Gas Embolism After Lung Biopsy: What You Need to Know
"A rare but serious complication, gas embolism following a lung biopsy requires quick diagnosis and treatment. Here’s how to stay informed and prepared."
Cerebral ischemia, or stroke, is a rare complication that can occur during surgical or interventional radiology procedures. While uncommon, it's crucial to recognize the potential for such events and understand the various underlying causes.
Gas embolism is one of the possible causes, making swift diagnosis and treatment essential. When air bubbles enter the bloodstream and block blood flow to the brain, the consequences can be severe.
This article explores a case of ischemic stroke following a CT-guided lung biopsy complicated by gas embolism, emphasizing the importance of vigilance and preparedness in medical settings.
Scale and Types of Embolism
The CDC says venous thromboembolism (VTE) includes deep vein thrombosis and pulmonary embolism, and as many as 900,000 people could be affected each year in the United States, although the precise number is unknown. Gas embolism is generally air embolism, but medical gases such as carbon dioxide, nitrous oxide, and nitrogen can also cause it. Gas embolism is broadly classified as venous or arterial according to how gas enters the circulation and where it ultimately lodges.
Early Clinical Recognition
ScienceDirect Topics describes intravascular gas embolism as the rarest but most catastrophic consequence of acute pulmonary barotrauma. Gregory and Tooley first reported a case of gas embolism in a newborn with respiratory distress syndrome who was receiving positive-pressure ventilation. A 1999 history of cerebral arterial gas embolism research also identified type 3 decompression sickness as a recognized diving-related subtype in which apparent spinal cord disease follows early cerebral manifestations.
Recognizing the Signs: What Does Gas Embolism Look Like?
A 56-year-old male, a smoker with a history of laryngeal cancer treated with radio-chemotherapy, underwent a follow-up chest CT scan. The scan revealed a 17mm pulmonary nodule in the left Fowler segment, prompting a CT-guided lung biopsy.
- Immediate Post-Procedure Symptoms: Sudden loss of consciousness, seizures, and incontinence.
- Neurological Deficits: Weakness on one side of the body, especially affecting the face and arm.
- Imaging Findings: CT scans showing air bubbles in the brain's blood vessels.
Cerebral Arterial Gas Embolism
Recent reviews describe cerebral arterial gas embolism (CAGE) as gas, usually air, entering the cerebral arterial circulation. Reported procedural settings include open and minimally invasive cardiovascular procedures, aortic procedures, cardiac catheterization, percutaneous coronary intervention, mechanical circulatory support, and transcatheter aortic procedures. Clinical presentation can range from hemodynamic and neurologic deterioration to delayed, subtle focal deficits, and cranial air may be detectable on computed tomography in only a minority of cases.
Mechanism and Physiologic Risk
The exact mechanism of air embolism during transbronchial lung biopsy (TBLB) is not clear. The New England Journal of Medicine describes gas embolism as largely iatrogenic and capable of causing serious morbidity or death. In venous gas embolism, gas enters the systemic venous system and travels through the pulmonary arteries, where it can interfere with gas exchange and cause arrhythmias, pulmonary hypertension, right-ventricular strain, and eventual cardiac failure.
Frequency and Gas-Specific Effects
Reported rates of systemic arterial gas embolism during percutaneous lung biopsy range from 0.06% to 0.9%. In one cited study, 16 of 19 cases were asymptomatic and identified only during routine head and chest CT after biopsy. A comparative study reported that, at higher injected doses, blood pressure fell immediately with both carbon dioxide and air; the drop was precipitous with carbon dioxide, reaching minimum readings within 5 to 10 seconds, whereas air took 20 to 30 seconds to reach similar shock levels.
Preventing Future Incidents: Steps to Minimize Risk
Gas embolism is a rare but serious complication of transthoracic lung biopsies. Recognizing the signs and acting quickly are essential. Early diagnosis via CT scan and prompt treatment, ideally with hyperbaric oxygen therapy, can significantly improve patient outcomes and reduce the risk of long-term complications.
Detection During Biopsy
A 2026 Frontiers report states that gas embolism may occur during CT-guided biopsy and, if not promptly detected under general anesthesia, could potentially lead to cardiac arrest. The report notes that general anesthesia in hybrid operating rooms can streamline workflow but may mask early signs of air embolism and create specific risks. Symptoms of air embolism can involve both the cardiopulmonary and nervous systems, although catastrophic air embolism is described as rarer than air embolism overall.
Long-Term Pulmonary Embolism Trends
A study titled “Temporal Trends and Future Projections of Pulmonary Embolism and Top Contributing Causes of Death in the United States, 1968-2040” examines pulmonary embolism mortality trends from 1968 through 2023 and forecasts rates through 2040. The researchers analyzed CDC WONDER death certificates for adults aged 25 years and older, using age-adjusted mortality rates, annual percent changes, and Auto-ARIMA and Prophet forecasting models. The study describes pulmonary embolism as the most severe form of venous thromboembolism, resulting from thrombus migration into the pulmonary arteries, typically from deep veins of the lower limbs.