 Definition & mechanism of shock.  Consequences of Shock.  How to diagnose shock?  Classification of Shock.  Causes of various types of shock  Basic principles in management of shock.

Reduction of effective tissue perfusion leading to cellular and circulatory dysfunction

 It is a medical emergency, if unrecognized or inadequately treated will result in high mortality

Reduced Perfusion Brain Decreased mental status Myocardial Depression Kidney Oliguria Liver Increased liver enzymes Lung Hypoxemia Pheripheral Circulation Hypotension Heart

The aim of perfusion is to achieve adequate Cellular Oxygenation This requires Red Cell Red Cell OxygenationDelivery To Tissues Fick Principle

Air’s gotta go in and out. Blood’s gotta go round and round. Any variation of the above is not a good thing!

 Red Cell Oxygenation 1. Oxygen delivery to alveoli  Adequate F i O 2  Patent airways  Adequate ventilation

 Red Cell Oxygenation 2. Oxygen exchange with blood  Adequate oxygen diffusion into blood  Adequate RBC capacity to bind O 2  pH  Temperature

 Red Cell Delivery To Tissues 1. Adequate perfusion  Blood volume  Cardiac output  Heart rate  Stroke volume  Conductance  Arterial resistance  Venous capacitance

 Red Cell Delivery To Tissues 2. Adequate Hgb  Adequate Hgb levels  Adequate RBC capacity to bind O 2  pH  Temperature

Inadequate tissue perfusion: Poor cellular Shift from aerobic Oxygenation to anaerobic metabolism

GLUCOSEMETABOLISM 2 LACTIC ACID 2 ATP HEAT (32 kcal) Glycolysis: Inefficient source of energy production; 2 ATP for every glucose; produces pyruvic acid

6 O 2 GLUCOSE METABOLISM 6 CO 2 6 H 2 O 36 ATP HEAT (417 kcal) Glycolysis: Inefficient source of energy production; 2 ATP for every glucose; produces pyruvic acid Oxidative phosphorylation: Each pyruvic acid is converted into 34 ATP

 Occurs without oxygen  oxidative phosphorylation can’t occur without oxygen  glycolysis can occur without oxygen  cellular death leads to tissue and organ death  can occur even after return of perfusion   organ dysfunction or death

Inadequate Cellular Oxygen Delivery Anaerobic Metabolism Inadequate Energy Production Metabolic Failure Lactic Acid Production Metabolic Acidosis CELL DEATH Ultimate Effects of Anaerobic Metabolism

 Markers Of Hypoperfusion  ↑ Serum Lactate  Metabolic acidosis  Hypotension

 Adequate Volume  Normal Cardiac Function  Normal Vessels Failure of one or more of these causes shock

● Hypovolemic Shock - Blood volume problem ● Cardiogenic Shock - Blood pump problem ● ObstructiveShock - Filling Problem ● Distributive Shock - Blood vessels problem

Loss of Volume Blood loss ▪ Trauma ▪ Non-traumatic  Vaginal  GI  GU Fluid loss - Dehydration - Burns - Diarrhea - Vomiting - Diuresis - Sweating Third space losses  Pancreatitis  Peritonitis  Bowel obstruction

Sign and Symptoms Brain Decreased mental status Kidney Oliguria Liver Increased liver enzymes Lung Hypoxemia Pheripheral Circulation  Hypotension  Cold Clammy skin

 Recognize & Treat during compensatory phase Best indicator of resuscitation effectiveness = Level of Consciousness Restlessness, anxiety, combativeness = Earliest signs of shock

Goal: Restore circulating volume, tissue perfusion & correct cause A B C Two large bore IV lines/central line Fluids / Blood & Products /vasopressors  Target arterial BP – SBP ≥ 90 mmHg  - MAP ≥65 mmHg. Bladder catheter Arterial Cannulation

 Tissue ischemic sensitivity  Heart, brain, lung: 4 to 6 minutes  GI tract, liver, kidney: 45 to 60 minutes  Muscle, skin: 2 to 3 hours Resuscitate Critical Tissues First!

Consequence Of Volume Loss :  15%[750ml]- compensatory mechanism maintains cardiac output  15-30% [ ml] -decreased BP & urine output  30-40% [ ml] -profound shock along with severe acidosis  40-50% - refractory stage

 Cardiogenic Shock = Pump Failure Myopathic M I CHF Cardiomyopathy Arrhythmic Tachy or bradyarrhythmias Mechanical Valvular Failure HOCM

 History :  Chest pain, Palpitations,SOB  RHD,IHD  Physical exam:  Signs of ventricular failure  Heart : Murmurs,S3,S4

 Treat rate, then rhythm, then BP  Correct bradycardia or tachycardia  Correct irregular rhythms  Treat BP  ↑ Cardiac contractility (inotropes)  Dobutamine, Dopamine

 Inadequate perfusion of tissues due to mal- distribution of blood flow. ( blood vessels problem )  Cardiac pump & blood volume are normal but blood is not reaching the tissues.

1. Septic Shock 2. Anaphylactic Shock 3. Neurogenic/Vasogenic(spinal cord) 4. Endocrinologic

 A B C  Assist ventilation & Augment Oxygenation  Restore Tissue perfusion- IV Fluids, Vasopressors  Identification & Eradication of septic foci  Specific Therapies (antibiotics)

 Patient supine; lower extremities elevated  Avoid Trendelenburg  Infuse isotonic crystalloid  Maintain body temperature

 ABC  Antihistamines  Corticosteroids  Epinephrine  Isotonic fluid

 Impaired cardiac filling  Cardiac tamponade  Constrictive pericarditis  Tension pneumothorax  Increased ventricular afterload Pulmonary embolism

 Control airway  Intubation  Treat the underlying cause  Tension Pneumothorax: Chest tube  Pericardial Tamponade: Pericardiocentesis  Pulmonary Embolism: Anticoagulation  Isotonic fluids

 Falling BP = LATE sign of shock.  BP is NOT same thing as perfusion.  Pallor, tachycardia, slow capillary refill = hypoperfusion, until proven otherwise.

Avoid vasopressors until hypovolemia ruled out, or corrected Squeezing partially empty tank can cause ischemia, necrosis of kidney and bowel