Intensive Care Medicine

, Volume 37, Issue 7, pp 1218–1218

Hyperbaric oxygen therapy for acute domestic carbon monoxide poisoning: two randomized controlled trials


Dear Editor,

We read with interest the recent randomized trial of hyperbaric oxygen (HBO) therapy for carbon monoxide (CO) poisoning [1]. This study failed to show a benefit of HBO in mildly ill patients and was terminated prematurely in severely ill patients because of the apparent harm of HBO therapy. We believe that these conclusions are unwarranted because of a critical methodological flaw in the current study.

Carbon monoxide-induced neurological injury most likely results from lipid peroxidation, which is mediated by the migration of inflammatory cells into the CNS [2]. Critical to this process is the ability of neutrophils to adhere to the CNS microvasculature in the areas of inflammation following CO poisoning. Beta-2 integrins on the cell surfaces of neutrophils enable this adherence and can be blocked experimentally at 2.5 or 3.0 atmospheres absolute (ATA), but not at 2.0 ATA [3]. Thus, by using only 2.0 ATA, the current trial could have been predicted to fail. Annane’s results stand in clear distinction to the previous randomized trial that demonstrated a benefit of HBO therapy at 3.0 ATA [4]. The apparent worsening of patients treated with inadequate HBO in the current trial may be reflective of oxygen toxicity in the absence of the benefit offered by HBO at higher pressures.


  1. 1.
    Annane D, Chadda K, Gajdos P, Jars-Guincestre MC, Chevret S, Raphael JC (2011) Hyperbaric oxygen therapy for acute domestic carbon monoxide poisoning: two randomized controlled trials. Intensive Care Med 37:486–492. doi:10.1007/s00134-010-2093-0 PubMedCrossRefGoogle Scholar
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    Tomaszewski C (2011) Carbon Monoxide. In: Nelson LS, Lewin NA, Howland MA (eds) Goldfrank’s toxicologic emergencies, Ninth edn. McGraw Hill, New York, pp 1658–1670Google Scholar
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    Thom SR, Mendiguren I, Hardy K, Bolotin T, Fisher D, Nebolon M, Kilpatrick L (1997) Inhibition of human neutrophil β2-integrin-dependent adherence by hyperbaric O2. Am J Physiol 272:C770–C777PubMedGoogle Scholar
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    Weaver LK, Hopkins RO, Chan KJ, Churchill S, Elliott CG, Clemmer TP, Orme JF Jr, Thomas FO, Morris AH (2002) Hyperbaric oxygen for acute carbon monoxide poisoning. N Engl J Med 347:1057–1067PubMedCrossRefGoogle Scholar

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© Copyright jointly held by Springer and ESICM 2011

Authors and Affiliations

  1. 1.Bellevue Hospital Center and New York City Poison CenterNew YorkUSA

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