Therapy

Why?

• It improves symptoms and CO levels better than normobaric oxygen at 2 hours, but there is no difference after 12 hours. ^a
• It is less effective than normobaric oxygen - more patients have continued mental retardation requiring further treatment after 3 sessions. ^a
• Patients are more likely to have delayed neurological sequelae and are not clearly less likely to die. ^a
• Chamber-related complications (ear barotrauma, oxygen toxicity, severe claustrophobia) are common. ^a
• It has not been shown to be clearly safe in pregnancy. ^c

Hyperbaric oxygen therapy increases the risk of delayed neurological sequelae.

Patient a	Treatment	Comparison	Outcome	CER	RRR (95% CI)	NNT (95% CI)
carbon monoxide poisoning	normobaric oxygen	hyperbaric oxygen	further treatment required at 3 days	13%	63% (32% to 79%)	5 (3 to 11)
carbon monoxide poisoning	normobaric oxygen	hyperbaric oxygen	chamber complications at 3 days	9.2%	90% (18% to 99%)	12 (7 to 53)
carbon monoxide poisoning	normobaric oxygen	hyperbaric oxygen	delayed neurological sequelae at 4 weeks	5.8%	100%	17 (9 to 120)