Dysbarism: An Overview of an Unusual Medical Emergency

Dysbarism is a general term which includes the signs and symptoms that can manifest when the body is subject to an increase or a decrease in the atmospheric pressure which occurs either at a rate or duration exceeding the capacity of the body to adapt safely. In the following review, we take dysbarisms into account for our analysis. Starting from the underlying physical laws, we will deal with the pathologies that can develop in the most frequently affected areas of the body, as the atmospheric pressure varies when acclimatization fails. Manifestations of dysbarism range from itching and minor pain to neurological symptoms, cardiac collapse, and death. Overall, four clinical pictures can occur: decompression illness, barotrauma, inert gas narcosis, and oxygen toxicity. We will then review the clinical manifestations and illustrate some hints of therapy. We will first introduce the two forms of decompression sickness. In the next part, we will review the barotrauma, compression, and decompression. The last three parts will be dedicated to gas embolism, inert gas narcosis, and oxygen toxicity. Such an approach is critical for the effective treatment of patients in a hostile environment, or treatment in the emergency room after exposure to extreme physical or environmental factors.

Department of Defense positions on alternative uses of hyperbaric oxygen therapy

Hyperbaric oxygen therapy is an existing and approved treatment to address multiple medical conditions, including decompression sickness, air or gas embolism, carbon monoxide poisoning, and profound blood loss when transfusion cannot be accomplished. However, recent efforts have emerged to promote hyperbaric oxygen therapy for other purposes. The most controversial applications have been utilizing this therapy as a treatment for mild traumatic brain injury and post-traumatic stress disorder. As evidence accumulates and the debate continues about whether published studies have satisfied the threshold of clinical significance, a common issue is raised regarding current clinical practices and health insurance coverage as allowed or recommended by the Department of Defense and other federal agencies. This review describes the current federal policies regarding medical insurance issues for providers and clinical practice guidelines as they pertain to alternative uses of hyperbaric oxygen therapy. First, the current policies are explored for what is reimbursable under federal insurance as approved clinical or research usages. Second, these policies are compared to the clinical practice guidelines to determine what might be clinical best practice versus exploratory research. Third, the evidence from government reports is reviewed as supporting documentation for these positions. As such, the current discussion addresses what can and cannot be covered under health insurance and where various federal health care organizations stand currently on using hyperbaric oxygen therapy as an alternative therapeutic technique. The primary goal is informing military healthcare practitioners and prospective patients about the treatment options available to them under current federal guidelines.

Massive cerebral air embolism following percutaneous transhepatic biliary drainage: A case report

RATIONALE

Cerebral air embolism from portal venous gas rarely occurs due to invasive procedures (e.g., endoscopic procedures, liver biopsy, or percutaneous transhepatic biliary drainage) that disrupt the gastrointestinal or hepatobiliary structures. Here, we report a rare case of fatal cerebral air embolism following a series of percutaneous transhepatic biliary drainage tube insertions.

PATIENT CONCERNS

A 50-year-old woman with a history of cholecystectomy, liver wedge resection, and hepaticojejunostomy for gallbladder cancer presented with altered mental status 1 week after percutaneous transhepatic biliary drainage tube placement.

DIAGNOSES

Extensive cerebral air embolism and acute cerebral infarction.

INTERVENTIONS

Brain computed tomography and magnetic resonance imaging, hyperbaric oxygen therapy, medical therapy.

OUTCOMES

Despite the use of hyperbaric oxygen therapy and medical treatment including vasopressors, the patient eventually died due to massive systemic air embolism.

LESSONS

To date, there have been no reports of cerebral air embolism due to percutaneous transhepatic biliary drainage with pronounced radiologic images. We reviewed previously reported fatal cases associated with endoscopic hepatobiliary procedures and assessed the possible mechanisms and potential causes of air embolism.

Gas in the Portal Vein: An Emergency or Just Hot Air?

We report the case of a 87-year-old woman admitted to our Emergency Department for mild abdominal pain associated with vomiting. An abdominal X-ray showed gas present in the portal venules of the left hepatic lobe, a finding associated with numerous surgical and medical conditions. The patient was successfully managed with conservative treatment. Isolated intrahepatic gas is a rare radiologic finding; emergency surgery should be performed only when there are signs of associated acute intestinal infarction.

Transesophageal echocardiography detection of air embolism during endoscopic surgery and validity of hyperbaric oxygen therapy: Case report

INTRODUCTION

Air embolism has the potential to be serious and fatal. In this paper, we report 3 cases of air embolism associated with endoscopic medical procedures in which the patients were treated with hyperbaric oxygen immediately after diagnosis by transesophageal echocardiography. In addition, we systematically review the risk factors for air embolism, clinical presentation, treatment, and the importance of early hyperbaric oxygen therapy efficacy after recognition of air embolism.

PATIENT CONCERNS

We present 3 patients with varying degrees of air embolism during endoscopic procedures, one of which was fatal, with large amounts of gas visible in the right and left heart chambers and pulmonary artery, 1 showing right heart enlargement with increased pulmonary artery pressure and tricuspid regurgitation, and 1 showing only a small amount of gas images in the heart chambers.

DIAGNOSES

Based on ETCO2 and transesophageal echocardiography (TEE), diagnoses of air embolism were made.

INTERVENTIONS

The patients received symptomatic supportive therapy including CPR, 100% O2 ventilation, cerebral protection, hyperbaric oxygen therapy and rehabilitation.

OUTCOMES

Air embolism can causes respiratory, circulatory and neurological dysfunction. After aggressive treatment, one of the 3 patients died, 1 had permanent visual impairment, and 1 recovered completely without comorbidities.

CONCLUSIONS

While it is common for small amounts of air/air bubbles to enter the circulatory system during endoscopic procedures, life-threatening air embolism is rare. Air embolism can lead to serious consequences, including respiratory, circulatory, and neurological impairment. Therefore, early recognition of severe air embolism and prompt hyperbaric oxygen therapy are essential to avoid its serious complications.

Gas embolism after periproctal abscess incision and lavage with hydrogen peroxide a case report Should the use of hydrogen peroxide in surgery be continued?

INTRODUCTION

Hydrogen peroxide is an antiseptic solution still often used in surgical departments for lavage of wounds. Its use is nevertheless linked to an important risk of gas embolism. Such a case report has not yet been published in the Czech literature and awareness of this danger is low among surgeons.

CASE REPORT

The author describes the case of gas embolism in a 40 years old patient after lavage of a periproctal abscess incision with 3% hydrogen peroxide. The lavage resulted in a cardiopulmonary arrest with the need of cardiopulmonary resuscitation. Fortunately, the patient recovered without any health consequences.

CONCLUSION

In the view of important risks and questionable and insufficiently proven benefits it may be the time to possibly reconsider the use of hydrogen peroxide in surgery and replace it with a different antiseptic agent.

Application of a new hyperbaric oxygen therapy protocol in patients with arterial and venous gas embolism due to hydrogen peroxide poisoning

Hydrogen peroxide (H2O2) ingestion can cause vascular gas embolism (GE). Hyperbaric oxygen therapy (HBO2) is known to improve neurological abnormalities in patients with arterial gas embolism (AGE). Previously, HBO2 based on the U.S. Navy Table 6 diving protocol has been adopted for treating AGE and preventing the progression of portal venous GE, caused by H2O2 ingestion, to AGE. However, the indication and protocol for HBO2 have not been established for GE related to H2O2 ingestion. Herein, we describe a case in which GE caused by H2O2 ingestion was treated using HBO2 with a short protocol. A 69-year-old female patient presented with abdominal pain, vomiting, and transient loss of consciousness after ingesting 35% H2O2. Computed tomography revealed gastric wall and portal venous gas. She was administered an HBO2 protocol with 2.8-atmosphere absolute (ATA) compression for 45 minutes. This was followed by a 2.0-ATA treatment for 60 minutes with a five-minute air break, after which all gas bubbles disappeared. After HBO2 treatment, brain magnetic resonance imaging revealed focal cytotoxic edema lesions; however, the patient was discharged without additional symptoms.

Ingestion of food grade hydrogen peroxide with resultant gastrointestinal and neurologic symptoms treated with hyperbaric oxygen therapy: case report and review with emphasis on the therapeutic value of HBO2 in vascular gas embolism

A 52-year-old male accidentally ingested approximately 100 mL of 35% hydrogen peroxide (H2O2), resulting in the sudden onset of gastrointestinal and neurologic symptoms. Non-contrast abdominal CT revealed extensive portal venous gas and gastric pneumatosis. The patient was treated with hyperbaric oxygen therapy which resulted in complete resolution of symptoms. The case highlights the therapeutic value of hyperbaric oxygen therapy in the treatment of vascular gas embolism and mitigation of concentrated H2O2 ingestion toxicity.

Seizure during hyperbaric oxygen therapy: experience at a single academic hospital in Korea

BACKGROUND

Hyperbaric oxygen (HBO2) therapy is a safe and well-tolerated treatment modality. Seizures, one of the most severe central nervous system side effects of HBO2 therapy, can occur. Episodes of seizures during HBO2 therapy have not yet been reported in countries such as Korea, where hyperbaric medicine is still in the developmental stage.

METHODS

The registry data of all patients treated with HBO2 therapy in a tertiary academic hospital in Korea were prospectively collected, and patients who developed seizures during HBO2 therapy between October 2016 and December 2019 were evaluated. In addition, we reviewed previous studies on occurrence of seizures during HBO2 therapy.

RESULTS

During the study period, a total of 10,425 treatments were provided to 1,308 patients. The most frequently treated indication was carbon monoxide (CO) poisoning ABSTRACT (n=547, 41.8%). During the HBO2 therapy sessions (total: 10,425), five seizure episodes occurred (patients with CO poisoning: n=4; patients with arterial gas embolism [AGE]: n=1). The frequency of seizures in patients with CO poisoning (0.148%) and AGE (3.448%) was significantly higher than that in patients with all indications (0.048%) (p=0.001). None of the patients had lasting effects due to the seizures.

CONCLUSION

Our study revealed a similar frequency rate in terms of all indications and CO poisoning, and a slightly higher rate in AGE. Seizures were observed in patients with CO poisoning and AGE. Therefore, if clinicians plan to operate a hyperbaric center in a country like Korea, where there are several patients with acute CO poisoning, they should be prepared to handle seizures that may occur during HBO2 therapy.

Treating ARDS-associated air embolism: a question of priorities

Gas embolism is a potential and often life-threatening complication of central venous catheters. We report a case of air embolism after tearing of the central catheter associated with severe acute respiratory distress syndrome. The severity of the clinical situation meant choices had to be made regarding the order of treatments. This clinical case provided useful eye-openers for patient management regarding the prioritization of treatments as well as the possibilities offered by hyperbaric oxygen therapy.

Gas Embolism After Hydrogen Peroxide Use During Spine Surgery: Case Report and Literature Review

BACKGROUND

As an irrigant, an antiseptic, and a hemostatic agent, hydrogen peroxide (H₂O₂) is widely used in surgical treatment, but it has been surrounded by persistent controversy. Fatal or near-fatal embolic events caused by H₂O₂ have been reported sporadically in spine surgery.

CASE DESCRIPTION

In this report, we present an 87-year-old man who underwent lumbar instrumentation removal and debridement consequent to surgical site infection in a prone position. H₂O₂ was used to irrigate the infected screw tracks and surrounding tissues during the procedures. Soon after irrigation, the patient suddenly developed tachycardia, hypotension, and rapid oxygen desaturation, followed by bradycardia. Transesophageal echocardiography indicated gas embolism. After prompt first aid treatment, the patient's condition improved and the gas embolus disappeared within a few minutes without any evidence of organ embolism.

CONCLUSIONS

Spine surgeons should reconsider the pending results of using H₂O₂ during surgery. Prolonged prone positioning and semiclosed cavities may increase the risk of gas embolism. An early diagnosis and timely intervention may be the key measures to prevent the occurrence of fatal consequences caused by gas embolism.

Optimal treatment strategies for hepatic portal venous gas: A retrospective assessment

BACKGROUND

Hepatic portal venous gas (HPVG) generally indicates poor prognoses in patients with serious intestinal damage. Although surgical removal of the damaged portion is effective, some patients can recover with conservative treatments.

AIM

To establish an optimal treatment strategy for HPVG, we attempted to generate computed tomography (CT)-based criteria for determining surgical indication, and explored reliable prognostic factors in non-surgical cases.

METHODS

Thirty-four cases of HPVG (patients aged 34-99 years) were included. Necessity for surgery had been determined mainly by CT findings (i.e. free-air, embolism, lack of contrast enhancement of the intestinal wall, and intestinal pneumatosis). The clinical data, including treatment outcomes, were analyzed separately for the surgical cases and non-surgical cases.

RESULTS

Laparotomy was performed in eight cases (surgical cases). Seven patients (87.5%) survived but one (12.5%) died. In each case, severe intestinal damage was confirmed during surgery, and the necrotic portion, if present, was removed. Non-occlusive mesenteric ischemia was the most common cause (n = 4). Twenty-six cases were treated conservatively (non-surgical cases). Surgical treatments had been required for twelve but were abandoned because of the patients’ poor general conditions. Surprisingly, however, three (25%) of the twelve inoperable patients survived. The remaining 14 of the 26 cases were diagnosed originally as being sufficiently cured by conservative treatments, and only one patient (7%) died. Comparative analyses of the fatal (n = 10) and recovery (n = 16) cases revealed that ascites, peritoneal irritation signs, and shock were significantly more frequent in the fatal cases. The mortality was 90% if two or all of these three clinical findings were detected.

CONCLUSION

HPVG related to intestinal necrosis requires surgery, and our CT-based criteria are probably useful to determine the surgical indication. In non-surgical cases, ascites, peritoneal irritation signs and shock were closely associated with poor prognoses, and are applicable as predictors of patients’ prognoses.

Extracorporeal Membrane Oxygenation in Transport Part 2: Complications and Troubleshooting

Factors taken for granted while the extracorporeal membrane oxygenation (ECMO) patient is maintained in a hospital setting can become critical when planning for transport. These issues include but are not limited to positioning of patients on a small transport stretcher, positioning of cannulas and equipment, ensuring adequate power sources and supply, inefficient temperature control, and a much higher risk of decannulation. It is paramount to be comfortable with the management strategies required to handle common complications of ECMO with limited resources in a relatively austere environment. Coagulopathy and bleeding are the most common complications occurring in up to 50% of ECMO patients. Loss of flow and hypotension from loss of volume or profound vasodilation after ECMO initiation need to be managed accordingly. Oxygenator malfunction can occur, and clinicians must be able to recognize the indicators of this complication promptly. Loss of pulsatility, low end-tidal carbon dioxide (ETCO₂), and differential hypoxia are common complications in venoarterial ECMO. In addition, an air embolism is life-threatening on venoarterial ECMO but may be better tolerated in the setting of venovenous ECMO. Recirculation in venovenous ECMO leads to circulation of poorly oxygenated blood and must be recognized and addressed. Lastly, pump failure, circuit rupture, and decannulation are devastating complications. Over the last decade, the use of extracorporeal membrane oxygenation (ECMO) has accelerated rapidly,^1-3 providing support for patients in severe respiratory or cardiac failure. With ongoing clinical experience and improvements in technology, the indications for ECMO are increasing.⁴ Many areas are developing centralized ECMO centers to serve their surrounding communities.^5-7 To use a centralized ECMO referral model, patients need access to effective, safe critical care transport, but transporting a patient on ECMO carries a significant risk of adverse events.^8-13 The purpose of this review is to highlight some of the most common adverse events in ECMO transports and provide management suggestions. Note that these recommendations are not a substitution for close collaboration with medical control, and all adverse events should be promptly reported per organizational protocols.

Cerebral arterial gas embolism in a patient with hypoplastic left heart syndrome treated with emergent hyperbaric oxygen: case report

A 30-year-old female with a history of seizure disorder and hypoplastic left heart syndrome treated with a Norwood procedure in 1986 followed by a modified non-fenestrated Fontan (Left SVC to IVC to pulmonary arteries) with a known baffle leak presented to the emergency department. On day of presentation, the patient became unresponsive, with perioral cyanosis, rightward gaze and a left facial droop near the end of a platelet transfusion. An emergent non-contrast head CT revealed intracranial air in the right MCA distribution. She was taken to the hyperbaric chamber and was treated with a U.S. Navy Table 6 in a multiplace chamber with no extensions. Ten minutes into the treatment patient became more alert and spontaneously asked questions. The following day she was treated with a U.S. Navy Table 5. Patient had repeat CT of the head, which showed resolution of intracerebral gas and small areas of ischemia in right frontal lobe and right caudate. On hospital day five neurologic exam was normal, with 5/5 strength and no residual deficits. Treating the patient was a concern because patient has a single ventricle, in which the pulmonary artery is connected directly to the vena cava. There is very little data regarding the effects of hyperbaric oxygen (HBO2)therapy on single-ventricle physiology. Only two case reports of three pediatric patients treated with HBO2 for CAGE in a similar setting are known. In these cases the patients had improvements in their symptoms following HBO2. These cases and ours indicate HBO2 is feasible and indicated for CAGE in patients with cyanotic congenital heart disease.

Endotracheal administration for intraoperative acute massive pulmonary embolism during laparoscopic hepatectomy: A case report

INTRODUCTION

Acute pulmonary embolism (APE) during an operation is a very urgent occurrence, especially when the patient with hemodynamic instability. Generally, drugs are administered intravenously; however, these drugs have little effects under most circumstances. We present a case of successful resuscitation in a patient with endotracheal administration.

PATIENT CONCERNS

A 67-year-old female presented for laparoscopic hepatectomy. Acute pulmonary gas embolism occurred during the operation with hemodynamic instability. The total amount of carbon dioxide and argon reached 300 mL. We used a novel way of administering drugs instead of intravenous administration for rescuing and the patient condition had improved greatly and was discharged from the hospital without any neurological deficits.

DIAGNOSES

A diagnosis of APE was made because of a lot of gas was extracted out from central venous catheter and sudden observable decrease in end-tidal CO2.

INTERVENTIONS

These measures included endotracheal administration, position adjustment, manual ventilation, and gas extraction.

OUTCOMES

The patient was discharged from the hospital and had no signs of neurological deficits.

CONCLUSION

Intravenous administration may not the best appropriate way of administration when patients occurred APE. Endotracheal administration as a unique method may work wonders and has the value of research and application.

A case of a critically injured diver with multiorgan failure and severe pulmonary overinflation syndrome in a resource-limited setting

A diver practicing controlled emergency ascent training on the island of Guam suffered bilateral pneumothorax, pneumomediastinum, coronary arterial gas embolism, and developed multiple organ dysfunction syndrome. Due to limitations of available resources he was medically managed in the intensive care unit until he could be transferred to University of California San Diego for definitive management. We provide an account of our management of the patient, the pathophysiology of injury as well as a review of the safety of recreational diving skills training, current standards of practice and potential pitfalls when considering proper management of a critically injured diver.

Diving medical officers as hospitalists: a case of arterial gas embolism following a routine GI procedure

Arterial gas embolism is a well-described and frequently seen injury encountered in both civilian and military diving operations. It is becoming increasingly reported and potentially increasingly more common in the hospital environment as a complication of more frequent gastroenterology procedures. We present a case of a 49-year-old, active-duty female who developed significant left-sided neurological deficits manifesting as diffuse left-sided weakness, subjective confusion, and severe headache following esophagogastroduodenoscopy. With increased clinical suspicion for arterial gas embolism, the patient was evaluated by the hyperbaric medicine team at our facility and subsequently treated to near-resolution of symptoms by multiple hyperbaric oxygen treatments. This case highlights the importance of considering this rare complication during or following common invasive procedures. Furthermore, the unique training and experience of physicians with expertise in diving medicine and their ability to recognize these types of injury in the hospital setting highlights the importance of continued training in these fields within Military Medicine in addition to civilian Undersea and Hyperbaric Medicine fellowships.

Hyperbaric treatment of air or gas embolism: current recommendations

Gas can enter arteries (arterial gas embolism, AGE) due to alveolar-capillary disruption (caused by pulmonary over-pressurization, e.g. breath-hold ascent by divers) or veins (venous gas embolism, VGE) as a result of tissue bubble formation due to decompression (diving, altitude exposure) or during certain surgical procedures where capillary hydrostatic pressure at the incision site is subatmospheric. Both AGE and VGE can be caused by iatrogenic gas injection. AGE usually produces stroke-like manifestations, such as impaired consciousness, confusion, seizures and focal neurological deficits. Small amounts of VGE are often tolerated due to filtration by pulmonary capillaries; however VGE can cause pulmonary edema, cardiac "vapor lock" and AGE due to transpulmonary passage or right-to-left shunt through a patient foramen ovale. Intravascular gas can cause arterial obstruction or endothelial damage and secondary vasospasm and capillary leak. Vascular gas is frequently not visible with radiographic imaging, which should not be used to exclude the diagnosis of AGE. Isolated VGE usually requires no treatment; AGE treatment is similar to decompression sickness (DCS), with first aid oxygen then hyperbaric oxygen. Although cerebral AGE (CAGE) often causes intracranial hypertension, animal studies have failed to demonstrate a benefit of induced hypocapnia. An evidence based review of adjunctive therapies is presented.

Delayed hyperbaric oxygen therapy for severe arterial gas embolism following scuba diving: a case report

We present the case of a 42-year-old female who was critically ill due to an arterial gas embolism (AGE) she experienced while diving in Maui, Hawaii. She presented with shortness of breath and dizziness shortly after surfacing from a scuba dive and then rapidly lost consciousness. The diver then had a complicated hospital course: persistent hypoxemia (likely secondary to aspiration) requiring intubation; markedly elevated creatine kinase; atrial fibrillation requiring cardioversion; and slow neurologic improvement. She had encountered significant delay in treatment due to lack of availability of local hyperbaric oxygen (HBO2) therapy. Our case illustrates many of the complications that can occur when a patient suffers a severe AGE. These cases may occur even without a history of rapid ascent or risk factors for pulmonary barotrauma, and it is imperative that they be recognized and treated as quickly as possible with HBO2. Unfortunately, our case also highlights the challenges in treating critically ill divers, particularly with the growing shortage of 24/7 hyperbaric chambers able to treat these ICU-level patients.

Hyperbaric Oxygen Therapy Emergencies

Emergent indications for HBO₂ are not only for some of the most serious conditions, but also may be the only modality to directly target the patient's pathophysiology. They are to begin emergently or urgently, but may be limited by either the instability of the patient's condition or transfer logistics. Often these emergent treatments involve several treatments in the first 24 hours for best outcomes. If one considers the effects of HBO₂ upon the body while breathing 100% oxygen at pressure many benefits become evident. This article will concisely review hyperbaric oxygen's emergent indications.

Cerebral arterial air embolism after computed tomography-guided hook-wire localization of a pulmonary nodule: A case report

RATIONALE

Cranial arterial air embolism is a rare but potentially fatal complication after computed tomography (CT)-guided pulmonary interventions.

PATIENT CONCERNS

A 64-year-old man was diagnosed with a pulmonary nodule (diameter: approximately 1 cm) in the right lower lobe. The patient developed convulsions after CT-guided hook-wire localization.

DIAGNOSIS

Cranial CT revealed arborizing/linearly distributed gas in the territory of the right middle cerebral artery.

INTERVENTIONS

The patient was administered hyperbaric oxygen, antiplatelet aggregation therapy, and dehydration treatment.

OUTCOMES

Clinical death occurred 55 hours after air embolism.

LESSONS

Systemic air embolism is a serious complication of lung puncture. Clinicians should improve their understanding of this complication and remain vigilant against air embolism.