Shock

Shock

Shock

Shock: Definitions

• Shock = inadequate tissue perfusion– Decreased O2 delivery, removal of metabolites

• Tissue perfusion is determined by: – Cardiac output (CO) = HR x SV

SV = function of preload, afterload, contractility– Systemic vascular resistance (SVR)

Shock

Shock: Types

• Hypovolemic• Septic (high CO, low SVRI)• Cardiogenic (high CVP)• Neurogenic• Anaphylactic• Adrenal insufficiency

Shock

Shock Types & Physiology

Shock CVP/PCWP CO SVRI

Hemorrhagic

Septic

Cardiogenic

Neurogenic

Hypoadrenal

Anaphylactic

Shock

Shock Types & Physiology

Shock CVP/PCWP CO SVRI

Hemorrhagic ↓ ↓ ↑

Septic

Cardiogenic

Neurogenic

Hypoadrenal

Anaphylactic

Shock

Shock Types & Physiology

Shock CVP/PCWP CO SVRI

Hemorrhagic ↓ ↓ ↑

Septic either ↑ ↓

Cardiogenic

Neurogenic

Hypoadrenal

Anaphylactic

Shock

Shock Types & Physiology

Shock CVP/PCWP CO SVRI

Hemorrhagic ↓ ↓ ↑

Septic either ↑ ↓

Cardiogenic ↑ ↓ ↑

Neurogenic

Hypoadrenal

Anaphylactic

Shock

Shock Types & Physiology

Shock CVP/PCWP CO SVRI

Hemorrhagic ↓ ↓ ↑

Septic either ↑ ↓

Cardiogenic ↑ ↓ ↑

Neurogenic ↓ ↓ ↓

Hypoadrenal

Anaphylactic

Shock

Shock Types & Physiology

Shock CVP/PCWP CO SVRI

Hemorrhagic ↓ ↓ ↑

Septic either ↑ ↓

Cardiogenic ↑ ↓ ↑

Neurogenic ↓ ↓ ↓

Hypoadrenal either ↓ ↓

Anaphylactic

Shock

Shock Types & Physiology

Shock CVP/PCWP CO SVRI

Hemorrhagic ↓ ↓ ↑

Septic either ↑ ↓

Cardiogenic ↑ ↓ ↑

Neurogenic ↓ ↓ ↓

Hypoadrenal either ↓ ↓

Anaphylactic ↓ ↓ ↓

Shock

Hypovolemic Shock• Body’s response to hypovolemia

– Rapid: peripheral vasoconstriction, increased cardiac activity

– Sustained: arterial vasoconstriction, Na/water retention, increased cortisol

• 2/2 hemorrhage or fluid loss • Classes of hemorrhage:

I: 15% II: 30% = tachycardiaIII: 40% = decreased SBP, confusionIV: >40% = lethargy, no UOP

Tx: stop source / fluids / blood

Shock

Septic Shock

• SIRS = T >38C or <36C, HR >90, RR >20, PaCO2 <32mmHg, WBC >12 or <4

• Sepsis = SIRS + focus of infection• Severe sepsis = sepsis + MSOF• Septic shock = sepsis + refractory hypotension• Remember: septic shock is a/w high CO• Tx: fluids, antibiotics

Shock

Cardiogenic Shock

• Cardiogenic shock 2/2 cardiac disease or cardiac compression– Cardiac disease: MI, arrhythmia, valve

dysfunction, increased PVR or SVR, increased ventricular resistance

– Cardiac compression: tension PTX, cardiac tamponade, positive pressure ventilation

• Look for Beck’s triad in tamponade (hypotension, JVD, muffled heart sounds)

• Tx: fluids, tx underlying cause (relieve PTX, pericardiocentesis, change ventilator settings)

Shock

Neurogenic Shock

• Shock 2/2 spinal cord injury, regional anesthesia, autonomic blockade

• Mechanism: loss of vasomotor control, expansion of venous capacitance bed

• Signs: warm skin, normal or low HR, normal CO, low SVR

• Tx: Fluids / pressors / +- steroids

Shock

Hypoadrenal

• Unresponsive to fluids or pressors• Tx: steroids

Shock

Shock: Signs

• Hypotension, tachycardia, tachypnea• Change in MS, lethargy• Decreased UOP

Shock

Shock: Evaluation

• Airway: includes brief evaluation of mental status• Breathing• Circulation: includes placement of adequate IV access• Disability: identification of gross neurologic injury• Exposure: ensures complete exam

• History: OPQRST, review PMHx, PSHx, ALL, SHx• PE: complete• Labs: include ABG (pH, base deficit, lactate)

Shock

Case 1

• 55y M post-op day 0 s/p colectomy• Called for tachycardia, hypotension, altered

mental status, abdominal distension, decreased UOP

• PE: pale, disoriented, abdomen tense, UOP 15mL/hr

• What is your diagnosis?• What additional information should you obtain?• What is the plan?

Shock

Case 1: Continued

• Dx: hemorrhagic shock• Additional information: CBC, coags, T&C• Management

– ABC (intubate, IV access)– Resuscitate (isotonic IVF)– Prepare for take-back

Shock

Case 2• 75y M h/o CAD, PVD, DM, POD 1 s/p AAA

repair c/o nausea

• What do you need to think about?• What is the plan?

Shock

Case 2: Continued

• Dx: MI

• Plan:– ABC– MONA, beta-blockade– Labs/x-rays: cardiac enzymes Q8H x3 sets

w/EKG, chemstick, BMP, CXR– Cardiology consult

Shock

Case 2: Continued

• Cath w/critical stenosis of left main s/p balloon angioplasty

• PE: intubated, 80/50, UOP 10mL/hr• Echo: severe LV dysfunction

• What is the diagnosis?• What is the plan?

Shock

Case 2: Continued• Dx: Post-myocardial infarction (cardiogenic) shock• Plan:

– ABC • Pressor support as needed• Placement of Swan-Ganz catheter• +/- Intra-aortic balloon pump, cardiac assist

device

Shock

Case 4

• 55y M POD 0 s/p colectomy, w/epidural placed for post-op pain control

• Called by nurse for hypotension and bradycardia

• PE: AAOx3, abdomen ND, NT• Recent post-op labs: HCT 35• What is your working diagnosis?

Shock

Case 4: Continued

• DX: Neurogenic shock 2/2 epidural• Treatment is:

– IVF– Turn down or turn off epidural– If BP does not respond to IVF, initiate pressor

support w/alpha-agonist such as phenylephrine

Shock

Case 5• 45y M p/w diffuse abdominal pain. PMHx

PUD, chronic NSAID usage. • PE: febrile, tachycardic, hypotensive,

lethargic, rigid abdomen w/ involuntary guarding

• What is your working diagnosis?• What is your plan?

Shock

Case 5

• Dx: septic shock 2/2 duodenal perforation

• Plan:– ABC– Broad-spectrum IV antibiotics– Emergent OR for ex-lap, washout & repair

Shock

Shock: Take Home Points

• Shock = inadequate tissue perfusion • Types of shock: hypovolemic, septic,

cardiogenic, neurogenic, anaphylactic• Signs of shock: altered MS, tachycardia,

hypotension, tachypnea, low UOP• Always start with ABCs• Resuscitation begins with fluid