What type of shock is characterized by bradycardia, decreased cardiac output, low Central Venous Pressure (CVP), and increased Venous Oxygen Saturation (SvO2)?

Neurogenic Shock

The hemodynamic profile described—bradycardia, decreased cardiac output, low CVP, and increased SvO2—is characteristic of neurogenic shock, a form of distributive shock caused by loss of sympathetic tone. 1

Hemodynamic Pattern Explanation

Key Distinguishing Features

Neurogenic shock presents with a unique combination of hemodynamic parameters that differentiate it from other shock types:

• Bradycardia occurs due to unopposed parasympathetic (vagal) tone following loss of sympathetic innervation, typically from spinal cord injury above T6 2, 1

• Decreased cardiac output results from both the bradycardia and loss of sympathetic-mediated cardiac contractility 1

• Low CVP reflects pathological vasodilation and venous pooling from loss of vascular sympathetic tone, leading to decreased venous return 1

• Increased SvO2 is the hallmark finding—tissue oxygen extraction is impaired due to distributive pathophysiology with arteriovenous shunting, resulting in paradoxically high venous oxygen saturation despite inadequate tissue perfusion 3

Differentiation from Other Shock Types

This hemodynamic profile is distinctly different from cardiogenic shock, which would show:

• Tachycardia (pulse rate >60 bpm) rather than bradycardia 2
• Elevated CVP (>15 mmHg) from backward failure, not low CVP 1
• Elevated systemic vascular resistance (SVR) as compensatory vasoconstriction, not decreased SVR 2, 1
• Low SvO2 from impaired cardiac output and increased oxygen extraction 3

Distributive shock (including neurogenic shock) demonstrates:

• Decreased SVR as the primary pathophysiologic mechanism 2, 1
• Normal or decreased CVP, contrasting with the elevated CVP of cardiogenic shock 1
• Normal or increased cardiac output in early stages (though decreased in neurogenic shock due to bradycardia) 2

Clinical Context

Neurogenic shock typically occurs following:

• High spinal cord injuries (cervical or upper thoracic) 2
• Severe head trauma affecting autonomic centers 2
• Spinal anesthesia complications 2

Critical Management Pitfall

Do not confuse late-stage septic shock with cardiogenic shock—septic shock can develop myocardial depression, but the primary hemodynamic pattern remains distributive with decreased SVR and often elevated SvO2 from impaired oxygen extraction. 1, 3 The presence of bradycardia with low CVP should immediately suggest neurogenic rather than cardiogenic or septic etiology.