Week 1 Introduction to Shock (Pathology & Therapeutics II) PDF

Pathology & Therapeutics II: Review and Shock Week 1 PATH 1017 2024-2025 1  Pathophysiology Framework- Review Do you Etiologic factors...

Pathology & Therapeutics II: Review and Shock Week 1 PATH 1017 2024-2025 1  Pathophysiology Framework- Review Do you Etiologic factors remember Etiology Risk factors what these terms mean? Mechanism of disease/illness Manifestations and complications Pathological Can you give process S & S, body responses an example for each? Diagnostic Tests Interventions Therapeutic Interventions PATH 1017 2024-2025 2  Review What is cardiac output? (CO) What is mean arterial pressure? (MAP) What is systemic/peripheral vascular resistance (SVR/PVR)? PATH 1017 2024-2025 3  Review Do you remember the autonomic nervous system? – What is released when the sympathetic nervous system is activated? Do you remember the renin-angiotensin- aldosterone system (RAAS)? – What is the end result? PATH 1017 2024-2025 4 Circulatory Failure (AKA SHOCK) PATH 1017 2024-2025 5  Circulatory failure (Shock) A condition in which tissue perfusion is inadequate to deliver oxygen and nutrients to support vital organs and cellular function Result of life-threatening conditions or trauma The body attempts to compensate for inadequate perfusion (homeostasis) What are the consequences of inadequate blood flow to tissues? PATH 1017 2024-2025 6  Pathophysiology of Shock- Do you remember the Cellular Level Effects key differences between aerobic and Metabolism changes to anaerobic due to anaerobic hypoperfusion. metabolism? ATP product is affected. What by-product is also produced? How does this affect the cell? Na-K pump becomes impaired. What effect will this have? Cells are injured. What is released? Cell death occurs. PATH 1017 2024-2025 7  Pathophysiology of Shock- Compensation Mechanisms Goal: Maintain BP and CO You learned about how the 2 Key Mechanisms: SNS and RAA work in anatomy 1. Sympathetic nervous system class. What is the role of the SNS? Now it is time to What is released? apply it! How will it help in shock? 2. Renin-angiotensin-aldosterone mechanism What is the effect of this mechanism? How will it help in shock? Other compensation mechanisms exist but have smaller effects on shock Overtime, compensation mechanism can lead to further deterioration. PATH 1017 2024-2025 8  Compensatory Mechanisms in Shock What are the other compensatory mechanisms? SNS PATH 1017 2024-2025 9  Fig 20-8- p503 Compensatory Mechanisms Attempts to Maintain Circulatory Function and Blood Volume Think about the SNS vs. RAA PATH 1017 2024-2025 10  Stages of Shock Compensatory Progressive Irreversible Patho Compensation Compensation Hypoperfusion mechanisms initiated mechanisms can’t keep severely damages in response to low up, hypoperfusion multiple organs perfusion worsens, cell damage Key BP normal BP ↓ BP ↓↓↓ Effects HR ↑ HR ↑↑ Metabolic acidosis Cool clammy skin Cardiac ischemia worsens Decreased bowel dysrhythmias Multiple organs fail sounds Urine output ↓↓ Urine output ↓ or absent Blood glucose ↑ Hypoxia, pulmonary RR ↑ edema Metabolic acidosis Decreased LOC Anxious or confused Altered liver, GI, hematological etc. Prognosis Good with early Worsens- Depends on Does not respond to intervention and time to restore treatment … Death correction of cause perfusion, damage etc. PATH 1017 2024-2025 11  Types of Shock (Overview) Cardiogenic Hypovolemic Obstructive Distributive Change in blood flow due to Alteration in Decrease in Obstruction increased cardiac blood of blood vasodilation function volume flow Anaphylactic Neurogenic Septic PATH 1017 2024-2025 12  Hypovolemic Shock Caused by diminished blood volume with decreased filling of the circulatory system Caused by loss of: – Whole blood hemorrhage, internal bleeding – Plasma severe burns – Extracellular fluid GI losses from vomiting & diarrhea, third-spacing PATH 1017 2024-2025 13 Pathophysiology of Hypovolemic Shock What compensatory mechanisms will be initiated? PATH 1017 2024-2025 14  Identify the Manifestations of Hypovolemic Shock Early Signs: Late Signs: PATH 1017 2024-2025 15  Hypovolemic Shock Treatment Correct or control Medications (vasoactive) underlying problem may be needed to increase BP AFTER blood volume deficit Reestablish vascular has been corrected to help improve blood flow to volume kidneys and other organs – IV fluid, blood products Positioning Ongoing assessment & monitoring Oxygen PATH 1017 2024-2025 16  Cardiogenic Shock Heart fails to pump blood adequately Causes are coronary and non-coronary in origin: – Damage to heart (MI) – Ineffective pumping (arrhythmias) – Mechanical defects (i.e. septal damage, valve damage) – Post-cardiac surgery complications – End-stage cardiac conditions (i.e. CAD, cardiomyopathy) PATH 1017 2024-2025 17 Pathophysiology of Cardiogenic Shock ** Don’t forget about the compensatory mechanisms… PATH 1017 2024-2025 18  Think about it… Decreased cardiac output & lowers BP – Effect on contractility? Preload? Afterload? – Hypoperfusion despite normal volume Sympathetic system responds – Vasoconstriction increases resistance to blood flow. RAA is activated. Effects? Increased workload on heart worsens heart failure and affects coronary perfusion. PATH 1017 2024-2025 19 Manifestations of Cardiogenic Shock Dysrhythmias Think about it… Hemodynamic instability What is the – MAP and BP decrease pathophysiology – Decreased urine output causing these Similar appearances to heart manifestations? failure – Cyanosis of lips, nail bed & skin – Pulmonary edema Changes in LOC PATH 1017 2024-2025 20  Treatment of Cardiogenic Shock Key goals: – Limit further myocardial damage and protect Improve CO healthy myocardium  workload  coronary and O2 needs perfusion PATH 1017 2024-2025 21  Treatment of Cardiogenic Shock Oxygen and pain control Hemodynamic monitoring Don’t forget to treat Medications (vasoactive) the cause of the Fluid therapy cardiogenic shock… Mechanical assistive devices (IABP) PATH 1017 2024-2025 22  Obstructive Shock Due to mechanical impediment to flow of blood through central circulation (great veins, heart, & pulmonary circulation). Caused by: Dissecting aortic aneurysm Cardiac tamponade Pneumothorax Pulmonary embolism (most common) Creates increased pressure within the right side of heart – This leads to decreased blood return to What will heart happen to the CO? PATH 1017 2024-2025 23  Obstructive Shock Symptoms of right sided heart failure develop Treatment focus on reversing underlying cause – Examples? PATH 1017 2024-2025 24  Distributive Shock Occurs when blood volume is abnormally displaced in the vasculature away from the heart and central circulation Further classified into 3 types: 1. Neurogenic shock 2. Anaphylactic shock 3. Septic shock PATH 1017 2024-2025 25 Pathophysiology of Distributive Shock Compensatory mechanisms are either impaired or unable to overcome the effects of distributive shock PATH 1017 2024-2025 26  Neurogenic Shock Caused by vasodilation resulting from loss of sympathetic tone Can result from – spinal cord injury – spinal anesthesia – nervous system damage – lack of glucose PATH 1017 2024-2025 27  Neurogenic Shock Interrupted SNS signals to blood vessels, baroreceptors and thermoregulation system Relaxation of smooth muscle in blood vessel walls Decreased systemic/peripheral vascular resistance (massive vasodilation) Result- hypotension, decreased CO, bradycardia Leading to: impaired peripheral perfusion PATH 1017 2024-2025 28  Neurogenic Shock Transient – Onset in minutes, duration up to 3 weeks Key Symptoms: – Bradycardia (baroreceptors cannot increase HR) – Hypotension (vasodilation, decreased CO) – Warm flushed skin – Piokilothermy (loss of SNS thermoregulation ability) Key treatments: – Restore BP with: IV fluids, vasoactive medications – Restore HR -Medication to increase HR (i.e.. atropine) – Restore Temp-Warming/cooling blankets if need PATH 1017 2024-2025 29  Anaphylactic Shock Occurs rapidly & is life-threatening Caused by severe allergic reaction – May occur with one exposure or after several exposures to an antigen – Involves an antigen-antibody reaction Mast cells release Histamine which causes widespread vasodilation, increased capillary permeability Most common triggers : – Medication reactions (i.e.. penicillin) – Foods (nuts, shellfish) What will happen to the – Insect venom (bee stings) CO and SVR? – Latex allergy PATH 1017 2024-2025 30 Anaphylactic Shock Manifestations: Anxiety Laryngeal edema (life-threatening) Bronchospasm Hypotension Tachycardia, weak pulse Pruritis (itching) Angioedema Urticaria (hives) Abdominal cramps (GI & uterine smooth muscle contraction) Loss of consciousness (late) PATH 1017 2024-2025 31  Anaphylactic Shock Treatment – Remove triggering agent immediately – ABCs – Fluids – Drugs: – Epinephrine (i.e.. Epi-Pen) – Antihistamines (benadryl), corticosteroids – Vasoactive drugs – Bronchodilators – Intubation & oxygen may be needed – Prevention is best! PATH 1017 2024-2025 32  Septic Shock Most common type of distributive shock Most commonly caused by gram-negative bacteria – Bacteremia and pneumonia common precursors Elderly patients at particular risk Prognosis: 28-50% die Prevention important PATH 1017 2024-2025 33  Septic Shock Microorganism invade tissues and triggers immune response Massive release of biochemical and inflammatory mediators (i.e.. cytokines etc.) Systemic inflammatory response occurs What will Leads to massive increase in capillary permeability happen to and vasodilation the CO and SVR? Result: inadequate perfusion, oxygenation and nutrients to tissues →eventually organ dysfunction PATH 1017 2024-2025 34  Septic Shock- 2 Phases High CO Vasodilation (SVR) Warm Phase BP normal; HR ; RR  (hyperdynamic, Fever, warm & flushed skin progressive) May have  urine output;  bowel sounds; confusion/agitation Low CO Vasoconstriction (cool, pale skin) Cold Phase temp;  HR;  RR (hypodynamic, Anuria irreversible) Leads to organ failure, death PATH 1017 2024-2025 35  Septic Shock Treatment Identify cause (i.e.. C&S) and treat cause if possible Fluid replacement Oxygen (may require mechanical ventilation if shock is progressing) Pharmacological: Antibiotics Vasoactive drugs Antipyretics Corticosteroids Other aspects of treatment; – Nutritional support – Control blood glucose levels (insulin tx) PATH 1017 2024-2025 36  Complications of Shock Acute respiratory distress Rapid onset of severe dyspnea syndrome Accumulation of neutrophils in alveoli Vasoconstriction causes renal tubule Acute renal failure ischemia/ATN Gastrointestinal Ischemia to GI tract → ulcers complications Decrease in mucosal perfusion Disseminated intravascular Microinfarcts, ischemia coagulation (DIC) Bleeding problems Multiple organ dysfunction Altered organ function such that homeostasis syndrome (MODS) cannot be maintained without intervention PATH 1017 2024-2025 37