Acute Hypotension ✅

Related Subjects: | Assessing Breathlessness | Acute Hypotension | Respiratory Failure | Pulmonary Embolism | Deep Vein Thrombosis | DVT/PE in Pregnancy | CTPA

⚠️ Acute hypotension is a life-threatening emergency defined as systemic blood pressure insufficient to maintain adequate organ perfusion (typically MAP <65 mmHg or SBP <90 mmHg, with signs of shock/hypoperfusion such as elevated lactate, oliguria, or altered mentation). Shock classification (standard 4-category framework, consistent through 2025–2026): Hypovolaemic, Cardiogenic, Distributive (septic, anaphylactic, neurogenic, adrenal crisis), Obstructive. Goal: Immediate cause identification + rapid restoration of perfusion to prevent multi-organ dysfunction (mortality remains 20–50%+ depending on type, timeliness, and comorbidities).

🔑 Step-by-Step Diagnostic & Management Process (Time-Critical)

1. 🚨 Immediate ABCDE Assessment (0–2 min)
   • Airway: Ensure patent; suction/secure if compromised (stridor/obstruction).
   • Breathing: Assess RR, SpO₂, work of breathing, auscultation → high-flow O₂ / NIV if SpO₂ <94% or respiratory distress.
   • Circulation:
     • Measure BP in both arms
     • HR/rhythm, capillary refill time (>2 s abnormal)
     • skin (cool/mottled vs warm), peripheral/central pulses, JVP.
   • Disability: AVPU/GCS, pupils, bedside glucose (hypoglycaemia can mimic or worsen shock).
   • Exposure: Full exam for haemorrhage, rash, meningism, abdominal signs, trauma, spinal tenderness.
   • Verbalise: “This patient has acute hypotension with signs of shock - calling for senior help/rapid response team, initiating ABCDE resuscitation, and preparing for cause-directed therapy.”
2. 💉 Initial Resuscitation & Stabilisation (2–10 min)
   • Secure 2 large-bore IVs (16G+); consider IO if difficult access.
   • Administer balanced crystalloid (Hartmann’s/Plasma-Lyte preferred) in titrated boluses (250–500 mL), reassess perfusion after each (avoid over-resuscitation).
   • Target MAP ≥65 mmHg (consider ≥70–80 mmHg in chronic hypertension, elderly, or brain injury to preserve autoregulation).
   • Measure lactate urgently (≥2 mmol/L indicates hypoperfusion; ≥4 mmol/L severe).
   • Continuous monitoring: ECG, non-invasive BP; consider arterial line early in unstable cases.
   • If no response to initial fluids → start vasopressor early (noradrenaline first-line in most shock types except pure hypovolaemia).
3. 🩺 Rapid Differential Diagnosis / Cause Identification (5–15 min)
   • Hypovolaemic: Blood loss/dehydration history, tachycardia, low JVP, dry mucosa, flat IVC on echo.
   • Cardiogenic: Chest pain/MI history, dyspnoea, pulmonary crackles, raised JVP, cool/clammy skin, narrow pulse pressure.
   • Distributive:
     • Septic: Fever/source of infection, warm/hyperdynamic initially (later cool), bounding pulses.
     • Anaphylactic: Urticaria/angioedema/wheeze, recent trigger (food/drug/sting).
     • Neurogenic: Spinal cord injury above T6, bradycardia, warm/dry skin below level.
   • Obstructive: Raised JVP, muffled heart sounds (tamponade), unequal pulses/widened mediastinum (dissection), acute dyspnoea/hypoxia (massive PE/tension pneumothorax).
4. 🧪 Bedside & Laboratory Investigations (run in parallel)
   • Point-of-care: ABG (lactate, pH, base excess, PaO₂), glucose, ketones if relevant.
   • Bloods: FBC, U&Es, creatinine, LFTs, coagulation, troponin, CRP/procalcitonin, blood cultures (before antibiotics), group & save/crossmatch if bleeding suspected.
   • ECG: Arrhythmia, ischaemia, pericarditis, PE signs.
   • Bedside ultrasound/echo: Cardiac function, RV strain (PE), pericardial effusion, IVC collapsibility/distensibility, lung sliding (pneumothorax), free fluid.
   • CXR: Oedema, pneumothorax, widened mediastinum, consolidation.

🛠️ Targeted Management by Shock Type (2025–2026 Evidence-Aligned)

🚩 Red Flags & Must-Not-Miss Points

• Chest pain + hypotension → ACS, dissection, PE - urgent ECG/echo/CT.
• Fever + hypotension + lactate ≥4 → septic shock (Sepsis Six / Hour-1 bundle: O₂, fluids, antibiotics, cultures, lactate, urine output monitor).
• Acute rash/wheeze after trigger → anaphylaxis (IM adrenaline first, always).
• Bradycardia + hypotension post-spinal injury → neurogenic shock (avoid pure beta-blockade).

💡 OSCE & Viva Pearls (2026 Tips)

• Always bilateral BP first assessment (≥20 mmHg difference → aortic dissection/coarctation).
• Verbalise correct BP technique: “Patient rested 5 min, correct cuff size, arm supported at heart level, no talking, average ≥2 readings.”
• In AF/irregular pulse: “Multiple readings averaged due to beat-to-beat variability.”
• Finish: “Plan = ABC stabilisation, titrated balanced fluids, lactate/ECG/echo, senior input, cause-specific therapy while monitoring for fluid overload.”
• Common pitfalls: Poor BP technique, missing bilateral measurement, delaying vasopressors in distributive shock, excessive fluids in cardiogenic/obstructive.

📚 Key References (as of March 2026)

• Surviving Sepsis Campaign (2021 core, with 2025–2026 refinements & webcasts; early noradrenaline emphasis post-CLOVERS follow-up).
• NICE NG136 Hypertension in adults (updated ~2025).
• AHA/ACC 2025 High Blood Pressure Guideline.
• Resuscitation Council UK Anaphylaxis & ALS algorithms (recent).
• ESICM 2025 circulatory shock/hemodynamic monitoring guidelines (focus on echo & dynamic assessment).