Question 2

Critically evaluate the role of hyperbaric oxygen therapy in the management of the critically ill patient.

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College Answer

Critically evaluate implies evaluation (including risk/benefit assessment) is required rather than just providing a list of indications. Many indications are not supported by high levels of evidence. Recognised indications that may be relevant in the critically ill include: decompression sickness, arterial gas embolism, severe carbon monoxide poisoning, aggressive soft tissue infections (e.g. clostridial myonecrosis, necrotising fasciitis and Fournier’s gangrene), and crush injuries. Randomised studies in humans have been performed in carbon monoxide poisoning (with variable results; eg. Scheinkestel MJA 1999, and Weaver NEJM 2002) and crush injuries (with positive results).

Hyperbaric oxygen therapy is not without risks to the patient (including general risks associated with transport , and specific risks of ear and pulmonary barotrauma, and pulmonary and cerebral oxygen toxicity).  The delivery of hyperbaric oxygen to the critically ill also raises some significant logistic problems (including inter-hospital transport), but within centres with expertise these are minimised.  For most indications in the critically ill there is limited human data (eg. case series, retrospective controls etc.), and minimal animal data.

Discussion is required with the hyperbaric unit on a case-by-case basis, and other supportive/adjunctive therapy is essential in all conditions.


There is a good NEJM article from 1996 which goes through the various applications of hyperbaric oxygen therapy. It also describes it as "a good treatment in search of a disease".

A systematic response would resemble the following:


  • 100% FiO2 at 3 times the normal atmospheric pressure equates to a tissue oxygen tension ~ 400mmHg
  • This has been proposed as a treatment for conditions in which tissue oxygenation is for whatever reason reversibly and dangerously impaired.
  • Anaerobic bacteria are unable to reproduce at such a high oxygen tension, and HBOT may improve the effectivenes of antibiotics in such infections.


  • Carbon monoxide poisoning
  • Arterial gas embolism, eg. decompression sickness
  • Clostridial myonecrosis
  • Necrotising fasciitis
  • Refractory osteomyelitis
  • Compromised skin grafts/flaps
  • Severe burns
  • Catastrophic anaemia (life without haemoglobin is possible)
  • Compartment syndrome
  • Burns
  • Radiation necrosis


  • Untreated tension pneumothorax
  • Paraquat toxicity
  • Therapy with the following drugs:
    • Doxorubicin
    • Cisplatin
    • Disulfiram
    • Mafenide
    • Bleomycin

Adverse effects

  • Safe when limited 120 minutes
  • Myopia (revrsible)
  • Cataract formation
  • Rupture of the middle ear and cranial sinuses
  • Seizures
  • Claustrophobia
  • Pulmonary irritation and pulmonary oedema



Shaw, Joshua J., et al. "Not Just Full of Hot Air: Hyperbaric Oxygen Therapy Increases Survival in Cases of Necrotizing Soft Tissue Infections." Surgical infections (2012).


Buckley, Nick A., et al. "Hyperbaric oxygen for carbon monoxide poisoning."Cochrane Database Syst Rev 4 (2011).


Stoekenbroek, R. M., et al. "Hyperbaric Oxygen for the Treatment of Diabetic Foot Ulcers: A Systematic Review." European Journal of Vascular and Endovascular Surgery 47.6 (2014): 647-655.


Eskes, Anne M., et al. "Hyperbaric oxygen therapy: solution for difficult to heal acute wounds? Systematic review." World journal of surgery 35.3 (2011): 535-542.


Tibbles, Patrick M., and John S. Edelsberg. "Hyperbaric-oxygen therapy." New England Journal of Medicine 334.25 (1996): 1642-1648.


Thom, Stephen R. "Hyperbaric oxygen–its mechanisms and efficacy." Plastic and reconstructive surgery 127.Suppl 1 (2011): 131S.