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Management of Blood Loss and Hypovolemic Shock Troy Phillips DO Assistant Professor VCOM Carolinas & Spartanburg Family Medicine Residency [email protected] Objectives • • • • • • • • Define shock Discuss physiology of shock Review the clinical presentation of shock Discuss normal blood volume of pediatric and adult patients Discuss the body’s compensatory responses to shock Review hemorrhage classification Describe appropriate IV access and initial fluid management in shock Discuss hemorrhage control Definitions • Shock – clinical syndrome that results from inadequate tissue perfusion – an imbalance between tissue oxygen supply and demand • Hypovolemic shock – Shock resulting from the loss of either red blood cell mass or plasma volume alone • Hemorrhagic shock – Hypovolemic shock secondary to either internal or external hemorrhage Physiology of Shock • heart rate X stroke volume = cardiac output Physiology of Shock Physiology of Shock Shock at the Cellular Level Anaerobic metabolism > lactic acid & metabolic acidosis Loss of cell membrane integrity & electrical gradient Swelling of ER & mitochondrial damage, Lysosomal rupture & enzyme release, Fluid influx, cellular edema and death Physiology of Shock Shock at the Systemic Level Moderate hypoperfusion may be tolerated compensation Prolonged /severe hypoperfusion leads to progressive cellular and organ dysfunction Clinical Presentation • Initial Findings – Tachycardia – Decreased peripheral perfusion (cool skin) – Increased respiratory rate – Mental status changes (anxiety) – What finding is absent? Hypotension Do not wait for hypotension! • An injured patient with tachycardia and cool skin is in shock until proven otherwise. • Hypotension is a late finding in shock (Class III) • Hypotension usually doesn’t present until a loss of 1/3 of total blood volume Normal Blood Volume • Normal blood volume in adult – 70cc/kg – Use ideal body weight, not actual • Normal blood volume in child – 80-90cc/kg Compensatory Responses • Microcirculation – Systemic vascular resistance rises – Maintain systemic pressure to perfuse heart and brain at expense of muscle, skin and GI tract – 2/3 of circulating blood is contained in the venous system • Cardiovascular – Increased heart rate to maintain cardiac output in setting of decreased stroke volume Compensatory Responses • Neuroendocrine – Increased adrenergic output and reduced vagal tone. – Norepinephrine causes peripheral and splanchnic vasoconstriction – Hypothalamic release of ACTH stimulating cortisol secretion • Hepatic – Increased gluconeogenesis further elevating blood glucose Compensatory Responses • Pulmonary – Tachypnea in response to relative hypoxia. However, this eventually leads to respiratory alkalosis from increased dumping of CO2 • Renal – Conservation of salt and water by increased afferent arteriolar resistance leading to reduced urine formation Treatment • Stop the bleeding. Replace fluids. • Diagnosis and treatment occur simultaneously. Treatment • Airway and Breathing – Provide high flow O2 for all patients in shock • Circulation – Find and control bleeding – Obtain IV access – Replace volume Hemorrhage Control • External Bleeding – Direct Pressure (first!) – Elevation – Pressure points – Immobilization (especially fractures) – Hemostatic agents – Tourniquet (expect limb loss) Hemorrhage Control • Internal bleeding – Have to find it first • Think chest, abdomen and retroperitoneum – Surgical intervention or angiographic embolization IV Access • Establish adequate IV access – 2 large bore peripheral IVs – Central access (central line or IO) IV Fluids • Give warmed NS or LR quickly • Only 1/3 of crystalloid volume stays intravascular IV Fluids • Adults – Give 1-2L of NS or LR – Repeat if needed – No improvement after 3L, give blood • Pediatrics – 20cc/kg bolus – Repeat if needed. If no relief, give blood. Practice Questions • What is the first sign of shock? – Tachycardia (and cool skin, inc respiration, and axiety but NOT hypotension) • What is an unreliable sign of early shock? – Hypotension • What is the blood volume in an adult with an ideal body weight of 70kg? – 70cc/kg = about 5 L • What is the blood volume in a child with a weight of 20kg? – (take 80 – 90 cc/kg, they weigh 20Kg = 1600 – 1800 cc) • What is the initial IV fluid of choice? – NS or LR • What is the initial bolus amount for a child? – 20cc/kg bolus Questions? References • UpToDate.com Shock in adults: Types, presentation, and diagnostic approach • Hemorrhagic Shock lecture, Dr. Jim Powers 2/23/12 – VCOM • Harrison’s Principle of Internal Medicine • Kaplan Medical COMLEX Review – Pathology • Emergency Care and Transportation of the Sick and Injured (6th edition)