scientific-skills/clinical-decision-support/references/clinical_decision_algorithms.md
Clinical decision algorithms provide systematic, step-by-step guidance for diagnosis, treatment selection, and patient management. This guide covers algorithm development, validation, and visual presentation using decision trees and flowcharts.
Decision Nodes
Action Nodes
Terminal Nodes
Clarity
Clinical Validity
Usability
Completeness
Chest Pain Evaluation Algorithm
Entry: Patient with chest pain
├─ STEMI Criteria? (ST elevation ≥1mm in ≥2 contiguous leads)
│ ├─ YES → Activate cath lab, aspirin 325mg, heparin, clopidogrel 600mg
│ │ Transfer for primary PCI (goal door-to-balloon <90 minutes)
│ └─ NO → Continue evaluation
├─ High-Risk Features? (Hemodynamic instability, arrhythmia, troponin elevation)
│ ├─ YES → Admit CCU, serial troponins, cardiology consultation
│ │ Consider early angiography if NSTEMI
│ └─ NO → Calculate TIMI or HEART score
├─ TIMI Score 0-1 or HEART Score 0-3? (Low risk)
│ ├─ YES → Observe 6-12 hours, serial troponins, stress test if negative
│ │ Discharge if all negative with cardiology follow-up in 72 hours
│ └─ NO → TIMI 2-4 or HEART 4-6 (Intermediate risk)
├─ TIMI Score 2-4 or HEART Score 4-6? (Intermediate risk)
│ ├─ YES → Admit telemetry, serial troponins, stress imaging vs CT angiography
│ │ Medical management: Aspirin, statin, beta-blocker
│ └─ NO → TIMI ≥5 or HEART ≥7 (High risk) → Treat as NSTEMI
Decision Endpoint: Risk-stratified pathway with 30-day event rate documented
Pulmonary Embolism Diagnostic Algorithm (Wells Criteria)
Entry: Suspected PE
Step 1: Calculate Wells Score
Clinical features points:
- Clinical signs of DVT: 3 points
- PE more likely than alternative diagnosis: 3 points
- Heart rate >100: 1.5 points
- Immobilization/surgery in past 4 weeks: 1.5 points
- Previous PE/DVT: 1.5 points
- Hemoptysis: 1 point
- Malignancy: 1 point
Step 2: Risk Stratify
├─ Wells Score ≤4 (PE unlikely)
│ └─ D-dimer test
│ ├─ D-dimer negative (<500 ng/mL) → PE excluded, consider alternative diagnosis
│ └─ D-dimer positive (≥500 ng/mL) → CTPA
│
└─ Wells Score >4 (PE likely)
└─ CTPA (skip D-dimer)
Step 3: CTPA Results
├─ Positive for PE → Risk stratify severity
│ ├─ Massive PE (hypotension, shock) → Thrombolytics vs embolectomy
│ ├─ Submassive PE (RV strain, troponin+) → Admit ICU, consider thrombolytics
│ └─ Low-risk PE → Anticoagulation, consider outpatient management
│
└─ Negative for PE → PE excluded, investigate alternative diagnosis
Step 4: Treatment Decision (if PE confirmed)
├─ Absolute contraindication to anticoagulation?
│ ├─ YES → IVC filter placement, treat underlying condition
│ └─ NO → Anticoagulation therapy
│
├─ Cancer-associated thrombosis?
│ ├─ YES → LMWH preferred (edoxaban alternative)
│ └─ NO → DOAC preferred (apixaban, rivaroxaban, edoxaban)
│
└─ Duration: Minimum 3 months, extended if unprovoked or recurrent
NSCLC First-Line Treatment Algorithm
Entry: Advanced/Metastatic NSCLC, adequate PS (ECOG 0-2)
Step 1: Biomarker Testing Complete?
├─ NO → Reflex testing: EGFR, ALK, ROS1, BRAF, PD-L1, consider NGS
│ Hold systemic therapy pending results (unless rapidly progressive)
└─ YES → Proceed to Step 2
Step 2: Actionable Genomic Alteration?
├─ EGFR exon 19 deletion or L858R → Osimertinib 80mg daily
│ └─ Alternative: Erlotinib, gefitinib, afatinib (less preferred)
│
├─ ALK rearrangement → Alectinib 600mg BID
│ └─ Alternatives: Brigatinib, lorlatinib, crizotinib (less preferred)
│
├─ ROS1 rearrangement → Crizotinib 250mg BID or entrectinib
│
├─ BRAF V600E → Dabrafenib + trametinib
│
├─ MET exon 14 skipping → Capmatinib or tepotinib
│
├─ RET rearrangement → Selpercatinib or pralsetinib
│
├─ NTRK fusion → Larotrectinib or entrectinib
│
├─ KRAS G12C → Sotorasib or adagrasib (if no other options)
│
└─ NO actionable alteration → Proceed to Step 3
Step 3: PD-L1 Testing Result?
├─ PD-L1 ≥50% (TPS)
│ ├─ Option 1: Pembrolizumab 200mg Q3W (monotherapy, NCCN Category 1)
│ ├─ Option 2: Pembrolizumab + platinum doublet chemotherapy
│ └─ Option 3: Atezolizumab + bevacizumab + carboplatin + paclitaxel
│
├─ PD-L1 1-49% (TPS)
│ ├─ Preferred: Pembrolizumab + platinum doublet chemotherapy
│ └─ Alternative: Platinum doublet chemotherapy alone
│
└─ PD-L1 <1% (TPS)
├─ Preferred: Pembrolizumab + platinum doublet chemotherapy
└─ Alternative: Platinum doublet chemotherapy ± bevacizumab
Step 4: Platinum Doublet Selection (if applicable)
├─ Squamous histology
│ └─ Carboplatin AUC 6 + paclitaxel 200 mg/m² Q3W (4 cycles)
│ or Carboplatin AUC 5 + nab-paclitaxel 100 mg/m² D1,8,15 Q4W
│
└─ Non-squamous histology
└─ Carboplatin AUC 6 + pemetrexed 500 mg/m² Q3W (4 cycles)
Continue pemetrexed maintenance if responding
Add bevacizumab 15 mg/kg if eligible (no hemoptysis, brain mets)
Step 5: Monitoring and Response Assessment
- Imaging every 6 weeks for first 12 weeks, then every 9 weeks
- Continue until progression or unacceptable toxicity
- At progression, proceed to second-line algorithm
Heart Failure Management Algorithm (AHA/ACC Guidelines)
Entry: Heart Failure Diagnosis Confirmed
Step 1: Determine HF Type
├─ HFrEF (EF ≤40%)
│ └─ Proceed to Guideline-Directed Medical Therapy (GDMT)
│
├─ HFpEF (EF ≥50%)
│ └─ Treat comorbidities, diuretics for congestion, consider SGLT2i
│
└─ HFmrEF (EF 41-49%)
└─ Consider HFrEF GDMT, evidence less robust
Step 2: GDMT for HFrEF (All patients unless contraindicated)
Quadruple Therapy (Class 1 recommendations):
1. ACE Inhibitor/ARB/ARNI
├─ Preferred: Sacubitril-valsartan 49/51mg BID → titrate to 97/103mg BID
│ └─ If ACE-I naïve or taking <10mg enalapril equivalent
├─ Alternative: ACE-I (enalapril, lisinopril, ramipril) to target dose
└─ Alternative: ARB (losartan, valsartan) if ACE-I intolerant
2. Beta-Blocker (start low, titrate slowly)
├─ Bisoprolol 1.25mg daily → 10mg daily target
├─ Metoprolol succinate 12.5mg daily → 200mg daily target
└─ Carvedilol 3.125mg BID → 25mg BID target (50mg BID if >85kg)
3. Mineralocorticoid Receptor Antagonist (MRA)
├─ Spironolactone 12.5-25mg daily → 50mg daily target
└─ Eplerenone 25mg daily → 50mg daily target
└─ Contraindications: K >5.0, CrCl <30 mL/min
4. SGLT2 Inhibitor (regardless of diabetes status)
├─ Dapagliflozin 10mg daily
└─ Empagliflozin 10mg daily
Step 3: Additional Therapies Based on Phenotype
├─ Sinus rhythm + HR ≥70 despite beta-blocker?
│ └─ YES: Add ivabradine 5mg BID → 7.5mg BID target
│
├─ African American + NYHA III-IV?
│ └─ YES: Add hydralazine 37.5mg TID + isosorbide dinitrate 20mg TID
│ (Target: hydralazine 75mg TID + ISDN 40mg TID)
│
├─ Atrial fibrillation?
│ ├─ Rate control (target <80 bpm at rest, <110 bpm with activity)
│ └─ Anticoagulation (DOAC preferred, warfarin if valvular)
│
└─ Iron deficiency (ferritin <100 or <300 with TSAT <20%)?
└─ YES: IV iron supplementation (ferric carboxymaltose)
Step 4: Device Therapy Evaluation
├─ EF ≤35%, NYHA II-III, LBBB with QRS ≥150 ms, sinus rhythm?
│ └─ YES: Cardiac resynchronization therapy (CRT-D)
│
├─ EF ≤35%, NYHA II-III, on GDMT ≥3 months?
│ └─ YES: ICD for primary prevention
│ (if life expectancy >1 year with good functional status)
│
└─ EF ≤35%, NYHA IV despite GDMT, or advanced HF?
└─ Refer to advanced HF specialist
├─ LVAD evaluation
├─ Heart transplant evaluation
└─ Palliative care consultation
Step 5: Monitoring and Titration
Weekly to biweekly visits during titration:
- Blood pressure (target SBP ≥90 mmHg)
- Heart rate (target 50-60 bpm)
- Potassium (target 4.0-5.0 mEq/L, hold MRA if >5.5)
- Creatinine (expect 10-20% increase, acceptable if <30% and stable)
- Symptoms and congestion status (daily weights, NYHA class)
Stable on GDMT:
- Visits every 3-6 months
- Echocardiogram at 3-6 months after GDMT optimization, then annually
- NT-proBNP or BNP trending (biomarker-guided therapy investigational)
TIMI Risk Score (NSTEMI/Unstable Angina)
Score Calculation (0-7 points):
☐ Age ≥65 years (1 point)
☐ ≥3 cardiac risk factors (HTN, hyperlipidemia, diabetes, smoking, family history) (1)
☐ Known CAD (stenosis ≥50%) (1)
☐ ASA use in past 7 days (1)
☐ Severe angina (≥2 episodes in 24 hours) (1)
☐ ST deviation ≥0.5 mm (1)
☐ Elevated cardiac biomarkers (1)
Risk Stratification:
├─ Score 0-1: 5% risk of death/MI/urgent revasc at 14 days (Low)
│ └─ Management: Observation, stress test, outpatient follow-up
│
├─ Score 2: 8% risk (Low-intermediate)
│ └─ Management: Admission, medical therapy, stress imaging
│
├─ Score 3-4: 13-20% risk (Intermediate-high)
│ └─ Management: Admission, aggressive medical therapy, early invasive strategy
│
└─ Score 5-7: 26-41% risk (High)
└─ Management: Aggressive treatment, urgent angiography (<24 hours)
CHA2DS2-VASc Score (Stroke Risk in Atrial Fibrillation)
Score Calculation:
☐ Congestive heart failure (1 point)
☐ Hypertension (1)
☐ Age ≥75 years (2)
☐ Diabetes mellitus (1)
☐ Prior stroke/TIA/thromboembolism (2)
☐ Vascular disease (MI, PAD, aortic plaque) (1)
☐ Age 65-74 years (1)
☐ Sex category (female) (1)
Maximum score: 9 points
Treatment Algorithm:
├─ Score 0 (male) or 1 (female): 0-1.3% annual stroke risk
│ └─ No anticoagulation or aspirin (Class IIb)
│
├─ Score 1 (male): 1.3% annual stroke risk
│ └─ Consider anticoagulation (Class IIa)
│ Factors: Patient preference, bleeding risk, comorbidities
│
└─ Score ≥2 (male) or ≥3 (female): ≥2.2% annual stroke risk
└─ Anticoagulation recommended (Class I)
├─ Preferred: DOAC (apixaban, rivaroxaban, edoxaban, dabigatran)
└─ Alternative: Warfarin (INR 2-3) if DOAC contraindicated
Bleeding Risk Assessment (HAS-BLED):
H - Hypertension (SBP >160)
A - Abnormal renal/liver function (1 point each)
S - Stroke history
B - Bleeding history or predisposition
L - Labile INR (if on warfarin)
E - Elderly (age >65)
D - Drugs (antiplatelet, NSAIDs) or alcohol (1 point each)
HAS-BLED ≥3: High bleeding risk → Modifiable factors, consider DOAC over warfarin
MELD Score (Hepatocellular Carcinoma Eligibility)
MELD = 3.78×ln(bilirubin mg/dL) + 11.2×ln(INR) + 9.57×ln(creatinine mg/dL) + 6.43
Interpretation:
├─ MELD <10: 1.9% 3-month mortality (Low)
│ └─ Consider resection or ablation for HCC
│
├─ MELD 10-19: 6-20% 3-month mortality (Moderate)
│ └─ Transplant evaluation if within Milan criteria
│ Milan: Single ≤5cm or ≤3 lesions each ≤3cm, no vascular invasion
│
├─ MELD 20-29: 20-45% 3-month mortality (High)
│ └─ Urgent transplant evaluation, bridge therapy (TACE, ablation)
│
└─ MELD ≥30: 50-70% 3-month mortality (Very high)
└─ Transplant vs palliative care discussion
Too ill for transplant if MELD >35-40 typically
Adjuvant! Online (Breast Cancer Recurrence Risk)
Input Variables:
- Age at diagnosis
- Tumor size
- Tumor grade (1-3)
- ER status
- Node status (0, 1-3, 4-9, ≥10)
- HER2 status
- Comorbidity index
Output: 10-year risk of:
- Recurrence
- Breast cancer mortality
- Overall mortality
Treatment Benefit Estimates:
- Chemotherapy: Absolute reduction in recurrence
- Endocrine therapy: Absolute reduction in recurrence
- Trastuzumab: Absolute reduction (if HER2+)
Clinical Application:
├─ Low risk (<10% recurrence): Consider endocrine therapy alone if ER+
├─ Intermediate risk (10-20%): Chemotherapy discussion, genomic assay
│ └─ Oncotype DX score <26: Endocrine therapy alone
│ └─ Oncotype DX score ≥26: Chemotherapy + endocrine therapy
└─ High risk (>20%): Chemotherapy + endocrine therapy if ER+
Node Styling
% Decision nodes (diamond)
\tikzstyle{decision} = [diamond, draw, fill=yellow!20, text width=4.5em, text centered, inner sep=0pt]
% Process nodes (rectangle)
\tikzstyle{process} = [rectangle, draw, fill=blue!20, text width=5em, text centered, rounded corners, minimum height=3em]
% Terminal nodes (rounded rectangle)
\tikzstyle{terminal} = [rectangle, draw, fill=green!20, text width=5em, text centered, rounded corners=1em, minimum height=3em]
% Input/Output (parallelogram)
\tikzstyle{io} = [trapezium, draw, fill=purple!20, text width=5em, text centered, minimum height=3em]
Color Coding by Urgency
Pathway Emphasis
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes, arrows, positioning}
\begin{document}
\tikzstyle{decision} = [diamond, draw, fill=yellow!20, text width=4em, text centered, inner sep=2pt, font=\small]
\tikzstyle{process} = [rectangle, draw, fill=blue!20, text width=6em, text centered, rounded corners, minimum height=2.5em, font=\small]
\tikzstyle{terminal} = [rectangle, draw, fill=green!20, text width=6em, text centered, rounded corners=8pt, minimum height=2.5em, font=\small]
\tikzstyle{alert} = [rectangle, draw=red, line width=1.5pt, fill=red!10, text width=6em, text centered, rounded corners, minimum height=2.5em, font=\small\bfseries]
\tikzstyle{arrow} = [thick,->,>=stealth]
\begin{tikzpicture}[node distance=2cm, auto]
% Nodes
\node [terminal] (start) {Patient presents with symptom X};
\node [decision, below of=start] (decision1) {Criterion A met?};
\node [alert, below of=decision1, node distance=2.5cm] (alert1) {Immediate action};
\node [process, right of=decision1, node distance=4cm] (process1) {Standard evaluation};
\node [terminal, below of=process1, node distance=2.5cm] (end) {Outcome};
% Arrows
\draw [arrow] (start) -- (decision1);
\draw [arrow] (decision1) -- node {Yes} (alert1);
\draw [arrow] (decision1) -- node {No} (process1);
\draw [arrow] (process1) -- (end);
\draw [arrow] (alert1) -| (end);
\end{tikzpicture}
\end{document}
Step 1: Literature Review and Evidence Synthesis
Step 2: Draft Algorithm Development
Step 3: Pilot Testing
Step 4: Prospective Validation
Step 5: Continuous Quality Improvement
Process Metrics
Outcome Metrics
User Experience Metrics
Electronic Health Record Integration
Point-of-Care Tools
Education and Training
Common Barriers
Mitigation Strategies
Change Log Documentation
Algorithm: NSCLC First-Line Treatment
Version: 3.2
Effective Date: January 1, 2024
Previous Version: 3.1 (effective July 1, 2023)
Changes in Version 3.2:
1. Added KRAS G12C-mutated pathway (sotorasib, adagrasib)
- Evidence: FDA approval May 2021/2022
- Guideline: NCCN v4.2023
2. Updated PD-L1 ≥50% recommendation to include pembrolizumab monotherapy as Option 1
- Evidence: KEYNOTE-024 5-year follow-up
- Guideline: NCCN Category 1 preferred
3. Removed crizotinib as preferred ALK inhibitor, moved to alternative
- Evidence: ALEX, CROWN trials showing superiority of alectinib, lorlatinib
- Guideline: NCCN/ESMO Category 1 for alectinib as first-line
Reviewed by: Thoracic Oncology Committee
Approved by: Dr. [Name], Medical Director
Next Review Date: July 1, 2024
Mandatory Updates (Within 3 Months)
Routine Updates (Annually)
Emergency Updates (Within 1 Week)