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.

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.