Septic Shock

Affect on hemodynamic variables:

1. HR: Tachycardia in response to fever and hypermetabolism and as a compensatory response for the low SVR and low preload.
2. BP: Hypotension is related to low SVR, low intravascular volume, and/or inadequate EF. The degree of diastolic hypotension correlates with the low SVR.
3. Preload: Cardiac filling pressures, CVP and PAOP are low before IV fluid resuscitation because of vasodilation, peripheral vascular shunt formation, and the increased third spacing of intravascular fluid secondary to severe capillary leak.
4. CO: Typically elevated to compensate for low SVR and increased metabolic needs related to sepsis. Occasionally, patients with septic shock present with low CO and biventricular hypokinesis on echocardiogram. This low-CO state is thought to be caused by thy cytokine myocardial depressant factor, which is released during sepsis. This type of cardiac dysfunction is completely reversible and usually lasts 2 to 4 days.
5. SVR: Low because of vasodilation and increased peripheral vascular shunt formation casued by the cytokine and inflammatory response.