Review Article

Use of Physiologic Reasoning to Diagnose and Manage Shock States

Table 2

Disruptions in the normal economy of oxygen supply and demand can have profound impacts on solid organ function and long-term outcomes. Typically, changes in metabolic mode from aerobic to anaerobic as evidenced by high lactate or decreased central oxyhemoglobin saturation (sCVO2) can be explained by changes in either supply, demand, or both. Except in rare instances of hypermetabolism, most pathology in oxygen supply/demand can be traced to problems with delivery (DO2).

Increased demand (VO2)Decreased supply, delivery (DO2)

UncommonHemorrhage
 ThyrotoxicosisDecreased cardiac output
 Malignant hyperthermia Decrease heart rate
Common Decreased stroke volume syndromes
 Fever  Low blood volume
 Systemic inflammation   Dehydration
 Shivering, thermogenesis   Hemorrhage
 Muscle contraction, fighting  Normal or elevated blood volume
   Heart failure, cardiogenic shock
   Inadequate filling time, tachycardia
   Valvular obstruction
   Valvular insufficiency
   Pulmonary hypertension
  Obstructive shock
   Pneumothorax
   Pulmonary embolus
   Cardiac tamponade