Shock



Shock


Anna D. Jarvis



Introduction



  • Shock is a syndrome characterized by inadequate supply of oxygen and nutrients to meet tissue needs


  • Causes: hypovolemic, distributive, obstructive, cardiogenic, and dissociative


  • Also classified as compensated, decompensated, and irreversible shock


  • Shock is a continuum of vital organ dysfunction, from a single system problem (e.g., hemorrhage) progressing to secondary organ damage leading to multisystem failure and eventually death

    (e.g., hemorrhage → tissue hypoxia → liver dysfunction → coagulopathy + brain hypoxia → coma → death)








Table 4.1 Causes of Shock


















Hypovolemic (decreased circulating blood volume)


  • Dehydration



  • Hemorrhage



  • Plasma loss


Distributive (vasodilation)


  • Sepsis



  • Anaphylaxis



  • Drug toxicity



  • Spinal cord injury


Obstructive (obstruction of cardiac filling)


  • Cardiac tamponade



  • Tension pneumothorax



  • Pulmonary embolism


Cardiogenic (decreased contractility)


  • Congenital heart disease



  • Myocarditis



  • Dysrhythmias


Dissociative (oxygen not released from Hg)


  • Carbon monoxide poisoning



  • Methemoglobinemia




Classification of Shock


Compensated Shock



  • Vital organ perfusion maintained


  • Early signs of shock include heart rate and respiratory rate above expected


  • Blood pressure is maintained via vasoconstriction with perfusion to vital organs


  • Nonperfused areas of the body are hypoxic with progressive dysfunction

Note: In young children cardiac output is dependent on heart rate


Decompensated Shock



  • Hypotension and impaired tissue perfusion


  • First sign may be fatigue (e.g., infant with bronchiolitis and apneic episodes)


  • Slowing of the heart and/or respiratory rate to normal values without improvement in condition


  • Changes in peripheral perfusion: loss of peripheral pulses, capillary refill time > 3 seconds, changes in level of consciousness, and decreased urine output


  • A fall in blood pressure is a late sign and signals impending cardiopulmonary arrest








Table 4.2 Compensated vs Decompensated Shock

COMPENSATED SHOCK

DECOMPENSATED SHOCK


Appearance

Alert, anxious

Altered mental status


Work of breathing

Tachypnea, hyperpnea

Tachypnea, bradypnea


Circulation

Tachycardia, decreased peripheral pulses, cool/pale skin

Tachycardia, absent peripheral pulses, mottled/cyanotic skin




Irreversible Shock



  • Multiorgan failure leading to death


  • May occur hours, days, or weeks after the episode

Tags:
Jun 22, 2016 | Posted by in EMERGENCY MEDICINE | Comments Off on Shock

Full access? Get Clinical Tree
Get Clinical Tree app for offline access