Oxygenation Index
Mild oxygenation impairment
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Evidence-based calculations Used in clinical settings worldwide Regular monitoring recommended
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Mild (OI <5)
Mild oxygenation impairment
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Moderate (OI 5-15)
Moderate respiratory failure
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Severe (OI 15-25)
Severe ARDS
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Critical (OI >25)
Refractory hypoxemia - consider ECMO
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Sample Scenarios
Mild (OI <5)
Mild oxygenation impairment
Moderate (OI 5-15)
Moderate respiratory failure
Severe (OI 15-25)
Severe ARDS
Critical (OI >25)
Refractory hypoxemia - consider ECMO
Enter Parameters
OI Components
Additional
For informational purposes only — not medical advice. Consult a healthcare professional before acting on results.
🏥 Health Facts
— WHO
— CDC
What is Oxygenation Index?
The Oxygenation Index (OI) is a measure of oxygenation difficulty that accounts for the intensity of ventilatory support. Unlike PF ratio, OI incorporates mean airway pressure, making it a better predictor of outcomes in patients requiring significant ventilatory support. OI >25 is commonly used as an ECMO referral criterion.
OI <5
Mild
OI 5-15
Moderate
OI 15-25
Severe
OI >25
Consider ECMO
OI vs PF Ratio Comparison
| Feature | Oxygenation Index | PF Ratio |
|---|---|---|
| Formula | (MAP × FiO2) / PaO2 | PaO2 / FiO2 |
| Accounts for MAP | Yes | No |
| Prognostic value | Superior in severe ARDS | Good |
| ECMO criteria | Primary metric | Secondary |
Berlin ARDS Definition
- • Timing: Within 1 week of clinical insult or new/worsening respiratory symptoms
- • Imaging: Bilateral opacities not fully explained by effusions, collapse, or nodules
- • Origin: Not fully explained by cardiac failure or fluid overload
- • Mild: PF ratio 200-300 (PEEP ≥5)
- • Moderate: PF ratio 100-200 (PEEP ≥5)
- • Severe: PF ratio ≤100 (PEEP ≥5)
ECMO Referral Criteria
- • OI >25: For 6+ hours despite optimal management
- • OI >40: At any time - urgent referral
- • PF ratio <80: With FiO2 ≥80% for 6+ hours
- • PF ratio <50: With FiO2 ≥80% for 3+ hours
- • Reversible cause: Underlying condition must be treatable
- • No contraindications: Check for exclusion criteria
ECMO Contraindications
Absolute
- • Irreversible underlying condition
- • Severe CNS injury
- • Uncontrolled bleeding
- • Contraindication to anticoagulation
Relative
- • Prolonged mechanical ventilation (>7 days)
- • Immunosuppression
- • Advanced age
- • Multiple organ failure
Mean Airway Pressure (MAP)
- • Definition: Average pressure during entire respiratory cycle
- • Determinants: PIP, PEEP, I:E ratio, flow pattern
- • Normal: 10-15 cmH2O on conventional ventilation
- • ARDS: May be 15-25+ cmH2O
- • Effect on OI: Higher MAP → higher OI (worse)
Lung Protective Ventilation in ARDS
- • Tidal volume: 6-8 mL/kg ideal body weight
- • Plateau pressure: ≤30 cmH2O
- • Driving pressure: ≤15 cmH2O (Pplat - PEEP)
- • PEEP: Titrate using PEEP-FiO2 table or EIT
- • Allow permissive hypercapnia: pH >7.20 acceptable
- • Goal: Minimize VILI while maintaining acceptable oxygenation
Prone Positioning
- • Indication: Moderate-severe ARDS (PF <150)
- • Duration: ≥16 hours per session (PROSEVA protocol)
- • Mechanism: Improves V/Q matching, reduces atelectasis
- • Effect on OI: May significantly reduce OI
- • Timing: Early prone (within 36 hours) most beneficial
- • Mortality benefit: 16% vs 33% in PROSEVA trial
Neuromuscular Blockade
- • Consider if: Severe ARDS with PF <150
- • Duration: Early use, typically 48 hours
- • Mechanism: Improves ventilator synchrony, reduces O2 consumption
- • Agent: Cisatracurium commonly used
- • ROSE trial: No mortality benefit, consider case-by-case
Step-by-Step OI Calculation
- Obtain mean airway pressure from ventilator (cmH2O)
- Note FiO2 setting (as percentage, e.g., 60%)
- Obtain arterial blood gas for PaO2 (mmHg)
- Calculate: OI = (MAP × FiO2) / PaO2
- Example: MAP=18, FiO2=70%, PaO2=65 → OI = (18 × 70) / 65 = 19.4
- Interpret: OI 19.4 = Severe ARDS
Clinical Pearls
- • OI > PF ratio: Better for severe cases needing high MAP
- • Trending: Serial OI more useful than single value
- • ECMO timing: Earlier referral with OI >25 improves outcomes
- • Don't wait: Contact ECMO center early, not as last resort
- • Optimize first: Ensure lung-protective ventilation before ECMO decision
Clinical Scenario Examples
Scenario 1: Mild ARDS
MAP 12, FiO2 40%, PaO2 85. OI = (12 × 40) / 85 = 5.6. Category: Moderate - optimize ventilation, monitor closely.
Scenario 2: Severe ARDS
MAP 20, FiO2 80%, PaO2 55. OI = (20 × 80) / 55 = 29.1. Category: Critical - ECMO evaluation needed.
Scenario 3: Refractory Hypoxemia
MAP 24, FiO2 100%, PaO2 45. OI = (24 × 100) / 45 = 53.3. Category: Critical - URGENT ECMO referral.
Key Formulas
- OI: (MAP × FiO2) / PaO2
- PF Ratio: PaO2 / FiO2 (decimal)
- A-a Gradient: (FiO2 × 713) - (PaCO2 / 0.8) - PaO2
- OSI (SpO2-based): (MAP × FiO2) / SpO2
OI Calculator Summary
Mild
<5
Moderate
5-15
Severe
15-25
ECMO
>25
Documentation Guide
- • Date/Time: When OI calculated
- • Ventilator settings: Mode, TV, FiO2, PEEP, MAP
- • ABG results: PaO2, PaCO2, pH
- • OI value: Calculated result and category
- • Clinical response: Actions taken based on OI
- • Trend: Compare to previous values
Key References
ELSO Guidelines
Extracorporeal Life Support Organization guidelines for adult respiratory failure.
Berlin Definition (2012)
ARDS Definition Task Force. ARDS: The Berlin Definition. JAMA.
PROSEVA Trial (2013)
Guerin et al. Prone positioning in severe ARDS. NEJM.
Memory Aids
- • "OI of 5-15-25" - The severity cutoffs
- • "25 for 6 hours" - ECMO evaluation trigger
- • "MAP times FiO2 over PaO2" - Formula
- • "Higher is worse" - Unlike PF ratio
- • "40 is urgent" - Very high mortality
Key Takeaways
- • OI accounts for ventilatory support intensity (MAP)
- • Superior to PF ratio for severe ARDS prognostication
- • OI >25 warrants ECMO evaluation
- • Serial measurements track response to therapy
- • Optimize conventional therapy before ECMO
- • Early ECMO referral improves outcomes
Important Disclaimer
The Oxygenation Index is one component of respiratory failure assessment. Clinical decisions, especially regarding ECMO, require comprehensive evaluation including reversibility of underlying condition, comorbidities, and institutional expertise. Always consult with critical care specialists and ECMO centers for patients with severe respiratory failure.
Types of ECMO
VV-ECMO (Veno-Venous)
- • For respiratory failure only
- • Drains venous blood, returns oxygenated blood
- • Heart must be functioning
- • Most common for ARDS
VA-ECMO (Veno-Arterial)
- • For cardiac ± respiratory failure
- • Provides circulatory support
- • More complex, higher risk
- • May cause differential hypoxia
ECMO Cannulation Strategies
- • Femoral-jugular: Drain from femoral, return to jugular
- • Dual-lumen: Single jugular cannula for both
- • Femoral-femoral: For VA-ECMO
- • Hybrid configurations: For specific clinical needs
- • Flow goals: 50-70 mL/kg/min for adequate support
Ventilator Settings on ECMO
- • Ultra-protective: TV 2-4 mL/kg, minimal FiO2
- • Low PEEP: 5-10 cmH2O to keep lungs open
- • Rest settings: Allow lung recovery
- • FiO2 via ECMO: Sweep gas provides oxygenation
- • Goal: Lung rest, prevent further VILI
ECMO Weaning Criteria
- • Improving compliance: Lung recovery evident
- • CXR improvement: Clearing infiltrates
- • Lower support: Able to reduce ECMO flow
- • Sweep gas trial: Reduce sweep to assess native lung
- • OI decreasing: Shows native lung improvement
- • Trial off: Short trial with clamped circuit
ECMO Complications
Bleeding
- • Anticoagulation required
- • Cannulation site bleeding
- • GI bleeding
- • Intracranial hemorrhage
Thrombosis
- • Circuit thrombosis
- • Limb ischemia
- • Stroke
- • PE (paradoxical)
Pediatric OI Considerations
- • Same formula: OI = (MAP × FiO2) / PaO2
- • Different thresholds: Lower OI may warrant action
- • OSI available: When ABG not feasible (SpO2 based)
- • ECMO criteria: Generally OI >25 or OI >40
- • Neonatal ECMO: Well-established for specific diagnoses
Oxygen Saturation Index (OSI)
- • Formula: OSI = (MAP × FiO2) / SpO2
- • Use: When arterial blood gas not available
- • Limitation: Less accurate with high FiO2 (SpO2 plateaus)
- • Correlation: OSI correlates with OI in pediatric studies
- • Cut-offs: Not as well established as OI
Rescue Therapies for Refractory Hypoxemia
- • Prone positioning: First-line rescue, proven mortality benefit
- • Neuromuscular blockade: Consider in severe ARDS
- • Inhaled pulmonary vasodilators: iNO, epoprostenol
- • High-frequency oscillatory ventilation: Limited evidence
- • Recruitment maneuvers: With caution
- • ECMO: Ultimate rescue for eligible patients
Inhaled Pulmonary Vasodilators
- • Inhaled nitric oxide (iNO): Selectively dilates pulmonary vasculature
- • Dose: Typically 5-20 ppm
- • Effect: Improves V/Q matching, reduces OI
- • Mortality: No proven survival benefit
- • Use: Bridge to other therapies, refractory hypoxemia
- • Epoprostenol: Alternative inhaled prostacyclin
OI Trending and Interpretation
- • Improving: Decreasing OI suggests lung recovery
- • Worsening: Increasing OI suggests deterioration
- • Plateau: May need therapy escalation
- • Response to prone: Often see OI decrease within hours
- • Document trend: Serial values more useful than single
Common Questions
Why use OI instead of PF ratio?
OI incorporates mean airway pressure, so it accounts for how much ventilatory support is needed. Two patients with PF ratio of 100 may have very different OIs if one needs MAP of 10 vs 25.
When should I contact an ECMO center?
Contact early when OI approaches 25, especially if trajectory is worsening. Don't wait until OI is >40 - earlier referral leads to better outcomes.
How often should I calculate OI?
In severe ARDS, calculate with each ABG or significant ventilator change. Trending OI helps assess response to interventions like prone positioning.
Common Causes of ARDS
Direct (Pulmonary)
- • Pneumonia (most common)
- • Aspiration
- • Pulmonary contusion
- • Inhalation injury
- • Near-drowning
Indirect (Extrapulmonary)
- • Sepsis
- • Pancreatitis
- • Multiple transfusions (TRALI)
- • Trauma
- • Burns
Step-by-Step ARDS Management
- Confirm ARDS diagnosis (Berlin criteria)
- Calculate OI and PF ratio
- Initiate lung-protective ventilation (TV 6 mL/kg IBW)
- Optimize PEEP (PEEP-FiO2 table)
- Target Pplat ≤30, driving pressure ≤15
- Consider prone if PF <150
- Consider NMB if severe dyssynchrony
- If OI >25 despite optimization → contact ECMO center
Final Clinical Summary
The Oxygenation Index (OI) is a valuable metric for assessing severity of oxygenation failure that incorporates mean airway pressure. Unlike PF ratio alone, OI accounts for the intensity of ventilatory support required. OI >25 sustained for 6+ hours despite lung-protective ventilation and adjunctive therapies warrants ECMO evaluation. Early referral improves outcomes.
Mild
<5
Moderate
5-15
Severe
15-25
ECMO
>25
Additional Resources
- • Extracorporeal Life Support Organization (ELSO) - elso.org
- • Society of Critical Care Medicine - sccm.org
- • ARDSNet - ardsnet.org
- • European Society of Intensive Care Medicine - esicm.org
- • Critical Care Reviews - criticalcarereviews.com
Quick Reference Card
- • OI Formula: (MAP × FiO2) / PaO2
- • Mild: OI <5
- • Moderate: OI 5-15
- • Severe: OI 15-25
- • ECMO threshold: OI >25 for 6+ hours
- • Urgent ECMO: OI >40 at any time
Fluid Management in ARDS
- • Conservative strategy: FACTT trial showed benefit
- • Goal: CVP <4 or PAOP <8 if tolerated
- • Diuretics: Furosemide to achieve negative balance
- • Avoid: Excessive fluid resuscitation
- • Effect: May improve oxygenation and reduce OI
- • Balance: Against tissue perfusion needs
Sedation and Analgesia
- • Light sedation: When possible (RASS -1 to 0)
- • Deep sedation: May be needed for severe ARDS
- • Paralysis: Consider for severe dyssynchrony
- • Daily awakening: When patient stable enough
- • ABCDEF bundle: Integrate into ICU care
COVID-19 ARDS Considerations
- • Phenotypes: May present with preserved compliance initially
- • PEEP response: Variable - individualize
- • Prone positioning: Very effective in COVID ARDS
- • ECMO: Used extensively during pandemic
- • Steroids: Dexamethasone showed mortality benefit
- • Prolonged duration: May have longer recovery
Driving Pressure Importance
- • Definition: Plateau pressure - PEEP
- • Target: ≤15 cmH2O
- • Significance: Best predictor of survival (Amato 2015)
- • Mechanism: Reflects lung strain
- • Optimization: Prioritize over TV or plateau alone
ARDSNet Protocol Highlights
- • Tidal volume: 6 mL/kg ideal body weight
- • Plateau pressure: ≤30 cmH2O
- • RR: Set to achieve minute ventilation (max 35)
- • pH target: 7.30-7.45 (permissive hypercapnia ok)
- • SpO2 target: 88-95%
- • PEEP-FiO2 table: Standardized approach
Landmark ARDS Trials
ARMA (2000)
Low tidal volume (6 vs 12 mL/kg) reduced mortality by 22%. Established lung-protective ventilation.
PROSEVA (2013)
Prone positioning ≥16 hours in severe ARDS reduced 28-day mortality (16% vs 33%).
CESAR (2009)
Transfer to ECMO center improved survival in severe ARDS.
OI and Mortality Prediction
- • OI <5: Mortality <10%
- • OI 5-15: Mortality 10-30%
- • OI 15-25: Mortality 30-50%
- • OI 25-40: Mortality 50-70%
- • OI >40: Mortality >70% without ECMO
- • ECMO survival: ~50-60% in selected patients
Timing of ECMO Initiation
- • Earlier is better: Don't wait until all else fails
- • Optimal window: OI >25 for 6 hours despite optimization
- • Too early: Some patients will improve without ECMO
- • Too late: Worse outcomes, more complications
- • Duration of MV: >7 days associated with worse outcomes
ECMO Transport Considerations
- • Retrieval teams: Specialized ECMO transport teams
- • Mobile ECMO: Initiate at referring hospital, transport on ECMO
- • Logistics: Air vs ground based on distance
- • Coordination: Early communication with ECMO center
- • Equipment: Portable ECMO systems available
Clinical Workflow for Severe ARDS
- Calculate OI with each ABG
- If OI 15-25: Ensure lung-protective ventilation, consider prone
- If OI >25: Intensify conventional therapy, contact ECMO center
- If OI >25 for 6+ hours: Strong consideration for ECMO
- If OI >40: Urgent ECMO evaluation
- Document OI trend and therapies tried
Summary Table
- • Purpose: Assess oxygenation accounting for support
- • Advantage: Incorporates MAP (ventilator effort)
- • Formula: (MAP × FiO2) / PaO2
- • Higher = worse: Unlike PF ratio
- • ECMO trigger: OI >25 sustained
- • Use: Serial measurements for trending
OI Calculator Final Summary
Mild
<5
Continue MV
Moderate
5-15
Optimize
Severe
15-25
Rescue therapies
Critical
>25
Consider ECMO
Final Disclaimer
This calculator provides oxygenation index calculations for educational purposes. Management of severe respiratory failure requires expertise in critical care medicine. ECMO decisions involve complex considerations beyond OI alone, including reversibility, comorbidities, and institutional capabilities. Always consult with critical care specialists and ECMO centers for severe cases.
ARDS Phenotypes
Hypo-inflammatory
- • Lower inflammatory markers
- • Better outcomes
- • Less responsive to corticosteroids
- • Often post-operative
Hyper-inflammatory
- • Higher inflammatory markers
- • Worse outcomes
- • May benefit from corticosteroids
- • Often sepsis-related
Corticosteroids in ARDS
- • Dexamethasone: Proven benefit in severe COVID-19
- • DEXA-ARDS: Dexamethasone reduced mortality in moderate-severe ARDS
- • Timing: Early initiation (within 14 days of ARDS onset)
- • Duration: Typically 10 days with taper
- • Caution: May increase infections, hyperglycemia
Ventilator Dyssynchrony
- • Definition: Mismatch between patient and ventilator
- • Types: Double triggering, breath stacking, flow starvation
- • Effect: Increases work of breathing, may worsen VILI
- • Detection: Examine ventilator waveforms
- • Management: Adjust settings, sedation, or paralysis
Dead Space in ARDS
- • Increased: ARDS causes increased dead space
- • Prognostic: High dead space = worse prognosis
- • Calculation: Vd/Vt = (PaCO2 - EtCO2) / PaCO2
- • Normal: ~30% - may be >60% in severe ARDS
- • Clinical effect: Difficult to ventilate, need higher RR
Oxygenation Targets in ARDS
- • SpO2: 88-95% (ARDSNet)
- • PaO2: 55-80 mmHg
- • Liberal vs conservative: ICU-ROX showed no difference
- • Avoid hyperoxia: May cause harm
- • Permissive hypoxemia: Acceptable to avoid high FiO2/PEEP
PEEP Titration Strategies
- • PEEP-FiO2 tables: Low or high PEEP tables (ARDSNet)
- • Esophageal pressure: Target transpulmonary pressure
- • EIT: Electrical impedance tomography for optimal PEEP
- • Best compliance: PEEP that maximizes compliance
- • Driving pressure: PEEP that minimizes driving pressure
Recruitment Maneuvers
- • Purpose: Open collapsed alveoli
- • Methods: Sustained inflation, incremental PEEP, sigh breaths
- • Evidence: ART trial showed harm with aggressive RMs
- • Current approach: Use cautiously, monitor closely
- • Risk: Barotrauma, hemodynamic compromise
Monitoring on ECMO
- • Circuit pressures: Pre-membrane, post-membrane
- • Sweep gas: Adjust for CO2 clearance
- • FiO2 sweep: Adjust for oxygenation
- • Blood flow: Monitor for adequate support
- • Hemolysis: Monitor plasma-free Hgb
- • Anticoagulation: ACT or anti-Xa monitoring
Nutrition in ARDS
- • Early EN: Within 24-48 hours if possible
- • Trophic feeds: Consider in early severe ARDS
- • Target: Gradual advancement to goal
- • Prone feeding: Possible with monitoring
- • ECMO: Continue nutrition, monitor for GI issues
Prognostic Factors in ARDS
- • OI: Higher OI = worse prognosis
- • Dead space: High Vd/Vt associated with mortality
- • Driving pressure: >15 cmH2O associated with worse outcomes
- • Age: Older patients have worse outcomes
- • Comorbidities: Immunosuppression, chronic disease
- • Etiology: Sepsis ARDS has worse prognosis
Final Memory Aids
- • "5-15-25" - OI severity cutoffs
- • "MAP times FiO2 over PaO2" - Formula
- • "25 for 6" - ECMO consideration trigger
- • "40 is urgent" - Very high risk
- • "Higher OI is worse" - Unlike PF ratio
- • "Trend over time" - Serial monitoring
Severe ARDS Checklist
- • ☐ Calculate OI and PF ratio
- • ☐ Lung-protective ventilation (TV 6 mL/kg IBW)
- • ☐ Pplat ≤30, driving pressure ≤15
- • ☐ Consider prone positioning if PF <150
- • ☐ Consider NMB if dyssynchrony
- • ☐ Conservative fluid strategy
- • ☐ If OI >25 sustained → contact ECMO center
Final Safety Note
Oxygenation Index is a critical metric for assessing severity of respiratory failure. Management of severe ARDS requires ICU-level care with expertise in mechanical ventilation. ECMO decisions should involve multidisciplinary discussion and consultation with ECMO centers. Early referral improves outcomes - don't wait until conventional therapy fails completely.
Final Reference Values
- • OI Mild: <5
- • OI Moderate: 5-15
- • OI Severe: 15-25
- • OI Critical: >25 (consider ECMO)
- • OI Very severe: >40 (urgent ECMO)
- • Formula: (MAP × FiO2) / PaO2
Long-term Outcomes After ARDS
- • Pulmonary function: Usually recovers but may have residual restriction
- • DLCO: May remain reduced
- • ICU-acquired weakness: Common, requires rehab
- • Cognitive impairment: Memory, attention issues
- • PTSD/depression: Significant psychological burden
- • Quality of life: May be impaired at 1-2 years
Post-ARDS Rehabilitation
- • Early mobilization: Begin in ICU when stable
- • Physical therapy: Address weakness, deconditioning
- • Pulmonary rehab: Improve exercise tolerance
- • Occupational therapy: ADL assessment and training
- • Psychological support: Screen for PTSD, depression
Post-Intensive Care Syndrome (PICS)
- • Physical: Weakness, fatigue, dyspnea
- • Cognitive: Memory, attention, executive function
- • Mental health: Anxiety, depression, PTSD
- • Prevention: ABCDEF bundle during ICU stay
- • Follow-up: ICU follow-up clinics recommended
Goals of Care Discussions
- • When: Early in severe ARDS, especially if OI >25
- • Topics: Prognosis, treatment options including ECMO
- • Patient values: Quality of life considerations
- • Family: Include in discussions, provide support
- • Documentation: Document discussions and decisions
ELSO Adult Respiratory ECMO Indications
- • Hypoxemic: PF ratio <100 on FiO2 >90%
- • Hypoxemic: PF ratio <80 on FiO2 >80% for 6 hours
- • OI based: OI >25 for 6+ hours
- • OI based: OI >40 at any time
- • Hypercapnic: pH <7.20 with CO2 retention despite RR 35
Clinical Decision Summary
- • OI <5: Continue standard care, monitor
- • OI 5-15: Optimize ventilation, consider adjuncts
- • OI 15-25: Lung-protective strategy, prone, consider NMB
- • OI >25: Contact ECMO center, maximize conventional therapy
- • OI >40: Urgent ECMO evaluation
Quick Reference Summary
- • OI formula: (MAP × FiO2) / PaO2
- • Severity: <5 mild, 5-15 moderate, 15-25 severe, >25 ECMO
- • Advantage: Accounts for ventilatory support (MAP)
- • ECMO trigger: OI >25 for 6 hours, OI >40 urgent
- • Trending: Serial values show response to therapy
- • Resources: elso.org for ECMO guidelines
Predictors of ECMO Success
- • Younger age: Better outcomes in younger patients
- • Single organ failure: Respiratory only vs multi-organ
- • Short MV duration: <7 days before ECMO
- • Reversible cause: Clear etiology that can resolve
- • No CNS injury: Neurologically intact pre-ECMO
- • Center experience: High-volume centers have better outcomes
Neonatal ECMO Indications
- • OI >40: Threshold for neonatal ECMO consideration
- • OI >25: For 4-6 hours despite maximal therapy
- • CDH: Congenital diaphragmatic hernia
- • MAS: Meconium aspiration syndrome
- • PPHN: Persistent pulmonary hypertension of newborn
- • Weight: Generally >2 kg, >34 weeks GA
Final Clinical Reference Card
- • OI Calculation: (MAP × FiO2) / PaO2
- • Mild (<5): Continue standard ventilation
- • Moderate (5-15): Optimize settings, monitor
- • Severe (15-25): Lung-protective strategy, prone
- • Critical (>25): Contact ECMO center
- • Urgent (>40): Immediate ECMO evaluation
- • Documentation: Serial OI with ABG and settings
Complete Reference Values
- • OI Mild: <5 - mortality <10%
- • OI Moderate: 5-15 - mortality 10-30%
- • OI Severe: 15-25 - mortality 30-50%
- • OI Critical: 25-40 - mortality 50-70%
- • OI Very severe: >40 - mortality >70%
- • ECMO threshold: OI >25 for 6+ hours
- • ECMO urgent: OI >40 at any time
- • ECMO survival: ~50-60% in appropriate candidates
- • Berlin ARDS: Mild PF 200-300, Moderate 100-200, Severe ≤100
- • Prone duration: ≥16 hours per session (PROSEVA)
- • Driving pressure: ≤15 cmH2O target
- • Plateau pressure: ≤30 cmH2O target
- • Tidal volume: 6 mL/kg ideal body weight
- • Resources: ELSO (elso.org), ARDSNet (ardsnet.org)
- • OSI formula: (MAP × FiO2) / SpO2 (when ABG unavailable)
- • Contact ECMO: Early referral improves outcomes
- • VV-ECMO: Respiratory failure only (most common for ARDS)
- • VA-ECMO: Combined cardiac and respiratory failure
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