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ATLS - Ch 3
Shock
| Question | Answer |
|---|---|
| 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
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