distributive shock; vasodilatory shock (multiple organ dysfunction syndrome)

Introduction

Failure to maintain adequate perfusion of vital organs secondary to, in part, decreased peripheral vascular resistance & loss of capillary integrity with transudation of intravascular fluid.

Etiology

• sepsis - systemic inflammatory response syndrome (SIRS)
• anaphylaxis
• neurogenic
  • anesthesia
  • vagotonic shock
  • spinal shock -trauma
• pharmacologic agents
  • alpha blockers
  • beta blockers
  • vasodilators
    • nitroprusside
    • ACE inhibitors
    • calcium channel blockers
• pulmonary predominant form
  • pneumonia, pulmonary aspiration, lung contusion, near-drowning, COPD exacerbation, hemorrhage, pulmonary embolism
• hemorrhage & vascular disease

Pathology

• vasodilation
• low central venous pressure
• decreased intravascular volume
• decreased peripheral vascular resistance
• loss of capillary integrity
• transudation of intravascular fluid
• increased cardiac output (initially)
• lungs may be predominant, & only, organ system affected until very late

Clinical manifestations

• mental status deterioration
• disseminated intravascular coagulation (DIC)
• acute respiratory distress syndrome (ARDS)
• dysuria & oliguria
• lactic acidosis
• hypotension
• fever or hypothermia
• tachycardia

Laboratory

• serum chemistries
  • azotemia
  • hyperbilirubinemia
  • increased serum transaminases
• complete blood count (CBC) with peripheral smear
  • schistocytes
  • leukocytosis with left shift
  • leukopenia may be present especially in elderly & immunocompromised
  • thrombocytopenia
• DIC panel (D-dimer, fibrinogen, PT/PTT)
• arterial blood gas
  • hypoxemia & respiratory alkalosis with acute respiratory distress syndrome (ARDS)
• serum lactate, lactic acidosis
• basic metabolic panel
  • metabolic acidosis
  • hyperglycemia
• serum cortisol to assess adrenal insufficiency
• cosyntropin stimulation test better than serum cortisol

Management

• intravenous (IV) fluids
  • saline
  • colloid more expensive than crystalloid (saline)
• vasopressors
  • dopamine
    • 2-5 ug/kg/min to maintain renal perfusion
    • 10-20 ug/kg/min is similar in effect to norepinephrine
  • norepinephrine (Levophed)
    • agent generally used when dopamine is inadequate
    • 0.05-2 ug/kg/min
  • vasopressin
    • norepinephrine + vasopressin associated with less atrial fibrillation but not lower mortality
  • phenylephrine (Neo-synephrine)
    • almost pure peripheral vasoconstriction
    • 2-10 ug/kg/min
  • epinephrine
    • agent of choice in cardiogenic shock
  • dobutamine
    • may actually decrease blood pressure in sepsis due to peripheral vasodilation
    • agent of choice in cardiogenic shock
  • synthetic angiotensin II
• antibiotics
• surgical drainage of abscesses
• removal of potential sources of infection
  • urethral catheter
  • intravenous (IV) catheters
  • wound packing
  • tampons
• treatment of anaphylaxis
• corticosteroids may be of benefit for adrenal insufficiency
  • hydrocortisone 50 mg IV every 6 hours +
  • fludrocortisone 50 ug PO QD

More general terms

• shock

More specific terms

• neurogenic shock
• septic shock
• warm shock

Additional terms

• anaphylaxis