Distributive Shock (Reduced SVR vasodilated)

Related Subjects: Atropine | Acute Anaphylaxis | Basic Life Support | Advanced Life Support | Adrenaline/Epinephrine |Acute Hypotension |Cardiogenic shock |Distributive Shock |Hypovolaemic or Haemorrhagic Shock |Obstructive Shock |Septic Shock and Sepsis |Shock (General Assessment) |Toxic Shock Syndrome |Non invasive ventilation (NIV) |Intubation and Mechanical Ventilation |Critical illness neuromuscular weakness |Multiple Organ Dysfunction Syndrome

Distributive Shock is characterised by a systemic loss of systemic vascular resistance seen in sepsis, anaphylaxis and neurogenic shock

Initial Shock Management: Oxygen 15 L/min unless COPD.
Insert large bore IV access and Start Crystalloid and assess Send FBC, U&E, LFT, Group and hold +/- Lactate, Trop, Dimer, ABG Consider Urinary catheter to measure urine output Fever, Temp, Sepsis, Tampon, Wound: Lactate, IV Fluids, Antibiotics, Inotrope Urticaria, Wheeze, Antigen exposure: Anaphylaxis IM Adrenaline, IV Steroid Spinal injury with loss of sympathetic tone, labile BP and hypotension

About

• Acute circulatory collapse with evidence of insufficient end-organ perfusion.
• There are multiple causes of shock which affect the onset and presentation.
• Vasodilated often warm peripheries and low diastolic BP

Pathophysiology

• Vasodilation with hypotension and hyperdynamic state

Causes: Usually 3 causes

• Septic shock: infection, burns, pancreatitis, TSS syndrome
• Anaphylactic shock e..g bee sting
• Neurogenic shock due to brain or spinal cord injury

A metabolic acidosis with base deficit > 5 mmol/L often indicates increased lactic acid production in poorly perfused, hypoxic tissues. Serial lactate measurements may help in monitoring response to treatment

Clinical

• Low BP, lying to sitting BP drop, thready pulse, tachycardia, Increased respiratory rate
• Poor capillary return, warm, vasodilated obtunded, comatose
• Oliguria, concentrated urine (except DKA/DI)
• Sepsis - UTI, chest, biliary, peritonitis, cellulitis, gangrene

Investigations

• FBC - ↓ Hb, U&E - ↑ creatinine in AKI or GI bleed
• CXR, ECG, D-Dimer, Echo
• LFTS, Prothrombin time, troponin, ALP
• Blood cultures, Amylase, lactate if unsure of the cause
• Imaging AXR, USS or CT abdomen/pelvis

Management

• ABCs, Oxygen, Get Good IV access x 2 quickly
• Commence IV Crystalloids and Transfusion if anaemic
• Commence IV antibiotics if infection suspected
• Consider CVP line and invasive monitoring to guide management
• Fluids fail to help consider Vaopressor such as Noradrenaline / Vasopressin