12-phase flow (12)

1. 1FRAME
   Establish cardiac-glycoside poisoning frame; separate ACUTE deliberate ingestion from CHRONIC accumulation; include plant/herbal glycosides not measured by digoxin assay (ACMT/EXTRIP; tox reviews 2024-2025)
   inputs: acute_vs_chronic_pattern, plant_glycoside_source
   advance: Glycoside frame set; acute vs chronic vs plant-glycoside pathway selected
2. 2ENTRY
   Recognize trigger: overdose history, chronic digoxin + precipitant, elevated level, plant ingestion, or unexplained hyperK + bradydysrhythmia (Bismuth 1973)
   inputs: age, ingestion_amount_and_time
   advance: Trigger captured + acute/chronic timeline established
3. 3CONTEXT
   Capture renal function, interacting drugs (amiodarone/verapamil/quinidine/macrolides/spironolactone/dronedarone), baseline electrolytes, indication for digoxin (AF vs HFrEF), plant source if herbal (tox reviews)
   inputs: interacting_drugs, acute_vs_chronic_pattern, plant_glycoside_source
   advance: Precipitant identified (renal, drug interaction, electrolyte) + phenotype classified
4. 4RED_FLAGS
   Life-threatening dysrhythmia (bidirectional VT, VT/VF, high-grade AV block, profound bradycardia), hemodynamic instability, K+ >5.0–5.5 in acute ingestion (Bismuth 1973 — pre-Fab mortality >50% if K+ >5.5), massive ingestion (ACMT)
   inputs: hr, sbp, serum_potassium, ecg
   actions: workup.bradycardia, workup.hyperk_emergency
   advance: Red flags screened; DigiFab decision triggered if any life-threatening criterion present
5. 5INITIAL_WORKUP
   Serum digoxin level (note timing ≥6 h post-dose), K+, Mg, Ca, BUN/Cr/eGFR, ECG/telemetry, glucose, tox co-ingestant screen; cardiac monitor (ACMT/EXTRIP)
   inputs: serum_digoxin, serum_potassium, creatinine_egfr, serum_magnesium, ecg
   actions: workup.bradycardia, workup.hyperkalemia, panel.metabolic, panel.cardiac, panel.renal, panel.tox_screen, cascade.electrolyte
   advance: Level + K/Mg/Ca + renal + ECG returned; level-interpretation caveats applied
6. 6BRANCHING_WORKUP
   Bradydysrhythmia/AV-block arm vs wide-complex tachydysrhythmia arm; if plant glycoside → assay may be falsely low/absent (treat clinically); if post-DigiFab → TOTAL digoxin assay is misleadingly high (measures Fab-bound), use free level or stop measuring (ACMT)
   inputs: ecg, hr, plant_glycoside_source
   actions: workup.brady_heart_block, workup.wide_complex_tach, workup.afib_new_onset
   advance: Dysrhythmia arm assigned; level caveats (chronic vs acute, free vs total post-Fab, DLIS, plant) reconciled
7. 7DIFFERENTIAL
   Distinguish from β-blocker / CCB overdose (bradycardia + shock but NOT hyperK from glycoside mechanism), hyperkalemia of other cause, primary AV-nodal disease, sick sinus, MI, sepsis, plant-glycoside vs digoxin (assay caveats), endogenous DLIS (renal failure/neonate/pregnancy false-positive low level)
   inputs: serum_digoxin, serum_potassium
   advance: Glycoside toxicity confirmed as principal driver; mimics excluded
8. 8RISK_STRATIFICATION
   Acute: K+ is the dominant prognostic marker (Bismuth 1973 — K+ <5.0 ~0% vs >5.5 ~100% mortality pre-Fab); any digoxin-related dysrhythmia, level interpreted in clinical context. Chronic: severity is clinical (dysrhythmia + end-organ) not level-bound. NEWS2/qSOFA for global deterioration only (ACMT/EXTRIP)
   inputs: serum_potassium, serum_digoxin, ecg, hr
   actions: calc.news2, calc.qsofa
   advance: Severity classified by K+ (acute) / clinical dysrhythmia + end-organ; DigiFab indication finalized
9. 9TREATMENT
   Digoxin immune Fab (DigiFab) FIRST for any life-threatening criterion; manage hyperK by treating the K+ (insulin/dextrose, bicarb if acidotic, β2-agonist; AVOID IV calcium — classic "stone heart" caution, modern evidence weaker → encode as caution not absolute); atropine + temporary pacing as bridge for bradydysrhythmia (DigiFab definitive); Mg + lidocaine/phenytoin for ventricular tachydysrhythmia; correct K/Mg; activated charcoal if early/awake; hemodialysis NOT effective for digoxin (large Vd, tissue-bound) — only for refractory hyperK (ACMT/EXTRIP 2016)
   inputs: serum_potassium, serum_digoxin, weight, hr, ecg
   actions: workup.hyperk_emergency, cascade.electrolyte
   advance: DigiFab given + reassessed; hyperK treated (NO empiric IV calcium); dysrhythmia bridged; charcoal if indicated
10. 10DISPOSITION
    ICU/monitored bed for any dysrhythmia, hyperK, DigiFab administration, or hemodynamic instability; observation for asymptomatic chronic with stable level + normal K + normal ECG; psychiatry for intentional ingestion; nephrology if dialysis-dependent hyperK (ACMT)
    inputs: serum_potassium, ecg
    advance: Disposition assigned (ICU vs monitored vs observation) + consults arranged
11. 11MONITORING
    Continuous telemetry; serial K+ (q1-2h after DigiFab — watch for HYPOkalemia rebound as glycoside-blocked Na/K-ATPase reactivates); recheck Mg/Ca/renal; FREE digoxin level only (total is uninterpretable post-Fab for ~5-7 days, longer if renal failure); reassess dysrhythmia resolution; redose DigiFab if recrudescent toxicity (ACMT)
    inputs: serum_potassium, serum_magnesium, ecg
    actions: panel.metabolic, panel.cardiac, cascade.electrolyte
    advance: Dysrhythmia resolved + K+ normalized + no recrudescence off DigiFab effect
12. 12FOLLOWUP
    Reconcile/withhold or dose-adjust chronic digoxin (re-evaluate indication — narrow therapeutic index, deprescribe in HFrEF if alternatives); review interacting drugs + renal dosing; patient/caregiver education on toxicity signs (visual halos, GI, confusion); psychiatry follow-up if intentional; plant-source removal counseling (ACMT)
    inputs: interacting_drugs, creatinine_egfr
    advance: Digoxin reconciled/deprescribed + interaction review + education + psych follow-up (if intentional) booked