44. References • Hazinski M F, Cummins R O & Field J M (ed) 2000 2000 Handbook of Emergency Cardiovascular Care for Healthcare Providers. American Heart Association. • Jackson K (ed) 2002 Mastering ACLS. Springhouse: Springhouse. • Leach R 2004 Critical Care Medicine at a Glance. UK: Blackwell Publishing. • Opie L H & Gersh B J 2005 Drugs for the Heart. 5th ed Philadelphia: W B Saunders. • Swearingen P L & Keen J H 2002 Manual of Critical Care Nursing: Nursing interventions and Collaborative Management. 4th ed St Louis: Mosby. • Urden L D, Stacy K M & Lough M E 2002 Thelan’s Critical Care Nursing: Diagnosis and Management. 4th ed St Louis: Mosby. • Wiegand L-M D J & Carlson K K (ed) 2005 AACN Procedure Manual for Critical Care. 5th ed Philadelphia: Saunders.

  45. References • Lo C B & WONG T W 2003 A&E Clinical Guidelines No.14 Guidelines on Rapid Sequence Intubation (RSI). Hospital Authority in Hong Kong, Electronic Knowledge Gateway. • Lau C C, Tong H K, Liu H W, Hung C T, Tsang D, Yam L & Yung R 2003 A&E Clinical Guidelines No.16 Guideline for in-hospital resuscitation of patients at risk of SARS . Hospital Authority in Hong Kong, Electronic Knowledge Gateway.

  46. Journals • American Heart Association. Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care: International Consensus on Science 2000 Part 3: Adult Basic Life Support: Section 1 - 8. Circulation, Vol 102 (8) Supplement August ppI-22-59. • American Heart Association. Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care: International Consensus on Science 2000 Part 6: Advanced Cardiovascular Life Support: Section 1 - 8. Circulation, Vol 102 (8) Supplement August ppI-86-171. • Burns S M 2001 Safely caring for patients with a laryngeal mask airway. Critical Care Nurse, Vol 21 (4) pp72-76.

  47. Journals • Cummins R & Hazinski M F 2000 Guidelines Based on the Principle “First, Do No Harm”: New Guidelines on Tracheal Tube Confirmation and Prevention of Dislodgment. Circulation, Vol 102 (8) Supplement I-380-I384. • Carroll P 1999 Respiratory Monitoring: EVOLUTIONS: CAPNOGRAPHY. RN Vol 62 (5) 68-71. • Soliz J M, Sinha A C & Thakar D R 2002 Airway Management: A Review & Update. The Internet Journal of Anesthesiology, Vol 6 (1). http://216.39.195.244/ostia/index.php?xmlFilePath=journals/ija/vol6n1/airway.xml Accessed on 20 February 2003.

  48. e-Book • Lippincott Clinical Choice • Harwood-Nuss, A., Wolfson, A. B., Linden, C. H., Shepherd, S. M. & Stenklyft, P. H. (ed) (2001) The Clinical Practice of Emergency Medicine. Philadelphia: Lippincott Williams & Wilkins. • Chapter 129: Cardiac arrest and resuscitation Video • Sudbury M 2001 Professional Rescuer CPR Academy or American Orthopaedic Surgeons, National Safety Council: Jones & Barlett Publishers (Call no.- RC87.9.P76)

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