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%''' | ||
| − | + | * 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 | ||
** à l'air ambiant '''4 heures''' | ** à l'air ambiant '''4 heures''' | ||
** sous masque à réserve 100%: '''40-50 minutes''' | ** 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 == | == Traitement == | ||
=== Carboxyhémoglobinémie inconnue === | === Carboxyhémoglobinémie inconnue === | ||
| − | * Traitement présomptif par O2 100% durant ''' | + | * Traitement présomptif par O2 100% durant '''4−6 heures'''<ref name="atls">Advanced Trauma Life Support (ATLS) 11e edition 2025</ref> |
| + | |||
=== Carboxyhémoglobinémie <20% === | === Carboxyhémoglobinémie <20% === | ||
* <u>Clinique:</u> peut être asymptomatique<ref name ="atls" /> | * <u>Clinique:</u> peut être asymptomatique<ref name ="atls" /> | ||
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* <u>Clinique:</u> céphalées et nausées (20-30%), confusion (30-40%), coma (40-60%), décès (>60%)<ref name="atls" /> | * <u>Clinique:</u> céphalées et nausées (20-30%), confusion (30-40%), coma (40-60%), décès (>60%)<ref name="atls" /> | ||
* Patients with high levels of carboxyhemoglobin (25% and greater) and evidence of organ ischemia should be treated with hyperbaric oxygen if possible. | * Patients with high levels of carboxyhemoglobin (25% and greater) and evidence of organ ischemia should be treated with hyperbaric oxygen if possible. | ||
| − | |||
== Références == | == Références == | ||
Version actuelle datée du 13 août 2026 à 22:54
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.
