🚑 Initial Shock Management

🧠 About

• Hypovolaemic shock = inadequate circulating volume → decreased venous return → ↓ stroke volume → ↓ cardiac output → tissue hypoxia.
• Common mechanisms: Haemorrhage (blood loss) or fluid loss (dehydration, burns, GI or renal losses).
• Results in anaerobic metabolism → lactic acidosis → worsening vasodilatation and cellular injury.

💡 Key diagnostic clue: A metabolic acidosis with base deficit >5 mmol/L indicates tissue hypoperfusion. Serial lactate measurements guide adequacy of resuscitation and prognosis.

⚠️ Causes

1️⃣ Haemorrhage

• Gastrointestinal: Haematemesis, melaena, raised urea, hypotension.
• Retroperitoneal: Trauma, pancreatitis, or anticoagulation-related bleed.
• Ruptured/Leaking AAA: Sudden hypotension + abdominal/back pain → urgent CT/surgical review.
• Thoracic/Pelvic Trauma: Internal bleeding, long-bone fractures, pelvic fractures.
• Penetrating Injury: Cardiac or vascular damage; consider coagulopathy.

2️⃣ Fluid Loss (Non-haemorrhagic)

• GI losses: Severe diarrhoea, vomiting, bowel obstruction, high-output stoma.
• Renal losses: Osmotic diuresis (DKA/HHS), diabetes insipidus.
• Skin losses: Burns, excessive sweating, inadequate fluid replacement.
• Third spacing: Pancreatitis, peritonitis, sepsis.

🩺 Clinical Features

• Low BP, tachycardia, thready pulse.
• Poor capillary refill, cold clammy peripheries.
• Oliguria → anuria (unless osmotic diuresis present).
• Altered mental state, confusion → coma in severe shock.
• Specific signs:
  • Grey-Turner’s and Cullen’s signs = retroperitoneal bleeding.
  • PR blood/melena → GI bleed.
  • Pulsatile abdominal mass → possible AAA.

🧪 Investigations

• FBC – ↓ Hb (though may be normal early in acute haemorrhage), ↑ if haemoconcentrated.
• U&E – ↑ urea in dehydration or upper GI bleed.
• Lactate >2 mmol/L → tissue hypoxia or sepsis.
• ABG – metabolic acidosis, raised base deficit.
• Crossmatch and prepare for transfusion.
• CT angiography or ultrasound if intra-abdominal source suspected.

💊 Management Overview

• 1️⃣ Airway & Breathing: Oxygen to maintain SpO₂ >94% (or 88–92% in COPD).
• 2️⃣ Circulation:
  • IV fluid boluses (250–500 mL crystalloid) until perfusion restored or signs of overload.
  • If bleeding → blood transfusion, early tranexamic acid (TXA) within 3 hours if trauma.
  • Monitor response: BP, HR, urine output, lactate, mental status.
• 3️⃣ Definitive Cause:
  • Endoscopy for GI bleed.
  • CT abdomen/pelvis for AAA or retroperitoneal haemorrhage.
  • Surgical or interventional radiology input early.
• 4️⃣ Haemodynamic Support:
  • CVP <6 mmHg → fluid challenge (250 mL 0.9% saline or colloid).
  • CVP >6 mmHg or poor cardiac function → smaller boluses or inotropes.
  • Vasopressors: Noradrenaline (first-line) if refractory hypotension after fluid resuscitation.
  • Inotropes: Dobutamine for cardiac contractility if myocardial dysfunction suspected.
• 5️⃣ Airway protection:
  • Consider intubation if GCS <8, hypoxaemia, or hypercapnia (PaCO₂ >6.7 kPa).

📈 Monitoring and Ongoing Care

• Continuous ECG, pulse oximetry, and blood pressure.
• Hourly urine output (target >0.5 mL/kg/h).
• Serial lactate and base deficit to monitor response.
• Review for ongoing bleeding or fluid loss every 15–30 minutes.

📚 References

• Resuscitation Council UK (ALS 2021). Management of Shock.
• NICE CG174: Intravenous Fluid Therapy in Adults in Hospital.
• ATLS 10th Edition. Hypovolaemic Shock Algorithm.
• Marik PE et al. Hemodynamic parameters to guide fluid therapy in shock. Crit Care Med. 2013.