2026 ICD-10-CM Diagnosis Code T71.29XSAsphyxiation due to being trapped in other low oxygen environment, sequela
T71.29XS is a billable ICD-10-CM diagnosis code for asphyxiation due to being trapped in other low oxygen environment, sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 922 through 923. The code is exempt from POA reporting. Coders also document this condition as accidental mechanical suffocation when diving due to insufficient air. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Effect of other external causes, sequela.
Code Identity
Code Classification
Present on Admission (POA)Billing
T71.29XS is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Accidental mechanical suffocation when diving due to insufficient air
- Accidental suffocation due to lack of oxygen in enclosed space
- Accidental suffocation due to lack of oxygen in storage tank
- Asphyxiation by environmental oxygen lack
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Asphyxiation (T71). Use the following options for the applicable episode of care:
- A - initial encounter
- D - subsequent encounter
- S - sequela
Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Convert T71.29XS to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T71.29XSOverview
Is T71.29XS a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report asphyxiation due to being trapped in other low oxygen environment, sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T71.29XS mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the asphyxiation due to being trapped in other low oxygen environment itself has resolved, not the original event.
What MS-DRG does T71.29XS group to?
When asphyxiation due to being trapped in other low oxygen environment, sequela is the principal diagnosis on an inpatient stay, it groups to MS-DRG 922, 923, with relative weights from 1.0177 to 1.7494 depending on complications. Higher weights mean higher Medicare reimbursement.
Is T71.29XS exempt from POA reporting?
Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for asphyxiation due to being trapped in other low oxygen environment, sequela on inpatient claims.
What is the ICD-9 equivalent of T71.29XS?
Under the General Equivalence Mappings, asphyxiation due to being trapped in other low oxygen environment, sequela converts to ICD-9-CM 909.4 (late eff cert ext cause). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
