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ATLS - Ch 3


Define shock A state of inadequate organ perfusion and tissue oxygenation.
Give four causes of shock, with the most common listed first Hemorrhagic, Cardiogenic, Neurogenic, Septic
Describe neurogenic shock Hypotension without tachycardia or vasoconstriction (low, low, open)
What percentage of blood is in the venous system? 70%
What is the earliest measurable circulatory sign of shock? Tachycardia
The initial step in managing shock in injured patients is to recognize its presence
The second step in managing shock in injured patients is to identify the probable cause of the shock state
Identifying shock in trauma patients is directly related to the mechanism of injury
How does tension pneumothorax produce shock? by reducing venous return
What does not cause shock? isolated brain injuries
Neurogenic shock results from extensive injury to the CNS or Spinal Cord
Spinal cord injury causes shock via vasodilitation and relative hypovolemia
Septic shock in trauma patients must be considered when arrival at ER has been delayed by many hours
What is the most common cause of shock in the injured patient? hemorrhage
Formula for Cardiac Output (CO) CO = HR x SV L/min = beats/min x cc/beat / 1000
Stroke Volume (SV) is determined by what three factors? 1-Preload 2-Myocardial contractility 3-Afterload
Preload is determined by what three factors? 1-venous capacitance 2-volume status 3-difference between venous systemic pressure and right atrial pressure
Volume of venous blood returned to heart determines myocardial muscle fiber length after ventricular filling at end of diastole
Myocardial contractility is the pump that drives the system
Afterload is systemic (peripheral) vascular resistance to the forward flow of blood
Progressive vasoconstriction of ___ ___ ___ preserves blood flow to the ___ ___ ___. cutaneous, muscle, and visceral circulation kidneys, heart, and brain
Acute circulating volume depletions leads to increase in HR to preserve CO
Endogenous catecholamines increases peripheral vascular resistance
Increased peripheral vascular resistance increases ____ and decreases ____ and does ____. diastolic BP pulse pressure little to increase organ perfusion
Restore venous return to normal by ____ volume repletion
Initial compensatory metabolic shift anaerobic
Anaerobic metabolism leads to (2) 1-formation of lactic acid 2-metabolic acidosis
Steps in cellular death (7) 1-loss of cellular membrane integrity 2-swelling of ER 3-mitochondrial damage 4-lysosomes rupture and release digestive enzymes 5-Na and H2O enter cell 6-cell swells 7-intracellular calcium deposition occurs
What helps combat cell death? isotonic electrolyte solutions
Three things to do in shock resuscitation 1-oxygenation 2-ventilation 3-fluid resuscitation
Goals in treatment of hemorrhagic shock (2) 1-control of hemorrhage 2-restoration of adequate circulating volume
Contraindicated in treatment of hemorrhagic shock vasopressors
Most injured patients with hypovolemic shock require a surgeon
Two categories of shock 1-hemorrhagic 2-non-hemorrhagic
Attention to shock directed to (4) 1-pulse rate 2-respiratory rate 3-skin circulation 4-pulse pressure
Two earliest physiologic responses to volume loss tachycardia and cutaneous vasoconstriction
Patient is cool and tachycardic in shock until proven otherwise
Tachycardia in infant > 160
Tachycardia in preschool-age child > 140
Tachycardia in children from school age to puberty > 120
Tachycardia in adult > 100
Elderly patients may not exhibit tachycardia in shock because of (3) 1-limited cardiac response to catecholamine stimulation 2-concurrent use of medications (B-blockers) 3-pacemaker
Hg and Hct for estimating acute blood loss unreliable
Primary focus in hemorrhagic shock identify and stop hemorrhage promptly
Five types of nonhemorrhagic shock 1-cardiogenic shock 2-cardiac tamponade 3-tension pneumothorax 4-neurogenic shock 5-septic shock
Myocardial dysfunction may be caused by (4) 1-blunt cardiac injury 2-cardiac tamponade 3-air embolus 4-myocardial infarction
Blunt cardiac injury suspected with MOI rapid deceleration
Cardiac tamponade and pericardial fluid can be determined by FAST
Four signs of Cardiac Tamponade 1-tachycardia 2-muffled heart sounds 3-dilated, engorged neck veins 4-hypotension resistant to fluid therapy
Temporarily relieves tension pneumothorax needle decompression
Management of cardiac tamponade 1-thoracotomy 2-pericardiocentesis (temporary)
Prevents return of air to lung in tension pneumothorax flap-valve mechanism
How can spinal cord injury cause shock? loss of sympathetic tone causing hypotension
Classic picture of neurogenic shock (2) hypotension without (1) tachycardia or (2) cutaneous vasoconstriction
What do you not see with neurogenic shock? a narrow pulse pressure
Septic shock may occur in patients with penetrating abdominal trauma and contamination of peritoneum
Hemorrhage is defined as an acute loss of circulating blood volume
Normal adult blood volume percent of body weight 7
70 kg male has circulating blood volume of approximately 5 L
Blood volume of obese patients based on ideal weight
Blood volume for child calculated as 8 to 9% of body weight (80-90 mL/kg)
Volume replacement is guided by patient's response to initial therapy
Class I hemorrhage characterstics as if donated one unit of blood
Class II hemorrhage characterstics uncomplicated, requiring crystalloid fluids
Class III hemorrhage characterstics complicated, requiring crystalloid infusion and, perhaps, blood
Class IV hemorrhage characterstics preterminal, patient will die within minutes
Blood loss (mL) in hemorrhage classes I up to 750 II 750-1500 III 1500-2000 IV > 2000
Blood loss (%) in hemorrhage classes I up to 15% II 15-30% III 30-40% IV >40%
Pulse rate in hemorrhage classes I <100 II 100-120 III 120-140 IV > 140
Blood pressure in hemorrhage classes I normal II normal III decreased IV decreased
Pulse pressure in hemorrhage classes I normal or increased II decreased III decreased IV decreased
Respiratory rate in hemorrhage classes I 14-20 II 20-30 III 30-40 IV > 35
Urine output (mL/hr) in hemorrhage classes I >30 II 20-30 III 5-15 IV negligible
CNS/Mental state in hemorrhage classes I slightly anxious II mildly anxious III anxious, confused IV confused, lethargic
Fluid replacement in hemorrhage classes I crystalloid II crystalloid III crystalloid and blood IV crystalloid and blood
Fractured tibia or humerus blood loss may be up to 750 mL
Fractured femur blood loss may be up to 1500 mL
Amount of blood with pelvic fracture retroperitoneal hematoma up to several liters
Nonresponse to fluid administration indicates (3) 1-persistent blood loss 2-unrecognized fluid losses or 3-nonhemorrhagic shock
How do major soft tissue injuries and fractures compromise hemodynamics? 1-blood lost into site of injury 2-edema in injured soft tissue
Tissue edema is result of fluid shift from plasma into extravascular, extracellular space
Fluid shift results in depletion of intravascular volume
What occurs simultaneously in shock? the diagnosis and treatment
Three important factors in physical exam in shock 1-vital signs 2-urinary output 3-level of consciousness
Priorities for circulation in shock (3) 1-controlling obvious hemorrhage 2-obtaining adequate IV access 3-assessing tissue perfusion
When undressing the patient, it is essential to prevent hypothermia
Gastric dilation may cause (2) 1-unexplained hypotention 2-cardiac dysrhythmia (bradycardia from vagal stimulation)
Unconscious with gastric distenstion rise of aspiration, could be fatal
Proger position of gastric tube ____ obviate risk of aspiration does not
Bladder catheterization used for (2) 1-assessment of hematuria 2-monitoring urinary output
Poiseuille's law rate of flow proportional to the fourth power of radius of cannula, and inversely related to length
Best site for IV forearms and antecubital veins
Central lines second best IV access location femoral, jugular, or subclavian
Central line techniques (2) 1-Seldinger 2-saphenous vein cutdown
In ER, central lines often not sterile, and should be changed
Priority of IV access in kids under 6 IV - IO - Central
Determinant for selecting proper IV access experience and skill of doctor
After jugular or subclavian CVP CXR
Usual fluid bolus NS or LR, 1-2 L for adults, 20 mL/kg for kids
Ratio of crystalloid replacement to blood loss 3-for-1 rule
Goal of resuscitation in shock restore organ perfusion
If BP raised rapidly and bleeding not controlled increased bleeding may occur
Fluid consideration in blunt trauma avoid hypotention
Fluid consideration in penetrating trauma control bleeding
Fluid resuscitation with continued bleeding referred to as (4) 1-controlled resuscitation 2-balanced resuscitation 3-hypotensive resuscitation 4-permissive hypotension
Signs suggesting perfusion is returning to normal 1-blood pressure 2-pulse pressure 3-pulse rate
Indicator of renal perfusion volume of urinary output
pH status in early hypovolemic shock respiratory alkolosis due to tachypnea
pH status in long-standing or severe shock severe metabolic acidosis due to anaerobic metabolism
What should not be used for metabolic acidosis secondary to hypovolemic shock? sodium bicarbonate
Key determinant of subsequent therapy patient's response to initial fluid resuscitation
Differentiate hemodynamically stable vs hemodynamically normal 1-stable: persistent tachycardia, tachypnea, and oliguria, underresuscitated and still inshock 2-normal: no signs of inadequate tissue perfusion
Tri-fold response to fluid administration 1-rapid 2-transient 3-minimal or no
Main purpose of blood transfusion restore oxygen-carrying capacity of intravascular volume
Blood product priority Crossmatched, Type-specific, O (neg for females)
Blood for transient responders Type-specific
Blood for rapid responders Crossmatched
Can be warmed in microwave crystalloids
Can not be warmed in microwave blood products
How do you warm blood? pass thru IV fluid warmer
Blood replacement with major hemothorax autotransfusion
Most patient receiving blood transfusion ____require calcium supplementation. do not
Ohm's Law V (blood pressure) = I (cardiac output) x R (systemic vascular resistance
Increase BP ____equated with increase CO. should not be
Elderly decrease in sympathetic activity deficit in receptor response to catecholamins
Consideration in volume resuscitation in elderly early invasive monitoring
Blood volume in athlete may increase 15 to 20%
Cardiac output in athlete may increase sixfold
SV in athlete may increase 50%
Resting pulse in athlete can average 50
Intoxicated trauma patient may have hypothermia due to vasodilation
Hypothermia is best treated by prevention
Most common complication of treating hemorrhagic shock inadequate volume replacement
Most common cause of poor response to fluid therapy in shock obscure hemorrhage
Ideal position for tip of catheter in central line superior vena cava just proximal to RA
Risks of central line placement (6) 1-infection 2-vascular injury 3-nerve injury 4-embolization 5-thrombosis 6-pneumothorax
CVP monitoring reflects right heart function
Consider when patient fails to respond to therapy in shock 1-cardiac tamponade 2-tension pneumothorax 3-ventilatory problems 4-unrecognized fluid loss 5-acute gastric distention 6-myocardial infraction 7-diabetic acidosis 8-hypoadrenalism 9-neurogenic shock
In trauma, assume shock is hypovolemic
Basic management principle, again, in shock stop the bleeding and replace the volume loss
Created by: tcrouch2000