Common Scoring Assessments for Anesthesia
The ASA Physical Status Classification System is the most universally used scoring assessment in anesthesia, serving as the primary tool for preoperative risk stratification despite its inherent limitations in inter-rater reliability. 1
Primary Scoring System
ASA Physical Status Classification
The ASA Physical Status classification remains the cornerstone assessment tool in anesthesiology, celebrating over 80 years of use since its development in 1941. 1 This system categorizes patients into six classes:
- ASA I: Healthy patient with no systemic disease 1
- ASA II: Patient with mild systemic disease 1
- ASA III: Patient with severe systemic disease 1
- ASA IV: Patient with severe systemic disease that is a constant threat to life 1
- ASA V: Moribund patient not expected to survive without operation 1
- ASA VI: Brain-dead patient for organ donation 1
The system's greatest strength lies in its simplicity, though this also represents its primary limitation in an era of comprehensive multisystem assessment tools. 1
Clinical Performance and Reliability
Inter-Rater Reliability
The ASA Physical Status system demonstrates moderate inter-rater reliability with a weighted Kappa coefficient of 0.53-0.61, meaning approximately 67% of patients receive the same classification when assessed by different anesthesiologists. 2, 3
Critical pitfall: Significant disagreement occurs most frequently in patients with:
- Co-existing diseases 2
- Obesity 2
- Sleep apnea 2
- Obstructive lung disease 2
- Renal insufficiency 2
- Hypertension 2
The degree of agreement varies between 31-85% depending on the clinical scenario, with only fair overall correlation (Kappa indices: 0.21-0.4) in some studies. 4
Validity as Risk Predictor
Despite being originally developed for statistical purposes rather than surgical risk prediction, the ASA Physical Status system demonstrates validity through correlation with multiple clinical parameters. 1
The system shows moderate predictive ability for:
- In-hospital mortality (ROC curve area 0.69) 3
- Cardiac complications (ROC curve area 0.70) 3
- Hospital length of stay (Spearman's ρ=0.16) 3
It correlates with:
- Patient age (Spearman's ρ=0.23) 3
- Charlson comorbidity index (ρ=0.24) 3
- Revised cardiac risk index (ρ=0.40) 3
Specialized Scoring Systems
MACOCHA Score for Difficult Intubation
For critically ill patients requiring tracheal intubation, the MACOCHA score (range 0-12) predicts difficult intubation based on seven factors. 5
Scoring components:
- Mallampati class III or IV: 5 points 5
- Obstructive sleep apnea syndrome: 2 points 5
- Reduced cervical spine mobility: 1 point 5
- Limited mouth opening <3 cm: 1 point 5
- Coma: 1 point 5
- Severe hypoxemia (SpO₂ <80%): 1 point 5
- Non-anesthesiologist operator: 1 point 5
Current Status and Limitations
The ASA Physical Status system remains widely used—appropriately or not—for risk prediction and multiple other purposes beyond its original intent. 1 The pattern of inter-observer inconsistency has remained essentially unchanged over the past 20 years, with particular variation between locally and overseas-trained specialists. 4
Key limitation: The system's inherent subjectivity means that 2% of patients may have their physical status underestimated, and 98.6% of paired assessments fall within one class of each other rather than achieving perfect agreement. 2, 3
The ASA methodology for developing practice parameters has evolved to include systematic evidence review using tools like AGREE II (Appraisal of Guidelines for Research and Evaluation), though only 13.7% of recent anesthesia guidelines meet high-quality standards. 5