Extended criteria (experimental). This is the broader ten-condition engine, kept as a secondary area. It shows ICD-10-CM codes and illustrative grouping effects for CDI staff. The primary surface is Before you sign (kidney, measurement only). All extended pages.

Acute hypoxic respiratory failure

Rule respiratory_failure version 2026.11-1 · condition: Acute respiratory failure

Published source

Merck Manual Professional Version: Acute Hypoxemic Respiratory Failure (AHRF), including ARDS (2026). Definition/evaluation: PaO2 <60 mmHg, PaO2/FiO2 <300, or SpO2 <88%, with dyspnea and tachypnea. https://www.merckmanuals.com/professional/critical-care-medicine/respiratory-failure-and-mechanical-ventilation/acute-hypoxemic-respiratory-failure-ahrf-including-acute-respiratory-distress-syndrome-ards · public page checked 2026-11-14

No professional society publishes a single numeric definition for coding purposes; the respiratory-rate cut-off below is a local convention.

Also: Caring for patients in respiratory failure (Am Nurse J 2014): SpO2 <91% on room air, PaCO2 >50 with pH <7.35 (2014). Commonly cited CDI-style thresholds (nursing article, not a guideline). link

Contested or local convention. Organizations use different oxygen-saturation cut-offs (SpO2 <88%, <=90% or <91% on room air). This rule uses <88% (the source above) and a LOCAL respiratory-rate cut-off of 28/min as one sign of respiratory distress.

Inputs

spo2_min_ra: Lowest SpO2 on room air (%)
pao2_min_ra: Lowest PaO2 on room air (mmHg)
pf_min: Lowest PaO2/FiO2 ratio
rr_max: Highest respiratory rate (/min)
o2_max_lpm: Highest supplemental oxygen flow (L/min)
adv_resp_support: High-flow nasal cannula, non-invasive or invasive ventilation charted
wob_increased: Increased work of breathing quoted from a note
home_o2: Home oxygen on the problem list / history

Thresholds

t.spo2_ra: 88
t.pao2: 60
t.pf: 300
t.rr_distress: 28
t.o2_low: 2

Derived values

Evaluated in order
Name	Expression
measured	`present(spo2_min_ra) or present(pao2_min_ra) or present(pf_min)`
hypoxemia	`coalesce(spo2_min_ra < t.spo2_ra, false) or coalesce(pao2_min_ra < t.pao2, false) or coalesce(pf_min < t.pf, false)`
distress	`coalesce(rr_max >= t.rr_distress, false) or coalesce(wob_increased, false) or adv_resp_support`

Outcomes

First true outcome wins; an unknown input makes an outcome unknown
Outcome	When	Status	Supports
chronic_baseline Hypoxaemia in a patient on home oxygen; acute-on-chronic failure needs comparison with the patient's baseline	`home_o2 and hypoxemia`	judgement	—
met Hypoxaemia criterion met with a sign of respiratory distress	`hypoxemia and distress`	supported	J96.01 Acute respiratory failure with hypoxia
hypoxemia_only Hypoxaemia without a charted sign of respiratory distress	`hypoxemia`	judgement	—
not_met No hypoxaemia on room air (lowest SpO2 {spo2_min_ra}%), oxygen no more than {o2_max_lpm} L/min, no advanced support	`measured and not hypoxemia and o2_max_lpm <= t.o2_low and not adv_resp_support`	not_supported	—

ICD-10-CM specificity ladder (FY2026 CC/MCC status as a secondary diagnosis)

R09.02 Hypoxemia · non-CC
J96.00 Acute respiratory failure, unspecified whether with hypoxia or hypercapnia · MCC
J96.01 Acute respiratory failure with hypoxia · MCC (refines J96.00, R09.02)
J96.21 Acute and chronic respiratory failure with hypoxia · MCC (refines J96.01)

Query topic: respiratory documentation · prompts for an undocumented diagnosis: yes

Where clinical judgement is required

Patients on home oxygen are never concluded (baseline needed).
Hypercapnic failure (PaCO2/pH) is not encoded in this reference build.