Multiple Organ Dysfunction Syndrome (MODS) Diagnostic Criteria
MODS is diagnosed when two or more organ systems demonstrate dysfunction following an identifiable trigger event, with specific physiological thresholds defining failure in each of seven organ systems. 1
Core Diagnostic Requirements
To establish a diagnosis of MODS, two essential elements must be present:
- Identification of the precipitating cause (sepsis, trauma, burns, cardiogenic shock, or other inflammatory insult) 1, 2
- Dysfunction in two or more organ systems based on specific physiological criteria 1, 3
Organ-Specific Dysfunction Criteria
Cardiovascular System
Any one of the following indicates cardiovascular dysfunction 1:
- Systolic blood pressure <90 mmHg
- Mean arterial pressure <70 mmHg
- Clinical signs of shock
- Ventricular tachycardia or ventricular fibrillation
- Myocardial infarction
Respiratory System
Respiratory dysfunction is defined by 1:
- PaO₂/FiO₂ ratio <300 mmHg
Neurological System
Central nervous system dysfunction includes 1:
- Altered mental status (indifference, restlessness, lethargy)
- Any level of coma (light or deep)
- Glasgow Coma Scale ≤14
Hematologic System
Coagulation dysfunction is present when any of the following occur 1:
- Platelet count <100 × 10⁹/L
- Prolonged or shortened clotting times (CT, APTT, PT)
- Positive plasma protamine paracoagulation test
Hepatic System
Liver dysfunction is indicated by 1:
- Total bilirubin >20.5 μmol/L
- Albumin <28 g/L
Renal System
Kidney dysfunction criteria include 1:
- Creatinine >123.8 μmol/L (>1.4 mg/dL)
- Urine output <500 mL/24 hours
Gastrointestinal System
GI dysfunction is demonstrated by any of 1:
- Decreased or absent bowel sounds
- Gastric retention
- Positive fecal occult blood with dark stools or hematemesis
- Intra-abdominal pressure (intravesical pressure) ≥11 cm H₂O
Scoring Systems for Assessment
Multiple Organ Dysfunction Score (MODS)
The MODS quantifies organ-specific physiology across six systems (cardiovascular, respiratory, renal, central nervous system, hepatic, hematologic) and should be measured at ICU admission and daily thereafter 3. The MODS provides both baseline assessment and serial monitoring, with serial scores calculated as daily component scores minus baseline scores 3.
Sequential Organ Failure Assessment (SOFA)
The SOFA score is included in critical care triage protocols and assesses six organ systems using specific physiological parameters 4, 5. In obstetric populations with suspected sepsis-related MODS, the MODS score demonstrated superior discrimination (AUROC 0.84) compared to SOFA (AUROC 0.79) for predicting severe maternal morbidity 4.
Prognostic Considerations
Four organ systems demonstrate the strongest independent association with ICU mortality when adjusted for all components: cardiovascular (baseline RR 1.5, serial RR 1.4), respiratory (baseline RR 1.4, serial RR 1.4), renal (baseline RR 1.3, serial RR 1.5), and central nervous system (baseline RR 1.6, serial RR 1.7) 3.
Time-Dependent Risk Patterns
The prognostic significance of organ dysfunction varies by timing 3:
- Respiratory dysfunction: Not significantly associated with mortality until the second ICU week (week 2 onward RR 1.9)
- Hepatic dysfunction: Not significantly associated with mortality until the fourth ICU week (week 4 onward RR 1.4)
- Cardiovascular, renal, and CNS dysfunction: Significant from ICU admission onward
Common Pitfalls
Do not confuse MODS with isolated organ failure—the syndrome requires multi-system involvement by definition 1, 6. Single organ dysfunction, even if severe, does not constitute MODS.
Avoid relying solely on baseline measurements—serial daily assessments provide critical additional prognostic information and track disease progression 3. The change in organ function over time is as important as the initial severity.
Recognize that autonomic dysfunction accompanies MODS and has independent prognostic implications, with attenuated heart rate variability and baroreflex sensitivity predicting 28-day mortality 7.