Shock

Shock

Types of shock:

Hypovolemic

• Caused by decrease in intravascular volume secondary to loss of blood , fluids, or electrolytes.
• >15% loss of intravascular volume can cause hypotension and progressive tissue hypoxia

Cardiogenic

• Cardiac failure where the heart is unable to maintain adequate tissue perfusion.
• Most often caused by MI but can be due to cardiomyopathy, myocardial contusion, valvular incompetence or stenosis, or arrhythmias.

Obstructive

• Caused by acute decrease if cardiac output due to cardiac tamponade, tension pneumo, or PE

Distributive

• Caused by sepsis, anaphylaxis, systemic inflammation, burns,

Setpic

• Caused by overload of gram negative bacteremia

Neurogenic shock

• Caused by spinal cord injury or spinal anesthetic

Treatments

• Dobutamine – is the first line agent for cardiogenic shock. Initial dose should be .5-1mcg/kg/min as continuous intravenous infusion, then titrated every few minutes. Amrinone or milrinone can be substituted for dobutamine
• Norepinephrine – usually used for vasodilatory shock. Initial dose is 1-2 mcg/min. Patients with refractory shock may need dosages of 10-30 mcg/min.
• Epinephrine – may be used in severe shock and during acute resuscitation. Initial dose is 1 mcg/min as a continuous IV.
• Dopamine –low dose (2-5 mcg/kg/min) stimulate dopaminergic and b-agonist receptors, producing increased glomerular filtration, heart rate, and contractility. Max dose is 50 mcg/kg/min.
• Phenylephrine – can be used as first line agent for hyperdynamic septic shock when there is low systemic venous resistance and dysrhythmias or tachycardias that prevent the use of agents with b-adrenergic activity.
• Vasopressin – used as adjunctive therapy in the tx of disbrutive or vasodilatory shock.
• Low dose corticosteroids in septic shock with acute adrenal insufficiency. Hydrocortisone 50 mg q 6 hours and 50 mcg of 9-alpha-fludroconrtisone once daily for 7 days.
• Volume replacement – is critical in initial management of shock
  • Hemorrhagic shock – rapid infusion of type O negative packed RBC or whole blood will give volume and clotting factors
  • Hypovolemic shock secondary to dehydration – give rapid boluses of isotonic crystalloid
  • Cardiogenic shock in absence of fluid overload requires smaller fluid challenges usually increments of 250 ml
  • Septic shock – requires large volumes of fluid for resuscitation

Citation:

Papadakis, Maxine; McPhee, Stephen. Current Medical Diagnosis and treatment 2013.