A 58-year-old man with severe COPD (FEV₁ 28% predicted) and hypertension is scheduled for transurethral resection of prostate (TURP) under spinal anesthesia. During the procedure, the anesthesiologist administers 3 mL of 0.5% bupivacaine at L3–L4. After 15 minutes, the patient develops sudden onset of dyspnea, hypotension (BP 85/50), and bradycardia (HR 42 bpm). Oxygen saturation drops to 88% despite supplemental oxygen. What is the most likely complication, and what is the immediate next step?

Explanation

## Diagnosis: High Spinal Block (Total Spinal Anesthesia) **Key Point:** High spinal block occurs when local anesthetic spreads beyond the intended level, causing paralysis of respiratory muscles (diaphragm, intercostals) and sympathetic blockade leading to cardiovascular collapse. **High-Yield:** This is a medical emergency requiring immediate airway management and mechanical ventilation. The classic triad is respiratory distress, hypotension, and bradycardia. ### Pathophysiology ```mermaid flowchart TD A[Excessive spread of LA in CSF]:::outcome --> B[Block extends to cervical/thoracic roots]:::outcome B --> C[Diaphragmatic paralysis<br/>C3-C5 involvement]:::urgent C --> D[Respiratory failure]:::urgent B --> E[Sympathetic blockade<br/>T1-T4 involvement]:::urgent E --> F[Vasodilation + bradycardia<br/>Hypotension]:::urgent D --> G[Hypoxemia, hypercarbia]:::urgent F --> G G --> H[Cardiovascular collapse<br/>if untreated]:::urgent ``` ### Risk Factors for High Spinal Block | Risk Factor | Mechanism | | --- | --- | | **Excessive volume of LA** | More drug → greater spread | | **High baricity** | Hyperbaric solutions spread cephalad | | **Patient position** | Trendelenburg increases cephalad spread | | **Pregnancy** | Engorged epidural veins ↓ CSF space | | **Obesity** | ↓ CSF volume | | **Spinal stenosis** | ↓ CSF space | ### Clinical Presentation **Early signs (within 5–15 minutes):** - Dyspnea, difficulty breathing - Hypotension (sympathetic blockade) - Bradycardia (vagal predominance) - Hypoxemia despite supplemental O₂ - Loss of consciousness (if severe) **Examination findings:** - Paralysis of lower limbs (expected) - Paralysis of intercostal muscles (abnormal) - Paralysis of diaphragm (C3–C5) → apnea - Loss of arm movement (cervical involvement) ### Immediate Management **1. Call for help** — anesthesiologist, ICU team, respiratory therapy **2. Airway & Ventilation (IMMEDIATE)** - Discontinue all local anesthetic administration - 100% oxygen by mask or bag-valve-mask - **Prepare for intubation** — if respiratory distress or SpO₂ < 90% - Intubate and mechanically ventilate (most cases require this) - Secure airway before complete respiratory failure **3. Circulation** - Establish large-bore IV access (if not already done) - Aggressive IV fluid resuscitation (crystalloid, 500 mL bolus, repeat as needed) - Vasopressors if hypotension persists: **phenylephrine** (100 mcg IV) or **ephedrine** (5–10 mg IV) - Atropine (0.5–1 mg IV) for symptomatic bradycardia - Position: **flat or slight Trendelenburg** (NOT head-up) **4. Supportive Care** - Monitor ECG, SpO₂, BP continuously - Maintain sedation/analgesia (propofol, remifentanil) - Continue mechanical ventilation until block regresses (2–4 hours for bupivacaine) - Maintain normothermia **5. Reassurance** - Inform patient (if conscious) that this is temporary and treatable - Complete recovery expected once block regresses **Clinical Pearl:** The key to survival is **early recognition and immediate intubation**. Do NOT wait for complete apnea — intubate as soon as respiratory compromise is evident. **Warning:** Do NOT use succinylcholine if hyperkalemia is suspected (prolonged paralysis may cause K⁺ release). Use rocuronium or vecuronium for paralysis during intubation.