Air embolism as a complication following CT-guided lung biopsy: A case report and literature review

Abstract

Systemic air embolism following computed tomography (CT)-–guided transthoracic lung biopsy is a rare but serious complication that can be life-threatening. We report the case of a 75-year-old male patient with a history of multi-drug-resistant bacterial pneumonia and chronic obstructive pulmonary disease (COPD), previously treated with bronchial artery embolization for hemoptysis. The patient underwent computed tomography (CT)–guided transthoracic lung biopsy. Post-procedure, he developed a systemic air embolism involving the aorta, which ultimately led to his death despite resuscitative efforts. This case highlights the potential risks associated with transthoracic lung biopsy in general and the devastating consequences of systemic air embolism in particular.

Introduction

Transthoracic needle biopsy (TTNB) is a common and essential procedure for both the definitive diagnosis and differential diagnosis of thoracic oncologic diseases. It is an invasive technique aimed at obtaining tissue samples for histopathological analysis of thoracic masses [1]. Pneumothorax is a common complication following transthoracic needle biopsy (TTNB), with an incidence of up to 26.3% [1]. In particular, systemic air embolism, although rare, is a serious complication of percutaneous lung intervention procedures, with an incidence ranging from 0.02% to 0.06% [2]. Air embolism—arterial or venous—may result from pneumothorax following TTNB, depending on the mechanism of air entry into the bloodstream and the final destination where the embolus causes vascular obstruction. Vascular or alveolar injury during the procedure, combined with elevated airway pressure during inspiration, can force air into the vascular system. The air can then travel through the circulation, causing embolic obstruction in various organs. Among these, cerebral arterial embolism is a particularly dangerous complication with potentially severe, even fatal, consequences. According to Valérie Monnin–Barres and colleagues, the incidence of pneumothorax among 559 patients undergoing TTNB ranged from 9% to 54%, with an average rate of approximately 20%. Of these cases, 4.8% resulted in systemic arterial air embolism [3]. In a study by Shi He Liu and Qing Fu, the most commonly observed location of air following biopsy-induced systemic air embolism was the left ventricle (89.5%), and in most cases, patients were asymptomatic. Subsequently, air may enter the systemic circulation and cause embolic occlusion in small vessels, such as the coronary or cerebral arteries. The mortality rate associated with coronary or cerebral arterial embolism can be as high as 26.3% [4]. We describe a 75-year-old male patient who developed air embolism in the aorta and intracranial arterial branches after a computed tomography (CT)-guided lung biopsy.

Case report

The patient, a 75-year-old male, had a longstanding history of chronic obstructive pulmonary disease (COPD). He was admitted to a pulmonary specialty hospital with a persistent cough producing purulent sputum and bright red hemoptysis that later turned dark. During hospitalization, the hemoptysis persisted and was accompanied by acute respiratory failure, requiring sedation, endotracheal intubation, and mechanical ventilation. Endotracheal suctioning yielded large volumes of fresh blood, and both lungs showed poor ventilation. Bronchial artery embolization was performed for hemostasis, and after the procedure, the hemoptysis improved. However, despite treatment with multiple antibiotics and therapeutic regimens, the patient’s respiratory status did not improve significantly. Chest CT revealed a parenchymal lung mass. As clinical symptoms remained unresponsive to prolonged medical therapy, TTNB was indicated to obtain histopathological tissue for definitive diagnosis. Due to the deep location of the lesion and its distance from the tracheobronchial tree, bronchoscopic biopsy was not feasible; therefore, transthoracic biopsy was considered the most appropriate approach (Fig. 1).

Fig. 1.

Computed tomography (CT) scan non-contrast axial: mass in the right upper lung lobe; biopsy target site indicated (arrow).

The patient underwent CT-guided TTNB while being maintained on positive-pressure mechanical ventilation throughout the procedure. The biopsy was performed following standard procedural steps. Immediate post-biopsy CT imaging revealed an air-fluid level within the ascending aorta, with a considerable volume of intraluminal air, raising suspicion of an aortic air embolism. After the procedure, the patient was transferred back to the ward for monitoring (Fig. 2).

Fig. 2.

Post-biopsy CT scan axial showing pneumothorax and air embolism in the ascending aorta.

Approximately 1 hour after the intervention, the patient became increasingly agitated and suddenly developed generalized tonic–clonic seizures involving the upper and lower limbs. Respiratory status deteriorated, as evidenced by an SpO₂ of 90% and increased bronchial secretions. The patient was immediately sedated and received maximal respiratory support, including aggressive airway suctioning, with close monitoring of pH, lactate, PaO₂, and PaCO₂ levels. A brain CT scan was indicated, revealing the presence of intracranial free air bubbles and air within the right vertebral artery, along with diffuse cerebral edema and effacement of the cortical sulci. These findings were suggestive of cerebral infarction due to air embolism (Fig. 3).

Fig. 3.

Cranial CT axial images 2 hours post-intervention: (A) presence of intracranial free air bubbles; (B) air within the right vertebral artery.

The patient subsequently underwent emergency bronchoscopy while on mechanical ventilation, which revealed no identifiable airway lesions. A contrast-enhanced CT scan of the chest and brain was performed, demonstrating multiple large intravascular air bubbles, suggestive of systemic arterial air embolism following TTNB. The patient was then transferred to another facility for more advanced resuscitative care. However, due to his advanced age and multiple underlying comorbidities, the prognosis was poor, and the family elected to discontinue further treatment.

Discussion

Arterial air embolism is a rare but extremely dangerous complication following CT-guided transthoracic lung biopsy. Systemic air embolism during percutaneous lung intervention typically occurs through three pathways: direct pulmonary vein cannulation (during needle/stylet handling), the creation of a fistula via accidental puncture of air-filled structures, or the introduction of microscopic bubbles generated by thermal ablation [5].

The imaging diagnosis of this complication depends on the volume of air present. In cases of small-volume embolism, the diagnosis is often made indirectly based on neurological symptoms in conjunction with a recent history of transthoracic biopsy. In contrast, large-volume embolism may be directly visualized on immediate post-biopsy imaging and is typically associated with a poor prognosis. The greater the volume of intravascular air within the systemic circulation, the higher the mortality rate. This complication often occurs early, and when clinical suspicion arises, it is essential to perform CT imaging of the chest and brain within 30 minutes after the procedure to evaluate for air embolism. The presence of intravascular air bubbles across multiple contiguous slices confirms the diagnosis of systemic arterial air embolism [6]. In our patient, although the procedure was performed according to standard protocol and the complication was detected immediately after the biopsy, clinical symptoms manifested later. This raises concerns regarding the timely recognition and management of this potentially fatal complication, particularly in critically ill patients on mechanical ventilation. Upon retrospective review of the biopsy procedure, we noted that air entered the aorta during needle advancement toward the lesion-prior to the actual tissue sampling step.

Risk factors that increase the likelihood of pneumothorax leading to systemic arterial air embolism after lung biopsy include positive-pressure mechanical ventilation, chronic obstructive pulmonary disease (COPD), the biopsy site and patient positioning during the procedure. In some cases, patient movement or coughing during the biopsy also contributes to a higher complication rate. Lesions located above the level of the left atrium and those situated deeper than ≥2 cm from the pleural surface are associated with an increased risk of complications. Therefore, some guidelines suggest that placing the patient in the lateral decubitus position combined with sedation or general anesthesia during the procedure may help reduce the risk of air embolism [4,7].

In our case, the patient was an elderly male with multiple risk factors predisposing to complications, including respiratory failure with an SpO₂ of 88%, unable to maintain normal physiological respiratory function without ventilatory support. In addition, several other factors contributed to the elevated risk, such as the lesion being located adjacent to the posterior chest wall of the upper lung lobe, the patient’s unstable neurological status that could result in involuntary movements during the procedure, and a history of COPD.

The patient’s compromised respiratory status required mechanical ventilation throughout the procedure—we believe this was the primary contributing factor leading to the development of massive air embolism in this patient. Under normal physiological conditions, the reduction in intrapulmonary pressure during expiration may help seal the biopsy tract. However, in mechanically ventilated patients, continuously positive intrathoracic pressure may facilitate the entry of air through the biopsy tract into the vascular system.

The deep location of the lesion necessitated a longer needle trajectory, increasing the risk of forming an air tract and, consequently, the likelihood of post-biopsy pneumothorax. A longer needle trajectory requires passage through a greater length of normal lung parenchyma, resulting in more disrupted airways and injured vessels, thereby increasing the likelihood of forming a fistulous tract between the alveoli and pulmonary veins. Deeply located lesions are also more difficult to accurately target, and any deviation in needle direction may lead to unintended parenchymal injury. In addition, the deeper lung parenchyma has a reduced capacity for passive air resorption, pre-disposing to air entrapment within the tissue and increasing the risk of delayed pneumothorax [8].

Additionally, the patient was comatose and unable to maintain voluntary posture or follow instructions during the procedure. Involuntary movements made it difficult to control the biopsy needle trajectory, increasing the risk of penetrating air-filled regions or inserting the needle too deeply—both of which contribute to a higher risk of air embolism following biopsy.

Pneumoembolism is a dangerous complication with potential for significant morbidity and high mortality. However, if recognized early and managed promptly, patient survival can be greatly improved. Studies have shown that oxygen therapy is an effective treatment modality. Vascular embolism leads to ischemia in affected organs—especially critical ones such as the brain and heart—thus, restoring perfusion and resolving the obstruction are primary therapeutic goals.

High-concentration oxygen therapy, including hyperbaric oxygen, is the standard treatment. It helps reduce the size of air bubbles and increases tissue oxygenation, being particularly effective in cases of small-volume air embolism. Supportive measures may also include placing the patient in the left lateral decubitus or Trendelenburg position to prevent air from migrating to the cerebral circulation, controlling neurological symptoms, and maintaining adequate blood pressure to ensure cerebral perfusion [9].

Regarding the prevention of pneumothorax and systemic arterial air embolism, some authors have reported the use of the BioSentry Hydrogel Plug—a bioabsorbable material deployed through the biopsy needle tract during needle withdrawal from the lung parenchyma—showing a significant reduction in post-biopsy pneumothorax rates. However, the cost of this technique remains a major limitation, particularly in middle-income countries such as Vietnam [10]. Injecting normal saline into the biopsy tract and rapidly positioning the patient with the biopsy side down is a simple and easily applicable method that can be implemented in most clinical settings. Given its favorable outcomes, this technique should be considered a practical option in routine clinical practice [11]. An autologous blood patch is a technique in which the patient’s own blood is injected along the needle tract after lung biopsy needle withdrawal, with the aim of reducing the risk of pneumothorax. This is a simple and cost-effective alternative to commercial devices such as the BioSentry plug, while still demonstrating reasonably good efficacy [12].

Conclusion

Arterial air embolism following CT-guided lung biopsy is a rare but life-threatening complication associated with high mortality and potentially severe long-term sequelae. Lung biopsy should be carefully considered in patients requiring positive-pressure mechanical ventilation. Risk reduction strategies during the procedure may include adjusting patient positioning, performing the biopsy under general anesthesia, and sealing the biopsy tract with various materials, such as bioabsorbable plugs, normal saline, or autologous blood. This case highlights the serious nature of post-biopsy complications, including pneumothorax, aortic air embolism, and cerebral arterial embolism, emphasizing the need for timely diagnosis and appropriate management to minimize the risks associated with CT-guided transthoracic lung biopsy.

Take-home note

Top risk factors

Positive-pressure ventilation, COPD, advanced age and deep lesions (>2 cm from pleura) or locations above the left atrium.

Key signs

+ Imaging: Air bubbles in the aorta, left ventricle, or cerebral arteries on post-biopsy CT.

+ Clinical: Sudden seizures, focal deficits, or rapid decompensation (can be delayed up to 1 hour).

Emergency response

+ 100% high-flow oxygen (or hyperbaric oxygen) to shrink bubbles.

+ Trendelenburg or left lateral decubitus position.

Prevention

Avoid biopsy in ventilated patients if possible; use tract-sealing techniques (autologous blood patch, saline, or hydrogel plugs).

Patient consent

Written informed consent was obtained from the patient for using her data and images for publication of this case report.