Chapter 6, Shock Flashcards
What is shock?
A physiological state of inadequate tissue perfusion that results when oxygen delivery, uptake, and utilization are insufficient to meet the metabolic demands of cells and organs.
Inadequate tissue perfusion for cellular metabolism
What is preload?
The central venous pressure or volume of blood return to the heart at the end of diastole.
What is afterload?
The pressure that the heart must overcome to pump blood into systemic circulation; it is a component of systemic vascular resistance.
What is contractility?
The capability of the ventricles to contract, forcefully ejecting blood.
What are the 3 stages of shock?
Compensated
Decompensated/Hypotensive
Irreversible
How is the transition from compensated to decompensated shock defined?
By hypotension.
What changes to blood flow occur in compensated shock?
Blood is shunted to the heart, brain, and lungs and away from the skin and splanchnic circulation.
What occurs during decompensated/hypotensive shock?
Compensatory mechanisms begin to fail and are unable to support or improve perfusion.
What occurs during irreversible shock?
Tissues and cells throughout the body become ischemic and necrotic, resulting in multiple organ dysfunction.
Ischemia, necrosis, organ dysfunction
How is the body’s vascular response to shock activated?
Baroreceptor activation: sense decrease in stretch which triggers Epi & NE release.
Chemoreceptor activation: sense changes in blood O2 levels (peripheral) & CO2 and pH which increases respiratory rate and depth, and blood pressure.
What does the adrenal gland stimulate the release of in addition to catecholamines?
Cortisol and aldosterone to raise blood glucose and promote renal retention of water and sodium.
What is one of the earliest pulmonary responses to inadequately perfused tissue?
Tachypnea resulting from metabolic acidosis stemming from anaerobic metabolism.
Cerebral autoregulation maintains a constant cerebral vascular blood flow as long as the MAP is maintained at what value?
50-150 mmHg
Hypoperfusion of the kidneys triggers the adrenal gland to improve tissue perfusion in which 2 ways?
Vasoconstriction
Retention of water
The trauma Triad of Death consists of which elements?
Hypothermia
Acidosis
Coagulopathy
What are the 4 types of shock?
Hypovolemic (volume problem)
Cardiogenic (pump problem)
Obstructive (mechanical problem)
Distributive (vessel problem)
What are etiologies of obstructive shock?
Tension pneumothorax
Cardiac tamponade
Air embolism
What are etiologies of cardiogenic shock?
Blunt cardiac injury
MI
Dysrhythmias
Cardiomyopathy
Toxicologic pathologies
What are etiologies of distributive shock?
Anaphylactic shock
Septic shock
Neurogenic shock
What is damage control resuscitation and its 2 strategies?
Restoration of homeostasis through the control of hemorrhage, administration of blood, and other interventions aimed to prevent the triad of death.
Hypotensive resuscitation
Hemostatic resuscitation
What is hypotensive resuscitation (permissive hypotension)?
Limited fluid resuscitation (crystalloid solutions) enabling a lower than normal blood pressure.
What is hemostatic resuscitation?
Optimizing tissue and cellular oxygenation and perfusion by preventing further losses through hemodilution coagulopathy.
1:1:1 (platelets, PRBC, plasma)
How should crystalloid fluid management be approached in the adult trauma patient?
Maximum of 1 liter
500 mL boluses
Until SBP of 90 mmHg
How should crystalloid fluid management be approached in the pediatric trauma patient?
20 mL/kg bolus if over 28 days
May repeat 1-2 times
How should crystalloid fluid management be approached in the neonatal trauma patient?
10 mL/kg
Why is a Massive Transfusion Protocol (MTP) beneficial?
Leads to early blood, plasma, and platelet transfusions with improved outcomes.
Why should calcium replacement be considered following a massive transfusion?
Citrate in blood products binds with calcium.
Calcium is a vital part of the clotting cascade (worsen hypovolemic shock via continued bleeding).
When can an autotransfusion be considered in the trauma patient?
When there is an isolated hemothorax without diaphragmatic perforation.
What is the purpose of resuscitative endovascular balloon occlusion of the aorta (REBOA)?
To stop life-threatening hemorrhage within the chest, abdomen, and pelvis.
What is damage control surgery?
Surgery intended to stop the bleeding, restore normothermia, and treat coagulopathy and acidosis.
Prevent/resolve Triad of Death.
Not definitive or complete repair.
What is the purpose of administering Tranexamic acid (TXA), a synthetic version of Lysine, to the trauma patient?
Prevents clot dissolving.
Inhibits activation of plasminogen.
What SBP is a criterion for trauma team activation?
SBP of less than 90 mmHg at any time.
What may the blood pressure differences between the right and left arm indicate?
A thoracic aorta injury.
What blood type is preferred in trauma resuscitation?
O-negative.
O-positive can be given to men and postmenopausal women.
What is considered adequate urinary output in an adult?
0.5 mL/kg per hour (70 kg adult)
How is oliguria determined?
Output of less than 0.5 mL/kg per hour for 2 consecutive hours.
What addition is included in the Diamond of Death?
Hypocalcemia.
