Neurologic manifestations of cerebral air embolism as a complication of central venous catheterization

Cerebral air embolism: Process change with unintended consequences

INTRODUCTION

During a cerebrovascular procedure, diligent care is made to ensure no air is present in lines and connectors. Should air enter the cerebral vasculature, cerebral air emboli can cause worsening neurological outcome or death. This communication outlines how a process change of refrigerating mixed heparin for storage lead to the presence of unintentional air, or off-gassing of the fluid.

MATERIAL & METHOD

The off-gassing phenomenon was noted during procedure. Various hypotheses were considered, including fluid preparation and manufacturing defects of lines and tubes. Further investigation identified a new process in mixing of heparin bags that were then refrigerated. The off-gassing was noted during the procedure when cold fluid flowed through tubing draped across a warming blanket. This article utilizes the explanatory research method to describe the cause and effect relationship. The aim is to provide knowledge of this phenomenon to prevent future occurrences.

RESULT

Fluids used for neuro endovascular procedures should be warmed to prevent off-gassing, which can lead to cerebral air embolus.

CONCLUSION

Air formation or out-gassing can occur when cold fluids are warmed. During neuro endovascular procedure, this unintentional air can cause significant morbidity or mortality to the patient. Understanding and recognizing this phenomenon is important to prevent patient harm.

Evaluation of a novel central venous access port for direct catheter insertion without a peel-away sheath

PURPOSE

This study retrospectively evaluated the feasibility and safety of implanting a newly developed central venous access port (CV-port) that allows catheter insertion into a vein without the use of a peel-away sheath, with a focus on its potential to minimize risks associated with conventional implantation methods.

MATERIALS AND METHODS

All procedures were performed using a new device (P-U CelSite Port™ MS; Toray Medical, Tokyo, Japan) under ultrasound guidance. The primary endpoint was the implantation success rate. The secondary endpoints were the safety and risk factors for infection in the early postprocedural period (< 30 days).

RESULTS

We assessed 523 CV-port implantations performed in a cumulative total of 523 patients (240 men and 283 women; mean age, 61.6 ± 13.1 years; range, 18-85 years). All implantations were successfully performed using an inner guide tube and over-the-wire technique through 522 internal jugular veins and one subclavian vein. The mean procedural time was 33.2 ± 10.9 min (range 15-112 min). Air embolism, rupture/perforation of the superior vena cava, or hemothorax did not occur during catheter insertion. Eleven (2.1%) intraprocedural complications occurred, including Grade I arrhythmia (n = 8) and subcutaneous bleeding (n = 1), Grade II arrhythmia (n = 1), and Grade IIIa pneumothorax (n = 1). Furthermore, 496 patients were followed up for ≥ 30 days. Six early postprocedural complications were encountered (1.1%), including Grade IIIa infection (n = 4), catheter occlusion (n = 1), and skin necrosis due to subcutaneous leakage of trabectedin (n = 1). These six CV-ports were withdrawn, and no significant risk factors for infection in the early postprocedural period were identified.

CONCLUSION

The implantation of this CV-port device demonstrated comparable success and complication rates to conventional devices, with the added potential benefit of eliminating complications associated with the use of a peel-away sheath.

Detection of Severe Neurological Complications Caused by the Removal of Central Venous Catheter Accidentally Inserted in the Epidural Space via Motor-Evoked Potential: A Case Report

The central venous catheter (CVC) has been in clinical use for more than half a century. It was initially used for total parenteral nutrition. However, its indication gradually expanded to chemotherapy, intensive care, anesthesia, and other areas. As the application of CVCs increased, complications also increased. Nevertheless, some guidelines for CVC insertion have been implemented, and clinicians worldwide are working hard to prevent complications during CVC insertion. However, the safety of CVC removal has not been given adequate attention. Because of a few reports on complications, such as air embolism and airway obstruction, clinicians are recognizing the potential risks associated with CVC. However, a few medical staff recognize the possibility of associated neurological complications. We herein report a case of a patient who underwent anesthesia for the removal of a CVC, which was inadvertently inserted in the epidural space. The catheter was used to monitor central venous pressure and as a route for medicine administration before the recognition of its abnormal position. Although the distal luminal wave pattern was similar to that of a normal central venous line, heparin did not exert its expected effect after administration from the distal lumen. Conversely, appropriate blood pressure responses were observed following the administration of inotropic agents from the proximal lumen. Objective neurological monitoring was required for removal because of the involvement of general anesthesia. After general anesthesia induction, the surrounding tissue of the CVC was dissected toward the deep layer of the neck. Arterial bleeding occurred immediately after removal. After 33 minutes, the motor-evoked potential (MEP) waves deteriorated. Angiography showed bleeding from the left vertebral artery into the spinal canal. Consequently, emergency coil embolization of the left vertebral artery was performed, followed by emergency laminectomy to decompress the spinal canal. All procedures were completed, and the MEP waves completely recovered. The postoperative course was uneventful, and the patient was discharged after 17 days. In this case report, we discuss the appropriate removal steps for a CVC inadvertently placed in the epidural space.

Cerebral air embolism: neurologic manifestations, prognosis, and outcome

Background

Cerebral air embolism (CAE) is an uncommon medical emergency with a potentially fatal course. We have retrospectively analyzed a set of patients treated with CAE at our comprehensive stroke center and a hyperbaric medicine center. An overview of the pathophysiology, causes, diagnosis, and treatment of CAE is provided.

Results

We retrospectively identified 11 patients with cerebral venous and arterial air emboli that highlight the diversity in etiologies, manifestations, and disease courses encountered clinically. Acute-onset stroke syndrome and a progressive impairment of consciousness were the two most common presentations in four patients each (36%). Two patients (18%) suffered from an acute-onset coma, and one (9%) was asymptomatic. Four patients (36%) were treated with hyperbaric oxygen therapy (HBTO), high-flow oxygen therapy without HBOT was started in two patients (18%), two patients (18%) were in critical care at the time of diagnosis and three (27%) received no additional treatment. CAE was fatal in five cases (46%), caused severe disability in two (18%), mild disability in three (27%), and a single patient had no lasting deficit (9%).

Conclusion

Cerebral air embolism is a dangerous condition that necessitates high clinical vigilance. Due to its diverse presentation, the diagnosis can be missed or delayed in critically ill patients and result in long-lasting or fatal neurological complications. Preventative measures and a proper diagnostic and treatment approach reduce CAE's incidence and impact.

Cerebral Arterial and Venous Air Embolism Following Removal of Percutaneous Sheath Introducer

Cerebral air embolism after removal of central venous catheter (CVC) is a rare complication but can lead to fatal outcomes. We report a rare case of both cerebral venous and arterial embolism occurring in a patient with underlying scleroderma-related interstitial lung disease (SSc-ILD) and pulmonary hypertension following removal of percutaneous introducer sheath for pulmonary artery catheterization. We discuss the mechanisms, pathophysiology, management and prevention of cerebral air embolism.

Subclinical to catastrophic: a range of outcomes in cerebral air embolism

Cerebral air embolism (CAE) is a rare, yet potentially devastating condition characterized by entrance of air into cerebral vasculature, that is nearly always iatrogenic. While many findings of CAE are subclinical and incidental at computed tomography (CT), there remain cases of catastrophic and fatal embolisms. Increasing physician awareness of prevention, presentation, and treatment for CAE is crucial for reducing morbidity and mortality. In this case series, we highlight this preventable entity by comparing three cases of CAE that showcase a diverse array of presentations, radiologic findings, and clinical outcomes. We will also explore predisposing factors, prognostic predictors, diagnostic considerations, and available treatments.

Central venous catheters: Which, when and how

Short-term or long-term CVCs are now considered the standard of practice for the administration of chemotherapy, fluid therapy, antibiotic therapy, and parenteral nutrition. Central venous access catheters are broadly divided into tunneled or non-tunneled catheters. Tunneled catheters can be further subdivided into totally implanted and totally not implanted devices. Device selection generally depends on various factors such as availability of peripheral veins, expected duration of therapy, and desired flow rate. Ultrasound-guided access is the safest technique for central venous access compared to the landmark technique and departments should strive to for a 100% ultrasound guided access. This review gives a basic overview of the differences of CVC catheters including PICCs, Hickman-catheters and port-catheters along with the criteria for CVC selection. It will also describe technical tips on placement of CVCs. Finally, it aims to highlight complications which are associated with CVC placement and options to treat or prevent them.

Cerebral arterial air emboli on immediate post-endovascular treatment CT are associated with poor short- and long-term clinical outcomes in acute ischaemic stroke patients

PURPOSE

To determine the incidence and predictors of cerebral arterial air emboli (CAAE) on immediate post-endovascular treatment (EVT) dual-energy CT (DECT) in acute ischaemic stroke (AIS) patients, and describe their association with clinical outcomes.

METHODS

EVT records from 2010 to 2019 were screened. Exclusion criteria included intracerebral haemorrhage on post-EVT DECT. In the affected middle cerebral artery (MCA)-territory, circular and linear (length ≥ 1.5*width) CAAE were counted. Clinical data were collected from prospective records. The modified Rankin Scale (mRS) at 90 days was the primary outcome. Multivariable linear, logistic, and ordinal regression were used to analyse the effect of (1) linear CAAE and (2) isolated circular CAAE.

RESULTS

Out of 651 EVT-records, 402 patients were included. In 65 patients (16%), at least one linear CAAE was found in the affected MCA-territory. 17 patients (4%) showed isolated circular CAAE. Multivariable regression showed an association between both the presence and the number of linear CAAE and the mRS at 90 days (presence: adjusted (a)cOR 3.10, 95%CI 1.75-5.50; number: acOR 1.28, 95%CI 1.13-1.44), NIHSS at 24-48 h (presence: aβ 4.15, 95%CI 1.87-6.43; number: aβ 0.88, 95%CI 0.42-1.34), mortality at 90 days (presence: aOR 3.34, 95%CI 1.51-7.40; number: aOR 1.24, 95%CI 1.08-1.43) and stroke progression (presence: aOR 4.01, 95%CI 1.96-8.18; number: aOR 1.31, 95%CI 1.15-1.50). Isolated circular CAAE were not significantly associated with any outcome measure.

CONCLUSION

CAAE were found frequently on post-EVT CT imaging. The presence and the number of linear CAAE, but not circular CAAE, are associated with unfavourable short- and long-term clinical outcomes.

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

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

Neurologic Complications of Surgery and Anesthesia

Surgery and anesthesia carry risks of ischemic, hemorrhagic, hypoxic, and metabolic complications, all of which can result in neurologic symptoms and deficits. Patients with underlying cardiovascular and cerebrovascular risk factors are particularly vulnerable. In this article the authors review the neurologic complications of surgery and anesthesia, with a focus on the role of the neurologic consultant in preoperative evaluation and risk stratification and diagnosis and management of postoperative complications.

Paradoxical and Retrograde Air Embolism from Pressurized Peripheral Bolus

Introduction

Cerebral air embolism is a rare, yet serious neurological occurrence with unclear incidence and prevalence. Here, we present a case of fatal cerebral arterial and venous cerebral gas embolism in a patient with infective endocarditis and known large right-to-left shunt and severe tricuspid regurgitation following pressurized fluid bolus administration. Case Presentation. A 32-year-old female was admitted to the medical intensive care unit from a long-term acute care facility with acute on chronic respiratory failure. Her medical history was significant for intravenous heroin and cocaine abuse, methicillin-sensitive Staphylococcus aureus tricuspid valve infective endocarditis on vancomycin, patent foramen ovale, septic pulmonary embolism with cavitation, tracheostomy with chronic ventilator dependence, multifocal cerebral infarction, hepatitis C, nephrolithiasis, anxiety, and depression. After intravenous fluid administration, she became unresponsive with roving gaze, sluggish pupils, and hypotensive requiring vasopressors. CT of the brain showed diffuse arterial and venous cerebral air embolism secondary to accidental air administration from fluid bolus. Magnetic resonance imaging of the brain showed diffuse global anoxic injury and flattening of the globe at the optic nerve insertion. Given poor prognosis, her family chose comfort measures and she died.

Conclusions

Fatal cerebral air embolism can occur through peripheral intravenous routes when the lines are inadequately primed and fluids administered with pressure. Caution must be exercised in patients with right-to-left shunting as air may gain access to systemic circulation.

Rare pathology in a trauma patient: air embolism following peripheral intravenous access

A 62-year-old man presented as a trauma alert after a farm tractor accident. He was managed according to ATLS protocol. During initial trauma resuscitation, he developed an iatrogenic air embolus. The patient was treated conservatively by positioning him head down and tilted to the left (Durant's manoeuvre). Repeat CT scan performed 4 hours later showed resolution of the air embolus. He had no sequelae.

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.

[Multiple Stroke Syndrome Caused by Air Embolism Following Removal of a Central Venous Catheter]

The removal of a central venous catheter on a ward leads to a paradox air embolism in a 53-year-old male patient with an unknown ventricular septal defect. The patient undergoes sufficient cardiopulmonary resuscitation but suffers from a multiple stroke syndrome with serious neurological deficits.

A High-pressure Solution for a High-pressure Situation: Management of Cerebral Air Embolism with Hyperbaric Oxygen Therapy

Cerebral air embolism can complicate many medical procedures, including cardiac surgery, venous and arterial access, and laparoscopic surgery. It can be a devastating diagnosis and can cause a life-threatening compromise to the cardiac, respiratory, or cerebrovascular system. It is a rare complication of central venous vascular access manipulation. A cerebral air embolism can lead to acute ischemic and cerebral oedema, which mimics other stroke syndromes, but the acute treatment differs, with prompt administration of hyperbaric oxygen therapy being the mainstay of treatment. A 59-year-old male became acutely unresponsive followed by the emergence of evolving neurology with fixed gaze palsy and a dense 0/5 left-sided hemiparesis. This occurred shortly after a right internal jugular central venous catheter (CVC) was removed (against protocol) during inspiration and sitting upright. Computed tomography (CT) imaging showed air in the right internal jugular vein, as well as intraparenchymal air. Treatment with hyperbaric oxygen was instituted within six hours. There was an excellent recovery of neurologic function, with power improving to 4+/5 over the course of the following week. Clinical staff need to be aware of the policy for central line removal, as well as having a high index of suspicion for air embolism in patients with evolving neurology immediately post-line removal. Early consideration of hyperbaric oxygen can result in improved functional outcomes.

Effects of Crystalloid Preloading (20 ml/kg) on Hemodynamics in Relation to Postural Changes in Patients Undergoing Neurosurgical Procedures in Sitting Position

Background:

Hemodynamic disturbances are common during positioning the patients from supine to sitting for neurosurgical procedures. The reported incidence of hypotension varies from 5% to 32%. The aim of the study was to study the effect of crystalloid preloading on hemodynamic parameters during positioning the patient from supine to sitting position.

Materials and Methods:

In this prospective observational trial, 20 patients were enrolled. Two patients had a patent foramen ovale on transesophageal echocardiography and were excluded from the study. All the patients received 20 ml/kg of crystalloid (Ringer's lactate) before initiation of positioning. Physiological hemodynamic parameters such as heart rate, mean arterial pressure, central venous pressure, cardiac output (CO), stroke volume variation (SVV), cardiac index (CI), stroke volume (SV), and maximum and minimum inferior vena caval diameter (IVCD) were recorded after induction, during positioning at 30°, 60° inclination of the operating table and after the final sitting position.

Results:

Hemodynamic parameters were well maintained during positioning of the patients from supine to sitting position. Crystalloid preloading prevented the hypotension during positioning. There were no significant changes in hemodynamic parameters such as CO, SVR, SVV, CI, and SV. We did not find any correlation with changes in IVCD with changes in CO.

Conclusion:

A volume of 20 ml/kg of crystalloid preloading before positioning the patient from supine to sitting position maintains the hemodynamic stability and avoids the vasopressor requirement.

Educational value of Internet videos in vascular access

Aim:

The aim of the study was to evaluate individually uploaded Internet materials about catheter insertion and removal in terms of their educative value.

Methods:

YouTube videos for both catheter insertion and catheter removal were investigated. Rating, like, dislike, the position of a patient, maneuvers during removal, immediate coverage of removal site, and type of cover material were noted. A survey regarding daily practices for catheter interventions and approaches to educative social media platforms had been taken from medical professionals as well to determine the effect of social media on learning practices.

Results:

A total of 50 insertion and 35 removal videos were investigated. The popularity of insertion and removal videos was 4.7 (1.6–16.5) and 1.88 (0.66–4.54), respectively. ( p = 0.011). The position of a patient during insertion was supine in 80%, Trendelenburg in 18%, and upright in 82.9% of the removal videos ( p = 0.000). The survey showed that medical professionals watched insertion videos (66%) more than removal videos (11.7%) ( p = 0.002). Catheter insertion positions were similar among participants ( p = 0.553). Removal positions were different in specialties ( p = 0.023) in which especially nephrologists tend to remove the catheter at the sitting position.

Conclusion:

Medical professionals think that removal is an easier procedure than insertion. They both search more for insertion videos and upload more insertion videos. Insertion practices are similar among different specialties. However, removal practices are more heterogeneous. Individually uploaded catheter videos at YouTube are not reliable educative materials. More free official work should be produced to maintain sufficient qualified online material on social media platforms.

Cardiac Arrest Due to Air Embolism: Complicating Image-guided Lung Biopsy

Cardiac arrest due to air embolism is an infrequent complication. Air embolism can be associated with procedures like endoscopic retrograde cholangiopancreatography, endoscopic variceal ligation, operative hysteroscopy, laparoscopic surgery, pacemaker placement, cardiac ablation, fiberoptic bronchoscopy, and decompression sickness. In rare cases, air embolus can be a catastrophic complication of computed tomography (CT) guided lung biopsy, which can lead to cardiac arrest. We present a case of a 67-year-old male chronic smoker with a left lower lobe pulmonary nodule who had a cardiac arrest due to air embolism as a consequence of CT guided biopsy of the pulmonary nodule found on a CT scan of the chest. He was successfully resuscitated and intubated for mechanical ventilation. He was managed conservatively and discharged home in a stable condition.

Cerebral air embolism from a Central Venous Catheter: A timely reminder of the importance of rapid diagnosis

Cerebral air embolism (CAE) is a rare, avoidable and potentially fatal iatrogenic complication. Here, we report a case of CAE associated with a central venous catheter in the internal jugular vein that resulted in neurological deficits and generalised epileptic seizures. A 64-year-old man admitted for fasciotomy for compartment syndrome developed CAE with left-sided neurological deficits. The suspected origin was retrograde air flow from the right internal jugular venous catheter. The air spontaneously resorbed without the need for specific therapy, and he made a good recovery. CAE is an infrequent iatrogenic complication that requires prompt diagnosis to avoid significant morbidity and mortality. This case serves as a timely reminder that adverse outcome such as stroke, seizures or death can be avoided by a high index of suspicion and prompt diagnosis. Hyperbaric oxygen is the prime therapeutic measure, but high-quality evidence on its clinical value is lacking.

Uncommon Occurrences of Air Embolism: Description of Cases and Review of the Literature

Many different risk factors have been associated with the occurrence of gas embolism making this potentially lethal complication easily avoidable. However, this condition can occur in circumstances not commonly reported. Three different and extremely uncommon cases of gas embolism are presented and discussed: the first was caused by the voluntary ingestion of hydrogen peroxide, the second occurred during a retrograde cholangiopancreatography, and the last followed the intrapleural injection of Urokinase. Whereas in the first patient the gas embolism was associated with only relatively mild digestive symptoms, in the remaining two it caused a massive cerebral ischemia and an extended myocardial infarction, respectively. Despite a hyperbaric oxygen therapy performed timely in each case, only the first patient survived. The classical risk factors associated with gas embolism like indwelling central venous catheters, diving accidents, etc. are rather well known and thus somewhat preventable; however, a number of less common and difficult-to-recognize causes can determine this condition, making the correct diagnosis elusive and delaying the hyperbaric oxygen therapy, whose window of opportunity is rather narrow. Thus, a gas embolism should be suspected in the presence of not otherwise explainable sudden neurologic and/or cardiovascular symptoms also in circumstances not typically considered at risk.

Hyperbaric oxygen therapy of air embolus in the cerebral venous sinuses after intracranial surgery: a case report

A case with cerebral venous air embolism (CVAE) after neurosurgery and treated with hyperbaric oxygen therapy (HBOT) is presented. This is a rare and potentially fatal complication that neurosurgeons should be aware of. A 52-year-old male was diagnosed with an intracerebral hematoma. An emergency evacuation of the hematoma was performed with a craniotomy and the postoperative CT scan showed a complete evacuation of the hematoma, but it also revealed a CVAE. The patient was immediately referred to HBOT and received three sessions within 48 h. The CT scan after the first HBOT showed no CVAE, venous thrombosis, or new hematoma.

Cortical Blindness and Altered Mental Status following Routine Hemodialysis, a Case of Iatrogenic Cerebral Air Embolism

Cerebral air embolism is a known complication from a myriad of iatrogenic causes. This case describes a 60-year-old female presenting from hemodialysis with altered mental status, bilateral homonymous hemianopia, and repetitive speech. A noncontrast head CT revealed air in the vein of Galen and the deep cerebral veins of the left thalamus and occipital sulcus, a complication from air being introduced into the patient via improper flushing of dialysis tubing. The retrograde flow of air bubbles in the upright patient during dialysis was likely responsible for the air embolus lodging in the cerebral vasculature. This patient was transferred to receive hyperbaric therapy, whereupon the patient survived with residual attention and spatial deficits.

Complications of Peripheral Venous Access Devices: Prevention, Detection, and Recovery Strategies

Most hospitalized patients have placement of a peripheral venous access device, either a short peripheral catheter or a peripherally inserted central catheter. Compared with central venous catheters that are not peripherally inserted, the other 2 types are generally perceived by health care providers as safer and less complicated to manage, and less emphasis is placed on the prevention and management of complications. Expertise of nurses in inserting, managing, and removing these devices may reduce the likelihood of complications, and increased recognition of complications associated with use of the devices is important to ensure continued improvements in the safety, quality, and efficiency of health care. Complications associated with short peripheral catheters and peripherally inserted central catheters include tourniquet retention, tubing and catheter misconnections, phlebitis, air embolism, device fragment embolization, and inadvertent discharge with a retained peripheral venous access device. Integration of prevention, detection, and recovery strategies into personal nursing practice promotes the quality and safety of health care delivery.

A Systematic Review of the Causes and Management of Ischaemic Stroke Caused by Nontissue Emboli

Introduction

The inadvertent or purposeful introduction of foreign bodies or substances can lead to cerebral infarction if they embolize to the brain. Individual reports of these events are uncommon but may increase with the increased occurrences of their risk factors, for example, intra-arterial procedures.

Method

We searched EMBASE and MEDLINE for articles on embolic stroke of nontissue origin. 1889 articles were identified and screened and 216 articles were ultimately reviewed in full text and included in qualitative analysis. Articles deemed relevant were assessed by a second reviewer to confirm compatibility with the inclusion criteria. References of included articles were reviewed for relevant publications. We categorized the pathology of the emboli into the following groups: air embolism (141 reports), other arterial gas embolisms (49 reports), missiles and foreign bodies (16 reports), and others, including drug embolism, cotton wool, and vascular sclerosant agents.

Conclusion

Air and gaseous embolism are becoming more common with increased use of interventional medical procedures and increased popularity of sports such as diving. There is increasing evidence for the use of hyperbaric oxygen for such events. Causes of solid emboli are diverse. More commonly reported causes include bullets, missiles, and substances used in medical procedures.

Vascular air embolism: A silent hazard to patient safety

PURPOSE

To narratively review published information on prevention, detection, pathophysiology, and appropriate treatment of vascular air embolism (VAE).

MATERIALS AND METHODS

MEDLINE, SCOPUS, Cochrane Central Register and Google Scholar databases were searched for data published through October 2016. The Manufacturer and User Facility Device Experience (MAUDE) database was queried for "air embolism" reports (years 2011-2016).

RESULTS

VAE may be introduced through disruption in the integrity of the venous circulation that occurs during insertion, maintenance, or removal of intravenous or central venous catheters. VAE impacts pulmonary circulation, respiratory and cardiac function, systemic inflammation and coagulation, often with serious or fatal consequences. When VAE enters arterial circulation, air emboli affect cerebral blood flow and the central nervous system. New medical devices remove air from intravenous infusions. Early recognition and treatment reduce the clinical sequelae of VAE. An organized team approach to treatment including clinical simulation can facilitate preparedness for VAE. The MAUDE database included 416 injuries and 95 fatalities from VAE. Data from the American Society of Anesthesiologists Closed Claims Project showed 100% of claims for VAE resulted in a median payment of $325,000.

CONCLUSIONS

VAE is an important and underappreciated complication of surgery, anesthesia and medical procedures.

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

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

Pneumocephalus in a patient with multiple stab wounds

Pneumocephalus is a complication of trauma to the chest and many iatrogenic interventions. It may arise due to systemic air embolism or retrograde cerebral venous air embolism which is an extremely rare complication. We report a 26-years-old female patient who presented to the Emergency Department suffering of multiple stab wounds. She was in a state of shock and after first aid and evaluation she was operated successfully. In the early postoperative period generalized tonic clonic convulsions were observed following cardiopulmonary resuscitation due to sudden cardiovascular collapse. Brain computerized tomography demonstrated free air in intracranial and extracranial venous structures. Pneumocephalus was diagnosed which may be due to a wide spectrum of etiologies including thorax or spinal stab wounds, tube thoracostomy, cardiopulmonary resuscitation or even central venous catheterization. Unfortunately, the patient ended up with brain death despite all effort. In conclusion, we recommend physicians to be aware of this catastrophic complication while taking care of patients with stab wounds.

Venous and arterial air embolism: a rare phenomenon with fatal consequences

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.

Cardiac Arrest as a Consequence of Air Embolism: A Case Report and Literature Review

Air embolism is an infrequent but potentially catastrophic complication. It could be a complication of invasive procedures including surgery, central line placement, positive pressure ventilation, trauma, hemodialysis, pacemaker placement, cardiac ablation, and decompression sickness. Usually, it does not cause any hemodynamic complication. In rare cases, it could lodge in the heart and cause cardiac arrest. We present a case of an 82-year-old white female who underwent computed tomography (CT) guided biopsy of right lung pulmonary nodule. When she was turned over after the lung biopsy, she became unresponsive and developed cardiopulmonary arrest. She underwent successful resuscitation and ultimately was intubated. CT chest was performed immediately after resuscitation which showed frothy air dense material in the left atrium and one of the right pulmonary veins suggesting a Broncho venous fistula with air embolism. Although very rare, air embolism could be catastrophic resulting in cardiac arrest. Supportive care including mechanical ventilation, vasopressors, volume resuscitation, and supplemental oxygen is the initial management. Patients with cardiac, neurological, or respiratory complications benefit from hyperbaric oxygen therapy.

Cerebral Air Embolism: A Clinical, Radiologic and Histopathologic Correlation

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

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

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.

An Infrequent but Life-Threatening Complication of a Simple Procedure

Venous air embolism is an underrecognized, potentially fatal, but easily preventable complication of central line placement and removal. It can result in cardiovascular, pulmonary, and central nervous system abnormalities, ranging from minor derangement to immediate cardiovascular collapse. The most serious consequence of venous air embolism is felt to be related to blood flow obstruction from a right ventricular airlock. Identifying risk factors, understanding the pathophysiology and recognizing clinical manifestations of venous air embolism will help to initiate appropriate therapy, prevent lethal sequelae and decrease the incidence of central line related venous air embolism.

Neurologic Complications in the Intensive Care Unit

Complications involving the central and peripheral nervous system are frequently encountered in critically ill patients. All components of the neuraxis can be involved including the brain, spinal cord, peripheral nerves, neuromuscular junction, and muscles. Neurologic complications adversely impact outcome and length of stay. These complications can be related to underlying critical illness, pre-existing comorbid conditions, and commonly used and life-saving procedures and medications. Familiarity with the myriad neurologic complications that occur in the intensive care unit can facilitate their timely recognition and treatment. Additionally, awareness of treatment-related neurologic complications may inform decision-making, mitigate risk, and improve outcomes.

Cerebral air embolism and subsequent transient neurologic abnormalities in a liver transplant recipient following the removal of the pulmonary artery catheter from the central venous access device: a case report

Cerebral air embolism is a rare but potentially life-threatening complication. We experienced a living-donor liver transplant recipient who presented with unexpected cerebral air embolism and transient neurologic abnormalities that subsequently developed just after the removal of the pulmonary artery catheter from the central venous access device. One day after the initial event, the patient's neurologic status gradually improved. The patient was discharged 30 days after liver transplantation without neurologic sequelae.

Unusual Cerebral Emboli

The heart and the carotid arteries are the most common sites of origin of embolic disease to the brain. Clots arising from these locations are the most common types of brain emboli. Less common cerebral emboli include air, fat, calcium, infected vegetations, and tumor cells as well as emboli originating in the venous system. Although infarcts can be the final result of any type of embolism, described herein are the ancillary and sometimes unique imaging features of less common types of cerebral emboli that may allow for a specific diagnosis to be made or at least suspected in many patients.

Sudden-Onset Bilateral Blindness in a Young Girl Receiving Parenteral Nutrition: Case Report and Review of Literature

BACKGROUND

Parenteral nutrition (PN) via a central venous catheter is routinely used for surgical patients without a functioning gastrointestinal tract. Complications of PN can be metabolic and thrombotic. Blindness is a rare and unexpected complication.

CASE

A young female patient with postcorrosive pyloric stenosis was started on PN through an indwelling central venous catheter. On the sixth day of PN, the patient reported sudden painless bilateral complete loss of vision. Examination revealed bilateral normal-sized pupils with normal pupillary reaction. There was complete bilateral absence of visual acuity with no perception of light. Fundus examination was normal. Magnetic resonance imaging revealed an acute infarct in the left occipital lobe, left corpus callosum, and posteromedial aspect of the left thalamus. No cardiac source of the thrombus could be identified. After supportive treatment, the vision started improving after 3 days; recovery was 95% after 10 days. A feeding jejunostomy was performed urgently under local anesthesia, and 1 month of enteral nutrition was administered. One month after the event, the patient's vision returned to normal. Definitive surgery in the form of antrectomy with Billroth II reconstruction was performed 8 weeks later.

CONCLUSION

Blindness secondary to central venous catheterization is very rare; possible mechanisms are venous thrombosis with paradoxical emboli, air emboli, or accidental arterial puncture. Clinicians must exercise caution while using PN. A high index of suspicion is required to diagnose and treat unexpected complications.

Presence of Gyriform Air Predicts Unfavorable Outcome in Venous Catheter-Related Cerebral Air Embolism

BACKGROUND

This study aimed to investigate the clinical predictors of unfavorable prognosis in patients with venous catheter-related cerebral air embolism.

METHODS

An extensive review of English literature was performed to obtain reports on cerebral air embolism published between January 1982 and July 2014 through PubMed, Journal at Ovid, and Web of Science using the Mesh terms and keywords "cerebral air embolism" and "cerebral gas embolism." Reports not fulfilling the diagnosis of cerebral air embolism and iterant articles were excluded. Demographics, clinical manifestations, and imaging findings were recorded. The air distribution on initial brain computed tomography (CT) was recorded as gyriform air (GF), cavernous sinus bubble, venous sinus bubble, and parenchymal and subarachnoid bubble. The enrolled subjects were further divided into favorable and unfavorable outcome groups for analyses.

RESULTS

Of the 33 cases enrolled, 31 had documented follow-up outcomes, including 14 with favorable and 17 with unfavorable prognoses. Patients with unfavorable outcome had older onset age (67.5 ± 15.8 versus 46.7 ± 17.0 years, P < .001), higher frequency of GF on brain CT (58.8% versus 0%, P < .01), initial consciousness disturbance (100% versus 42.9%, P < .001), and hemiparesis (100% versus 42.9%, P < .001), but lower frequency of cardiopulmonary symptoms (5.9% versus 64.3%, P < .01). In patients with central venous catheter-related cerebral air embolism, the retrograde mechanism had a tendency for worse outcomes (43.8% versus 0%, P = .023).

CONCLUSIONS

In patients with venous catheter-related cerebral air embolism, the presence of GF on brain CT imaging, old age, initial conscious disturbance, and hemiparesis may predict unfavorable outcomes.