Shock

shock is a life threatening medical condition characterized by inadequate tissue perfusion and hypoxia.

1. SHOCK SUBMITTED BY- MS. AMBIKA BAGORA

2. Shock is a life threatening medical condition whereby the body suffers from insufficient blood flow throughout the body (circulatory collapse). -It is characterized by inadequate tissue perfusion in which there is insufficient delivery of oxygen and nutrients to the body’s tissues .

3. Causes- Heart conditions (heart attack, heart failure). Heavy internal or external bleeding, such as from a serious injury. Dehydration Infection Severe allergic reaction Spinal injuries

4. Types of shock- Cardiogenic shock Hypovolemic shock Obstructive shock Distributive shock -Anaphylactic shock -Septic shock - Neurogenic shock

5. Other types- Endocrine shock- Endocrine shock is caused by a disturbance in the endocrine system. Example – - severe hypothyroidism - thyrotoxicosis - severe adrenal insufficiency 2. Insulin shock- shock resulting from an overdosage of insuline which causes too much reduction of blood sugar characterized by sweating, trembling, dizziness, with other shock features.

6. 1. Cardiogenic shock- Cardiogenic Shock resulting from inadequate pumping action of the heart because of cardiac muscle dysfunction or mechanical obstruction of blood flow. Causes of cardiogenic shock include- acute myocardial infarction , rupture of heart valves , acute myocarditis , end-stage heart disease , severe dysrhythmias or traumatic injury to the heart .

7. 2. Hypovolemic Shock- This is the most common type of shock and based on insufficient circulating volume. It occurs due to decrease in the circulating blood volume resulting from- - dehydration - internal hemorrhage - external hemorrhage - burns with loss of plasma protien

8. 3. Obstructive shock- It occure when there is a blockage of blood flow in the cardiovascular circuit outside the heart. Example- cardiac tamponade , tension pneumothorax , massive pulmonary embolism. 4. Distributive shock- It includes anaphylactic shock, septic and neurogenic shock.

9. Anaphylactic shock- It is a shock state resulting from severe allergic reaction producing overwhelming systemic vasodilation and relative hypovolemia . Septic shock- Septic shock is caused by an overwhelming systemic infection and inflammation resulting in vasodilation leading to hypotension. Neurogenic shock- Neurogenic shock occurs when dysfunction or injury to the nervous causes extensive vasodilatation of peripheral blood vessels and hypotension.

10. Stages of shock- Initial stage- During this stage, the hypoperfusion state causes hypoxia, and cells perform anerobic respiration, this causes a build up of lactic acid which results in systemic metabolic acidosis. Compensatory stage- compensatory mechanism are activated to maintain perfusion to heart and brain. Reduce blood flow to the kidney activates the rennin – angiotensin - aldosteron system (RAAS) causing vasoconstriction and sodium and water retention, leading to increased blood volume and venous return. As a result of compensatory mechanism, cardiac output and tissue perfusion are maintaned

11. c. Progressive stage- The progressive stage of shock begins as compensatory mechanism fail to maintain cardiac output and blood pressure starts to fall. d. Irreversible stage- At this stage, the vital organs have failed and the shock can no longer be reversed. Eventually, circulatory and respiratory failures occur. Brain damage and cell death have occurred. Death will occur imminently.

12. FINDINGS STAGES OF SHOCK Heart rate Pulse Respiration BP Skin Urine output A-B balance Mental status Compensatory Progressive Irreversible Tachycardia Bounding pulse Tachypnea Normal Cool and pale Normal/ Respiratory alkalosis Restless/irritable Tachycardia Weak pulse Shallow Hypotension Cool, moist Oliguria Metabolic acidosis Confused Slow heart rate Weak/Absent pulse Slow Worsen hypotension Cynosis Anuria Profound acidosis Unconcious

13. Overall management of shock- Management in all types and all phases of shock include the following- Management of airway, breathing and circulation. Fluid replacement to restore intravascular volume. Vasoactive medication to restore vasomotor tone and improve cardiac function.

14. 1 . Managment of airway, breathing, and circulation- Fundamentals such as airway control, breathing and circulatory support must be addresed as a higher priority. Assessment of the adequacy of breathing and whether it may need to be assisted with bag and mask or intubation with an endotracheal tube and mechanical ventilation may be necessary to maintain a patent airway. Patient will be treated with oxygen supplementation through nasal cannula , face mask or ET tube.

15. 2. Fluid replacement to restore intravascular volume- Beyond reversing the primary cause of decreased intravascular volume, fluid replacement is primary concern. At least two intravenous lines with large gauge needle should be initiated and maintained for fluid and drug administration. Fluid administration- Intravenous fluid crystalloids, colloids, or blood products may be administered to maintain intravascular fluid volume.

16. Crystalloids- They are electrolyte solution that moves free between intravascular compartment. Common intravenous fluids are 0.9% normal saline and riger lactate. Ringer’s lactate is the initial fluid choice. Normal saline is the second choice because hyperchloremic acidosis may develop if massive amount normal saline is infused. Colloids- Intravascular colloidal solutions are considered to be plasma protien , which are molecules that are too large to pass through capillary membranes. 5% albumin solution , synthetic colloid preparations such as 6% beta starch , 6% dextran and hetastarch solution are administered to increase or maintain intravascular fluid volume

17. 3. Blood transfusion- Blood transfusion is necessary for loss of large amounts of blood (e.g. Greater than 20% of blood volume). Blood may be transfused if bleeding ( hemorrhage ) is the cause of shock state. Packed R.B.Cs. Are infused when there is massive blood loss.

18. 3. Vasoactive medication Vasoconstrictor drugs- They work by stimulating the heart beat stronger and by squeezing blood vessels to increase the flow within them. Vasoactive medications are frequently used in the management of shock to increase mean arterial blood pressure (MAP), restore organ perfusion and oxygen delivery.

19. Following are vasoconstructive drugs- 1. DOPAMIN- Low doses (1-3 ug /kg/min.) act only on dopamin receptors in kidney to increase blood flow. Medium doses (3-10 ug /kg/min) acts on beta receptor to increase cardiac contractility and cardiac output. Higher doses (10 ug /kg/min) act on alpha receptors to act as vasoconstrictor

20. 2. DOBUTAMINE- It acts on both a 1 and a 2 receptors of the sympathetic nervous system. Dobutamine increases cardiac output by help heart to pump better by strengthening the heart muscle and also improves blood flow by vasodilation . Dobutamine is good for cardiogenic shock. Usual doses to increase cardiac output are 2.5-15 mcg/kg/min IV.

21. 3 . NOREPINEPHRINE- It is also known as noradrenaline is an apha agonist (causes vasoconstriction) and some beta activity (increases heart contractility). Doses 8-12 mcg/min. Titrate to BP. Usual maintenance dose 2-4 mcg/min. 4. EPINEPHRINE- Epinephrine is also an alpha agonist and some beta agonist activity. Epinephrine causes more tachycardia than norepinephrine . Continuous IV infusion 1-10 mcg/min titrate dosage to desired effect .