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Background: Very few studies have examined the association between contrast-enhanced computed tomography (CT) findings observed in portal venous gas (PVG) and pneumatosis intestinalis (PI) and the underlying diseases in these conditions., Objectives: In this study, we analyzed this association and report the findings for predicting mortality., Materials and Methods: Overall, 50 patients diagnosed with PVG or PI, observed on contrast-enhanced CT, underwent treatment at our hospital. Based on the underlying disease, we divided the patients into three groups, those with ischemic disease, infectious disease, or gastrointestinal dilatation. Furthermore, cases that underwent surgical treatment or needed surgery but were inoperable were assigned to the high risk group (n=16) and patients who received conservative treatment were assigned to the low risk group (n=34). We reviewed the patients' medical charts, laboratory data, and CT images retrospectively, and analyzed the relationship between CT findings, underlying disease, and association with the high risk or low risk group in each case., Results: Poor enhancement of the intestinal wall, mesenteric fat stranding, extrahepatic PVG, advanced age, and renal disease were significantly associated with ischemic disease (p=0.02, p=0.02, p=0.005, p=0.008 and p=0.049, respectively). PI alone was strongly associated with gastrointestinal dilatation (p=0.009). Patients in the low risk group had more favorable outcomes with conservative treatment. In multivariate analysis, extrahepatic PVG was the only factor associated with the high risk group (p=0.002)., Conclusion: Extrahepatic PVG associated with ischemic disease was the strongest predictive factor of mortality. Other CT findings, though useful in diagnosing the underlying disease, were not significant predictive factors.

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 CO 2 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.

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 (CHA 2 DS 2 -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., (© 2023. The Author(s).)

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., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Azarang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

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.

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., (Copyright © 2022 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

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., (© 2022. The Author(s).)

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., (Copyright © 2022 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2021 Elsevier Inc. All rights reserved.)

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., (© 2021. The Author(s).)

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.

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.

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.

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., (Copyright © 2019 Elsevier Inc. All rights reserved.)

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-1β (IL-1β), 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-1β, 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., (Copyright © 2019. Published by Elsevier Inc.)

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.

Introduction: Arterial gas embolism (AGE) is a rare but severe complication of scuba diving. While AGE is most commonly encountered in coastal areas with high volumes of recreational divers, at-risk populations exist throughout the United States, making basic knowledge of the disease important for all emergency medicine (EM) physicians., Methods: We used a hypothetical simulation case to train EM residents on diagnosis and management of AGE. A 32-year-old male presented with shortness of breath and unilateral neurologic deficits immediately after scuba diving. Residents were challenged to emergently diagnose and treat tension pneumothorax followed by diagnosis and treatment of AGE. A resident, attending, and simulation technician ran the case for four separate simulation teams in the simulation center with the addition of chest tube supplies to the basic resuscitation bay setup. Teams were allowed to use the internet in real time as a reference tool., Results: Most teams arrived at the correct diagnosis using real-time internet searches, but none found the Divers Alert Network Emergency Hotline. Learners were debriefed both immediately and in a formal lecture. A follow-up survey showed good retention of knowledge., Discussion: This case fills a significant knowledge and training gap for many EM physicians. AGE is a rare but highly morbid complication of diving, and EM residents should have knowledge of the disease and available consultation resources. Most EM residents will not have the opportunity to treat a diver during training, and the simulation environment provides a means to teach and practice this skill set., Competing Interests: None to report.

Ultrasonography (US) is believed to be the most available method of detecting hepatic portal venous gas (HPVG) with real-time imaging capability. Hepatic portal venous gas has characteristic image appearances in various ultrasound modes such as bright mode, Doppler mode, and even motion (M) mode. In this article, we give a comprehensive review of the image appearances of HPVG among different modes of US with a special focus on the M mode US. Hepatic portal venous gas was recognized as linear echogenicities in various oblique directions (the meteor shower sign) on the M mode US. This specific sign may expand some potential of HPVG detection by US.

Cerebral arterial gas embolism (CAGE) shows various manifestations according to the quantity of gas and the brain areas affected. The symptoms range from minor motor weakness, headache, and confusion to disorientation, convulsions, hemiparesis, unconsciousness, and coma. A 46-year-old man was transferred to our emergency department due to altered sensorium. Immediately after a controlled ascent from 33 m of seawater, he complained of shortness of breath and rigid extremities, lapsing into unconsciousness. He was intubated at another medical center, where a brain computerized axial tomography scan showed no definitive abnormal findings. Pneumothorax and obstructing lesions were apparent in the left thorax of the computed tomography scan. Following closed thoracostomy, we provided hyperbaric oxygen therapy (HBOT) using U.S. Navy Treatment Table (USN TT) 6A. A brain magnetic resonance imaging diffusion image taken after HBOT showed acute infarction in both middle and posterior cerebral arteries. We implemented targeted temperature management (TTM) to prevent worsening of cerebral function in the intensive care unit. After completing TTM, we repeated HBOT using USN TT5 and started rehabilitation therapy. He fully recovered from the neurological deficits. This is the first case of CAGE treated with TTM and consecutive HBOTs suggesting that TTM might facilitate salvage of the penumbra in severe CAGE.

Perforation of a peptic ulcer into the ventricle is uncommon, and the definitive diagnosis is difficult in living patients. We herein report a case of perforation of a peptic ulcer in a hiatal hernia into the left ventricle with systemic air and food embolism. This is the first case report of the perforation diagnosed by computed tomography and confirmed by autopsy. Computed tomography was useful for the diagnosis of perforation into the ventricle.

Rationale: Although venous air embolism (VAE) during liver operation has been reported occasionally, fatal VAE in hepatic resection is uncommon. Prompt detection of VAE by transesophageal echocardiography (TEE) is crucial for effective therapy. We describe a case of fatal VAE that caused repeated cardiac arrest during hepatic resection and was confirmed by TEE., Patient Concerns: A 51-year-old woman with a body weight of 50 kg underwent partial liver resection due to intrahepatic duct calculus. She had a 1-year history of intrahepatic duct calculus without cardiopulmonary disease. The operation was performed under general anesthesia combined with epidural block. When the inferior vena cava was compressed, the PetCO2 level decreased abruptly from 30 to 10 mmHg, followed by a decrease in SpO2 and the development of hypotension. Her heart rate increased with ST interval elevation on electrocardiography monitoring. Ephedrine and phenylephrine were administered immediately but had little effect. Cardiac arrest occurred., Diagnoses: Air embolism was detected by TEE., Interventions: Resuscitation was successful although cardiac arrest occurred repeatedly., Outcomes: The patient returned to consciousness 6 hours postoperatively but died of multiorgan dysfunction 10 days later., Lessons: Fatal air embolism may happen during hepatic resection. Prompt detection of VAE by TEE is crucial for effective therapy and should always be available during hepatic resection.

OBJECTIVE Surgical simulation has the potential to supplement and enhance traditional resident training. However, the high cost of equipment and limited number of available scenarios have inhibited wider integration of simulation in neurosurgical education. In this study the authors provide initial validation of a novel, low-cost simulation platform that recreates the stress of surgery using a combination of hands-on, model-based, and computer elements. Trainee skill was quantified using multiple time and performance measures. The simulation was initially validated using trainees at the start of their intern year. METHODS The simulation recreates intraoperative superior sagittal sinus injury complicated by air embolism. The simulator model consists of 2 components: a reusable base and a disposable craniotomy pack. The simulator software is flexible and modular to allow adjustments in difficulty or the creation of entirely new clinical scenarios. The reusable simulator base incorporates a powerful microcomputer and multiple sensors and actuators to provide continuous feedback to the software controller, which in turn adjusts both the screen output and physical elements of the model. The disposable craniotomy pack incorporates 3D-printed sections of model skull and brain, as well as artificial dura that incorporates a model sagittal sinus. RESULTS Twelve participants at the 2015 Western Region Society of Neurological Surgeons postgraduate year 1 resident course ("boot camp") provided informed consent and enrolled in a study testing the prototype device. Each trainee was required to successfully create a bilateral parasagittal craniotomy, repair a dural sinus tear, and recognize and correct an air embolus. Participant stress was measured using a heart rate wrist monitor. After participation, each resident completed a 13-question categorical survey. CONCLUSIONS All trainee participants experienced tachycardia during the simulation, although the point in the simulation at which they experienced tachycardia varied. Survey results indicated that participants agreed the simulation was realistic, created stress, and was a useful tool in training neurosurgical residents. This simulator represents a novel, low-cost approach for hands-on training that effectively teaches and tests residents without risk of patient injury.

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., (Copyright © 2018 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Mesenteric ischaemia is relatively uncommon, but is an important diagnosis to remember as it can lead to significant morbidity and mortality. Improvements in clinical imaging technology have made rapid diagnosis and treatment possible, but this relies on awareness of the condition. This article summarizes current best practice in diagnosis and management of mesenteric ischaemia to guide the clinician.

Background: Cerebral air embolism is a rare cause of cerebral infarction. In cerebral air embolism, T2 star-weighted imaging shows numerous spotty hypointense signals. Previous reports have suggested that these signals represent air in the brain and are gradually diminished and absorbed. We experienced two cases of cerebral air embolism, and in one of them, we conducted an autopsy., Case Presentation: Case 1 was a 76-year-old Japanese man with lung cancer and emphysema. A spasmodic cough induced massive cerebral and cardiac air embolisms and the patient died because of cerebral herniation. T2 star-weighted imaging of brain magnetic resonance imaging showed multiple spotty low signals. Brain autopsy showed numerous spotty hemorrhagic infarcts in the area of T2 star-weighted imaging signals. Case 2 was an 85-year-old Japanese man with emphysema who suffered from acute stroke. Similar spotty T2 star-weighted imaging signals were observed and remained unchanged 2 months after the onset., Conclusions: These findings indicate that T2 star-weighted imaging in cerebral air embolism partially represents micro-hemorrhagic infarction caused by air bubbles that have migrated into the brain.

During a period of 1 month, 3 episodes of probable or actual venous air embolism occurred during hysteroscopic surgery. All patients developed the same symptoms of ventilatory and hemodynamic decompensation, beginning with a reduction in end-tidal carbon dioxide, arterial desaturation, and cyanosis on the upper trunk, and rapidly progressed to hypotension and 2 cardiac arrests. While entrainment of some air is common during hysteroscopy, life-threatening embolism is a rare but serious complication for which an anesthetist needs to be vigilant and prepared. If even a small drop in end-tidal carbon dioxide occurs, venous air embolism should be suspected and the operation should be discontinued.

Background: Cerebral venous air embolism is a severe clinical condition related to an unfavourable outcome in patients with neurological impairment. Cerebral venous air embolism may occur secondarily to arterial or venous interventions. A rare mechanism of cerebral venous air embolism is retrograde embolism, which is characterized by gas flow in a direction that is opposite to that of the normal blood flow., Case Report: A 69-year-old female was admitted to our hospital with shortness of breath and abdominal pain. Abdominal computed tomography revealed intramural gas in the bowel and free gas in the mesenteric veins and portal vein. Cranial computed tomography, which was performed due to impaired consciousness, demonstrated cerebral air embolism with the appearance of a gyriform pattern. A bedside echocardiography and chest computed tomography revealed no evidence of right-to-left shunt., Conclusion: Cerebral venous air embolism may occur after pneumatosis intestinalis by a retrograde flow of air from the mesenteric veins and portal vein. Low cardiac output and supine position are contributing factors for a retrograde flow of air bubbles into the venous circulation of the brain.

BACKGROUND Carbon dioxide (CO2) is believed to be the safest gas for laparoscopic surgery, which is a standard procedure. We experienced severe cerebral infarction caused by paradoxical CO2 embolism during laparoscopic liver resection with injury of the hepatic vessels despite the absence of a right-to-left systemic shunt. CASE REPORT A 60-year-old man was diagnosed with hepatocellular carcinoma in the right hepatic lobe secondary to alcoholic liver disease. We planned the laparoscopy-assisted liver resection. During the surgery, the root of the right hepatic vein was injured. A 1.5-cm hole was accidentally made in the right hepatic vein, while mobilizing the right hepatic lobe laparoscopically. End-tidal CO2 dropped from 39 to 15.5 mmHg, and systemic blood pressure dropped from 121 to 45 mmHg, returning to normal with the administration of inotropes. The transesophageal echocardiography revealed numerous bubbles in the left atrium and ventricle. The Bispectral Index monitoring system showed low brain activity, suggesting cerebral infarction due to paradoxical gas embolism. The hepatectomy was completed by conversion to open laparotomy. The patient went into a coma and suffered quadriplegia after surgery, despite the cooling of his head and the administration of Thiamylal. Brain MRI revealed cerebral infarction in the broad area of the cerebral cortex right side predominantly, with poor blood flow confirmed by the brain perfusion single-photon emission CT. Rehabilitation was gradually achieved with Botox injections. CONCLUSIONS Cerebral infarction by paradoxical gas embolism is a rare complication in laparoscopic surgery, but it is important to be aware of the risk and to be prepared to treat it.

Introduction: Important developments in the diagnosis of scuba diving fatalities have been made thanks to forensic imaging tool improvements. Multi-detector computed tomography (MDCT) permits reliable interpretation of the overall gaseous distribution in the cadaver. However, due to post-mortem delay, the radiological interpretation is often doubtful because the distinction between gas related to the dive and post-mortem decomposition artifactual gases becomes less obvious., Methods: We present six cases of fatal scuba diving showing gas in the heart and other vasculature. Carbon dioxide (CO₂) in cardiac gas measured by gas chromatography coupled to thermal conductivity detection were employed to distinguish decomposition from embolism based on the detection of decomposition gases (hydrogen, hydrogen sulfide and methane) and to confirm arterial gas embolism (AGE) or post-mortem offgasing diagnoses. A Radiological Alteration Index (RAI) was calculated from the scan., Results: Based on the dive history, the intra-cadaveric gas was diagnosed as deriving from decomposition (one case, minimal RAI of 61), post-mortem decompression artifacts (two cases, intermediate RAI between 60 and 85) and barotrauma/AGE (three cases, maximal RAI between 85 and 100), illustrating a large distribution inside the bodies., Conclusion: MDCT scans should be interpreted simultaneously with compositional analysis of intra-cadaveric gases. Intra-cadaveric gas sampling and analysis may become useful tools for understanding and diagnosing scuba diving fatalities. In cases with short post-mortem delays, the CO₂ concentration of the cardiac gas provides relevant information about the circumstances and cause of death when this parameter is interpreted in combination with the diving profile.

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., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Foreign bodies in the heart are rare occurrences with a limited evidence base to guide recommendations on management. We report a case of multiple cardioembolic strokes as a result of a self-inflicted sewing needle puncture from the anterior chest through the right ventricle and interventricular septum with its tip in the left ventricle close to the subvalvular apparatus in a 39-year-old psychiatric patient. We discuss issues surrounding decision making and ongoing care and highlight the importance of further follow-up and reporting of cases to form a robust evidence base to guide future recommendations., (© 2017, Wiley Periodicals, Inc.)

The term nonthrombotic pulmonary embolism (NTPE) is defined as embolization of pulmonary arteries caused by foreign bodies (e. g. detached catheter fragments), biological substances (e. g. septic thrombus) or exogenous substances (e. g. gas). The frequency of NTPE is underestimated. Symptoms can cover the spectrum from undetectable to sudden death. In addition to mechanical obstruction of the pulmonary arteries, some NTPEs trigger an inflammatory cascade that causes deterioration of vascular, pulmonary and cardiac function. Radiological imaging in combination with the medical history of patients is sufficient to identify most NTPEs with certainty. The aim of this article is to make readers aware of the symptoms, frequency, relevance, classification, pathophysiology, laboratory findings and radiological findings of the most frequent forms of NTPE. The spectrum of forms presented here includes pulmonary embolisms due to foreign bodies (intravascular, intracorporeal and extracorporeal), amniotic fluid, endogenous tissue, fat, tumors, septic thrombi, hydatids, cement, metallic mercury, gas, silicone and particles.

Context: It has been widely believed that tissue nitrogen uptake from the lungs during breath-hold diving would be insufficient to cause decompression stress in humans. With competitive free diving, however, diving depths have been ever increasing over the past decades., Methods: A case is presented of a competitive free-diving athlete who suffered stroke-like symptoms after surfacing from his last dive of a series of 3 deep breath-hold dives. A literature and Web search was performed to screen for similar cases of subjects with serious neurological symptoms after deep breath-hold dives., Case Details: A previously healthy 31-y-old athlete experienced right-sided motor weakness and difficulty speaking immediately after surfacing from a breathhold dive to a depth of 100 m. He had performed 2 preceding breath-hold dives to that depth with surface intervals of only 15 min. The presentation of symptoms and neuroimaging findings supported a clinical diagnosis of stroke. Three more cases of neurological insults were retrieved by literature and Web search; in all cases the athletes presented with stroke-like symptoms after single breath-hold dives of depths exceeding 100 m. Two of these cases only had a short delay to recompression treatment and completely recovered from the insult., Conclusions: This report highlights the possibility of neurological insult, eg, stroke, due to cerebral arterial gas embolism as a consequence of decompression stress after deep breath-hold dives. Thus, stroke as a clinical presentation of cerebral arterial gas embolism should be considered another risk of extreme breath-hold diving.

Air embolism is often an iatrogenic complication which may occur in venous or arterial circulation depending on the port of entry. We present two cases in which air embolism occurred in venous and arterial circulation after contrast medium injection (CMI) and coronary artery bypass graft (CABG) surgery, respectively. In one case, accumulation of air bubbles was observed in the pulmonary artery after CMI. This was attributed to inadvertent injection of air owing to improper connection of the injector and the catheter. The patient was managed with 100% oxygen in the Trendelenburg and left lateral decubitus position. Repeat imaging demonstrated resorption of the emboli. In another case, air was introduced during CABG in the left atrium and ventricle. Immediate suction of air was attempted however, the patient developed cardiogenic shock requiring vasopressors, and subsequently seizures and coma due to diffuse ischaemic stroke. The patient eventually expired., Competing Interests: Conflicts of Interest: None declared., (2016 BMJ Publishing Group Ltd.)

A 54-year-old caucasian male developed bilateral blindness during an oxygen-ozone injection for disc herniation. The visual loss (VL) was immediately followed by severe frontal headache, vomiting, and nausea. The patient underestimated the VL showing Anton's syndrome, with a complete visual recovery after 2-month follow-up. Magnetic resonance data were consistent with recent ischemic lesions in bilateral vascular territories of posterior cerebral arteries.

Background: Vascular air embolism is a rare but potentially deadly phenomenon. Early diagnosis allows providers to initiate measures aimed at preventing further air entry, preventing the migration of air to the lungs, and mitigating the hemodynamic effects of pulmonary air embolism., Case Report: An emergency physician used point-of-care ultrasound to identify intravascular air before embolization to the pulmonary vasculature. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Bedside ultrasound can be used as a tool for early diagnosis of intravascular air. Emergency physicians should be aware of the typical sonographic manifestations of intravascular air and the initial steps in treating vascular air embolism., (Copyright © 2016 Elsevier Inc. All rights reserved.)