ICD-10-CM > S00-T88 > T66-T78 > T71 > T71.2 > T71.29 T71.29 Asphyxiation due to being trapped in other low oxygen environment Non-Billable/Non-Specific Codes T71.29XA..., initial encounterT71.29XD..., subsequent encounterT71.29XS..., sequela