Charlson Comorbidity Index (Age-Adjusted)

Calculate base excess (BE) using the Siggaard-Andersen formula. BE < −3 metabolic acidosis, > +3 metabolic alkalosis. HCO₃⁻ auto-calculated from pH + PaCO₂ if omitted. Derived from Siggaard-Andersen 1974, Cornell PICU, Medscape, and Langer 2022. Not medical advice.

Complete ABG analysis: pH, primary disorder, compensation (Winter's formula), anion gap ± albumin correction, delta ratio for mixed disorder detection. Derived from Emmett 2016, Kraut 2007, Rastegar 2007, LITFL, MDCalc, and Adrogué 1998. Not medical advice.

Calculate the 2005 Caprini Risk Assessment Model to stratify venous thromboembolism (VTE) risk in surgical patients. ~40 items weighted 1/2/3/5 points: 1 point (age 41-60, minor surgery, BMI >25, swollen legs, varicose veins, pregnancy/postpartum, recurrent miscarriage, OCP/HRT, sepsis <1mo, lung disease/pneumonia <1mo, COPD, acute MI, CHF <1mo, bedridden, medical bed rest, IBD); 2 points (age 61-74, arthroscopic surgery, major open surgery >45min, laparoscopic >45min, malignancy, bed >72h, plaster cast, central line); 3 points (age ≥75, personal/family VTE history, factor V Leiden, prothrombin 20210A, lupus anticoagulant, anticardiolipin, homocysteine, HIT, other thrombophilia); 5 points (stroke <1mo, elective major lower-extremity arthroplasty, hip/pelvis/leg fracture <1mo, acute spinal cord injury <1mo, multiple trauma <1mo). Management tiers: 0 lowest, 1-4 low-moderate (mechanical), 5-6 high (consider LMWH 7-10d), 7-8 high (LMWH 7-10d), ≥9 highest (LMWH 30d). Derived from Caprini 2005. Not medical advice.

Calculate the CHA₂DS₂-VASc score to stratify stroke risk in non-valvular atrial fibrillation and guide oral anticoagulation. Components: Congestive heart failure/LV dysfunction (+1), Hypertension (+1), Age ≥75 (+2), Diabetes (+1), prior Stroke/TIA/thromboembolism (+2), Vascular disease — prior MI/PAD/aortic plaque (+1), Age 65–74 (+1), Sex category female (+1). Range 0–9 (women) / 0–8 (men). Thresholds: men ≥2 or women ≥3 → recommend oral anticoagulation (DOAC preferred over warfarin); men 1 or women 2 → consider anticoagulation; men 0 or women ≤1 → omit. Female sex alone is not an independent risk factor (score 1 from sex alone is treated as 0). Includes an approximate annual stroke-risk estimate (Lip 2010 derivation cohort). Derived from Lip 2010 (Chest), 2019 AHA/ACC/HRS update, and 2023 ACC/AHA/ACCP/HRS AF guideline. Combine with bleeding risk (HAS-BLED) and shared decision-making. Not medical advice.