Vascular Air Embolism Research Articles

Vascular Air Embolism During Bronchoscopy Procedures- Incidence, Pathophysiology, Diagnosis, Management and Outcomes.

Vascular air embolism (VAE) is a rare, but potentially fatal complication of invasive medical or surgical procedures. It is a very rare complication of bronchoscopy and is most frequently reported with therapeutic bronchoscopy with Argon plasma coagulation (APC) or neodymium-doped yttrium aluminum garnet (Nd-YAG) laser. Despite being rare, as a result of its high chance of mortality and morbidity, it is imperative that physicians have high clinical suspicion to allow for early recognition and treatment. In this article, we provide a concise review of the incidence, pathophysiology, diagnosis management and outcomes of air embolism during bronchoscopy procedures.

Point-Of-Care Ultrasound Diagnosis of Intravascular Air After Lower Extremity Intraosseous Access

BackgroundVascular 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 ReportAn 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.

Over-catheter tract suture to prevent bleeding and air embolism after tunnelled catheter removal.

Severe, life-threating, complications might occur on dialysis catheter removal. We present a useful technique that may prevent vascular air embolism and severe bleeding. The suture is placed around the catheter and tied over previous tract just after device removal. Applying a compressing suture to the tract left after removal of a tunnelled haemodialysis catheter is a simple manoeuvre that could prevent severe complication.

Intraoperative air embolism during hepatectomy.

Sir, Vascular air embolism (VAE) is a rare and lethal complication of partial hepatectomy with a relative risk of <5%.[1] Even in the absence of intracardiac abnormalities, paradoxical embolism can occur in cirrhotic patients undergoing liver resection because of abnormal arteriovenous communications in the pulmonary circulation.[2] Anaesthetic vigilance along with thorough knowledge of surgical interventions and ensuing physiological perturbations is essential for ensuring patient survival. A 56-year-old female diagnosed with hilar cholangiocarcinoma was posted for extensive right hepatectomy. Clinical examination was normal except for the presence of jaundice with elevated bilirubin and liver enzymes. Anaesthetic technique included general anaesthesia with thoracic epidural block. Electrocardiogram (ECG), oxygen saturation, blood pressure and end-tidal carbon dioxide (ETCO2) were monitored. Left radial artery was cannulated for invasive blood pressure (IBP) monitoring and right internal jugular vein for central venous pressure (CVP), with double lumen 7 Fr central venous catheter (CVC). To reduce the blood loss and transfusion requirements, a low CVP (≈5 mmHg) was targeted. Hepatic resection using cavitron ultrasonic surgical aspirator (CUSA) began after clamping the branches of portal vein and hepatic artery to the right lobe. Three hours into the surgery, surgeon informed accidental opening of a branch of hepatic vein which got retracted into liver parenchyma. Simultaneously, a distinct sucking-in sound was heard, following which IBP dropped to 50/40 mmHg and ETCO2 to 22 mmHg from 34 mmHg while oxygen saturation and CVP (8 mmHg) remained stable. VAE was suspected and nitrous oxide was cut off and the patient ventilated with 100% oxygen. Surgical field was immediately covered with saline-soaked gauze, and then flooded with saline. Resuscitative measures were initiated rapidly with fluid resuscitation, dopamine infusion at 10μg/kg/min and adopting a Trendelenburg position. Aspiration of CVC produced 3 ml of frothy blood. As IBP remained low, epidural infusion was discontinued and a bolus of 50μg adrenaline was administered intravenously. Once vitals stabilised, surgery proceeded with 100% oxygen after giving fentanyl and midazolam. Fifteen minutes later, a second episode of VAE occurred and was accompanied by a fall in oxygen saturation, IBP, ETCO2 and a rise in CVP to 18 mmHg. ECG showed frequent atrial ectopic beats. Dopamine infusion rate was increased and CVC aspirated to obtain 3–4 ml of air. Two more episodes of haemodynamic instability occurred which was treated similarly. At the end of the procedure, her vitals were stable with dopamine support. She was shifted to intensive care unit and was weaned from haemodynamic and ventilator support next day. Factors predisposing to VAE during liver resection include surgical technique, size and site of the tumour, blood loss and low CVP.[3] There are reports of increased incidence and severity of VAE during hepatic resection using CUSA.[4,5] Resection of large tumours situated in the right lobe close to inferior vena cava or the cavo-hepatic junction increases the risk of VAE.[3] Low CVP further enhances the negative pressure gradient and increases the possibility of VAE. Hepatic vascular control using selective hepatic vascular exclusion (SHVE) technique reduces both blood loss and risk of VAE.[3] In our case, site of the tumour, resection using CUSA and lack of SHVE technique along with low CVP anaesthesia all contributed to the incident. Although lethal volume of venous air for adults is about 200–300 ml, the proximity of the entraining vessel to the heart makes even smaller volumes fatal in liver resection.[1,3] Management consists of steps to prevent further entrainment of air and haemodynamic support with inotropic agents.[1,2,3,4] To conclude, both surgeons and anaesthesiologists should be aware of the risk for VAE during hepatectomy and employ appropriate surgical techniques and levels of monitoring to ensure patient safety. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

A Case of Iatrogenic Vascular Air Embolism Treated with Bipap and Nitroglycerin

Vascular air embolisms are very rare but fatal complication of diving and many procedures, mostly central line catheterizations. Treatment is mostly supportive with 100% oxygen and in severe cases, hyperbaric therapy. Recent therapy has shown that nitric oxide can decrease the rate of bubble formation in animal studies after compression. We describe a case of iatrogenic air embolism treated with Bi-level non-invasive positive pressure ventilation (BiPAP) and IV nitroglycerin. This case illustrated the importance of recognizing this rare but potentially fatal syndrome, and the need for further research on the utility of nitroglycerin in the treatment of this syndrome.

A Case of Iatrogenic Vascular Air Embolism Treated with Bipap and Nitroglycerin

Background: There is little scientific data to guide inter-hospital transport of critically ill patients. This leads to practice variation with how providers communicate healthcare information between facilities and inappropriate communication can lead to significant patient harm. We analyzed data used by accepting providers during hospital transfer to form a rational protocol for information exchange. Methods: We conducted a prospective observational study of inter-hospital patient transfers to our medical intensive care unit (ICU). We recorded data that receiving clinicians requested, and whether that information was available upon admission. Following observation, we asked providers to complete a survey indicating whether a data point was useful for clinical decision making for the particular clinical case they had received. We analyzed the relative frequency of data requests and the discordance between available and requested data. Results: Twenty-five physician-patient interactions were observed with 45 surveys completed by critical care providers. On average, 13 data points were utilized for patients with perceived “mild” illness versus 18 data points for patients with “severe” illness. The most requested data were code status (19/25), blood culture status (19/25), and medications administered to the patient (16/25). Other data points identified as useful were past medical history, vital signs, white blood cell count, hemoglobin, lactate, pH, PaCO2 and chest x-ray findings with minimal variability depending on presumed diagnosis (respiratory failure, sepsis or other). Code status (7/19), arterial/venous blood gas (5/12), lactate (4/10), and medical power of attorney (3/5) were the most frequently unavailable data points when requested. Conclusion: Critical care providers use a small number of data points during the inter-hospital admission process, but many of these are frequently unavailable. A formal structured hand off tool is needed to improve information management during inter-hospital transfer. Such a tool must emphasize resuscitation status, critical labs, and ongoing interventions.

Fatal vascular air embolism during fluid resuscitation as a complication of pressure infuser bag.

Fatal vascular air embolism during fluid resuscitation as a complication of pressure infuser bag.

Vascular air embolism after contrast administration on 64 row multiple detector computed tomography: A prospective analysis.

Background:Vascular air embolism is being progressively reported as a nonfatal event with increase in use of computed tomography (CT) as a diagnostic modality. This study was undertaken to study the frequency and site of vascular air embolism in patients undergoing contrast-enhanced CT (CECT) and analyze CT parameters that influence its prevalence and final outcome.Materials and Methods:This was a prospective study approved by departmental ethics committee. Presence and location of air emboli in 200 patients who underwent CT scan of chest on a 64 detector scanner was recorded. We analyzed the role of various factors that could influence the prevalence of air embolism after injection of contrast in CECT scans. These factors included the amount of contrast injected, rate of flow of injection of contrast, site of injection of contrast, and size of intravenous access line.Results:Iatrogenic vascular air emboli were seen in 14 patients (7% of total). The locations of air emboli were main pulmonary artery in 12 (6% of total), left brachiocephalic vein in 3 (1.5% of total), right atrial appendage in 4 (2% of total), and superior vena cava (SVC) in 1 (0.5%) patient. There was no association between volume of contrast, flow rate, site and size of intravenous access, and presence of air emboli.Conclusion:Radiologists as well as referring physicians should be aware of vascular air embolism, which can occur after contrast injection in patients undergoing CT scan. Age, volume of contrast, flow rate of pressure injector, and site and size of venous cannula do not influence the likelihood or incidence of detection of venous air emboli on CT scans.

Pefluorocarbon inhibition of bubble induced Ca2+ transients in an in vitro model of vascular gas embolism

Endothelial injury resulting from deleterious interaction of gas microbubbles occurs in many surgical procedures and other medical interventions. The symptoms of vascular air embolism (VAE), while serious, are often difficult to detect, and there are essentially no pharmaceutical preventative or post-event treatments currently available. Perfluorocarbons (PFCs), however, have shown particular promise as a therapeutic option in reducing endothelial injury both in- and ex-vivo. Recently, we demonstrated the effectiveness of Oxycyte, a third-generation PFC formulated in a phosphotidylcholine emulsion, using an invitro model of VAE developed in our laboratory. This apparatus allows live cell imaging concurrent with precise manipulation of physiologically sized microbubbles so that they may be brought into individual contact with human umbilical vein endothelial cells dye-loaded with the Ca(2+) sensitive Fluo-4. Herein, we expand use of this fluorescence microscopy-based cell culture model. Specifically, we examined the concentration dependence of Oxycyte in reducing both the amplitude and frequency of large intracellular Ca(2+) currents that are both a hallmark of bubble contact and a quantifiable indication that abnormal intracellular signaling has been triggered. We measured dose dependence curves and fit the resultant data using a modified Black and Leff operational model of agonism. The half maximal inhibitory concentrations of Oxycyte for (i) inhibition of occurrence and (ii) amplitude reduction were 229 ± 49 µM and 226 ± 167 µM, respectively. This investigation shows the preferential gas/liquid interface occupancy of the PFC component of Oxycyte over that of mechanosensing glycocalyx components and validates Oxycyte's specific surfactant mechanism of action. Further, no lethality was observed for any concentration of this bioinert PFC, as it acts as a competitive allosteric inhibitor of syndecan activation to ameliorate cell response to bubble contact.

Vascular air embolism

Vascular air embolism is a rare but potentially fatal event. It may occur in a variety of procedures and surgeries but is most often associated as an iatrogenic complication of central line catheter insertion. This article reviews the incidence, pathophysiology, diagnosis, treatment, and prevention of this phenomenon.

Anesthetic Considerations in Hepatectomies under Hepatic Vascular Control.

Background. Hazards of liver surgery have been attenuated by the evolution in methods of hepatic vascular control and the anesthetic management. In this paper, the anesthetic considerations during hepatic vascular occlusion techniques were reviewed. Methods. A Medline literature search using the terms “anesthetic,” “anesthesia,” “liver,” “hepatectomy,” “inflow,” “outflow occlusion,” “Pringle,” “hemodynamic,” “air embolism,” “blood loss,” “transfusion,” “ischemia-reperfusion,” “preconditioning,” was performed. Results. Task-orientated anesthetic management, according to the performed method of hepatic vascular occlusion, ameliorates the surgical outcome and improves the morbidity and mortality rates, following liver surgery. Conclusions. Hepatic vascular occlusion techniques share common anesthetic considerations in terms of preoperative assessment, monitoring, induction, and maintenance of anesthesia. On the other hand, the hemodynamic management, the prevention of vascular air embolism, blood transfusion, and liver injury are plausible when the anesthetic plan is scheduled according to the method of hepatic vascular occlusion performed.

Encuesta sobre el tratamiento anestesiológico de los pacientes sometidos a neurocirugía de fosa posterior

ObjectivesTo find out, by means of a questionnaire, the procedures used by Spanish anaesthetists in peri-operative management of patients subjected to neurosurgery of the posterior cranial fossa. Material and methodsA closed-question type questionnaire was sent to Anaesthesiology Departments with a Neurosurgery Department on the participation of anaesthetists in the peri-operative treatment of patients subjected posterior fossa surgery. ResultsThe questionnaire was completed by 42 (57.5%) of the 73 national public hospitals with a Neurosurgery Department. The posterior fossa surgery was performed in the sitting position in 36 hospitals, although it was less frequently used than the lateral decubitus or prone decubitus position. There was little specific neurological monitoring, as well as little use of precordial and/or transcranial Doppler for detecting vascular air embolism. Nitrous oxide was used in less than 10% of the centres, and 15% avoided neuromuscular block when neurophysiological monitoring was used during the surgery. Cardiovascular problems were mentioned as being the most frequent in 29% of the centres, while in the post-operative period the most common complications were, cranial nerve déficit, airway oedema (23%), and post-operative vomiting (47%). ConclusionsThe results obtained from the questionnaire showed that the sitting position was less used than the prone position in posterior fossa surgery, and that neurophysiological monitoring is during surgery is hardly used.

Paradoxical air embolism following contrast material injection through power injectors in patients with a patent foramen ovale

In patients with a patent foramen ovale, use of air filters during intravenous infusions is common, but they are not compatible with power injection. Therefore we aimed to assess the incidence of paradoxical air embolism on CT of the chest and brain following contrast material injection through a power injector in patients with a patent foramen ovale, without the use of a filter. In this IRB approved, HIPAA compliant retrospective study, two independent radiologists reviewed 289 CT scans of the chest (n = 233) and brain (n = 56) for vascular air embolism following contrast material injection through a power injector in 93 subjects (43 men, mean age 66 y) with a known patent foramen ovale. The location and amount of the air were assessed. The medical records were reviewed for embolic symptoms. The prevalence and location of right sided and systemic luminal air were determined and inter-observer agreement for detection of intraluminal vascular air was calculated. Vascular air embolism was observed in 19.3% (56/289) of the studies; small in 52 and moderate in 4. In 42 studies, intravascular air was seen in a single territory and 14 studies had intravascular air in multiple territories. None had air in the left side of the heart or brain to suggest paradoxical air embolism. The inter-observer agreement for detection of vascular air was moderate (k = 0.6). Paradoxical air embolism in patients with a patent foramen ovale following contrast material injection with a power injector is rare.

Cerebral Arterial Air Embolism Associated with Mechanical Ventilation and Deep Tracheal Aspiration

Arterial air embolism associated with pulmonary barotrauma has been considered a rare but a well-known complication of mechanical ventilation. A 65-year-old man, who had subarachnoid hemorrhage with Glasgow coma scale of 8, was admitted to intensive care unit and ventilated with the help of mechanical ventilator. Due to the excessive secretions, deep tracheal aspirations were made frequently. GCS decreased from 8–10 to 4-5, and the patient was reevaluated with cranial CT scan. In CT scan, air embolism was detected in the cerebral arteries. The patient deteriorated and spontaneous respiratory activity lost just after the CT investigation. Thirty minutes later cardiac arrest appeared. Despite the resuscitation, the patient died. We suggest that pneumonia and frequent tracheal aspirations are predisposing factors for cerebral vascular air embolism.

Mechanotransductional basis of endothelial cell response to intravascular bubbles

Vascular air embolism resulting from too rapid decompression is a well-known risk in deep-sea diving, aviation and space travel. It is also a common complication during surgery or other medical procedures when air or other endogenously administered gas is entrained in the circulation. Preventive and post-event treatment options are extremely limited for this dangerous condition, and none of them address the poorly understood pathophysiology of endothelial response to intravascular bubble presence. Using a novel apparatus allowing precise manipulation of microbubbles in real time fluorescence microscopy studies, we directly measure human umbilical vein endothelial cell responses to bubble contact. Strong intracellular calcium transients requiring extracellular calcium are observed upon cell-bubble interaction. The transient is eliminated both by the presence of the stretch activated channel inhibitor, gadolinium, and the transient receptor potential vanilliod family inhibitor, ruthenium red. No bubble induced calcium upsurge occurs if the cells are pretreated with an inhibitor of actin polymerization, cytochalasin-D. This study explores the biomechanical mechanisms at play in bubble interfacial interactions with endothelial surface layer (ESL) macromolecules, reassessing cell response after selective digestion of glycocalyx glycosoaminoglycans, hyaluran (HA) and heparin sulfate (HS). HA digestion causes reduction of cell-bubble adherence and a more rapid induction of calcium influx after contact. HS depletion significantly decreases calcium transient amplitudes, as does pharmacologically induced sydencan ectodomain shedding. The surfactant perfluorocarbon Oxycyte abolishes any bubble induced calcium transient, presumably through direct competition with ESL macromolecules for interfacial occupancy, thus attenuating the interactions that trigger potentially deleterious biochemical pathways.

Transesophageal Echocardiography Effectively Detected Vascular Air Embolism at the Early Stage of a Posterior Fossa Procedure in the Sitting Position

座位手術で，経食道心エコー図法によって，早期に空気塞栓を検出できた症例を経験したので報告する．症例は44歳の男性で，座位による脳動静脈奇形摘出術が予定された．全身麻酔導入後，右内頚静脈に中心静脈カテーテルを挿入し，経食道心エコー図法のプローブを挿入した．後頭骨開頭中に経食道心エコー図で右心房内に高輝度所見があり，中心静脈カテーテルから約10mlの空気が吸引できた．このとき，呼気終末二酸化炭素分圧の低下はなかった．矢状静脈洞に空気流入部位を発見し指で圧迫したところ経食道心エコー図で高輝度所見はなくなった．呼気終末二酸化炭素分圧が低下する前に経食道心エコーで右心房内に流入した空気を発見でき，静脈空気塞栓症の検出における経食道心エコー図法の有用性を再確認した．

Venous air embolism during laparoscopic cholecystectomy

Vascular air embolism is a rare and potentially life-threatening event. In this study, a case of venous air embolism during laparoscopic cholecystectomy due to an injured inferior vena cava is presented. Anesthesiologists and surgeons must be aware of this dangerous complication. Emphasis is given to the prevention and prompt recognition of this event and to the use of all available tools in the management of cardiovascular complications.

Use of High Fidelity Operating Room Simulation to Assess and Teach Communication, Teamwork and Laparoscopic Skills: Initial Experience

Structured opportunities for learning communication, teamwork and laparoscopic principles are limited for urology residents. We evaluated and taught teamwork, communication and laparoscopic skills to urology residents in a simulated operating room. Scenarios related to laparoscopy (insufflator failure, carbon dioxide embolism) were developed using mannequins, urology residents and nurses. These scenarios were developed based on Accreditation Council for Graduate Medical Education core competencies and performed in a simulation center. Between the pretest scenario (insufflation failure) and the posttest scenario (carbon dioxide embolism) instruction was given on teamwork, communication and laparoscopic skills. A total of 19 urology residents participated in the training that involved participation in at least 2 scenarios. Performance was evaluated using validated teamwork instruments, questionnaires and videotape analysis. Significant improvement was noted on validated teamwork instruments between scenarios based on resident (pretest 24, posttest 27, p = 0.01) and expert (pretest 16, posttest 25, p = 0.008) evaluation. Increased teamwork and team performance were also noted between scenarios on videotape analysis with significant improvement for adherence to best practice (p = 0.01) and maintenance of positive rapport among team members (p = 0.02). Significant improvement in the setup of the laparoscopic procedure was observed (p = 0.01). Favorable face and content validity was noted for both scenarios. Teamwork, intraoperative communication and laparoscopic skills of urology residents improved during the high fidelity simulation course. Face and content validity of the individual sessions was favorable. In this study high fidelity simulation was effective for assessing and teaching Accreditation Council for Graduate Medical Education core competencies related to intraoperative communication, teamwork and laparoscopic skills.

Acute management of vascular air embolism

Vascular air embolism (VAE) is known since early nineteenth century. It is the entrainment of air or gas from operative field or other communications into the venous or arterial vasculature. Exact incidence of VAE is difficult to estimate. High risk surgeries for VAE are sitting position and posterior fossa neurosurgeries, cesarean section, laparoscopic, orthopedic, surgeries invasive procedures, pulmonary overpressure syndrome, and decompression syndrome. Risk factors for VAE are operative site 5 cm above the heart, creation of pressure gradient which will facilitate entry of air into the circulation, orogenital sex during pregnancy, rapid ascent in scuba (self contained underwater breathing apparatus) divers and barotrauma or chest trauma. Large bolus of air can lead to right ventricular air lock and immediate fatality. In up to 35% patient, the foramen ovale is patent which can cause paradoxical arterial air embolism. VAE affects cardiovascular, pulmonary and central nervous system. High index of clinical suspicion is must to diagnose VAE. The transesophgeal echocardiography is the most sensitive device which will detect smallest amount of air in the circulation. Treatment of VAE is to prevent further entrainment of air, reduce the volume of air entrained and haemodynamic support. Mortality of VAE ranges from 48 to 80%. VAE can be prevented significantly by proper positioning during surgery, optimal hydration, avoiding use of nitrous oxide, meticulous care during insertion, removal of central venous catheter, proper guidance, and training of scuba divers.

A case of pulmonary vascular air embolism in a very-low-birth-weight infant with massive hydrops

Pulmonary vascular air embolism is a rare and, universally, almost a fatal complication of positive pressure ventilation in newborn infants. Here, we report a case of this unusual complication in a very-low-birth-weight infant who showed the clinical and radiological features of this complication along with pulmonary hypoplasia and massive hydrops. The possible pathogenesis has been discussed and a brief review of related literature has been presented.