Différences entre versions de « Intoxication au monoxyde de carbone »
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Cited indications for hyperbaric oxygen therapy include loss of consciousness, ischemic cardiac changes, neurological deficits, significant metabolic acidosis, or carboxyhemoglobin level greater than 25%. A carboxyhemoglobin level of 50% is critical and needs to be reduced as quickly as possible. Breathing 100% oxygen at normal atmospheric pressure, this patient will clear the carboxyhemoglobin with a half-life of 90 minutes, but hyperbaric oxygen therapy will lower the half-life to 30 minutes. Also, there is considerable risk of delayed neurocognitive impairment following a severe exposure such as this, and hyperbaric oxygen is believed to lower the risk of this long-term complication, although the strength of this evidence is disputed.<ref>https://mksap18.acponline.org/app/topics/pm/mk18_b_pm_s13/mk18_b_pm_s13_7_2</ref> | Cited indications for hyperbaric oxygen therapy include loss of consciousness, ischemic cardiac changes, neurological deficits, significant metabolic acidosis, or carboxyhemoglobin level greater than 25%. A carboxyhemoglobin level of 50% is critical and needs to be reduced as quickly as possible. Breathing 100% oxygen at normal atmospheric pressure, this patient will clear the carboxyhemoglobin with a half-life of 90 minutes, but hyperbaric oxygen therapy will lower the half-life to 30 minutes. Also, there is considerable risk of delayed neurocognitive impairment following a severe exposure such as this, and hyperbaric oxygen is believed to lower the risk of this long-term complication, although the strength of this evidence is disputed.<ref>https://mksap18.acponline.org/app/topics/pm/mk18_b_pm_s13/mk18_b_pm_s13_7_2</ref> | ||
| − | == | + | == Physiopathologie == |
* Carboxyhémoglobinémie normale: '''<3%''' | * Carboxyhémoglobinémie normale: '''<3%''' | ||
* Carboxyhémoglobinémie chez les fumeurs: '''10%-15%''' | * Carboxyhémoglobinémie chez les fumeurs: '''10%-15%''' | ||
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* Affinité du CO pour l'hémoglobine 200× supérieure à celle de l'O<sub>2</sub> | * Affinité du CO pour l'hémoglobine 200× supérieure à celle de l'O<sub>2</sub> | ||
* Demi-vie approximative d'élimination du monoxyde de carbone<ref name="atls" />: | * Demi-vie approximative d'élimination du monoxyde de carbone<ref name="atls" />: | ||
Version du 13 août 2026 à 22:45
Cited indications for hyperbaric oxygen therapy include loss of consciousness, ischemic cardiac changes, neurological deficits, significant metabolic acidosis, or carboxyhemoglobin level greater than 25%. A carboxyhemoglobin level of 50% is critical and needs to be reduced as quickly as possible. Breathing 100% oxygen at normal atmospheric pressure, this patient will clear the carboxyhemoglobin with a half-life of 90 minutes, but hyperbaric oxygen therapy will lower the half-life to 30 minutes. Also, there is considerable risk of delayed neurocognitive impairment following a severe exposure such as this, and hyperbaric oxygen is believed to lower the risk of this long-term complication, although the strength of this evidence is disputed.[1]
Physiopathologie
- Carboxyhémoglobinémie normale: <3%
- Carboxyhémoglobinémie chez les fumeurs: 10%-15%
- Affinité du CO pour l'hémoglobine 200× supérieure à celle de l'O2
- Demi-vie approximative d'élimination du monoxyde de carbone[2]:
- à l'air ambiant 4 heures
- sous masque à réserve 100%: 40-50 minutes
Diagnostic
- Lors d'intoxication au CO, l'oxymètre de pouls peut indiquer une saturation normale (98-100%) → pratiquer une gazométrie artérielle
Traitement
Carboxyhémoglobinémie inconnue
- Traitement présomptif par O2 100% durant 4−6 heures[2]
Carboxyhémoglobinémie <20%
- Clinique: peut être asymptomatique[2]
Carboxyhémoglobinémie >20%
- Clinique: céphalées et nausées (20-30%), confusion (30-40%), coma (40-60%), décès (>60%)[2]
- Patients with high levels of carboxyhemoglobin (25% and greater) and evidence of organ ischemia should be treated with hyperbaric oxygen if possible.
- Methylene blue would be recommended for toxic levels of methemoglobin, usually 20% to 30% or higher.
