Shock Flashcards
what is shock?
inadequate tissue perfusion to meet metabolic demand and tissue oxygenation
what are the physiological categories of shock?
cardiogenic
hypovolemic
distributive
obstructive
what are the stages of shock?
compensated
decompensated
irreversible
what is compensated shock?
reflex compensatory mechanisms activated and perfusion to vital organs is maintained
*increased HR and BP
what is decompensated shock?
tissue hypoperfusion and onset of worsening circulatory and metabolic derangement
- hypotension
- lactic acidosis
what is irreversible shock?
organ and tissue injury is so severe that even if hemodynamic effects are corrected, survival is not possible
what are the subtypes of distributive shock?
septic
non-septic (inflammatory, anaphylactic, neurogenic)
what are the subtypes of cardiogenic shock?
cardiomyopathic
arrhythmogenic
mechanical
what are the subtypes of hypovolemic shock?
hemorrhagic
non-hemorrhagic (fluid loss)
what are the subtypes of obstructive shock?
pulmonary vascular
mechanical
what are the hemodynamic changes of cardiogenic shock?
decreased CO
increased SVR
increased CVP/PCWP
what are the hemodynamic changes of hypovolemic shock?
decreased CO
increased SVR
decreased CVP/PCWP
what are the hemodynamic changes of septic and anaphylactic shock?
increased CO
decreased SVR
decreased CVP/PCWP
what are the hemodynamic changes of neurogenic shock?
decreased CO
decreased SVR
decreased CVP/PCWP
what are the hemodynamic changes of obstructive shock?
decreased CO
increased SVR
variable CVP/PCWP
what are signs of shock?
hypotension tachycardia oliguria AMS tachypnea cold, cyanotic skin metabolic acidosis elevated lactate
what’s the most important thing to remember with an unstable patient?
Airway Breathing Circulation Disability Exposure
how do you treat shock?
IVFs
vasopressors
US evaluation (RUSH protocol)
broad-spectrum abx (if sepsis suspected)
Equation to determine BP
CO x TPR
Where is BP the highest?
Proximal Aorta
- hits about 30 mmHg at capillaries
- almost 0 in the RA
64% of blood is held where in circulation?
Veins
- SNS decreases venous compliance, shifting blood to the heart and to arterial circulation
- Also a mechanism by which Nitrates work to decrease O2 demand by the cardiac myocytes. Shift the blood more into the veins to decrease preload
Possible outcomes of anoxic cells
- Thrombosis
- Hemorrhage
- Edema
Release of inflammatory cytokines IL-1 and TNF
2 phases of distributive septic shock
- Warm shock- High CO but low TPR causing edema. Treat with Fluid resuscitation
- Cold shock- low CO, high TPR causing hypo perfusion. Skin is cold and petechiae form.
What is the mainstay treatment for hypotension in the absence of cariogenic shock (aka pump failure)
Give IVF to raise JVP!
Review Anaphylactic Shock
- IgE-mediated (type I hypersensitivity)
- Mast cell degranulation (Histamine, Leukotrienes, PGe’s)
- Vasodilation, bronchoconstriction
- Can cause ACS
Tx: Epi +/- Antihistamine +/- Albuterol
At what stage of hypovolemic shock do you typically start to give blood products instead of just saline?
Class III aka >30% blood loss
- Drugs typically not needed
Typical inotropes/Vasopressers to give in shock
- Dobutamine (B1 agonist)
- Epi (all receptors)
- NE (all - B2)
- DA
- Phenylephrine
- Vasopressin (want V1 receptor activation in vasculature, not V2 in kidney where ADH acts)
Common causes of cardiogenic shock aka pump failure
MI
Arrhythmias
Valvular Dz
Describe how Systolic dysfunction progresses to failure and death
- Decreased CO (reduced EF)
- Decreased perfusion of coronary and peripheral vessels
- Compensatory vasoconstriction
- Progressive failure
Describe how diastolic dysfunction progresses to failure and death
- Increased LVEDP (Left Ventricle End Diastolic Pressure)
- Pulmonary Congestion due to back up
- Hypoxemia
- Ischemia
- Progressive failure
Primary drug for cardiogenic shock
NE
- Dobutamine can be used when decreased CO in presence of adequate filling
Review signs of sepsis
- Hypotensive
- Tachycardic
- Tachypnic
- edema
- AMS
- Fever
First choice vasopressor for septic shock
NE +/- Epi
Vasopressin can be added
Dobutamine if needed
What other hormone is necessary to survive critical illness and is elicited by corticosteroid dosage in shock?
Cortisol
