SHOCK 2007

Ariel G. Bentancur, MD Emergency Department, Sheba Medical Center, Israel

“ Dry ” Definition of Shock A circulatory situation where inadequate tissue/end organ oxygenation and perfusion is present.

End Organ? Brain Brain Heart Heart Kidneys Kidneys Gut Gut

Expanded definition: A generalized circulatory derangement causing multiple organ hypoperfusion and strong sympathetic activation, and when intense or sustained enough ( minutes to hours) irreversible metabolic, inflammatory, and clotting disorders leading to the patient ’ s permanent function deficit or death.

So how we recognize shock? Grossly by: Signs of strong sympathetic activation: Tachycardia Tachycardia Pallor Pallor Extremity coldness Extremity coldness Sweating Sweating Tachypnea Tachypnea Signs of hemodynamic instability: Inappropriate low blood pressure values Inappropriate low blood pressure values Signs of organ dysfunction: Altered consciousness Altered consciousness Oliguria Oliguria

BUT … Depends on: CATEGORY of shock CATEGORY of shock DEGREE of shock severity DEGREE of shock severity

SHOCK CATEGORIES 1. HYPOVOLEMIC 2. CARDIOGENIC 3. NEUROGENIC 4. SEPTIC 5. ANAPHILACTIC 6. OBSTRUCTIVE 7. OVERDOSE/TOXIN RELATED

HYPOVOLEMIC SHOCK The initial insult is a loss of circulatory fluid volume, by: Bleeding Bleeding Burns Burns Vomiting Vomiting Diarrhea Diarrhea Sweating Sweating “ Stomas ” “ Stomas ” Third space fluid sequestration Third space fluid sequestration

CARDIOGENIC SHOCK Severe myocardial pump failure due to: Extensive anterior wall myocardial infarction Extensive anterior wall myocardial infarction Right ventricular infarction Right ventricular infarction Arrhythmia Arrhythmia Commotio cordis Commotio cordis

CARDIOGENIC SHOCK Defined by: Systolic blood pressure <90 mmHg Systolic blood pressure <90 mmHg and and Wedge pressure of >20 mmHg Wedge pressure of >20 mmHgOr Cardiac index <1.8 L/min Cardiac index <1.8 L/minOr Inotropics or intra-aortic balloon couterpulsation used to achieve Systolic blood pressure >90 mmHg. Inotropics or intra-aortic balloon couterpulsation used to achieve Systolic blood pressure >90 mmHg.

CARDIOGENIC SHOCK Recognized by: History: Acute Cardiac Syndrome or chest trauma. ECG changes: arrhythmia or ST segment changes. Echocardiographic demonstration of ventricular hypokinesia.

NEUROGENIC SHOCK Caused by severe injury to the CNS Mechanism: A distribution Shock loss of nervous control of the vascular tone and subsequent fall of peripheral vascular resistance. loss of nervous control of the vascular tone and subsequent fall of peripheral vascular resistance. loss of vascular regulation. loss of vascular regulation. pooling of blood in the splanchnic bed pooling of blood in the splanchnic bed Clinical characteristics: Despite of shock presence the skin is warm and pink. Despite of shock presence the skin is warm and pink. Pulse is normal or slow due to unmatched parasympathetic tone. Pulse is normal or slow due to unmatched parasympathetic tone.

SEPTIC SHOCK It is also a distribution shock caused by severe systemic infection. Mechanism: Increased circulatory demand. Increased circulatory demand. A loss of the vascular tone with a subsequent decrease of the peripheral vascular resistance. A loss of the vascular tone with a subsequent decrease of the peripheral vascular resistance. Circulatory volume unchanged but splachnic bed volume sequestration is present. Circulatory volume unchanged but splachnic bed volume sequestration is present.

SEPTIC SHOCK Recognized by: History: present or recent febrile disease. History: present or recent febrile disease. Physical examination: Hypotension Hypotension Warm, dry skin. Warm, dry skin. Tachycardia. Tachycardia.

ANAPHYLACTIC SHOCK Caused by exposure to allergen. Mechanism: Distribution shock Distribution shock IgE/Mastocyte mediated acute reaction. IgE/Mastocyte mediated acute reaction. Histamine/bradichinine/cytokine(ILC4)/PAF/ PGD2 mediated vasodilatation and blood volume sequestration in the splanchnic bed. Histamine/bradichinine/cytokine(ILC4)/PAF/ PGD2 mediated vasodilatation and blood volume sequestration in the splanchnic bed.

ANAPHYLACTIC SHOCK Recognized by: History of exposure. History of exposure. History of past anaphylactic reaction. History of past anaphylactic reaction. Coexistence of: skin rush, angioedema, bronchospasm. Coexistence of: skin rush, angioedema, bronchospasm.

OBSTRUCTIVE SHOCK A restriction to blood flow or diastolic heart filling like in: Pericardiac Tamponade Tension Pneumothorax Stacked cardiac prosthetic valve Massive Pulmonary Emboli

OBSTRUCTIVE SHOCK Mechanism: Blood Volume is normal Cardiac pump function is normal Vascular tone is normal Increased resistance to blood flow or ventricular diastolic function cause a low cardiac output!

OVERDOSE/TOXIN RELATED SHOCK Caused by: Medications: Medications: Drugs used for the treatment of hypertension: Ca++ channel blockers β-blockers orDigoxin Tryciclic antidepressants Toxins Toxins Digested- scombroid fish poisoning Snake bite

OVERDOSE/TOXIN RELATED SHOCK May develop through mixed mechanisms: Vasodilatation and a decrease of peripheral vascular resistance. Vasodilatation and a decrease of peripheral vascular resistance. Decreased ventricular systolic function. Decreased ventricular systolic function.

SHOCK SEVERITY DEGREE Best understood by the severity classification of hemorrhagic shock: Class 4 Severe Class 3 Moderate Class 2 Mild Class 1 Very Mild Degree of Hemorrhage 40%≤ >2000 ml 26-39% ml 15-25% ml <15% <750 ml Estimated volume of blood loss HR >140 Deep hypotension HR >120 Hypotension HR >100 Normal b.p. HR <100 Normal b.p. Cardiovascular signs Severe tachypnea >35 Moderate tachypnea Mild tachypnea Normal RR Respiratory signs Lethargic/coma Lethargic/low pain response Irritable/confused/ combative Anxious CNS signs Cool extremities/ Delayed capillary fill Cool extremities/ Delayed capillary fill Cool extremities/ Delayed capillary fill Warm/pink/normal capillary refill Skin signs Anuria Severe acidosis Oliguria<15ml/m/↑ urea/Metabolic acidosis Oliguria 20-30ml/m Normal serum PH Normal urine output Normal serum PH Kidney/metabolicsigns

Shock Signs Tachycardia-age Infant > 160 bpm Infant > 160 bpm Pre-school >140 bpm Pre-school >140 bpm School-puberty >120 bpm School-puberty >120 bpm Puberty-adult >100 bpm Puberty-adult >100 bpm

Shock Signs Tachycardia-age Influenced by: Age Age Pacemaker Pacemaker Medications Medications

SHOCK Summary: Should be early recognized. Should be early recognized. Sole reliance on SBP results in delayed recognition. Sole reliance on SBP results in delayed recognition. Treat shock and the causes early. Treat shock and the causes early. Hypovolemic versus cardiogenic versus distribution versus obstructive versus mixed shock. Hypovolemic versus cardiogenic versus distribution versus obstructive versus mixed shock. The clinical picture depends on type and severity. The clinical picture depends on type and severity. If treated partially or late it becomes almost irreversible resulting in MOF and death. If treated partially or late it becomes almost irreversible resulting in MOF and death.

DISCUSSION

COMMON SENSE-MECHANISM YES, SHOCK PRESENT

NO SHOCK PRESENT