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Shock Resident Survival Guide
Overview
Causes
Management
FIRE
Do's
Don'ts

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Synonyms and keywords: Circulatory shock

Overview

Shock is the syndrome of circulatory failure that results in inadequate cellular oxygen utilization. The diagnosis of shock is based on clinical signs and biochemical abnormalities indicative of tissue hypoperfusion.

Causes

Life Threatening Causes

Shock is a life-threatening condition and must be treated as such irrespective of the underlying cause.

Common Causes

• Cardiogenic shock

• Arrhythmic

• Sinoatrial block
• Atrioventricular block
• Ventricular tachycardia
• Supraventricular tachycardia

• Mechanical

• Hypertrophic cardiomyopathy
• Acute mitral regurgitation
• Ventricular septal defect

• Myopathic

• Cardiomyopathy
• Myocardial contusion
• Myocardial infarction
• Myocarditis
• Postischemic myocardial stunning
• Septic myocardial depression

• Pharmacologic

• Anthracycline
• Calcium channel blockers

• Obstructive shock

• Decreased cardiac compliance

• Cardiac tamponade
• Constrictive pericarditis

• Decreased ventricular preload

• Intrathoracic tumor
• Mechanical ventilation with positive end-expiratory pressure (PEEP)
• Tension pneumothorax

• Increased ventricular afterload

• Aortic dissection
• Pulmonary embolism
• Acute pulmonary hypertension

• Hypovolemic shock

• Fluid depletion

• Dehydration
• Diarrhea
• Polyuria
• Vomiting

• Hemorrhage

• Gastrointestinal bleeding
• Retroperitoneal hemorrhage
• Trauma

• Distributive shock

• Sepsis
• Toxic shock syndrome
• Anaphylactic or anaphylactoid reaction
• Neurogenic shock
• Endocrinologic

• Adrenal crisis
• Thyroid storm

Click here for the complete list of causes.

Management

Shock

Initial Management Ventilate—Infuse—Pump (VIP) ❑ Intubation with mechanical ventilation ❑ Normal saline 0.5–1.0 L q10–15 min ❑ ± Transfusion as needed ❑ ± Norepinephrine 0.1–2.0 μg/kg/min ❑ Arterial blood gas ❑ Pulse oximetry ❑ ECG monitor ❑ Central venous catheter ❑ ICU admission

Workups ❑ CBC/DC/SMA-7/LFT/PT/PTT/INR ❑ Troponin ± CK-MB ❑ Lactate ❑ CXR ❑ ± Echocardiography ❑ ± Pulmonary artery catheter

Immediate Goals ❑ SaO2 >90%–92% ❑ CVP 8–12 mmHg ❑ MAP >65–70 mmHg ❑ PCWP 12–15 mmHg ❑ CI >2.1 L/min/m2 ❑ MVO2 >60% ❑ SCVO2 >70% ❑ Hemoglobin >7–9 g/dL ❑ Lactate <2.2 mM/L ❑ Urine output >0.5 mL/kg/h

Classify Shock and Treat Accordingly

Cardiogenic Shock

Obstructive Shock

Distributive Shock

Hypovolemic Shock

Classification of shock based on hemodynamic profiles and echocardiographic findings.

Type of Shock		CO	SVR	PCWP	CVP	SVO2	Echocardiographic Findings
Cardiogenic	Acute Ventricular Septal Defect	↓↓	↑	N — ↑	↑↑	↑ — ↑↑	Large ventricles with poor contractility
	Acute Mitral Regurgitation	↓↓	↑	↑↑	↑ — ↑↑	↓
	Myocardial Dysfunction	↓↓	↑	↑↑	↑↑	↓
	RV Infarction	↓↓	↑	N — ↓	↑↑	↓	Dilated RV, small LV, abnormal wall motions
Obstructive	Pulmonary Embolism	↓↓	↑	N — ↓	↑↑	↓	Dilated RV, small LV
	Cardiac Tamponade	↓ — ↓↓	↑	↑↑	↑↑	↓	Pericardial effusion, small ventricles, dilated inferior vena cava
Distributive	Septic Shock	N — ↑↑	↓ — ↓↓	N — ↓	N — ↓	↑ — ↑↑	Normal cardiac chambers with preserved contractility
	Anaphylactic Shock	N — ↑↑	↓ — ↓↓	N — ↓	N — ↓	↑ — ↑↑
Hypovolemic	Volume Depletion	↓↓	↑	↓↓	↓↓	↓	Small cardiac chambers with normal or high contractility

FIRE: Focused Initial Rapid Evaluation

Do's

• Resuscitation should be initiated while investigation of the cause is ongoing. Correct the cause of shock immediately once it is identified.

Don'ts

References

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