Iatrogenic air embolism following CT-guided lung needle biopsy
Immediate and 30-minute post-biopsy CT scans showed air in the left
ventricle, root, and descending aorta. A small left-sided pneumothorax
was also detected (Figures 1 and 2). Interestingly, air bubbles were
also found in the small mesenteric arteries and a small splenic infarct
was noted as well (Figure 3). A CT scan of the patient’s head did not
reveal any abnormality.
Echocardiogram and contrast-enhanced CT
examinations within the next 24 hours confirmed complete resolution of
air in the left ventricle and aorta (Figure 4). There was no change in
size of the pneumothorax on repeating CT scans (Figure 4).
Histopathology of biopsy material showed primary lung adenocarcinoma.
Percutaneous lung biopsy is a generally accepted and widely used
method of establishing the etiology of lung masses. Despite its
usefulness, the procedure is not without morbidity and, rarely, results
in mortality. Complication rates differ greatly within different
centers. One recent survey performed by Richardson et al in the United
Kingdom showed complication rates of 20.5% for pneumothorax, and 5.3%
for hemoptysis. The survey also found that air embolisms occurred in
1 case of 5444 biopsies in the survey. The death rate following lung
biopsies is estimated at 0.02%, and most fatal cases follow air
Air embolism, the entry of gas into the
vascular system, could be an iatrogenic problem following invasive
procedures, such as cardiac surgery and neurosurgery, percutaneous
biopsies, or central vascular catheterization, or following accidental
trauma, such as chest trauma or pulmonary barotrauma in diving
operations. The effects of air emboli differ greatly depending on their
size, whether they are venous or arterial, and on the organ where they
Arterial gas embolism can happen when air bubbles blow directly to the pulmonary veins through lung procedures.2
This seems to have been the cause of air embolism in this patient’s
case, as there was no air detected in the right side of the heart on a
CT scan performed immediately after the procedure.
pulmonary venous system in 3 main ways: 1) when the needle tip is
inserted in a pulmonary vein and the stylet is removed, resulting in a
direct connection with atmosphere; 2)when a broncho-venous fistula is
created by insertion of a needle; and 3)when air introduced into the
pulmonary arteries reaches the microvasculature and then passes through
to the venous system.3 Air infusion rates of more than 1.5 ml/kg/min are associated with bradycardia and cardiovascular decompensation.4
air goes to left ventricle and aorta, it can occlude any peripheral
arteries. Occlusion of the cerebral and cardiac circulation is more
significant, as these systems are highly vulnerable to hypoxia.2
The fact that the patient was in the right lateral position during the
procedure might have prevented the large amount of air from entering the
left ventricular outflow tract; hence, decreasing the chance of distal
artery emboli lodgment. Moreover, being in the head-down position
immediately after diagnosis prevented air from entering the cerebral
vasculature. As a result, unlike the recent recommendations to place
patients with arterial gas embolism in the supine position,3,5
the head down, laterally lying position was helpful in our case.
Depending on the amount of gas, a coronary air embolism could cause
temporary ischemia of the myocardium, infarction, short hypertensive
crisis, ventricular fibrillation and/or other dysrhythmias, cardiac
failure, and cardiac arrest.5 Although a retrospective review
of the postprocedure CT scan did not reveal air in the coronary
arteries, the presence of air in the root and descending parts of aorta,
transient ischemic changes on EKG, and mild cardiac enzyme elevation
without any obliterative thrombus on coronary angiogram test made
coronary artery air embolism the primary cause of this patient’s
Diagnosing air embolism as a complication of lung biopsy
is based on a good clinical suspicion and detection of air on a
postprocedure CT scan. However, pathologic changes are sometimes very
subtle and not well visualized on CT. Magnetic resonance imaging (MRI)
and single photon emission computer tomography (SPECT) have been
attempted to detect cerebral air embolisms (CAE), but a review study
conducted by Elliott and Moon in 1996, concluded that clinical
evaluation and CT are still preferred for the assessment of CAE.
of air embolism consists of basic life support, high-flow oxygen (often
with the aid of a ventilator), and IV fluid therapy.2,5 It
has been shown that the left lateral decubitus position in venous/right
ventricular air embolism redistributes the air above the right
ventricular outflow tract, relieving air lock and improving survival.7 In our patient we found that right lateral positioning in left ventricular/arterial air embolism is effective in the same way.
benefits of corticosteroids, anticoagulants or lignocaine in air
embolism are not yet confirmed. For arterial gas embolism, hyperbaric
oxygen is the treatment of choice, as soon as cardiopulmonary
stabilization has been achieved.5,8 This reduces bubble size by producing a diffusion gradient for oxygen into the bubble and for nitrogen out of the bubble.3 That was not available in our service, so only high-flow oxygen was applied.
Air embolism is a rare but serious complication of percutaneous lung biopsy, which has high mortality and morbidity rates.Early
detection, aggressive supportive treatment, and hyperbaric oxygen will
reduce adverse outcomes. Positioning the patient in a way that air
remains higher than the root of the vessel in the ventricle seems to be
an important factor in managing these patients. Prevention could be
achieved by selecting the shortest possible needle track through the
lung, performing biopsy while the patient is in full inspiration, and
occlusion of the needle end when the stylet is taken off.
- Manhire AR, Richardson, CM, Gleeson, FV. Lung biopsy guidelines. Thorax. 2003;58:913-914.
- Vanhulst RA, Klein J, Lachmann B. Gas embolism: Pathophysiology and treatment. Clin. Physiol. Funct. Imaging. 2003;23:237-246.
- Mansour A, AbdeRaouf S, et al. Acute coronary artery air embolism following CT-guided lung biopsy. Cardiovascular Interventional Radiology. 2005;28:131-134.
- Shetty PG, Fatterpekar F, et al. Fatal cerebral air embolism as a complication of trans-bronchoscopic lung biopsy. Australasian Radiology. 2001;45:215-217.
- Muth M, Shank C, Eric S. Primary care: Gas embolism. New Eng J Med. 2000;342:276-282.
- Faer MJ, Messerschmidt GL. Nonfatal pulmonary air embolism: Radiographic demonstration. AJR Am J Roentgenol. 1978;131:705-706.
- Chakaravarti R, Singh V, Isaac, R, John MJ. Fatal paradoxical
pulmonary air embolism complicating percutaneous computed
tomography-guided needle biopsy of the lung. Australasian Radiology. 2004;48:204-206.
- Aurora T, Ward KR, Garza R, Rivers E. Iatrogenic venous air embolism. J Emerg Med. 2000;18: 255-256.