1	Chapter 21 Hemorrhage and Shock
2	Objectives Describe how to recognize signs and symptoms of internal and external hemorrhage Define shock Outline factors needed for tissue oxygenation Describe how resistance vessels’ diameter influences preload
3	Objectives Describe function of blood components Outline changes in microcirculation during shock List causes of hypovolemic, cardiogenic, neurogenic, anaphylactic, septic shock Describe pathophysiology as basis for signs and symptoms through stages of shock
4	Objectives Describe assessment findings to distinguish cause of shock state Outline prehospital management of shock Discuss how to integrate assessment and management of patients in shock
5	Scenario Your patient is a 15-year-old who was thrown from his horse during a jumping competition. His skin is pale and cool. Vitals are: BP-98/68, P-132/min, R-24/min. He has an abrasion from his left nipple laterally down to his pelvis. His abdomen and pelvis are are diffusely tender. He has mild difficulty breathing, and breath sounds are diminished on the left.
6	Discussion What is the probable cause of his shock? Is this compensated or uncompensated shock? Explain how you will initiate IV therapy to gain maximum benefit for this patient. What other prehospital care will be needed for him?
7	Hemorrhage Disruption or “leak” in vascular system External hemorrhage Internal hemorrhage Higher morbidity and mortality than external hemorrhage
8	Physiological Response to Hemorrhage Initial response: Stop bleeding by chemical means (hemostasis) Vascular reaction involves: Local vasoconstriction Formation of platelet plug Coagulation Growth of fibrous tissue into blood clot permanently closes and seals injured vessel If hemorrhage is severe, mechanisms may fail, resulting in shock (hypoperfusion)
9	Shock
10	Defining Shock Inadequate tissue perfusion Can result from variety of disease states and injuries Can affect entire organism or occur at tissue or cellular level Not adequately defined by: Pulse rate Blood pressure Cardiac function Hypovolemia Loss of systemic vascular resistance
11	Tissue Oxygenation Adequate oxygenation of tissue cells (perfusion) depends on: Heart Vasculature Lungs If any one malfunctions, decrease in cellular oxygenation may occur
12	Cardiac Output Blood pumped by each ventricle per minute (liters per minute): = Heart rate x Volume of blood ejected by each ventricle during each beat (stroke volume) Depends on: Strength of contraction Rate of contraction Venous return to ventricle (preload)
13	Shock Fick principle Vasculature Pressure gradients Peripheral vascular resistance Afterload Viscosity Microcirculation
14	Compensatory Mechanisms CNS ischemic response Hormonal mechanisms Adrenal medullary mechanism Renin-angiotensin-aldosterone mechanism Vasopressin mechanism Atrial natriuretic factor Reabsorption of tissue fluids Splenic discharge of blood
15	Baroreceptor Reflexes Help control BP by two negative feedback mechanisms: Lower BP in response to increased arterial pressure Increase BP in response to decreased arterial pressure
16	Chemoreceptor Reflexes Low arterial pressure stimulates peripheral chemoreceptor cells in carotid and aortic bodies If oxygen or pH decreases, stimulate vasomotor center of medulla
17	Renin-Angiotensin-Aldosterone Mechanism in Regulating BP
18	Vasopressin (ADH) Mechanism in Regulating BP
19	Lungs Adequate cellular oxygenation requires that adequate oxygen be available to red blood cells at the capillary membrane in the lungs First component of Fick principle Made possible by: High pressure of oxygen in inspired air Adequate depth and rate of ventilation Matching of pulmonary ventilation and perfusion
20	The Body as a Container Blood is smooth-flowing delivery system inside container Container must be filled to achieve adequate preload and tissue oxygenation
21	The Body as a Container External size of body container is relatively constant Container volume directly related to diameter of resistance vessels Change in vessel diameter changes volume of fluid container holds Affects preload
22	Capillary-Cellular Relationship in Shock Stage 1: Vasoconstriction Stage 2: Capillary and venule opening Stage 3: Disseminated intravascular coagulation Stage 4: Multiple organ failure
23	Capillary-Cellular Relationship in Shock
24	Classifications of Shock Hypovolemic shock Distributive shock Neurogenic shock Anaphylactic shock Septic shock Cardiogenic shock Obstructive shock
25	Compensated Shock Signs and symptoms of early shock Blood pressure normal or high Treatment typically results in recovery
26	Compensated Shock
27	Uncompensated Shock Signs and symptoms of late shock Blood pressure abnormally low Treatment sometimes results in recovery
28	Uncompensated Shock
29	Irreversible Shock Signs and symptoms of late shock Blood pressure abnormally low Even aggressive treatment does not result in recovery
30	Irreversible Shock
31	Physiological Response to Shock Variations and determining factors Age and relative health Older adults Children General physical condition Preexisting disease Ability to activate compensatory mechanisms Medications Specific organ system affected
32	Management of Shock Goals of prehospital care Patent airway Adequate oxygenation and ventilation Restore perfusion
33	Initial Assessment Airway Breathing Circulation Disability Expose body surfaces
34	Differential Shock Assessment Findings Assumed to be hypovolemic until proven otherwise Cardiogenic shock Differentiate from hypovolemic shock by: Chief complaint Chest pain Dyspnea Tachycardia Heart rate Signs of congestive heart failure Dysrhythmias
35	Differential Shock Assessment Findings Distributive shock Differentiate from hypovolemic shock by: Mechanism suggesting vasodilation Spinal cord injury Drug overdose Sepsis Anaphylaxis Warm, flushed skin Lack of tachycardia response (not reliable)
36	Differential Shock Assessment Findings Obstructive shock Differentiate from hypovolemic shock by signs and symptoms of: Cardiac tamponade Tension pneumothorax Pulmonary embolism
37	Detailed Physical Examination Vital signs Pulse Blood pressure Orthostatic vital signs Evaluate patient’s ECG
38	Resuscitation Restore adequate tissue oxygenation by: Ensuring adequate oxygenation Maintaining effective volume-to-container size ratio Rapid transport to appropriate medical facility
39	Red Blood Cell Oxygenation Need adequate tissue oxygenation For red blood cell oxygenation: Patent airway Support ventilation with high FiO₂ If necessary, positive-pressure ventilation Correct airway abnormalities that interfere with adequate ventilation
40	Ratio of Volume to Container Size Container must be full of fluid to carry oxygen Accomplish by: Decreasing size of container Especially in shock states not associated with hemorrhage Vasoactive medications in some distributive shock Volume replacement may be needed
41	Pneumatic Antishock Garment Effects Mechanism Indications Contraindications
42	Crystalloids Solutions with dissolved crystals in water Less osmotic pressure than colloids Can equilibrate more quickly between vascular and extravascular spaces 2/3 of crystalloid fluid leaves vascular space < 1 hr 3 mL of crystalloid replaces 1 mL of blood
43	Hypertonic and Hypotonic Solutions Hypertonic solutions Higher osmotic pressure than body cells 7.5% saline Hypotonic solutions Lower osmotic pressure than body cells Distilled water 0.45% sodium chloride (0.45% NaCl)
44	Isotonic Solutions Lactated Ringer's solution Normal saline Glucose-containing solutions (e.g., D₅W)
45	Colloids Solutions that contain molecules too large to pass through capillary membrane Remain within blood vessels longer Examples Whole blood Plasma Packed red blood cells
46	Theory of Fluid Flow Flow of fluid through catheter Directly related to diameter (to the fourth power) Inversely related to length Also affect fluid flow: Diameter and length of tubing Size of vein Viscosity and temperature of fluid Viscosity is affected by temperature Warm fluids flow faster
47	Key Principles in Managing Shock Open airway High-concentration oxygen Assist ventilation as needed Control external bleeding (if present) IV fluid replacement if appropriate Consider PASG Maintain body temperature Monitor ECG and oxygen saturation Reassess vital signs
48	Hypovolemic Shock Correct circulatory deficit and its causes Crystalloid fluid replacement for dehydration Volume replacement for hemorrhage (controversial) Definitive surgery Critical care support Postoperative rehabilitation
49	Hypovolemic Shock Fluid volume replacement Large volume fluid replacement if: Systolic BP >100 mmHg AND Isolated head or extremity injuries Not for penetrating trauma in urban center Blunt or penetrating trauma in rural area: IVFs to maintain systolic BP>90 mm Hg
50	Cardiogenic Shock Improve pumping action of heart and manage dysrhythmias Fluid replacement Drug therapy (if needed) Cardiogenic shock due to myocardial ischemia or infarction requires: Reperfusion strategies Possible circulatory support Manage tension pneumothorax and cardiac tamponade
51	Neurogenic Shock Treatment similar to hypovolemia Avoid circulatory overload Monitor lung sounds for pulmonary congestion Vasopressors may be indicated
52	Anaphylactic Shock Subcutaneous epinephrine in acute anaphylactic reactions Other therapy Oral, IV, or IM antihistamines Bronchodilators Steroids reduce inflammatory response Crystalloid volume replacement Airway management
53	Septic Shock Treatment Management of hypovolemia (if present) Correction of metabolic acid-base imbalance Prehospital care Fluid resuscitation Respiratory support Vasopressors to improve cardiac output Thorough history to find source of sepsis
54	Integration of Patient Assessment and the Treatment Plan For severe hemorrhage or shock: Rapid recognition Initiation of treatment Prevention of additional injury Rapid transport to appropriate hospital Advance notification to receiving facility
55	Conclusion The paramedic must be able to integrate history and assessment findings to form a field impression and to implement a treatment plan for the patient with hemorrhage or shock.