Makindo Medical Notes

💨 Air Embolism occurs when air bubbles enter the bloodstream, obstructing circulation. This can happen during surgery, trauma, medical procedures, or diving accidents 🏊‍♂️. The severity depends on the volume of air and site of obstruction, with potential for life-threatening complications. 📌 Positioning the patient: Place head down + left side down (left lateral decubitus, Trendelenburg) → traps air in the right ventricular apex, slowing systemic entry.

📌 About Air Embolism

• ⚙️ Mechanism: Air enters venous or arterial circulation → obstructs blood flow → impaired perfusion.
• 🫀 Venous Air Embolism (VAE): Air reaches right heart → pulmonary artery blockage → hypoxia & cardiovascular collapse.
• 🤿 Divers & Decompression: Rapid ascent → nitrogen bubbles (decompression sickness) mimics air embolism.
• ⚠️ Severity: Even 0.5–1 mL in coronary/cerebral arteries can be fatal; 50 mL+ venous air can cause cardiovascular collapse.

🔬 Pathophysiology

• 🩸 Venous entry favoured when site above right atrium → negative venous pressure sucks in air.
• 🚪 Arterial embolism may arise from pulmonary barotrauma or paradoxical embolism via PFO/ASD.
• 🧠 Cerebral and coronary circulation are most vulnerable → stroke-like deficits or MI.

📋 Causes

• 🩻 Surgical Procedures: Neurosurgery, cardiothoracic surgery, or central line manipulation.
• 🪓 Trauma: Chest/neck penetrating injuries or fractured veins.
• 💉 Central Lines & Catheters: Insertion/removal mishaps → most common iatrogenic cause.
• 🤿 Diving Accidents: Poor decompression control → nitrogen embolism/air embolism overlap.
• 💨 Positive Pressure Ventilation: Barotrauma → alveolar-vascular air entry.

🧾 Types

• 🫀 Venous Air Embolism (VAE): → Right heart & lungs → pulmonary hypertension, hypoxia, RV strain.
• 🧠 Arterial Air Embolism (AAE): → Brain, heart, kidneys → stroke, MI, multiorgan injury.

⚠️ Clinical Signs

• 😮 Dyspnoea, hypoxia, cyanosis
• ❤️ Chest pain, arrhythmias
• 🧠 Neurological deficits → dizziness, seizures, confusion, focal stroke
• 📉 Hypotension, obstructive shock
• 💔 Cardiac arrest in severe cases

🔎 Investigations

• 🧪 ABG: Hypoxia ± metabolic acidosis.
• 📈 ECG: RV strain, tachycardia, ST changes.
• 🩻 CXR: Non-specific; may show pulmonary oligemia.
• 🫀 TEE: Sensitive → visualises air bubbles in right atrium/ventricle.

🩺 Differentials

• PE 🫁
• Stroke / TIA 🧠
• MI ❤️
• Tension pneumothorax 🫁
• Cardiac tamponade 💔

🚨 Complications

• 💔 Cardiac arrest (obstructive shock)
• ❤️ Myocardial infarction (coronary embolism)
• 🧠 Hypoxic brain injury (cerebral embolism)
• 🫁 ARDS & respiratory failure

🛡️ Prevention

• 🏥 Procedures: Careful central line insertion/removal, IV filters.
• 🤿 Divers: Controlled ascent & decompression stops.
• 💉 Hospital: Positioning during catheter removal, air-tight line handling.

⚕️ Management

• 🔄 Resuscitation: ABCs, 100% high-flow O₂ (non-rebreather).
• 🛏️ Position: Left lateral decubitus + Trendelenburg.
• 🤐 Intubation/Ventilation: For severe hypoxia.
• 💧 Fluids ± Inotropes: To maintain preload and cardiac output.

💡 Advanced Management

• 💉 Aspiration: Via central venous catheter in RA if accessible.
• 🌊 Hyperbaric Oxygen Therapy (HBOT): Shrinks bubbles, improves oxygenation; gold standard in cerebral/cardiac involvement.
• 🔪 Open Chest Aspiration: Rare; in intra-op cases, direct removal of air from RV or pulmonary artery.

📉 Prognosis

• ⏱️ Depends on speed of recognition & management.
• ✅ Early O₂ + positioning can reverse symptoms.
• ❌ Delayed treatment → permanent neurological injury or death.

📚 References

• Air Embolism: A Comprehensive Review
• NEJM: Management of Air Embolism
• Medscape: Overview

Case – Venous air embolism after central line removal

A 62-year-old on a surgical ward becomes acutely dyspnoeic and hypotensive minutes after removal of a right IJ central line; she is upright when the dressing lifts and a hissing sound is heard. On exam: tachycardia, hypoxia, raised JVP, and a fleeting “mill–wheel” precordial sound; bedside echo shows RV strain without thrombus. Suspect venous air embolism precipitated by negative intrathoracic pressure. Immediate actions: 100% oxygen (reduces bubble size & treats shunt), place in left lateral decubitus with slight Trendelenburg (Durant’s), apply occlusive pressure dressing over the insertion site, support circulation (IV fluids/vasopressors) and call ICU; if a central line remains, attempt aspiration of air from the right heart. Consider hyperbaric oxygen urgently if neurological deficits or coronary/cerebral involvement suggest arterial gas embolism. Differentiate from PE and tension pneumothorax. Prevention: remove lines with the patient supine/Trendelenburg, during end-expiration or Valsalva, maintain firm occlusive pressure for ≥5–10 min, and use an airtight dressing.