Arterial gas embolism
Background
- Also known as "air embolism"
- May be fatal when air entry reaches 200-300 mL (pressure gradient of 5 mmHg across 14 ga catheter entrains air at 100 mL/sec)[1]
- Dialysis related
- Due to negative intrathoracic pressure from spontaneous breathing
- Scuba related
- Results from pulmonary barotrauma (most common) and decompression sickness
Prevention
- Positive pressure mechanical ventilation reduces positive pressure gradient
- Trendelenburg for insertion/removal of IJV and subclav lines
- Reverse Trendelenburg for femoral
Clinical Features
- Asymptomatic
- Mild: dyspnea, cough
- Cardiogenic shock: hypotension, oliguria, AMS, chest pain
- Dialysis related
- Acute dyspnea, chest tightness, LOC, cardiac arrest
- Scuba related
- Symptoms develop during ascent or immediately upon surfacing
- Causes variety of stroke syndromes depending on part of brain affected
- Immediate death, loss of consciousness, seizure, blindness, hemiplegia
Differential Diagnosis
Dialysis Complications
- Dialysis-associated hypotension
- Dialysis disequilibrium syndrome
- Air embolism
- Missed dialysis (pulmonary edema)
Diving Emergencies
- Barotrauma of descent
- Otic barotrauma
- Pulmonary barotrauma
- Sinus barotrauma
- Mask squeeze
- Barodentalgia (trapped dental air causing squeeze)
- Barotrauma of ascent
- Pulmonary barotrauma (pulmonary overpressurization syndrome)
- Decompression sickness (DCS)
- Arterial gas embolism
- Alternobaric vertigo
- Facial baroparesis (Bells Palsy)
- At depth injuries
- Oxygen toxicity
- Nitrogen narcosis
- Hypothermia
- Contaminated gas mixture (e.g. CO toxicity)
- Caustic cocktail from rebreathing circuit
Diagnosis
- Low ETCO2 in significant venous air embolism
Management[2]
- Place in supine position
- 100% O2 non-rebreather
- Hemodynamic support with positive inotropes
- Rapid CPR in large air embolus
Dialysis Related
- Prevent any further air entry
- Immediately cover puncture site with saline soaked gauze
Scuba Related
- IVF (increases tissue perfusion)
- Rapid recompression