Carbon monoxide poisoning: pregnancy: hyperbaric oxygen was probably safe.

Clinical bottom line (level 4)

  1. Around a third of pregnant women exposed to carbon monoxide who had hyperbaric oxygen still have at least one symptom of poisoning after one month.
  2. Around 8% will had an abnormal birth.
Elkharrat et al: Intensive Care Medicine 1991; 17: 289-292
Expires July 2003

The study

Case series with objective outcomes, not adjusted for confounding factors, not validated in an independent set of patients.

Setting: university hospital, France

44 patients (aged mean 28 years, 100% female) pregnant women with acute carbon monoxide intoxication at home, and HbCO level upon admission >5% (non-smokers) or 10% (smokers) (mean 19%+/- 11%)

Excluded if
  • multiple intoxications (ie. CO combined with another toxic gas or drugs)
  • contraindication to hyperbaric therapy
  • hyperbaric therapy technically unfeasible within 24 hours of exposure


    • All patients had two hours of hyperbaric oxygenation at 100% oxygen, with 0.5 hour for compression, 1 hour at two atmospheres, and 0.5 h for decompensation. This was accompanied by a total of 4 h of normobaric oxygenation.

    86% followed for to term
    Outcomes studied:
  • mother symptomatic one or more maternal symptom at 1 month
  • abnormal birth

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    mother symptomatic to term 10/35 29%
    (14% to 44%)
    abnormal birth to term 3/38 7.9%
    (0.0% to 14%)

    • Twelve women sustained either loss of consciousness or coma, while the remainder had less severe symptoms at presentation.

    Comments

    1. Although this study is a case series, it does suggest that hyperbaric oxygen delivery at two atmospheres is not harmful to the foetus (abnormal births- two spontaneous early deliveries and one case of trisomy 21). However, only short-term assessment of the neonate was made, thus not allowing for later developmental sequelae to manifest, if present.

    Citation

    1. Elkharrat D, Raphael JC, Korach JM, et al: Acute carbon monoxide intoxication and hyperbaric oxygen in pregnancy. Intensive Care Medicine 1991; 17: 289-292
    Contributor: Joel Ray and Chris Ball, July 2000
    Reviewer:

    Clinical Question.
    Patient pregnant women
    Intervention or Exposure CO poisoning
    Outcome further complications