12-phase flow (12)

1. 1FRAME
   Catastrophic obstetric emergency — anaphylactoid syndrome of pregnancy with sudden cardiopulmonary collapse + hypoxia + DIC during labor, delivery, or within 30 min postpartum. Clark 2016 case definition (PMID 27372270) requires ALL FOUR criteria: (1) sudden cardiorespiratory arrest OR hypotension with hypoxia, (2) DIC after cardiovascular event but before large-volume hemorrhage, (3) onset during labor or within 30 min postpartum, (4) no fever and no alternative explanation. Biphasic hemodynamic pattern: phase 1 acute pulm HTN + RV failure ± arrest (minutes), phase 2 LV failure + pulmonary edema + DIC + hemorrhage. Treatment is parallel resuscitation + emergent delivery + DIC management; no specific test exists — diagnosis is clinical.
   inputs: gestational_age_weeks
   advance: GA cohort tagged; phase 1 vs phase 2 hemodynamic pattern recognised if possible (often retrospective)
2. 2ENTRY
   Recognise via sudden cardiopulmonary collapse + hypoxia ± DIC in labor or immediate postpartum (within 30 min); early prodrome includes severe dyspnea + altered mental status + agitation + seizure-like activity. Differential includes pulmonary embolism, anaphylaxis, eclampsia, septic shock (chorio overlap), hemorrhagic shock (placental abruption, uterine rupture, atony), peripartum cardiomyopathy with cardiogenic shock, acute MI / SCAD, tension pneumothorax, total spinal anesthetic. Maternal cardiac arrest pattern triggers perimortem cesarean within 4–5 min if ≥ 20–24 wk.
   inputs: event_timing_in_relation_to_labor_or_delivery
   advance: Clinical suspicion documented; ACLS / ATLS framework activated; multidisciplinary team paged (OB + anesthesia + critical care + cardiothoracic / ECMO + neonatology + hematology)
3. 3CONTEXT
   Capture event timing (Clark 2016 criterion 3), recent intrauterine instrumentation (membrane rupture, amnioinfusion, D&C), GA, fever / no-fever (criterion 4 — fever favors sepsis), maternal allergy history (anaphylaxis ddx), thromboembolism risk factors (PE ddx), pre-eclampsia history (eclampsia ddx), current medications, prior obstetric history. Fever ≥ 38.0°C / 100.4°F EXCLUDES AFE per Clark 2016 criterion 4.
   inputs: event_timing_in_relation_to_labor_or_delivery, maternal_temperature, recent_intrauterine_instrumentation, allergy_or_anaphylaxis_history, thromboembolism_risk_factors, preeclampsia_or_eclampsia_history, maternal_hr, maternal_rr, maternal_spo2, fetal_heart_rate_baseline
   advance: Temporal-association tier set; differential anchors (fever/no-fever, recent instrumentation, allergy/eclampsia/PE history) captured
4. 4RED_FLAGS
   Maternal cardiac arrest in 3rd trimester → ACLS + left-uterine displacement + perimortem cesarean within 4–5 min (AHA 2015 PMID 26443610; AHA 2024 update). Profound hypoxia (SpO2 < 90 + cyanosis) → immediate intubation + FiO2 1.0 + lung-protective ventilation. Sudden hypotension (SBP < 90 / MAP < 65) → vasoactive support (NE first-line, MAP target ≥ 65). DIC features → massive transfusion protocol activation + cryoprecipitate + TXA. RV failure pattern on echo → inhaled NO + milrinone + ECMO consideration if refractory.
   inputs: maternal_bp, maternal_hr, maternal_spo2, fetal_heart_rate_baseline
   actions: protocol.septic_shock
   advance: Maternal cardiac arrest pathway activated if applicable; emergent delivery decision (perimortem cesarean) executed if criteria met; vasoactive + ventilatory support escalated; massive transfusion protocol activated if DIC features
5. 5INITIAL_WORKUP
   STAT CBC + coag panel (PT/INR, aPTT, fibrinogen) + CMP + lactate + ABG + type & screen / crossmatch ≥ 4 units PRBC + troponin + BNP. Bedside transthoracic echocardiogram (phase 1 RV failure pattern — dilated RV, flattened septum, acute pulm HTN; differentiates from LV-predominant CMP / ACS). Chest x-ray or lung US (pulmonary edema pattern, pneumothorax ddx). Do NOT delay resuscitation for imaging — bedside echo + lung US are point-of-care.
   inputs: maternal_cbc_with_diff, maternal_coagulation_panel_pt_inr_aptt_fibrinogen, maternal_type_and_screen_or_crossmatch, maternal_metabolic_panel, maternal_lactate, maternal_arterial_blood_gas, bedside_transthoracic_echocardiogram
   actions: panel.cbc, panel.coag, panel.renal
   advance: Labs drawn; type & screen + crossmatch up; echo performed; ventilatory + vasoactive baseline established
6. 6BRANCHING_WORKUP
   CT-PA if patient stable enough + AFE / PE ambiguity persists after initial resuscitation; do NOT delay treatment for imaging in unstable patient. D-dimer (markedly elevated in both AFE + PE — not diagnostic). Repeat coag at 30–60 min if active bleeding (DIC trajectory). ROTEM / TEG if available for targeted blood-product replacement. Blood cultures + procalcitonin if sepsis ddx active. Tryptase + IgE if anaphylaxis ddx persists. Right heart catheterization if pulmonary HTN trajectory unclear (rarely possible acutely).
   inputs: maternal_d_dimer, ct_pulmonary_angiogram_if_stable_and_PE_ambiguous, maternal_troponin_and_bnp
   advance: DIC trajectory documented; PE / sepsis / anaphylaxis differentials evaluated in parallel with resuscitation
7. 7DIFFERENTIAL
   Pulmonary embolism (CT-PA + d-dimer + echo RV strain — overlapping; DIC pattern of AFE differentiates), anaphylaxis (allergen trigger + skin findings + tryptase + epinephrine response — overlapping anaphylactoid pattern), eclampsia (HTN + seizure + pre-eclampsia history + magnesium response), septic shock (fever + chorio overlap — Clark criterion 4 excludes AFE), peripartum cardiomyopathy with CS (LV-predominant + earlier subacute presentation), acute MI / SCAD (ECG + troponin pattern; coronary angiography), tension pneumothorax (asymmetric breath sounds + tracheal shift), total spinal anesthetic (recent neuraxial procedure + bilateral motor block), uterine rupture (prior cesarean + abdominal pain + fetal station change), placental abruption with DIC (painful bleeding + uterine tenderness + retroplacental clot if visible).
   advance: Mimics excluded or co-managed; AFE clinical diagnosis confirmed by Clark 2016 criteria or treated empirically given temporal association + DIC + cardiopulmonary collapse pattern
8. 8RISK_STRATIFICATION
   Phase 1 (acute pulm HTN + RV failure, minutes) vs phase 2 (LV failure + pulm edema + DIC + hemorrhage) staging drives treatment emphasis. Severity tiers: at-presentation requiring ATLS + ACLS, post-arrest with ROSC, refractory shock requiring VA-ECMO, survivor with hypoxic-ischemic injury. Maternal cardiac arrest + GA ≥ 20–24 wk → perimortem cesarean within 4–5 min (AHA 2015 PMID 26443610). MAP target ≥ 65 with norepinephrine first-line. ECMO consideration when refractory to NE + milrinone + iNO + MTP; multidisciplinary team decision.
   inputs: maternal_bp, maternal_hr, fetal_heart_rate_baseline, gestational_age_weeks, bedside_transthoracic_echocardiogram
   actions: calc.qsofa
   advance: Phase 1 vs phase 2 staging assigned; severity tier + MCS / ECMO decision documented
9. 9TREATMENT
   ATLS-style resuscitation + ACLS if cardiac arrest (left-uterine displacement if undelivered). PERIMORTEM CESAREAN WITHIN 4–5 MIN if maternal arrest + GA ≥ 20–24 wk. Mechanical ventilation FiO2 1.0 → lung-protective Vt 6 mL/kg PBW + PEEP per ARDSnet. Pulmonary vasodilators for phase 1: inhaled NO 20–40 ppm, sildenafil 20–40 mg PO/NG, IV milrinone 0.25–0.75 mcg/kg/min, inhaled / IV epoprostenol. Vasoactive support: norepinephrine first-line MAP ≥ 65; add vasopressin 0.03 U/min if NE > 0.25 mcg/kg/min; dobutamine for low CO; methylene blue 1–2 mg/kg if vasoplegia. Massive transfusion 1:1:1 (Pacheco SMFM 47 2019 PMID 26348379); cryoprecipitate 10 units if fibrinogen < 200; TXA 1 g IV within 3 h (WOMAN 2017 PMID 28456509); factor VIIa or factor concentrates as rescue per hematology. A-OK (atropine 1 mg IV + ondansetron 8 mg IV + ketorolac 30 mg IV) low-evidence empiric (Rezai 2017 PMID 29430313). VA-ECMO for refractory cardiopulmonary collapse (ELSO 2020; Sharma 2017 PMID 25248040). Targeted temperature management 32–36°C × 24 h if comatose post-ROSC.
   inputs: gestational_age_weeks, maternal_bp, maternal_spo2
   advance: Resuscitation framework executed; perimortem cesarean decision made if arrest; pulmonary vasodilator / vasoactive / MTP / ECMO decisions made per severity tier
10. 10DISPOSITION
    OR + ICU for perimortem cesarean + post-resuscitation care. ICU level-1 trauma / cardiothoracic capability for refractory shock + ECMO. Multidisciplinary team: critical care + OB + anesthesia + cardiothoracic / ECMO + neonatology + hematology. Postpartum mother-baby unit deferred until maternal stability (typically multi-day ICU course). Neonatology / NICU coordination for emergent delivery + hypoxic-ischemic injury risk in newborn.
    inputs: maternal_bp, maternal_spo2
    advance: ICU level of care set; multidisciplinary team coordinated; neonatology pathway initiated; family + ethics conversation initiated if poor prognosis
11. 11MONITORING
    Continuous MAP + ECG + SpO2 + capnography + arterial line + central venous catheter once on vasopressors. ABG q1–4 h during instability. Lactate q2–4 h until normalised. Serial coag panel q1–2 h while active bleeding then q4–6 h stabilising; fibrinogen target ≥ 200 with cryoprecipitate replacement; platelet target > 50K intrapartum > 100K with active hemorrhage. Echocardiography q12–24 h to track RV recovery + ECMO weaning readiness. Daily SOFA + cultures. Fetal monitoring continuous if not yet delivered. CAM-ICU once sedation lightened. Targeted temperature management 32–36°C × 24 h if comatose post-ROSC.
    inputs: maternal_bp, maternal_hr, maternal_spo2, maternal_coagulation_panel_pt_inr_aptt_fibrinogen, maternal_lactate
    actions: panel.cbc, panel.coag
    advance: Maternal stable off vasopressors; lactate < 2; coag stabilised; RV recovery on echo; extubated; CAM-ICU negative
12. 12FOLLOWUP
    6-wk postpartum visit + AFE-specific anticipatory guidance. Survivors at risk for hypoxic-ischemic encephalopathy → neurology + neuropsychology evaluation; rehabilitation services as needed. Mental health screen — high risk for peripartum PTSD (PCL-5) + postpartum depression (EPDS) given catastrophic peripartum event. Subsequent-pregnancy counseling: recurrence rare (~ 1%; AFE Registry data); NOT a contraindication to pregnancy but high-risk MFM coordination + delivery at tertiary center with on-call critical care + ECMO capability. Newborn outpatient peds 24–48 h post-discharge + developmental tracking for first year (high CP / BPD risk if hypoxic-ischemic exposure). Cardiothoracic / pulmonology follow-up if RV recovery incomplete. Hematology follow-up if persistent coagulopathy. Family + psychosocial support; survivor support groups (AFE Foundation).
    advance: Postpartum visit complete; neurology / neuropsych / rehab assessment if HIE; mental health support engaged; subsequent-pregnancy counseling delivered; newborn developmental tracking initiated; family support arranged