Hyperbaric oxygen and carbon monoxide poisoning: a critical review

Abstract

CO is likely to be the most common cause of poisoning worldwide and often results in persistent neuropathologic and cognitive sequelae. While the displacement of oxygen from hemoglobin by CO has overshadowed the myriad mechanisms by which CO causes injury, mere oxygen displacement has endured as the etiology of CO poisonings and perpetuated a cascade of misdiagnosis, misunderstandings and confusion regarding how and when to treat CO poisoning. Hyperbaric oxygen benefits the brain more than normobaric oxygen by, e.g. improving energy metabolism, preventing lipid peroxidation and decreasing neutrophil adherence. Randomized controlled trials have definitively shown hyperbaric oxygen as the only efficacious therapy for acute CO poisoning if delayed neurological sequelae are to be minimized. Normobaric oxygen should not be used between multiple hyperbaric oxygen treatments as this can contribute to toxicity. Hyperbaric oxygen seems to also have potential in the delayed treatment of CO poisoning using multiple treatments of low dose of oxygen; however, oxygen dosing issues are not yet fully understood for either acute or delayed treatment. It would behoove medical decision-makers to embrace this important tool and make it more accessible as well as helping to disseminate to the medical community what is now known from the available literature.

Toxicology in the Critical Care Unit

“…Consultation with a hyperbaric oxygen specialist should be performed to assess the need for and specifics associated with the therapy. [71][72][73] Methemoglobinemia Topical anesthetics such as lidocaine and benzocaine are well recognized to cause methemoglobinemia, especially when skin or mucosal integrity is compromised leading to greater systemic absorption. Methemoglobinemia associated with topical anesthetic use is most commonly associated with transesophageal echocardiography, endoscopy, and bronchoscopy.…”

Long-term treatment with hyperbaric air improves hyperlipidemia of db/db mice

“…HBO has been utilized for the treatment of various diseases, including gas poisoning (7,8) and autism (9). In diabetic patients, HBO is also utilized for therapy of gangrene (10) and retinopathy (11).…”

Neuropsychiatric aspects of carbon monoxide poisoning: diagnosis and management

“…This allows more oxygen to attach to the free-binding sites of haemoglobin, reducing lipid peroxidation and neuropsychiatric sequelae associated with CO poisoning (Prockop 2007). In addition, hyperbaric oxygen offers more benefits to the brain compared with normobaric oxygen by improving energy metabolism and decreasing neutrophil adherence (Stoller 2007). The indications for hyperbaric oxygen treatment include a COHb level above 25% (regardless of symptomatology), evidence of ongoing end-organ ischaemia (regardless of COHb level), profound metabolic acidosis (pH <7.1), loss of consciousness and, in pregnant women, a COHb level >15% or evidence of fetal distress (Hampson 1995;Ernst 1998;Weaver 1999;Kao 2004).…”