For over 100 years, hyperbaric chambers have been used as an evidenced based treatment for diving emergencies. However, hyperbaric indications are typically not common knowledge outside of diving and outpatient wound care fields. This primer is intended to help intensivists understand hyperbaric oxygen therapy (HBOT) indications and challenges relevant to critical care.
Cite this post as: D. Kurtiss Laipple, BA, DMT, CHT. “Hyperbaric Oxygen Therapy (HBOT) for Intensivists”, eddyjoemd blog, November 20, 2021. Available at: https://eddyjoemd.com/hbot-intensivists/
Finding a Chamber for Intensivists to Provide HBOT
The Resources section at the end of this primer has links to organizations that may assist you in locating your “nearest” critical care enabled chambers. Keep in mind that critical care chambers are rare and becoming rarer due to costs and industry trends.
Once you find one, you can discuss what indications they’re able to help you with, what their after hours emergency number is, if they have a helipad, and any other pertinent information that will help ensure efficient communication and smooth handoffs from and possibly back to your facility, if necessary.
Indications for HBOT in the Critically Ill
Hyperbaric oxygen therapy is currently the primary treatment modality for vascular gas embolism, carbon monoxide poisoning (especially effective against cyanide complications), high altitude sickness and decompression sickness. Critical Care indications for Hyperbarics also include:
- Gas gangrene and necrotizing fasciitis
- Crush injury and compartment syndrome
- Acute peripheral ischemia. It should be noted that there is success treating frostbite and COVID-19 related peripheral ischemia and gangrene using HBOT and Pentoxifylline, although treating under those specific codes instead of acute peripheral ischemia is currently considered off-label.
- Severe hypovolemic anemia
- Intracranial abscess
Contraindications that Intensivists should know about HBOT
The only absolute contraindication to hyperbaric oxygen therapy is untreated pneumothorax due to the lung volume changes accompanying an unvented lung undergoing pressure changes. However, please discuss all comorbidities and medications with the hyperbaric physician, as many of these factors interact with the large increase in blood oxygen levels, so that medications and hyperbaric treatment profiles can be adjusted if needed.
Mechanisms of Action
Hyperbaric oxygen therapy works via several mechanisms to treat patients in a critical care setting. More detailed information and supporting evidence for each indication is available on UHMS.org.
- Hyperoxygenates blood plasma, via Henry’s Law, and reoxygenates ischemic tissue. At a pressure of 3 ATA, which any clinical chamber can reach, a patient could achieve full oxygenation without any RBCs present (Boerema, 1960). This facet is useful in acute ischemic events to preserve tissue and reduce oxygen debt even with RBC and hemoglobin pathologies.
- Reduces leukocyte adhesion and ischemic reperfusion injury. This is useful in crush injuries, compartment syndrome, and peripheral ischemia.
- Mitigates cytokine cascade, inhibits lipid peroxidation, and reduces excessive inflammation. These benefit patients suffering systemic inflammatory events often accompanying other critical care indications.
- Decreases cerebral edema. This is critical for patients with intracranial abscess.
- Shrinks gas bubbles. This helps in treatment of decompression illness, vascular gas embolism, and gas gangrene. Vascular gas embolism sources are mostly iatrogenic, especially from endovascular procedures and radiocontrast injectors, and can be especially dangerous in patients with AV malformations or PFOs.
- Hastens COHb dissociation much more successfully than normobaric O2 alone. This is gold standard for CO poisoning cases.
- Deactivates alpha toxins. This greatly helps treat patients with clostridial infections.
Transport, Preparation and Monitoring
Chamber staff should be consulted as soon as possible for the listed indications as it takes time to end current treatments if necessary, follow chamber disinfection protocols, check chamber compatibility of implanted medical devices, and prepare associated peripherals. Patients should arrive with jewelry and makeup removed, any inflated closed air spaces such as trach cuffs emptied and refilled with water, ostomy and foley bags evacuated and deflated, and the patient already changed into a clean cotton gown or scrubs with no metal. Conscious patients who are nervous about the chamber are often given Lorazepam around 30 minutes before treatment.
It is very important when treating patients with COVID to monitor patient vitals frequently after HBOT as this therapy recruits dysfunctional alveoli and reverses pulmonary shunting by oxygenating through pulmonary fluids and increasing diffusion distance. This can lead to VQ mismatch and decompensation post-treatment, especially endangering patients who feel energized after HBOT and attempt unaccompanied movement from bed.
Hyperbaric oxygen therapy is a valuable immediate primary and adjunctive therapy for several critical care indications, and knowledge of these indications coupled with access to a critical care chamber can improve your clinical outcomes. However, finding a critical care enabled hyperbaric chamber and arranging transport when “time is tissue” are obstacles that should be addressed by critical care teams before the need arises by discussing capabilities and protocols with your nearest chambers.
Divers Alert Network (http://dan.org) provides emergency hyperbaric chamber locations and guidance for diving emergencies.
Undersea and Hyperbaric Medical Society (http://uhms.org) provides accredited chamber locations, HBOT evidence and guidance, and detailed information on HBOT indications, mechanisms, contraindications, regulations, and new developments.
Written by D. Kurtiss Laipple, BA, DMT, CHT. Hat tip to Dick Clarke for his contributions.
Additional Citations Intensivists can use for HBOT
Schneidewind L, Anheuser P, Schönburg S, Wagenlehner FME, Kranz J. Hyperbaric Oxygenation in the Treatment of Fournier’s Gangrene: A Systematic Review. Urol Int. 2021;105(3-4):247-256. doi: 10.1159/000511615. Epub 2020 Dec 7. PMID: 33285541; PMCID: PMC8006587.
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