HWN Suggests

Carbon Monoxide Poisoning…in a Rush

For all patients where you suspect carbon monoxide poisoning, immediately place patient on 100% non re-breather oxygen face mask until patient is asymptomatic. If patient is pregnant, the patient should be on 100% non re-breather oxygen face mask for 5x the length of time needed for carbon monoxide level to be less than 5%. The goal is to continue therapy until COHb level is less than 10, or less than 5 for pregnant patients. For more moderate or severe symptoms or CoHb > 25, consider end organ damage, and thus can obtain EKG/troponin, ABG with lactate, chemistry panel, CT head noncontrast for patients with neurological disturbances looking for cerebral edema or basal ganglia defects (literature…

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 Tox in The Land: Carbon Monoxide

Per ACEP Clinical Policy: Emergency physicians should use HBO2 therapy or high flow normobaric therapy for acute CO poisoned patients. It remains unclear whether HBO2 therapy is superior to normobaric oxygen therapy for improving long term neurocognitive outcomes. (Level B recommendation). A Cochrane review from 2011 examined six clinical trials; two were positive trials showing decreased neurologic sequelae, and the remaining four trials failed to demonstrate a benefit. However, all of the studies suffered from various degrees of methodologic flaws, and it was unclear whether hyperbaric oxygen improves long-term neurocognitive outcomes. Two additional trials published since the Cochrane review were negative.

Articles of Interest

Carbon monoxide poisoning (acute)

Carbon monoxide poisoning is considered to be one of the leading causes of death and injury worldwide, and is a major public health problem.

Carbon Monoxide Poisoning In Children: Diagnosis And Management In The Emergency Department

Although the mainstay of treatment is 100% oxygen, the current evidence and controversies in the use of hyperbaric oxygen therapy in pediatric patients is reviewed, along with its possible benefit in preventing delayed neurologic sequelae.

Carbon Monoxide Poisoning: Common Questions and Dilemmas

Carbon monoxide poisoning is a common situation encountered by emergency physicians with often challenging decisions regarding appropriate treatment and disposition due to conflicting data. Based on the available data and consensus recommendations, there isn’t an absolute answer regarding HBO therapy at this time. While standard treatment involves administering 100% oxygen, the jury is still out regarding the utility of HBO therapy. The decision to use HBO therapy should be made based on an individual patient basis and will largely depend on the institution and feasibility of getting your patient to a hyperbaric chamber.

Hyperbaric oxygen for acute carbon monoxide poisoning

While it is common practice in emergency medicine to treat carbon monoxide poisoning, the verdict is still out on whether or not there is true benefit for hyperbaric therapy over normobaric therapy.

Hyperbaric Oxygen for Carbon Monoxide Poisoning

ACEP Guidelines for acute carbon monoxide poisoning offer a lukewarm Level C recommendation stating that “HBO is a therapeutic option for CO-poisoned patients; however, its use cannot be mandated.” Our review of the highest quality literature concurred with the ACEP Guideline...

Resources

EMCrit Project

Although many references relate carboxyhemoglobin level to symptoms, this appears to be a myth. There is no validated relationship between carboxyhemoglobin levels and specific symptoms.

Life in the Fastlane

High flow O2 via NRB until asymptomatic (or for 24 hours while fetal wellbeing is assessed if pregnant) •consider transfer to hyperbaric facility (severe intoxication or persistent symptoms after 4 hrs) •hyperbaric O2 (3 ATM) will decrease the half life of carboxyHb from 6 hours -> 24 minutes •if associated with cyanide intoxification and nitrites use -> sodium thiosulphate 12.5mg IV (this will prevent left shift of oxy-Hb curve)

Maimonides Emergency Medicine

If the patient is only mildly symptomatic, they can be discharged after 4 hours of observation, symptom resolution, and return of COHb level to normal. COHb levels of >25% (>15% in pregnant patients) should make you think about hyperbaric oxygen therapy (board world). In the real world, if a patient has severe symptoms (LOC, AMS, coma, cardiac ischemia), you should consider HBO.

CDC

Administer 100% oxygen until the patient is symptom-free, usually about 4-5 hours. Serial neurologic exams should be performed to assess progress, and to detect the signs of developing cerebral edema.

WikEM

A "great mimicker" due to the presentation of poisoning being diverse and nonspecific.