[Air embolism after biliary stent removal during endoscopic retrograde cholangiopancreatography for cholangitis after biliary reconstruction: a case report].

A 62-year-old male patient underwent pancreaticoduodenectomy with modified Child reconstruction for distal cholangiocarcinoma. After eight years, a contrast-enhanced computed tomography (CT) revealed a recurrent lesion at the biliojejunal anastomosis, and a biliary stent was placed for obstructive cholangitis in the right posterior segment of the liver. A right hepatectomy was planned for a local recurrent lesion;thus, percutaneous transhepatic portal embolization was performed on the portal vein's right branch to enlarge the left liver. However, he was referred to our department for endoscopic retrograde biliary drainage for the subsequent cholangitis and liver abscess appearance. A double-balloon enteroscope under CO2 insufflation was used to reach the bile duct-jejunal anastomosis. After removing the bile duct stent with grasping forceps, his general condition suddenly deteriorated, causing cardiopulmonary arrest. He was diagnosed with air embolism based on the findings of air in the heart, aorta, and brain on CT after the return of spontaneous circulation. Treatment for the air embolism and subsequent complications continued in the intensive care unit, but he eventually died 114 days after the onset of the air embolism due to his deteriorating general condition. Pathological autopsy revealed cholangiocarcinoma that extends from the porta hepatis to the posterior segment. Additionally, the proximity between the bile duct and vein extended by the adenocarcinoma and the fibrous obstruction of the vein were revealed, indicating the possibility of a bile duct-vein shunt.

Pulmonary vein perforation into the respiratory tract with systemic air embolism: a rare complication of left atrial appendage closure.

BACKGROUND: Pulmonary vein perforation is an uncommon complication during cardiac intervention. We present a rare case of pulmonary vein perforation into the respiratory tract with systemic air embolism during left atrial appendage closure (LAAC). CASE PRESENTATION: A 77-year-old man with persistent nonvalvular atrial fibrillation was referred for percutaneous LAAC under local anaesthesia (CHA2DS2-VASc score of 4, HAS-BLED score of 3, and prior ischaemic stroke). During the procedure, after delivering a super-stiff guidewire into the left superior pulmonary vein (LSPV), the patient suddenly developed a severe cough with haemoptysis upon advancement of a delivery sheath along the guidewire. Fluoroscopy showed signs of blood entering the left main bronchus, and fast transthoracic echocardiography revealed bubbles in the left heart without pericardial effusion. The procedure was terminated because of a major complication indicated by the repeated haemoptysis and headache, and haemostatic drugs were immediately administered. Subsequent chest computed tomography angiography (CTA) revealed a filling defect in the LSPV branches and bubbles in the aorta. The patient was transferred to the critical care unit for haemostasis and antibacterial treatment. Transthoracic echocardiography later that day showed no bubbles in the heart. The headache and haemoptysis significantly abated the following day. The bubbles in the aorta disappeared on chest CTA 7 days later. CONCLUSIONS: Interventional cardiologists should pay attention to anatomical variations of the pulmonary vein, which are associated with a high risk of complications of pulmonary vein perforation during LAAC. Preoperative CTA examination and intraoperative transoesophageal echocardiography might be helpful to avoid this complication.

Development of a graphical user interface for automatic separation of human voice from Doppler ultrasound audio in diving experiments.

Doppler ultrasound (DU) is used in decompression research to detect venous gas emboli in the precordium or subclavian vein, as a marker of decompression stress. This is of relevance to scuba divers, compressed air workers and astronauts to prevent decompression sickness (DCS) that can be caused by these bubbles upon or after a sudden reduction in ambient pressure. Doppler ultrasound data is graded by expert raters on the Kisman-Masurel or Spencer scales that are associated to DCS risk. Meta-analyses, as well as efforts to computer-automate DU grading, both necessitate access to large databases of well-curated and graded data. Leveraging previously collected data is especially important due to the difficulty of repeating large-scale extreme military pressure exposures that were conducted in the 70-90s in austere environments. Historically, DU data (Non-speech) were often captured on cassettes in one-channel audio with superimposed human speech describing the experiment (Speech). Digitizing and separating these audio files is currently a lengthy, manual task. In this paper, we develop a graphical user interface (GUI) to perform automatic speech recognition and aid in Non-speech and Speech separation. This constitutes the first study incorporating speech processing technology in the field of diving research. If successful, it has the potential to significantly accelerate the reuse of previously-acquired datasets. The recognition task incorporates the Google speech recognizer to detect the presence of human voice activity together with corresponding timestamps. The detected human speech is then separated from the audio Doppler ultrasound within the developed GUI. Several experiments were conducted on recently digitized audio Doppler recordings to corroborate the effectiveness of the developed GUI in recognition and separations tasks, and these are compared to manual labels for Speech timestamps. The following metrics are used to evaluate performance: the average absolute differences between the reference and detected Speech starting points, as well as the percentage of detected Speech over the total duration of the reference Speech. Results have shown the efficacy of the developed GUI in Speech/Non-speech component separation.

An unusual case of neurocardiogenic syncope: A case report and systematic review.

We present a case of syncopal episode in emergency department (ED) and subsequent admission to the geriatric assessment unit. The patient presented with self-limiting central abdominal pain. Given a history of previous aortic aneurysm repair, a contrast CT angiogram was performed. With no evidence of leaking aneurysm, the patient was discharged from the ED. The syncopal episode happened while waiting for a taxi. A review of the earlier CT scan showed the presence of air in the venous circulatory system. In hindsight, it was thought the syncopal episode occurred due to air embolism introduced during or shortly after venous cannulation. We discuss the aetiology of venous air embolism and highlight the lack of evidence regarding tolerable amounts of air in the circulatory system. Physiological changes associated with age may suggest that elderly patients are uniquely maladapted to overcome sudden insults to their cardiovascular status.

Complications After Transthoracic Needle Biopsy of Pulmonary Nodules: A Population-Level Retrospective Cohort Analysis.

OBJECTIVE: To provide recent population-based estimates of transthoracic needle biopsy (TTNB) complications and risk factors associated with these complications. METHODS: This retrospective cohort analysis included adults from a nationally representative longitudinal insurance claims data set who underwent TTNB in 2017 or 2018. Complications that were evaluated included pneumothorax, hemorrhage, and air embolism. Separate logistic regression models estimated the association of pneumothorax or hemorrhage with the setting of care (ie, inpatient or outpatient) and selected baseline patient demographic and clinical characteristics including age, gender, history of chronic obstructive pulmonary disease, diagnosis of pleural effusion, tobacco use, use of oral anticoagulants and antiplatelet agents, prior lung cancer screening, previous bronchoscopy within 1 year, and Elixhauser comorbidity index. RESULTS: Among 16,971 patients who underwent TTNB, 25.8% experienced a complication within 3 days of the procedure (pneumothorax 23.3%, hemorrhage 3.6%, and air embolism 0.02%). Among patients who experienced pneumothorax, 31.9% required chest tube drainage. Among patients undergoing an outpatient TTNB (n = 12,443), 6.9% were hospitalized within 7 days. Biopsy in an inpatient setting, chronic obstructive pulmonary disease diagnosis, and prior bronchoscopy were associated with higher rates of both pneumothorax and hemorrhage. Prior lung cancer screening was associated with an increased risk of pneumothorax, and prior use of oral anticoagulants or antiplatelets was associated with higher rates of hemorrhage. CONCLUSION: This contemporary population-based cohort study demonstrated that approximately one-quarter of patients undergoing TTNB experienced a complication. Pneumothorax was the most frequent complication, and hemorrhage and air embolism were rare. Among outpatients, complications from TTNB are an important cause of hospitalization.

CT Findings of the Massive Air Embolism in a Case with Thoracic Gunshot Wound: A Special Case Report as if a Whole Body Pneumo- Angiography was Performed.

BACKGROUND: Massive Systemic Arterial Air Embolism (SAAE) associated with penetrating trauma is a rare condition. A few cases were reported for massive arterial air embolism in the literature. Computed tomography is a fast and easily accessible modality for detecting air in the vasculature. We report CT findings of a rare case with a thoracic gunshot wound, which demonstrate air almost in all systemic vessels like ''full body pneumoangiography''. CASE PRESENTATION: A 42-year-old male patient with a thoracic gunshot wound was admitted to the Accident and Emergency (A&E) unit in a state of cardiac arrest. Postmortem Computed Tomography (CT) was performed and extensive air was revealed in several great vessels. CONCLUSION: We conclude that the underline causes of massive air embolism in our case are two main mechanisms: firstly, massive air enters the vasculature via bronchovascular fistula as there was bilateral lung contusion and directly through cardiac truncus, secondly while CPR was being conducted, massive air was pumped to the systemic circulation.

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.

Triplegic Stroke After Air Embolism From Bronchogenic Cyst Secondary to Barotrauma.

Emergency medical assistance is rare regarding air travel. Pulmonary barotrauma during air travel can occur in asymptomatic patients who have underlying intraparenchymal pulmonary pathology such as bullae or bronchogenic cysts. During aircraft travel the resultant decrease in pressure during the ascent can lead to expansion of cyst volume, culminating in tears and leakage of air into the surrounding vasculature and thus the potential for air embolism. We describe a case of massive cerebral air embolism secondary to pulmonary barotrauma in a previously asymptomatic patient.

Pneumatosis intestinalis and porto-mesenteric venous gas: a multicenter study.

BACKGROUND: Estimating the prognosis of patients with pneumatosis intestinalis (PI) and porto-mesenteric venous gas (PMVG) can be challenging. The purpose of this study was to refine prognostication to improve decision making in daily clinical routine. METHODS: A total of 290 patients with confirmed PI were included in the final analysis. The presence of PMVG and mortality (90d follow-up) were evaluated with regard to the influence of possible risk factors. Furthermore, a linear estimation model was devised combining significant parameters to calculate accuracies for predicting death in patients undergoing surgery by means of a defined operation point (ROC-analysis). RESULTS: Overall, 90d mortality was 55.2% (160/290). In patients with PI only, mortality was 46.5% (78/168) and increased significantly to 67.2% (82/122) in combination with PMVG (median survival: PI: 58d vs. PI and PMVG: 41d; p < 0.001). In the entire patient group, 53.5% (155/290) were treated surgically with a 90d mortality of 58.8% (91/155) in this latter group, while 90d mortality was 51.1% (69/135) in patients treated conservatively. In the patients who survived > 90d treated conservatively (24.9% of the entire collective; 72/290) PMVG/PI was defined as "benign"/reversible. PMVG, COPD, sepsis and a low platelet count were found to correlate with a worse prognosis helping to identify patients who might not profit from surgery, in this context our calculation model reaches accuracies of 97% specificity, 20% sensitivity, 90% PPV and 45% NPV. CONCLUSION: Although PI is associated with high morbidity and mortality, "benign causes" are common. However, in concomitant PMVG, mortality rates increase significantly. Our mathematical model could serve as a decision support tool to identify patients who are least likely to benefit from surgery, and to potentially reduce overtreatment in this subset of patients.

Portal venous gas in a girl with chronic intestinal pseudoobstruction.

Hepatic portal venous gas (HPVG) is associated with various fatal conditions requiring urgent surgical intervention. In patients with chronic intestinal pseudoobstruction (CIPO), HPVG results from intestinal dilation. CIPO is a condition that is generally not surgically remediable; however, in emergency cases, an operative approach is often considered to prevent additional complications or to restore intestinal propulsion. However, surgery in these patients is associated with high postoperative morbidity and mortality rates and frequent reoperation. Intestinal resection and adhesion formation can potentially worsen the underlying dysmotility and are associated with refractory postoperative ileus, which often requires reoperation. Here, we present a case of HPVG in a patient with chronic intestinal pseudoobstruction (CIPO), treated conservatively and discuss the management of patients with HPCG.

Enhancing vigilance for cerebral air embolism after pneumonectomy: a case report.

BACKGROUND: Vascular air embolism (VAE) is a rare but important complication that has not been paid enough attention to in the medical process such as surgery and anesthesia. CASE PRESENTATION: We report for the first time that a 54-year-old male patient with central lung cancer developed severe complications of CAE after right pneumonectomy. After targeted first-aid measures such as assisted breathing, mannitol dehydration and antibiotic treatment, the patient gradually improved. The patient became conscious at discharge after 25 days of treatment but left limb was left with nerve injury symptoms. CONCLUSION: We analyzed the possible causes of CAE in this case, and the findings from this report would be highly useful as a reference to clinicians.

Potentially fatal complications of systemic air embolism after computed tomography-guided transthoracic needle biopsy in lung cancer harboring epithelial growth factor receptor mutation: A case report.

Air embolism is a rare, fatal complication of computed tomography (CT)-guided transthoracic needle biopsy (TTNB) of the lung. Here, we report a patient who developed an air embolism after CT-guided TTNB, which led to ST-elevation myocardial infarction and acute cerebral ischemia. The patient recovered completely without critical sequelae and was diagnosed with adenocarcinoma harboring activating epidermal growth factor receptor (EGFR) mutation. The patient responded to subsequent treatment with gefitinib. KEY POINTS: SIGNFICANT FINDINGS OF THE STUDY: Air embolism is a rare, fatal complication of CT-guided transthoracic lung biopsy. Only a few cases have been previously reported where myocardial and cerebral infarction occurred after TTNB, demonstrated not only on CT scan, but also electrocardiogram and electroencephalogram. WHAT THIS STUDY ADDS: Detection of driver gene mutation is crucial for planning lung cancer treatment. Despite the need for tissue biopsy, air embolism propagation to vital organs could result in severe end-organ damage and multidisciplinary approaches are needed to improve initial outcomes.

Extensive pneumatosis intestinalis and portal venous gas mimicking mesenteric ischaemia in a patient with SARS-CoV-2.

We present the case of a critically ill 47-year-old man diagnosed with SARS-CoV-2 (COVID-19) who developed extensive pneumatosis intestinalis and portal venous gas in conjunction with an acute abdomen during the recovery phase of his acute lung injury. A non-surgical conservative approach was taken as the definitive surgical procedure; a complete small-bowel resection was deemed to be associated with an unacceptably high long-term morbidity. However, repeat computed tomography four days later showed complete resolution of the original computed tomography findings. Pneumatosis intestinalis from non-ischaemic origins has been described in association with norovirus and cytomegalovirus. To our knowledge, this is the first time that this has been described in COVID-19.

Association of the incidence of venous air embolism on coronary computed tomography angiography with the intravenous access route preparation process.

Venous air embolism (VAE) can be observed in the right heart system on contrast-enhanced computed tomography (CT), following injection of contrast media with a power injector system. Although most VAEs are mostly asymptomatic, they may result in paradoxical air embolism (PAE).To evaluate whether the incidence of VAE on coronary CT angiography is associated with the process of preparation of the intravenous access route.We retrospectively evaluated 692 coronary CT examinations at 3 institutions. Trained CT nurses placed an intravenous cannula in the forearm. Tubes connected to the cannula were prepared in the following ways: A, using an interposed three-way cock and a 20-mL syringe filled with normal saline to collect air contamination in the tube; B, through direct connection to the power injector system without the interposed 3-way cock; and C, using an interposed three-way cock and a 100-mL normal saline drip infusion bottle system to keep the tube patent. The incidence and location of VAE and preparation of intravenous injection were assessed.The overall incidence of VAE was 55.3% (383/692), most frequently observed in the right atrium (81.5%, 312/383). Its incidence varied significantly across the 3 techniques (A: 21.6% (35/162), B: 63.2% (237/375) and C: 71.6% (111/155); P < .001). No patient demonstrated any symptom associated with VAE.Using a 3-way cock with syringe demonstrated the lowest incidence of VAE on coronary CT angiography. It is thus recommended to reduce potential complication risks related to intravenous contrast media injection.

Intraoperative Visible Air Bubbling Recorded as a Sign of Massive Venous Air Embolism During Prone Position Surgery for Extensive Ossification of Spinal Ligaments: A Case Report with a Video Clip.

BACKGROUND: Venous air embolism (VAE) is a rare but, frequently, fatal complication that can occur during surgery. Several reported studies have shown visible bubbling of air at the surgical site as the first clinical indication of VAE-induced cardiovascular collapse during prone-position spine surgery. However, to the best of our knowledge, video imaging of this phenomenon has not been previously reported. CASE DESCRIPTION: A 41-year-old man had undergone cervical laminoplasty for ossification of the posterior longitudinal ligament and thoracic laminectomy for ossification of the posterior longitudinal ligament and ossification of the ligamentum flavum in the prone position. The entire surgery was recorded with video imaging. Before cardiac arrest due to the massive VAE, visible air bubbling had been observed at the operated site of the thoracic laminectomy, and this phenomenon had been incidentally recorded with the video. The patient recovered with cardiopulmonary resuscitation and intensive treatment against severe acute respiratory distress syndrome due to pulmonary damage. CONCLUSIONS: The present case report offers the first video imaging evidence of intraoperative visible air bubbling as a sign of a massive VAE during prone-position spine surgery. To the best of our knowledge, this is also the first report of intraoperative VAE in a patient with extensive ossification of the spinal ligaments.

A case of cardiac arrest due to air embolism during scoliosis surgery.

Cardiac arrest during scoliosis surgery is rare in idiopathic scoliosis. We present a case of cardiorespiratory collapse during corrective surgery in a young patient with idiopathic scoliosis. A diagnosis of venous air embolism was made by exclusion. A cardiorespiratory resuscitation was performed in supine position. Patient recovered without any sequelae and had operation completed 6 weeks later.

Phosphodiesterase-4 Inhibitor Roflumilast Attenuates Pulmonary Air Emboli-Induced Lung Injury.

BACKGROUND: Pulmonary air embolism (PAE)-induced acute lung injury (ALI) can be caused by massive air entry into the lung circulation. PAE can occur during diving, aviation, and some iatrogenic invasive procedures. PAE-induced ALI presents with severe inflammation, hypoxia, and pulmonary hypertension, and it is a serious complication resulting in significant morbidity and mortality. Phosphodiesterase-4 (PDE4) inhibitors can regulate inflammation and are therefore expected to have a therapeutic effect on ALI. However, the effect of the PDE4 inhibitor roflumilast on PAE-induced ALI is unknown. METHODS: The PAE model was undertaken in isolated-perfused rat lungs. Four groups (n = 6 in each group) were defined as follows: control, PAE, PAE + roflumilast 2.5 mg/kg, and PAE + roflumilast 5 mg/kg. Induction of PAE-induced ALI was achieved via the infusion of 0.7 cc air through the pulmonary artery. Roflumilast was administered via perfusate. All groups were assessed for pulmonary microvascular permeability, lung histopathology changes, pulmonary edema (lung weight/body weight, lung wet/dry weight ratio), tumor necrosis factor alpha (TNF-α), interleukin-1ß (IL-1ß), IL-6, IL-17, nuclear factor-kappa B (NF-κB), and inhibitor of NF-κB alpha (IκB-α). RESULTS: After the induction of air, PAE-induced ALI presented with pulmonary edema, pulmonary microvascular hyperpermeability, and lung inflammation with neutrophilic sequestration. The PAE-induced ALI also presented with increased expressions of IL-1ß, IL-6, IL-8, IL-17, TNF-α, and NF-κB and decreased expression of IκB-α. The administration of roflumilast decreased pulmonary edema, inflammation, cytokines, NF-κB, and restored IκB-α level. CONCLUSIONS: PAE-induced ALI presents with lung inflammation with neutrophilic sequestration, pulmonary edema, hyperpermeability, increased cytokine levels, and activation of the NF-κB pathway. Roflumilast attenuates lung edema and inflammation and downregulates the NF-κB pathway and cytokines.