Drugs for Shock

1. Drugs for Shock Chapter 29

2. Shock Condition in which vital tissue and organs are not receiving enough blood to function properly Without adequate oxygen and other nutrients, cells cannot carry out the normal metabolic processes.

3. Shock Medical Emergency Failure to reverse the causes and symptoms may lead to irreversible organ damage and death

4. Signs and Symptoms Many are nonspecific Pale �feel sick�, weak with no specific complaint Behavioral changes Thirsty Cold or clammy Without immediate treatment, multiple body systems will be affected and respiratory or renal failure may result.

5. Shock Central problem in most types of shock is the inability of the cardiovascular system to send sufficient blood to vital organs, with the heart and brain being affected early in the progression of the disease Blood pressure Cardiac output diminished Heart rate , rapid weak thready pulse RR rapid and shallow

6. Types of Shock Hypovolemic shock Neurogenic shock Cardiogenic shock Septic shock Anaphylactic shock

7. Treatment Priorities for Shock ABC�s of life support Airway Breathing Circulation Identify underlying cause; then start more specific treatment Keep client warm and quiet Offer psychological support

8. Pharmacotherapy Goals Restore normal fluid volume and compositions Maintain adequate blood pressure For anaphylaxis: prevent or stop hypersensitive inflammatory response

9. Immediate Fluid Replacement Essential with significant fluid loss Causes of fluid loss include Hemorrhage; extensive burns; severe dehydration Persistent vomiting or diarrhea; intensive diuretic therapy

10. Hypovolemic Shock Three categories of fluid replacement agents used Blood Colloids Crystalloids

11. Whole Blood Indicated for treatment of acute, massive blood loss 30% or more of total volume Supply depends on donor Requires careful cross-matching Can transmit infections such as hepatitis or HIV

12. Drugs for Shock � Fluid Replacement Blood or blood products May be administered to restore fluid volume Whole blood for acute, massive blood loss (more than 30% of total volume) Replace plasma volume and supply red blood cells Components Whole blood, plasma protein fraction Fresh-frozen plasma, packed red blood cells

13. Colloids Expand plasma volume and maintain blood pressure Used when up to one-third of adult client�s blood volume lost Stay suspended in blood Draw molecules from body�s cells and tissues into blood vessels Oncotic pressure Examples: normal human serum albumin, plasma protein fraction, dextran, hetastarch

14. Colloid Agents Mechanism of action: to maintain plasma osmotic pressure; transport substances through blood Primary use: restoration of plasma volume and blood proteins Examples of blood colloids: normal human serum albumin, plasma protein fraction, serum globulins Examples of nonblood-product colloids: dextan (40, 70, and high-molecular weight)and hetstarch (Hespan)

15. Crystalloids Intravenous solutions that contain electrolytes Concentration resembling those of plasma Mechanism of action: can readily leave blood and enter cells Primary use: to replace fluids that have been lost and to promote urine output Examples: normal saline, lactated Ringer�s, Plasmalyte, and hypertonic saline

16. Vasoconstrictors for Shock Strongly activate alpha-adrenergic receptors in arterioles Mechanism of action: to act directly on alpha-adrenergic receptors to raise blood pressure Positive inotropic effects Primary Use: to treat acute shock and cardiac arrest Example: norepinephrine

17. Vasoconstrictors/ Sympathomimetics Prototype drug: norepinephrine (Levaterenol, Levophed) Mechanism of action: to act directly on alpha-adrenergic receptors to raise blood pressure; also has positive inotropic effects Primary use: to treat acute shock and cardiac arrest Adverse effects: tachycardia, bradycardia, and hypertension

18. Vasoconstrictors/Vasopressors Some types of shock, most serious medical challenge is hypotension Cause collapse of the circulatory system Vasonconstrictors Drugs used for maintaining blood pressure when vasodilation has caused hypotension but fluids have not been lost and when fluid replacement agents have proved ineffective

19. Vasocontrictors/Vasopressors Early stages in shock, body is able to compensate for initial fall in blood pressure Activating the sympathetic nervous system produces vasoconstriction raises blood pressure and increases the rate and force of myocardial contraction Purpose of compensatory measure is to maintain blood flow to vital organs (heart and brain) and to decrease flow to other organs (kidneys and liver)

20. Vasocontrictors/Vasopressors Sympathomimetic vasoconstrictors or vasopressors Used to stabilize blood pressure in patients with shock IV Rapid onset with short duration and will immediately raise blood pressure

21. Vasocontrictors/Vasopressors Only used after fluid and electrolyte restoration has failed to raise blood pressure Drugs have serious side effects and can have the potential to cause organ damage due to the rapid and intense vasoconstriction

22. Vasocontrictors/Vasopressors Critical care agents Continuously monitored and adjusted to ensure the desired therapeutic effect Discontinued when patient stabilizes Always gradual discontinuation, due to the possibility of rebound hypotension and undesirable cardiac effects Drugs: Norepinephrine (Levophed), isoproterenol (Isuprel), Phenylephrine (Neo-Synephrine), and Mephentermine (Wyamine)

23. Nursing Considerations Careful monitoring Blood pressure and heart rate Assess for cardiovascular disease ECG Urine Output Telemetry Assess for history of narrow-angle glaucoma as vasoconstrictors increase intraocular pressure

24. Nursing Considerations Neo-Synephrine Cause necrosis of tissue if extravasation occurs Ensure patent IV Monitor IV site Titrate doses based on blood pressure readings

25. Client Teaching Educate on goals of therapy Have patients Immediately report any pain or burning at the IV site Immediately report blanching or blueness of fingers Immediately report chest pain or palpitations

26. Inotropic Drugs for Shock Increases strength of myocardial contraction, increases cardiac output Examples: digoxin, dobutamine, and dopamine

27. Inotropic Agents Prototype drug: dopamine (Dopastat, Inotropin) Mechanism of action: is dose dependent; low doses= dopaminergic effect, high doses= beta-adrenergic effect Primary use: to treat hypervolemic and cardiogenic shock Adverse effects: dysrhythmias, hypertension, gangrene

28. Inotropic Agents Cardiotonic drugs Increase force of contraction of the heart In shock, used to increase cardiac output Digoxin (Lanoxin, Lanoxicaps) Dobutamine (Dobutrex) and Dopamine (Dopastat, Intropin)

29. Inotropic Agents Shock progresses Heart may begin to fail Cardiac output decreases, lowering the amount of blood reaching vital tissues and deepening the degree of shock Inotropic agents have the potential to reverse the cardiac symptoms of shock by increasing the strength or myocardial contraction

30. Inotropic Agents Digoxin Increases myocardial contractility and cardiac output, and quickly brings critical tissue their essential oxygen

31. Inotropic Agents Dobutamine Selective beta1-adrenergic agent Short-term treatment of certain types of shock Causes heart to beat more forcefully Beneficial when primary cause of shock is related to heart failure Result increase in cardiac output which assists in maintaining blood flow to vital organs Half-life is 2 minutes Only given as IV infusion

32. Inotropic Agents Dopamine Activated both alpha and beta adrenergic receptors Utilized at different dosage levels Primarily used for shock to increase blood pressure by causing peripheral vasoconstriction (alpha1 activation) and increasing force of myocardial contraction (beta1 activation) Potential for dysrhythmias Only given as IV infusion

33. Nursing Considerations Careful monitoring Blood pressure Telemetry Calculated in micrograms per kilogram per minute Always use IV pump Monitor IV site, central in is preferred Monitor renal function closely

34. Nursing Considerations Dopamine Monitor IV site because extravasation of dopamine can cause severe localized vasoconstriction, resulting in sloughing of tissue and tissue necrosis if not reversed with phentolamine (Regitine) injections at site of infiltration

35. Client Teaching Expect continuous cardiac monitoring while receiving the medication Immediately report chest pain, difficulty breathing, palpitations, or headache Immediately report burning or pain at the IV site Immediately report numbness or tingling in the extremities

36. Anaphylaxis Serious hypersensitivity in response to allergen May be caused by common drugs Penicillins, cephalosporins Nonsteroidal anti-inflammatory drugs (NSAIDS) ACE inhibitors

37. Signs and Symptoms of Anaphylaxis Periorbital edema, urticaria, wheezing and difficult breathing Other signs of shock Palpitations, chest pain, nausea, vomiting Sweating, weakness, dizziness, confusion Blurred vision, headache, anxiety Sense of impending doom

38. Treatment of Anaphylaxis Sympathomimetics, antihistamines, glucocorticoids used Therapy is symptomatic To support cardiovascular system To prevent further hyperreaction of immune system

39. Treatment of Anaphylaxis Give oxygen immediately Antihistamine � prevents release of histamine Bronchodilator � relieves shortness of breath Corticosteroids � suppresses inflammation

40. Sympathomimetic/ Anaphylaxis Prototype drug: epinephrine (Adrenalin) Mechanism of action: for use as nonselective adrenergic agonist Primary use: to treat anaphylaxis, shock, cardiac arrest Adverse effect: hypertension and dysrhythmias

41. Drugs for Anaphylaxis Symptomatic: support cardiovascular system to prevent further hyperresponse Epinephrine is initial drug of choice Rapidly reverse hypotension Mechanism of action: as nonselective adrenergic agonist (sympathomimetic) Other Medications Antihistamines, bronchodilators, and corticosteroids

42. Drug Therapy for Shock Assessment Complete health history Assess breath sounds and vital signs Assess renal function (BUN and creatinine) Assess level of consciousness Assess knowledge level about medications

43. Drug Therapy for Shock Nursing diagnoses Risk for injury Excess fluid volume Ineffective tissue perfusion Knowledge deficit, related to drug therapy

44. Drug Therapy for Shock Planning- client will Report difficulty breathing, itching, or flushing Maintain urine output of at least 50ml/hour Maintain systolic blood pressure greater than 90mmHg Remain alert and oriented Demonstrate understanding of drug�s action

45. Drug Therapy for Shock Implementation Monitor respiratory status Monitor intake and output for changes in renal function Monitor electrolytes Observe client for signs of allergic reactions Observe urine for changes in color

46. Drug Therapy for Shock Evaluation- client Is free of itching, flushing, and shortness of breath Maintains urine output of at lease 50ml/hour Has systolic blood pressure greater than 90mmHg Is alert and oriented Verbalizes understanding of drug�s action