Cerebral gas embolism associated with central venous catheter: Systematic review

[Complications of mechanical thrombectomy]

CLINICAL PROBLEM

Ischemic stroke is the most common cause of disability in adults and an important disease for society; therefore, the prevention, diagnosis, and treatment play an important role. Endovascular mechanical recanalization to reopen large occlusions of the intracerebral vessels has established itself as the gold standard in therapy, which is why knowledge of the most important complications and their management is essential for interventionalists.

PRACTICAL RECOMMENDATIONS

Intracranial hemorrhages, which include intracerebral and subarachnoid hemorrhages, are dreaded complications that significantly worsen the clinical outcome. Early monitoring and optimal management are therefore essential. Cerebral air embolism is a rare but dangerous complication whose prevention is paramount, as treatment options are limited.

Knowledge and Practices Regarding Prevention of Central Venous Catheter Removal-Associated Air Embolism: A Survey of Nonintensive Care Unit Medical and Nursing Staff

INTRODUCTION

Air embolism is a potentially serious complication of central venous catheter (CVC) use. While CVC insertion is usually performed by a trained specialist, extraction is frequently the responsibility of junior staff members. This complication can be easily prevented by following several simple measures described in common guidelines.

AIM

We conducted a single-center survey to assess knowledge and practices concerning the prevention of air embolism associated with CVC removal among healthcare workers from nonintensive care units.

METHODS

The correct answers to the questionnaire were determined according to best-practice recommendations for CVC removal. Based on a comparison of the total sum of correct answers between the categories of groups, factors that predicted the level of knowledge were identified using an independent sample t test.

RESULTS

Of the 156 respondents, one-third were unfamiliar with air embolism as a complication of CVC extraction. Almost 80% were unaware of the existence of a CVC removal protocol. Almost half of respondents did not follow guidelines regarding patient position when removing a CVC, 72% did not ask the patient to perform the Valsalva maneuver during the procedure, and 54% did not ask the patient to remain supine after the procedure. Adherence to the protocol was correlated with professional experience, with a lower level among those with experience of less than 1 year and, particularly, among interns.

CONCLUSIONS

Our survey revealed inappropriately low awareness of CVC removal-associated air embolism risk and low familiarity with CVC removal best-practice recommendations among nonintensive care unit healthcare workers. Staff members with experience of less than 1 year, including interns, were found to have a lower level of knowledge. These findings emphasize the importance of development and distribution an internal hospital protocol and the integration of educational intervention into a preliminary internship program.

Cerebral Venous Air Embolism: A Rare Clinical Challenge and Management Insights

Cerebral air embolism (CAE) is a rare but life-threatening condition often associated with trauma, such as chest and skull injuries, which allow air to enter the venous system, as well as medical procedures and surgical interventions. It can occur during the insertion of peripheral cannulas or central midline catheters, following lung biopsy procedures, or during vascular surgeries, particularly those involving the head and neck region. CAE can also develop during the removal of central venous cannulas, as air may enter the bloodstream in the process. When air enters the bloodstream, it can travel to the cerebral blood vessels, where it may be trapped, forming bubbles that obstruct the blood flow. This blockage reduces oxygen supply to brain tissue, which can quickly lead to cell damage or ischemia if not resolved. We present the case of a 62-year-old male with an infective exacerbation of chronic obstructive pulmonary disease who developed acute unilateral sensorimotor weakness several days following midline catheter insertion for a prolonged course of antibiotic administration. Prompt detection and intervention are essential in managing CAE to minimize risks and prevent permanent damage. The role of diagnostic radiology is essential in the rapid diagnosis and management of CAE. Imaging techniques such as computed tomography (CT) scans, carotid and cerebral angiograms, and magnetic resonance imaging (MRI) of the head are invaluable for assessing cerebral arteries and determining the extent of ischemic damage over time. They can also show signs of air trapped either in the venous or arterial system as the complexity of CAE is heightened by air emboli affecting various vascular regions, including the cerebral venous sinuses, requiring comprehensive imaging for accurate diagnosis and management. While CT of the brain is essential for immediate diagnosis, follow-up MRI scans provide detailed insights into the progression of ischemic changes that may result from CAE.

Cerebral air embolism following a hemodialysis session successfully treated with hyperbaric oxygen: a case report

We describe here the first case of cerebral air embolism (CAE) due to a dysfunctional long-term central venous catheter for hemodialysis in a 39-year-old woman with a history of lung transplantation. Air emboli are rare but potentially fatal complications of hemodialysis, in particular, when they involve the brain. Early management with hyperbaric oxygen therapy (HBOT) is critical to prevent deterioration of the patient's condition. In this case, our patient presented her first symptoms, likely a seizure due to multiple cerebral air emboli, during her hemodialysis session. She was then monitored in the Nephrology Intensive Care Unit in accordance to the medical reference center (with HBOT). Twelve hours later, she experienced secondary deterioration, presenting with acute aphasia, left hemineglect syndrome, and hemiplegia. She was rapidly transferred to the medical reference center for HBOT. The patient fully recovered after receiving three sessions of HBOT. She also presented a seizure during each HBOT session, attributed to hyperoxia. She never experienced another seizure after the episode of CAE. This case highlights the importance of considering patients who have a lung transplant to be at increased risk for air emboli during hemodialysis and the need to rapidly recognize symptoms and start treatment, including HBOT, to optimize recovery.

Characteristic MR Imaging Findings of Cerebral Air Embolism Infarcts: A Case Series

Infarcts from cerebral air embolism are rare events with potentially catastrophic clinical consequences. The imaging features of cerebral air embolism are not well-defined in the literature. We report a novel constellation of MR imaging findings of cerebral arterial air emboli-induced infarcts in a series of 6 patients. Awareness of the more distinguishing MR imaging patterns of cerebral air embolism may help establish this diagnosis and facilitate implementation of timely treatment.

Experimental Model of Cerebral Arterial Air Embolism in Conscious Rats

In this work, an optimal air supply mode was selected to create a model of cerebral arterial air embolism (CAAE) on conscious male Sprague-Dawley rats (n=49). The efficacy of the selected model (administration of 100 μl/kg of air at a rate of 10 μl/min with an infusion pump) was determined by changes in serum biochemical parameters (cholesterol, alkaline phosphatase, inorganic phosphates, AST, and triglycerides), impaired motor functions in the Rotarod test, and visual assessment of the ischemic foci (staining of frontal sections with 1% triphenyltetrazolium chloride solution) at different terms after AAE. The model of AAE created by us confirmed impairment of coordination and motor function in conscious animals and reproduced the lethal consequences of this condition. The obtained results can serve as the basis for drug testing and the development of new approaches to the treatment of ischemic stroke.

Air embolism as a rare complication of lung biopsy: A case report

Lung biopsy is an important interventional radiology procedure allowing the characterization of lesions with suspected malignancy. The most frequent complications are pneumothorax and hemorrhage. Air embolism is a rare but potentially fatal occurrence. In this case report, we present an air embolism after core needle CT-guided biopsy showing CT and MRI features that radiologists should expect in the everyday clinical practice.

A Rare Case of Spontaneous Pneumothorax Leading to Cerebral Air Embolism

Cerebral arterial air embolism (CAE), a rare subtype of air embolism, carries a 21% mortality rate. We present a unique case involving a 69-year-old female with a history of usual interstitial pneumonia (UIP) who suffered a transient ischemic attack (TIA) due to CAE. Unlike typical cases, CAE in this instance resulted from spontaneous pneumothorax, not the more common iatrogenic causes. Adding complexity, an unexpected discovery emerged during evaluation: a patent foramen ovale, contributing to paradoxical embolism. This underscores the vital need to consider CAE as a differential diagnosis in UIP patients with neurological symptoms, highlighting its rarity and diagnostic challenges.

Iatrogenic air embolism: pathoanatomy, thromboinflammation, endotheliopathy, and therapies

Iatrogenic vascular air embolism is a relatively infrequent event but is associated with significant morbidity and mortality. These emboli can arise in many clinical settings such as neurosurgery, cardiac surgery, and liver transplantation, but more recently, endoscopy, hemodialysis, thoracentesis, tissue biopsy, angiography, and central and peripheral venous access and removal have overtaken surgery and trauma as significant causes of vascular air embolism. The true incidence may be greater since many of these air emboli are asymptomatic and frequently go undiagnosed or unreported. Due to the rarity of vascular air embolism and because of the many manifestations, diagnoses can be difficult and require immediate therapeutic intervention. An iatrogenic air embolism can result in both venous and arterial emboli whose anatomic locations dictate the clinical course. Most clinically significant iatrogenic air emboli are caused by arterial obstruction of small vessels because the pulmonary gas exchange filters the more frequent, smaller volume bubbles that gain access to the venous circulation. However, there is a subset of patients with venous air emboli caused by larger volumes of air who present with more protean manifestations. There have been significant gains in the understanding of the interactions of fluid dynamics, hemostasis, and inflammation caused by air emboli due to in vitro and in vivo studies on flow dynamics of bubbles in small vessels. Intensive research regarding the thromboinflammatory changes at the level of the endothelium has been described recently. The obstruction of vessels by air emboli causes immediate pathoanatomic and immunologic and thromboinflammatory responses at the level of the endothelium. In this review, we describe those immunologic and thromboinflammatory responses at the level of the endothelium as well as evaluate traditional and novel forms of therapy for this rare and often unrecognized clinical condition.

Subtypes and Mechanistic Advances of Extracorporeal Membrane Oxygenation-Related Acute Brain Injury

Extracorporeal membrane oxygenation (ECMO) is a frequently used mechanical cardiopulmonary support for rescuing critically ill patients for whom conventional medical therapies have failed. However, ECMO is associated with several complications, such as acute kidney injury, hemorrhage, thromboembolism, and acute brain injury (ABI). Among these, ABI, particularly intracranial hemorrhage (ICH) and infarction, is recognized as the primary cause of mortality during ECMO support. Furthermore, survivors often suffer significant long-term morbidities, including neurocognitive impairments, motor disturbances, and behavioral problems. This review provides a comprehensive overview of the different subtypes of ECMO-related ABI and the updated advance mechanisms, which could be helpful for the early diagnosis and potential neuromonitoring of ECMO-related ABI.

Clinical Characteristics, Imaging Findings, and Outcomes of Cerebral Air Embolism

BACKGROUND

Arterial cerebral air embolism (CAE) is an uncommon but potentially catastrophic event. Patients can present with focal neurologic deficits, seizures, or coma. They may be treated with hyperbaric oxygen therapy. We review the causes, radiographic and clinical characteristics, and outcomes of patients with CAE.

METHODS

We performed a retrospective chart review via an existing institutional database at Mayo Clinic to identify patients with arterial CAE. Demographic data, clinical characteristics, and diagnostic studies were extracted and classified on predefined criteria of diagnostic confidence, and descriptive and univariate analysis was completed.

RESULTS

Fifteen patients met criteria for inclusion in our study. Most presented with focal deficits (80%) and/or coma (53%). Seven patients (47%) had seizures, including status epilepticus in one (7%). Five presented with increased muscle tone at the time of the event (33%). Computed tomography (CT) imaging was insensitive for the detection of CAE, only identifying free air in 4 of 13 who underwent this study. When obtained, magnetic resonance imaging typically showed multifocal areas of restricted diffusion. Six patients (40%) were treated with hyperbaric oxygen therapy. Age, Glasgow Coma Scale score at nadir, and use of hyperbaric oxygen therapy were not associated with functional outcome at 1 year in our cohort. Twenty-six percent of patients had a modified Rankin scale score of 0 one year after the event, and functional improvement over time was common after discharge.

CONCLUSIONS

A high index of clinical suspicion is needed to identify patients with CAE because of low sensitivity of free air on CT imaging and nonspecific clinical presentation. Acute alteration of consciousness, seizures, and focal signs occur frequently. Because improvement over time is possible even among patients with severe presentation, early prognostication should be approached with caution.

Ischaemic Stroke of the "Hand-Knob" Area Due to Paradoxical Cerebral Air Embolism after Central Venous Catheterization-A Doubly Rare Occurrence: A Case Report and an Overview of Pathophysiology, Diagnosis, and Treatment

Central venous catheters (CVCs) are increasingly used across specialties for invasive haemodynamic monitoring and for the delivery of fluids, medications, and nutritional support. Cerebral air embolism (CAE) is a rare but potentially fatal complication associated with the insertion, maintenance, and removal of CVCs. It can occur through different mechanisms, including the direct retrograde ascension of air into the cerebral veins and paradoxical embolism due to a right-to-left intracardiac or intrapulmonary shunt. The "hand-knob" area is the cortical region within the primary motor cortex that contains the representation of the hand. It is located in the superior precentral gyrus and is the site of less than 1% of all ischaemic strokes. We report here the case of a patient who experienced an ischaemic stroke of the right "hand-knob" area, due to paradoxical CAE through a previously undiagnosed patent foramen ovale (PFO), after the insertion of a catheter in the right internal jugular vein. We also provide an overview of the pathophysiology, diagnosis, and treatment of CAE. Suspecting CAE in the case of an acute neurological event occurring in close temporal relationship with central venous catheterization is paramount to allow the early recognition and treatment of this uncommon form of iatrogenic stroke.

Association of immediate reinsertion of new catheters with subsequent mortality among patients with suspected catheter infection: a cohort study

Background

Central venous catheter (CVC) insertion complications are a prevalent and important problem in the intensive care unit (ICU), and source control by immediate catheter removal is considered urgent in patients with septic shock suspected to be caused by catheter-related bloodstream infection (CRBSI). We sought to determine the impact of immediate reinsertion of a new catheter (IRINC) on mortality among patients after CVC removal for suspected CRBSI.

Methods

A propensity score-matched cohort of patients with suspected CRBSI who underwent IRINC or no IRINC in a 32-bed ICU in a university hospital in China from January 2009 through April 2021. Catheter tip culture and clinical symptoms were used to identify patients with suspected CRBSI. The Kaplan–Meier method was used to analyse 30-day mortality before and after propensity score matching, and adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for mortality in the matched cohort were estimated with Cox proportional hazards models.

Results

In total, 1,238 patients who had a CVC removed due to suspected CRBSI were identified. Among these patients, 877 (70.8%) underwent IRINC, and 361 (29.2%) did not. Among 682 propensity score-matched patients, IRINC was associated with an increased risk of 30-day mortality (HR, 1.481; 95% CI, 1.028 to 2.134) after multivariable, multilevel adjustment. Kaplan–Meier analysis found that IRINC was associated with the risk of mortality both before matching (P = 0.00096) and after matching (P = 0.018). A competing risk analysis confirmed the results of the propensity score-matched analysis. The attributable risk associated with bloodstream infection was not significantly different (HR, 1.081; 95% CI 0.964 to 1.213) among patients with suspected CRBSI in terms of 30-day mortality compared with that associated with other infections.

Conclusions

In this cohort study, IRINC was associated with higher 30-day mortality compared to delayed CVC or no CVC among patients with suspected CRBSI. A large-sample randomized controlled trial is needed to define the best management for CVC in cases of suspected CRBSI because IRINC may also be associated with noninfectious complications.

Trial registration This study was registered with the China Clinical Trials Registry (URL: http://www.chictr.org.cn/index.aspx) under the following registration number: ChiCTR1900022175.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01014-8.

Electroencephalographic findings after convulsive seizures due to cerebral arterial air embolism secondary to lung cancer: a case report

Background

Cerebral arterial air embolism is often associated with an invasive iatrogenic etiology and a high rate of convulsive seizures. There are only a few descriptions of electroencephalogram findings in convulsive seizures due to cerebral arterial air embolism of noniatrogenic etiology. Herein, we describe the case of a patient with lung cancer and convulsive seizures with abnormalities detected on electroencephalogram caused by cerebral arterial air embolism of noniatrogenic etiology.

Case presentation

A 55-year-old Japanese man underwent radiotherapy and chemotherapy for cancer in the hilum of the left lung that was diagnosed after hemoptysis. One year after the diagnosis, he developed fever and chest pain that required hospitalization. At admission, he was in shock, and chest computed tomography revealed invasion of the left atrium and left main bronchus by the hilar cancer. Chest and abdominal computed tomography revealed small low-density areas within the tumor and around the intestinal membrane, which were interpreted as the presence of air due to invasion of the lung cancer. He was diagnosed with septic shock due to necrotic infection secondary to cancer invasion into the left atrium. The following day, he complained of difficulty in speaking and weakness in the left side of his body. A head computed tomography scan revealed multiple small low-density areas in the right cortex and bilateral subcortex, which were interpreted as air emboli. On day 3, he experienced generalized tonic–clonic seizures for approximately 1 minute, followed by myoclonus-like convulsions in the left lower limb and a right-sided gaze. The electroencephalogram findings after the convulsive seizures revealed partial epilepsy-like waves with intermittent spikes in the bilateral cerebral hemispheres and a diffuse slow wave in the left frontal lobe. He recovered from sepsis without recurrence of convulsive seizures; however, he died of hemoptysis on day 50 after discharge.

Conclusions

Electroencephalogram findings of focal spike activities and diffuse slow waves were detected in early seizures due to cerebral arterial air embolism of noniatrogenic etiology associated with lung cancer. Additional case descriptions are warranted to establish patterns in electroencephalogram findings specific to cerebral arterial air embolism.

A rare cause of stroke: fail-implanted venous port catheter system - a case report

Background

We present the case of a 75-year-old female with acute embolic cerebral infarction caused by a fail-implanted venous port catheter system in the left subclavian artery.

Case presentation

A 75-year-old woman presented to our emergency room after acute onset of a right-sided hemiparesis and dysarthria. Within 2 days after admission, she developed a left-sided hemiparesis, ataxia with concordant gait disturbance and incoordination of the left upper limb. DWI-MRI showed acute multiple infarcts in both cerebral and cerebellar hemispheres. Laboratory examination, 24-h Holter electrocardiography and transthoracic echocardiography provided no pathological findings. Further examination revealed an arterially fail-implanted port catheter, placed in the left subclavian artery with its tip overlying the ascending aorta, as the source of cerebral embolism.

Conclusion

This is the first case report of thromboembolic, cerebral infarction due to a misplaced venous port catheter in the subclavian artery, emphasizing the imperative need for a thorough diagnostic workup, when embolism is suspected but cannot be proven at first glance.

Brain Injury in Extracorporeal Membrane Oxygenation: A Multidisciplinary Approach

Extracorporeal membrane oxygenation (ECMO) represents an established technique to provide temporary cardiac and/or pulmonary support. ECMO, in veno-venous, veno-arterial or in extracorporeal carbon dioxide removal modality, is associated with a high rate of brain injuries. These complications have been reported in 7 to 15% of adults and 20% of neonates, and are associated with poor survival. Thromboembolic events, loss of cerebral autoregulation, alteration of the blood-brain barrier, and hemorrhage related to anticoagulation represent the main causes of severe brain injury during ECMO. The most frequent forms of acute neurological injuries in ECMO patients are intracranial hemorrhage (2-21%), ischemic stroke (2-10%), seizures (2-6%), and hypoxic-ischemic brain injury; brain death may also occur in this population. Other frequent complications are infarction (1-8%) and cerebral edema (2-10%), as well as neuropsychological and psychiatric sequelae, including posttraumatic stress disorder.

Postoperative cerebral air embolism with delayed abnormal brain MRI findings

Cerebral air embolism (CAE) is a rare but well-known complication resulting from invasive medical procedures; however, previous studies have not examined the postoperative longitudinal MRI changes in CAE. In particular, the likelihood that such changes may be observed after an initial delay when using magnetic resonance imaging (MRI) has not been explored. We herein report a case of CAE with no MRI abnormalities 4 h after a pulmonary vein isolation (PVI) procedure and where the first abnormality was found 22 h after the procedure. A 65-year-old man underwent PVI for paroxysmal atrial fibrillation and showed no signs of recovery from anesthesia after the procedure; thus, he was transferred to our emergency department for further examination. Neurological examination revealed conjugate eye deviation to the right and quadriplegia. Although initial computed tomography (CT) and MRI revealed no abnormalities, CAE was suspected, and a high-concentration oxygen treatment was administered. MRI performed 22 h after the procedure revealed restricted diffusion affecting the cortical areas. At the same day, he was transferred for hyperbaric‑oxygen chamber treatment. After 7 days of treatment, the patient recovered clinically and neurologically. He regained consciousness and was able to communicate. As suggested by this case, CT and MRI findings may fail to reveal CAE abnormalities initially. In such cases, as urgent treatment is necessary, it is important to consider diagnosing CAE based on the patient's history and administering a high concentration of oxygen. Finally, to reach a correct diagnosis, repeated brain MRI should be considered for patients with suspected CAE.

Iatrogenic cerebral gas embolism-A systematic review of case reports

BACKGROUND

Cerebral gas embolism is a complication of several medical procedures and occurs when gas enters the cerebral circulation. Knowledge about etiology and outcome in affected patients is limited, and prospective trials on management and treatment are hardly feasible. Case reports are therefore an important source of information.

METHODS

A systematic literature search was conducted in June 2016 and May 2018, supplemented by a manual search. Titles and abstracts were systematically assessed for eligibility, followed by full-text screening for included papers. Screening and data extraction were performed independently by two researchers. Cases of cerebral gas embolism due to any iatrogenic cause were included. Criteria for exclusion were: animal studies, non-cerebral localization, extravascular gas only, and non-iatrogenic causes. 264 cases reported in 189 papers were included.

RESULTS

A broad range of procedures leading to iatrogenic cerebral gas embolism (ICGE) were identified and a comprehensive list is presented in this article. Procedures were mostly reported as conducted correctly, but procedure related error, patient activity, or defective equipment were also reported as causes. Neurological, neuropsychological, and cardiopulmonary symptoms were common. The diagnosis was frequently based on or confirmed by radiology, usually CT. Hyperbaric oxygen therapy was applied in a large number of cases.

CONCLUSION

The reported causes, symptoms and signs, and outcomes of ICGE vary significantly, and awareness of the condition in the medical community is essential. A standardized method of reporting could facilitate higher quality research in the field.

A Case of Massive Cerebral Arterial Air Embolism Induced by Artificial Pneumothorax and Its Analysis

OBJECTIVE

This study aimed to investigate the characteristics of cerebral arterial air embolism.

CLINICAL PRESENTATION AND INTERVENTION

The clinical data of a patient with cerebral arterial air embolism induced during artificial pneumothorax were retrospectively analyzed. The patient needed the induction of artificial pneumothorax for medical thoracoscopy but developed hemiplegia and disturbance of consciousness during the induction. Cerebral arterial air embolism was detected by head computed tomography.

CONCLUSION

Artificial pneumothorax may induce cerebral arterial air embolism.

Catheter-associated venous air embolism in hospitalized horses: 32 cases

Background

Venous air embolism is a potentially life‐threatening complication of IV catheter use in horses. Despite widespread anecdotal reports of their occurrence, few cases have been reported in the literature and the prognosis is currently unknown.

Hypothesis/Objectives

Our objective was to describe the surrounding circumstances, clinical signs, treatment, progression, and outcome of venous air embolism in hospitalized horses.

Animals

Thirty‐two horses with acute onset of compatible clinical signs associated with IV catheter disconnection or damage.

Methods

Multicenter retrospective study. Data extracted from clinical records included signalment, presenting complaint, catheter details, clinical signs, treatments, and outcome.

Results

Most cases resulted from extension set disconnection occurring within approximately 24 hours after catheter placement. In fewer horses, extension set damage was cited as a cause. Common clinical signs included tachycardia, tachypnea, recumbency, muscle fasciculations and agitation, with abnormal behavior including kicking and flank biting. Less commonly, pathological arrhythmias or more severe neurologic signs, including blindness and seizures, were noted. Progression was unpredictable, with some affected horses developing delayed‐onset neurologic signs. Mortality was 6/32 (19%), including 2 cases of sudden death and other horses euthanized because of persistent neurologic deficits. Negative outcomes were more common in horses with recorded blindness, sweating or recumbency, but blindness resolved in 5/8 affected horses.

Conclusions and Clinical Importance

The prognosis for resolution of clinical signs after air embolism is fair, but permanent neurologic deficits or pathologic cardiac arrhythmias can arise. Unpredictable progression warrants close monitoring. Systematic clinic‐based surveillance could provide additional useful information to aid prevention.

Venous air embolism related to the use of central catheters revisited: with emphasis on dialysis catheters

Venous air embolism is a dreaded condition particularly relevant to the field of nephrology. In the face of a favourable, air-to-blood pressure gradient and an abnormal communication between the atmosphere and the veins, air entrance into the circulation is common and can bring about venous air embolism. These air emboli can migrate to different areas through three major routes: pulmonary circulation, paradoxical embolism and retrograde ascension to the cerebral venous system. The frequent undesirable outcome of this disease entity, despite timely and aggressive treatment, signifies the importance of understanding the underlying pathophysiological mechanism and of the implementation of various preventive measures. The not-that-uncommon occurrence of venous air embolism, often precipitated by improper patient positioning during cervical catheter procedures, suggests that awareness of this procedure-related complication among health care workers is not universal. This review aims to update the pathophysiology of venous air embolism and to emphasize the importance of observing the necessary precautionary measures during central catheter use in hopes of eliminating this unfortunate but easily avoidable mishap in nephrology practice.

Air Embolism: Diagnosis, Clinical Management and Outcomes

Air embolism is a rare but potentially fatal complication of surgical procedures. Rapid recognition and intervention is critical for reducing morbidity and mortality. We retrospectively characterized our experience with air embolism during medical procedures at a tertiary medical center. Electronic medical records were searched for all cases of air embolism over a 25-year period; relevant medical and imaging records were reviewed. Sixty-seven air embolism cases were identified; the mean age was 59 years (range, 3–89 years). Ninety-four percent occurred in-hospital, of which 77.8% were during an operation/invasive procedure. Vascular access-related procedures (33%) were the most commonly associated with air embolism. Clinical signs and symptoms were related to the location the air embolus; 36 cases to the right heart/pulmonary artery, 21 to the cerebrum, and 10 were attributed to patent foramen ovale (PFO). Twenty-one percent of patients underwent hyperbaric oxygen therapy (HBOT), 7.5% aspiration of the air, and 63% had no sequelae. Mortality rate was 21%; 69% died within 48 hours. Thirteen patients had immediate cardiac arrest where mortality rate was 53.8%, compared to 13.5% (p = 0.0035) in those without. Air emboli were mainly iatrogenic, primarily associated with endovascular procedures. High clinical suspicion and early treatment are critical for survival.

Cerebral Air Embolism: A Clinical, Radiologic and Histopathologic Correlation

Cerebral air embolism is a recognized life-threatening complication, sometimes iatrogenic. Its timely diagnosis is essential because it can result in neurologic deficits or death. We report a case of a 58-year-old man who died from cerebral air embolism diagnosed by nonenhanced computed tomography scan of the head after a cardiac bypass surgery with Biventricular Assist Device and multiple vascular line placements. Autopsy revealed extensive subcutaneous emphysema, intravascular and perivascular air bubbles in the central nervous system and associated cerebral and cerebellar hemorrhagic infarction. The autopsy was helpful in documenting the extent of the air embolism and its appearance in soft tissue and central nervous system.

Fatal Cerebral Air Embolism: A Case Series and Literature Review

Cerebral air embolism (CAE) is an infrequently reported complication of routine medical procedures. We present two cases of CAE. The first patient was a 55-year-old male presenting with vomiting and loss of consciousness one day after his hemodialysis session. Physical exam was significant for hypotension and hypoxia with no focal neurologic deficits. Computed tomography (CT) scan of head showed gas in cerebral venous circulation. The patient did not undergo any procedures prior to presentation, and his last hemodialysis session was uneventful. Retrograde rise of venous air to the cerebral circulation was the likely mechanism for venous CAE. The second patient was a 46-year-old female presenting with fever, shortness of breath, and hematemesis. She was febrile, tachypneic, and tachycardic and required intubation and mechanical ventilation. An orogastric tube inserted drained 2500 mL of bright red blood. Flexible laryngoscopy and esophagogastroduodenoscopy were performed. She also underwent central venous catheter placement. CT scan of head performed the next day due to absent brain stem reflexes revealed intravascular air within cerebral arteries. A transthoracic echocardiogram with bubble study ruled out patent foramen ovale. The patient had a paradoxical CAE in the absence of a patent foramen ovale.

Republished: Paradoxical cerebral air embolism causing large vessel occlusion treated with endovascular aspiration

Cerebral air embolism is a dreaded complication of invasive medical procedures. The mainstay of therapy for patients with cerebral air embolism has been hyperbaric oxygen therapy, high flow oxygen therapy, and anticonvulsants. We present a novel therapeutic approach for treatment of cerebral air embolism causing large vessel occlusion, using endovascular aspiration. Our patient developed a cerebral air embolism following sclerotherapy for varicose veins. This caused near total occlusion of the superior division of the M2 segment of the right middle cerebral artery. Symptoms included unilateral paralysis, unintelligible speech, and hemianopia; National Institutes of Health Stroke Scale (NIHSS) on presentation was 16. The air embolism was treated using a distal aspiration technique. Angiography following aspiration showed Thrombolysis in Cerebral Infarction 2B reperfusion. Following aspiration, the patient was re-examined; NIHSS at that time was 4. At 1 month follow-up, the modified Rankin Scale score was 1 and NIHSS was 1. Treatment of cerebral air embolism is discussed.

Paradoxical cerebral air embolism causing large vessel occlusion treated with endovascular aspiration

Cerebral air embolism is a dreaded complication of invasive medical procedures. The mainstay of therapy for patients with cerebral air embolism has been hyperbaric oxygen therapy, high flow oxygen therapy, and anticonvulsants. We present a novel therapeutic approach for treatment of cerebral air embolism causing large vessel occlusion, using endovascular aspiration. Our patient developed a cerebral air embolism following sclerotherapy for varicose veins. This caused near total occlusion of the superior division of the M2 segment of the right middle cerebral artery. Symptoms included unilateral paralysis, unintelligible speech, and hemianopia; National Institutes of Health Stroke Scale (NIHSS) on presentation was 16. The air embolism was treated using a distal aspiration technique. Angiography following aspiration showed Thrombolysis in Cerebral Infarction 2B reperfusion. Following aspiration, the patient was re-examined; NIHSS at that time was 4. At 1 month follow-up, the modified Rankin Scale score was 1 and NIHSS was 1. Treatment of cerebral air embolism is discussed.