Cerebral arterial gas embolism by helium: an unusual case successfully treated with hyperbaric oxygen and lidocaine

Cerebral Arterial Gas Embolism due to Helium Inhalation from a High-Pressure Gas Cylinder

Cerebral arterial gas embolism (CAGE) is a rare but serious cause for acute neurologic deficit that occurs most often in divers who breathe compressed gas at depth or iatrogenically from a variety of invasive medical procedures. We present a rare case of CAGE caused by inhaling helium from an unregulated, high-pressure gas cylinder. Following inhalation, the patient experienced loss of consciousness, neurologic deficits, pneumomediastinum, and pneumothorax requiring transfer and treatment at a hyperbaric facility with resulting resolution of neurologic symptoms. This case highlights the importance of rapid diagnosis and hyperbaric oxygen treatment (HBO), facilitated by close coordination among community emergency departments, pediatric tertiary care centers, hyperbaric facilities, and poison control.

Two cases of fatal iatrogenic air embolism confirmed by autopsies

The occurrence of air embolism is highly related to medical operations, and air embolism can cause sudden death. Such situations require attention in forensic work. This article reports two cases of iatrogenic air embolism confirmed by autopsy. In case 1, air embolism occurred after hydrogen peroxide was used to irrigate and disinfect a wound on the patient's left forearm. Approximately 90 ml of 3% hydrogen peroxide solution was used in case 1, and this volume can produce approximately 890 ml of oxygen by complete decomposition, which is far more than the average lethal air embolism volume. Attention should be given to the risk of air embolism when using hydrogen peroxide for irrigation and disinfection. In case 2, air embolism occurred during left ureteroscopy and stent placement. Due to inappropriate processing, the normal saline pump infused air into the patient at a high pressure of 120 mmHg. Based on our autopsy findings, we discuss the pathways of arterial air embolism and cerebral air embolism. In addition to the air entrainment volume and accumulation rate, the location of air accumulation also significantly impacts the risk of air embolism. After an arterial air embolus develops into a coronary and/or cerebral air embolus, the lethal air volume drops to only a few milliliters.

Brain Protection in the Endo-Management of Proximal Aortic Aneurysms

Neurological brain injury (NBI) remains the most feared complication following thoracic endovascular aortic repair (TEVAR), and can manifest as clinically overt stroke and/or more covert injury, detected only on explicit neuropsychological testing. Microembolic signals (MES) detected on transcranial Doppler (TCD) monitoring of the cerebral arteries during TEVAR and the high prevalence and incidence of new ischaemic infarcts on diffusion-weighted magnetic resonance imaging (DW-MRI) suggests procedure-related solid and gaseous cerebral microembolisation to be an important cause of NBI. Any intervention that can reduce the embolic burden during TEVAR may, therefore, help mitigate the risk of stroke and the covert impact of ischaemic infarcts to the function of the brain. This perspective article provides an understanding of the mechanism of stroke and reviews the available evidence regarding potential neuroprotective strategies that target high-risk procedural steps of TEVAR to reduce periprocedural cerebral embolisation.

Intravenous Lidocaine Does Not Improve Neurologic Outcomes after Cardiac Surgery: A Randomized Controlled Trial

BACKGROUND

Cognitive decline after cardiac surgery occurs frequently and persists in a significant proportion of patients. Preclinical studies and human trials suggest that intravenous lidocaine may confer protection in the setting of neurologic injury. It was hypothesized that lidocaine administration would reduce cognitive decline after cardiac surgery compared to placebo.

METHODS

After institutional review board approval, 478 patients undergoing cardiac surgery were enrolled into this multicenter, prospective, randomized, double-blinded, placebo-controlled, parallel group trial. Subjects were randomized to lidocaine 1 mg/kg bolus after the induction of anesthesia followed by a continuous infusion (48 μg · kg · min for the first hour, 24 μg · kg · min for the second hour, and 10 μg · kg · min for the next 46 h) or saline with identical volume and rate changes to preserve blinding. Cognitive function was assessed preoperatively and at 6 weeks and 1 yr postoperatively using a standard neurocognitive test battery. The primary outcome was change in cognitive function between baseline and 6 weeks postoperatively, adjusting for age, years of education, baseline cognition, race, and procedure type.

RESULTS

Among the 420 allocated subjects who returned for 6-week follow-up (lidocaine: N = 211; placebo: N = 209), there was no difference in the continuous cognitive score change (adjusted mean difference [95% CI], 0.02 (-0.05, 0.08); P = 0.626). Cognitive deficit (greater than 1 SD decline in at least one cognitive domain) at 6 weeks occurred in 41% (87 of 211) in the lidocaine group versus 40% (83 of 209) in the placebo group (adjusted odds ratio [95% CI], 0.94 [0.63, 1.41]; P = 0.766). There were no differences in any quality of life outcomes between treatment groups. At the 1-yr follow-up, there continued to be no difference in cognitive score change, cognitive deficit, or quality of life.

CONCLUSIONS

Intravenous lidocaine administered during and after cardiac surgery did not reduce postoperative cognitive decline at 6 weeks.

A case of hypoxic encephalopathy induced by the inhalation of helium that resolved with no neurological complications: a case report and analysis of similar cases

Background

Nowadays, it is getting easier to search information about helium‐assisted suicide online. Therefore, healthcare professionals must understand helium‐associated medical conditions.

Case Presentation

A 27‐year‐old man was found with his head covered with a bag connected to a helium tank. Hyperbaric oxygen therapy was not given because his head computed tomography showed no cerebral vasculature air embolism and there was no obvious limb paralysis. The diagnosis was impaired consciousness with hypoxic encephalopathy; he needed mechanical ventilation for 2 days. He was discharged after intelligence tests with no obvious higher brain dysfunction.

Conclusion

We successfully treated a patient with hypoxic encephalopathy due to helium inhalation. Our analysis suggests that the pathophysiology and appropriate intervention of helium intoxication might be different according to the devices used.

A prospective case series evaluating use of an in-line air detection and purging system to reduce air burden during major surgery

Background

Intravascular air embolism (AE) is a preventable but potentially catastrophic complication caused by intravenous tubing, trauma, and diagnostic and surgical procedures. The potentially fatal risks of arterial AE are well-known, and emerging evidence demonstrates impact of venous AEs on inflammatory response and coagulation factors. A novel FDA-approved in-line air detection and purging system was used to detect and remove air caused by administering a rapid fluid bolus during surgery.

Methods

A prospective, randomized, case series was conducted. Subjects were observed using standard monitors, including transesophageal echocardiography (TEE) in the operating room. After general anesthesia was induced, an introducer and pulmonary artery catheter was inserted in the right internal jugular to administer fluids and monitor cardiac pressures. Six patients undergoing cardiac surgery were studied. Each patient received four randomized fluid boluses: two with the in-line air purging device, two without. For each bolus, a bulb infuser was squeezed three times (10–15 mL) over 5 s. The TEE was positioned in the mid-esophageal right atrium (RA) to quantify peak air clearance, and images were video recorded throughout each bolus. Air was quantified using optical densitometry (OD) from images demonstrating maximal air in the RA.

Results

All subjects demonstrated significantly lower air burden when the air reduction device was used (p = 0.004), and the average time to clear 90% of air was also lower, 3.7 ± 1.2 s vs. 5.3 ± 1.3 s (p < 0.001).

Conclusion

An air purging system reduced air burden from bolus administration and could consequently reduce the risk of harmful or fatal AEs during surgery.

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.

Incidence of venous air embolism during myomectomy: the effect of patient position

PURPOSE

Venous air embolism (VAE) is characterized by the entrainment of air or exogenous gases from broken venous vasculature into the central venous system. No study exists regarding the effect of patient positioning on the incidence of VAE during abdominal myomectomy. The purpose of this study was to assess the incidence and grade of VAE during abdominal myomectomy in the supine position in comparison to those in the head-up tilt position using transesophageal echocardiography.

MATERIALS AND METHODS

In this study, 84 female patients of American Society of Anesthesiologist physical status I or II who were scheduled for myomectomy under general anesthesia were included. Patients were randomly divided into two groups: supine group and head-up tilt group. Transesophageal echocardiography images were videotaped throughout the surgery. The tapes were then reviewed for VAE grading.

RESULTS

In the supine group, 10% of the patients showed no VAE. Moreover, 10% of the patients were classified as grade I VAE, while 50% were categorized as grade II, 22.5% as grade III, and 7.5% as grade IV. In the head-up tilt group, no VAE was detected in 43.2% of the patients. In addition, 18.2% of the patients were classified as grade I VAE, 31.8% as grade II, and 6.8% as grade III; no patients showed grade IV. VAE grade in the head-up tilt group was significantly lower than that in the supine group (p<0.001).

CONCLUSION

The incidence and grade of VAE in the head-up tilt group were significantly lower than those in the supine group during abdominal myomectomy.

Randomized, double-blinded, placebo controlled study of neuroprotection with lidocaine in cardiac surgery

BACKGROUND AND PURPOSE

Cognitive decline after cardiac surgery remains common and diminishes patients' quality of life. Based on experimental and clinical evidence, this study assessed the potential of intravenously administered lidocaine to reduce postoperative cognitive dysfunction after cardiac surgery using cardiopulmonary bypass.

METHODS

After IRB approval, 277 patients undergoing cardiac surgery were enrolled into this prospective, randomized, double-blinded placebo controlled clinical trial. Subjects were randomized to receive: (1) Lidocaine as a 1 mg/kg bolus followed by a continuous infusion through 48 hours postoperatively, or (2) Placebo bolus and infusion. Cognitive function was assessed preoperatively and again at 6 weeks and 1 year postoperatively. The effect of lidocaine on postoperative cognition was tested using multivariable regression modeling; P<0.05 was considered significant.

RESULTS

Among the 241 allocated subjects (Lidocaine: n=114; Placebo: n=127), the incidence of cognitive deficit in the lidocaine group was 45.5% versus 45.7% in the placebo group (P=0.97). Multivariable analysis revealed a significant interaction between treatment group and diabetes, such that diabetic subjects receiving lidocaine were more likely to suffer cognitive decline (P=0.004). Secondary analysis identified total lidocaine dose (mg/kg) as a significant predictor of cognitive decline and also revealed a protective effect of lower dose lidocaine in nondiabetic subjects.

CONCLUSIONS

Lidocaine administered during and after cardiac surgery does not reduce the high rate of postoperative cognitive dysfunction. Higher doses of lidocaine and diabetic status were independent predictors of cognitive decline. Protective effects of lower dose lidocaine in nondiabetic subjects need to be further evaluated.

Cerebral air gas embolism from concentrated hydrogen peroxide ingestion

INTRODUCTION

Ingestion of a small amount of concentrated hydrogen peroxide can cause cerebral air gas embolism (CAGE). Hyperbaric oxygen therapy (HBOT) is the standard of care in the treatment of CAGE. We report a case of CAGE after accidental ingestion of 33%hydrogen peroxide treated with HBOT resulting in reversal of both the clinical and radiologic abnormalities.

CASE REPORT

A 48 year-old male took two sips of 33% hydrogen peroxide. A short time later, he developed hematemesis, left sided hemiplegia, confusion, and left homonymous hemianopsia. Initial laboratory studies, chest x-ray, and brain CT were normal. MRI demonstrated areas of restricted diffusion and T2 hyper intensities in multiple vascular territories consistent with ischemia due to CAGE. Eighteen hours after arrival, the patient underwent HBOT at 3 atmospheres absolute (ATA) for 30 minutes and 2.5 ATA for 60 minutes with clinical improvement. Follow-up MRI at six months demonstrated resolution of the hyper intensities.

DISCUSSION

A search of MEDLINE from 1950 to present revealed only two cases of CAGE from ingestion of concentrated hydrogen peroxide treated with HBOT. Both cases, similar to ours, had complete resolution of symptoms. Of the seven reported cases of CAGE from hydrogen peroxide that did not undergo HBOT, only in one patient was there a report of symptom resolution.

CONCLUSION

Ingestion of even a small amount of concentrated hydrogen peroxide can result in cerebral air gas embolism. Hyperbaric oxygen therapy may be of benefit in reversing the symptoms and preventing permanent neurological impairment.

Venous air embolism during surgery, especially cesarean delivery

Venous air embolism (VAE) is the entrapment of air or medical gases into the venous system causing symptoms and signs of pulmonary vessel obstruction. The incidence of VAE during cesarean delivery ranges from 10 to 97% depending on surgical position or diagnostic tools, with a potential for life-threatening events. We reviewed extensive literatures regarding VAE in detail and herein described VAE during surgery including cesarean delivery from background and history to treatment and prevention. It is intended that present work will improve the understanding of VAE during surgery.

Gas embolism: pathophysiology and treatment

Based on a literature search, an overview is presented of the pathophysiology of venous and arterial gas embolism in the experimental and clinical environment, as well as the relevance and aims of diagnostics and treatment of gas embolism. The review starts with a few historical observations and then addresses venous air embolism by discussing pulmonary vascular filtration, entrapment, and the clinical occurrence of venous air emboli. The section on arterial gas embolism deals with the main mechanisms involved, coronary and cerebral air embolism (CAE), and the effects of bubbles on the blood-brain barrier. The diagnosis of CAE uses various techniques including ultrasound, perioperative monitoring, computed tomography, brain magnetic resonance imaging and other modalities. The section on therapy starts by addressing the primary treatment goals and the roles of adequate oxygenation and ventilation. Then the rationale for hyperbaric oxygen as a therapy for CAE based on its physiological mode of action is discussed, as well as some aspects of adjuvant drug therapy. A few animal studies are presented, which emphasize the importance of the timing of therapy, and the outcome of patients with air embolism (including clinical patients, divers and submariners) is described.

Cerebral and coronary gas embolism from the inhalation of pressurized helium

OBJECTIVE

Inhalation of helium, which produces a change in the voice, is frequently used among young rock singers to improve their performance.

DESIGN

A case report.

SETTINGS

Adult medical intensive care unit in a university hospital.

PATIENT

A 23-yr-old singer, who accidentally inhaled helium from a high pressurized tank without pressure reduction, presented with transient loss of consciousness and chest pain.

INTERVENTIONS

Electrocardiogram, chest radiograph, biochemical and toxicological analyses, echocardiography, coronary angiography were performed.

MEASUREMENTS AND MAIN RESULTS

At admission, the patient slowly regained consciousness. An electrocardiogram showed significant ST elevations in leads I, aVL, and V4-V6. The chest radiograph was consistent with pulmonary congestion and pneumomediastinum. The echocardiogram showed normal sized heart chambers with hypokinesis of the left ventricular lateral wall. Ethanol and urine cannabinoids were present in low concentrations, but no presence of opiates, methadone, cocaine, or amphetamines was documented. Troponin T was positive. Elevation of ST segments gradually disappeared within 30 mins, the drowsiness within 10 hrs, and the thoracic pain within 24 hrs. Coronary angiography showed normal coronary arteries. The patient was discharged on day 3 without any symptoms and with normal electrocardiogram and chest radiograph.

CONCLUSION

Accidental inhalation of helium under high pressure can cause symptomatic cerebral and coronary artery gas embolism.