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gi.acute-mesenteric-ischemia.core.v1PRODUCTION
gi.acute-mesenteric-ischemia.core.v1

Acute Mesenteric Ischemia

vascularacuteadult
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12/12 authored

Canonical 12-phase frame with authored status for this dossier.

Current phase

Frame

Detailed

Frame: acute interruption of mesenteric blood flow leading to bowel ischemia and necrosis; 50% mortality untreated; four etiologies (arterial embolism, arterial thrombosis, mesenteric venous thrombosis, NOMI) (WSES 2017)

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AMI considered plausible by clinical context

Patient inputs (13)

Elderly + atherosclerosis = arterial; younger = venous or NOMI; influences risk (WSES 2017)

Hypotension drives NOMI risk and sepsis resuscitation (WSES 2017)

Tachycardia + AF (embolic source); shock physiology

Embolic vs thrombotic vs venous vs NOMI etiology (WSES 2017)

Pain out of proportion = hallmark; peritoneal signs = transmural infarction (WSES 2017)

Elevation late but specific for bowel ischemia / transmural infarction (WSES 2017)

Leukocytosis (often >20,000) supports diagnosis (WSES 2017)

Contrast safety for CTA + heparin / endovascular planning

Anticoagulation baseline; heparin and thrombolytic planning

CT angiography triphasic = first-line gold standard imaging; STAT (WSES 2017)

Fever suggests bowel infarction or perforation (WSES 2017)

Reverses risk; baseline for heparin decision

High sensitivity but low specificity; rules out at low value (WSES 2017)

* = hard-required. Engine cannot meaningfully run until these are filled.

Severity triggers (5)

5 need judgement
  • informationallife_threateningperitoneal_signs_transmural_infarction
    Peritoneal signs (rigidity, rebound, guarding) on exam = transmural bowel infarction (WSES 2017)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationallife_threateningpneumatosis_or_portal_venous_gas
    CT shows pneumatosis intestinalis or portal venous gas = bowel necrosis (WSES 2017)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationallife_threateningsevere_lactic_acidosis_progressive
    Lactate >4 mmol/L AND rising despite resuscitation = ongoing bowel infarction (WSES 2017)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseverenomi_low_flow_state
    NOMI confirmed on CTA — diffuse vasoconstriction without occlusion in a critically ill / low-flow patient (WSES 2017)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseveremesenteric_venous_thrombosis_isolated
    MVT on CTA without arterial involvement, no peritoneal signs (WSES 2017)
    Trigger could not be auto-evaluated — needs clinician judgement.

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Recommended regimen

Acute mesenteric ischemia — etiology-driven anticoagulation + revascularization + sepsis support (WSES 2017)
axis: ami_etiology_pathwaystep 1 - Step 1 — Immediate anticoagulation + resuscitation (all confirmed AMI)
Selected step "Step 1 — Immediate anticoagulation + resuscitation (all confirmed AMI)" — CTA confirmed AMI of any etiology, no active hemorrhage
  • heparin
    first line
    unfractionated_heparin
    80 U/kg IV bolus then 18 U/kg/h infusion titrated to aPTT 1.5-2.5x control (or anti-Xa 0.3-0.7) • IV • continuous
    triggers: confirmed_AMI, no_active_hemorrhage
    WSES 2017 — IV UFH first-line for all AMI etiologies; preferred over LMWH due to titrability and potential need for emergent surgery
    rxcui 5224
  • crystalloid_resuscitation
    first line
    fluid
    Balanced crystalloid 20-30 mL/kg IV titrated to MAP ≥65 and UOP ≥0.5 mL/kg/h • IV • continuous
    triggers: hypovolemia, shock
    WSES 2017 — restore perfusion; avoid excessive saline (worsens acidosis)

ed playbook — drug actions (4)

  1. 1. heparin
    rxcui 5224
    80 U/kg IV bolus then 18 U/kg/h drip; aPTT q6h target 1.5-2.5x • IV • continuous
    trigger: Suspected AMI; no active hemorrhage (WSES 2017)
    WSES 2017 — IV UFH first-line all AMI etiologies
  2. 2. crystalloid resuscitation
    20-30 mL/kg balanced crystalloid IV titrated to MAP ≥65 • IV • bolus then maintenance
    trigger: Hypovolemia or shock (WSES 2017)
    Restore mesenteric perfusion
  3. 3. pip-tazo
    rxcui 74169
    4.5 g IV q6h • IV • q6h
    trigger: Suspected perforation or bowel translocation / sepsis (WSES 2017)
    Broad-spectrum gram-neg + anaerobic
  4. 4. norepinephrine
    rxcui 7512
    0.05-0.5 mcg/kg/min • IV • continuous
    trigger: MAP <65 despite adequate fluid (WSES 2017)
    Avoid pure-alpha vasopressors (worsen NOMI)

Auto-drafted A&P note

ed

Subjective

- Possible entry pathways: Severe abdominal pain out of proportion to exam findings (WSES 2017 hallmark); Sudden severe periumbilical pain with vomiting / diarrhea (SMA embolism); Atrial fibrillation, recent MI, or known atherosclerosis with new abdominal pain (embolic source).

Objective

- No vitals, labs, or imaging entered for this encounter.

Assessment

**Acute Mesenteric Ischemia** (gi.acute-mesenteric-ischemia.core.v1).
Phenotype framing: Distinguish from acute pancreatitis, perforated viscus, ruptured AAA, intestinal obstruction, ischemic colitis, DKA, sickle cell crisis (WSES 2017)
Scope: Frame: acute interruption of mesenteric blood flow leading to bowel ischemia and necrosis; 50% mortality untreated; four etiologies (arterial embolism, arterial thrombosis, mesenteric venous thrombosis, NOMI) (WSES 2017)

No severity triggers fired against current inputs.

Plan

Regimen axis: **Acute mesenteric ischemia — etiology-driven anticoagulation + revascularization + sepsis support (WSES 2017)** — step "Step 1 — Immediate anticoagulation + resuscitation (all confirmed AMI)".
1. heparin 80 U/kg IV bolus then 18 U/kg/h infusion titrated to aPTT 1.5-2.5x control (or anti-Xa 0.3-0.7) IV continuous (unfractionated_heparin, first line) — WSES 2017 — IV UFH first-line for all AMI etiologies; preferred over LMWH due to titrability and potential need for emergent surgery
2. crystalloid_resuscitation Balanced crystalloid 20-30 mL/kg IV titrated to MAP ≥65 and UOP ≥0.5 mL/kg/h IV continuous (fluid, first line) — WSES 2017 — restore perfusion; avoid excessive saline (worsens acidosis)

Setting playbook (ed) — Recognize AMI via pain out of proportion, AF + sudden abdominal pain, or unexplained lactic acidosis; STAT CTA triphasic (NO oral contrast); IV heparin bolus + drip; fluid resuscitation; vascular surgery + IR consult; OR for peritoneal signs (WSES 2017)
3. heparin 80 U/kg IV bolus then 18 U/kg/h drip; aPTT q6h target 1.5-2.5x IV continuous — Suspected AMI; no active hemorrhage (WSES 2017) (WSES 2017 — IV UFH first-line all AMI etiologies)
4. crystalloid resuscitation 20-30 mL/kg balanced crystalloid IV titrated to MAP ≥65 IV bolus then maintenance — Hypovolemia or shock (WSES 2017) (Restore mesenteric perfusion)
5. pip-tazo 4.5 g IV q6h IV q6h — Suspected perforation or bowel translocation / sepsis (WSES 2017) (Broad-spectrum gram-neg + anaerobic)
6. norepinephrine 0.05-0.5 mcg/kg/min IV continuous — MAP <65 despite adequate fluid (WSES 2017) (Avoid pure-alpha vasopressors (worsen NOMI))

Non-pharmacologic actions:
- NPO (WSES 2017)
- NG decompression if vomiting / obstruction (WSES 2017)
- IV access x 2 large bore (WSES 2017)
- Foley + hourly UOP (WSES 2017)
- STAT vascular surgery + IR consults (WSES 2017)
- OR for peritoneal signs without delay (WSES 2017)
- Cross-match 4 units pRBC (WSES 2017)

AVOID / contraindication checks:
- Oral_contrast_HARMFUL_skip_for_CTA (WSES 2017)
- Pure_alpha_vasopressor_avoid_worsens_NOMI (WSES 2017)
- Thrombolysis_contraindicated_in_peritonitis_or_active_bleed
- Heparin_hold_if_active_bleed_or_imminent_surgery_until_intraoperative
- NSAID_avoid_in_septic_AKI_and_perioperative_bleed_risk

Monitoring

Regimen monitoring:
- serial lactate q4h (WSES 2017)
- aPTT or anti Xa q6h during heparin titration (WSES 2017)
- abdominal exam q2h for peritoneal signs (WSES 2017)
- UOP q1h (WSES 2017)
- second look laparotomy 24 to 48h post damage control (WSES 2017)
- reperfusion injury monitoring post revascularization (WSES 2017)
- CBC LFT lactate daily until stable (WSES 2017)

Setting (ed) monitoring:
- Continuous telemetry + vitals (WSES 2017)
- Serial lactate q2-4h (WSES 2017)
- Hourly UOP (WSES 2017)
- Abdominal exam q2h (WSES 2017)
- aPTT q6h during heparin titration (WSES 2017)

Follow-up plan: Long-term anticoagulation per etiology (MVT lifelong if unprovoked / thrombophilia; arterial per source); short-bowel syndrome management if extensive resection; nutrition support; secondary prevention (statin, antiplatelet, AF anticoagulation) (WSES 2017)
- Close-out criterion: long-term plan documented

Monitoring phase: Serial lactate, abdominal exam, vitals, UOP; post-revascularization reperfusion injury monitoring; second-look laparotomy 24-48h (WSES 2017)

Disposition

Current setting: ed — Recognize AMI via pain out of proportion, AF + sudden abdominal pain, or unexplained lactic acidosis; STAT CTA triphasic (NO oral contrast); IV heparin bolus + drip; fluid resuscitation; vascular surgery + IR consult; OR for peritoneal signs (WSES 2017)

Disposition criteria:
- ICU for all confirmed AMI (WSES 2017)
- IR suite for endovascular revascularization (no peritoneal signs) (WSES 2017)
- OR for peritoneal signs / failed endovascular / second-look laparotomy (WSES 2017)

Escalation triggers (move to higher acuity):
- Peritoneal signs → emergent OR (WSES 2017)
- Refractory shock → ICU + vasopressors (WSES 2017)
- Worsening lactate / acidosis → escalate to revascularization or OR (WSES 2017)

Earlier-Return Triggers

Return-precaution thresholds (watch for):
- [LIFE_THREATENING] Peritoneal signs (rigidity, rebound, guarding) on exam = transmural bowel infarction (WSES 2017)
- [LIFE_THREATENING] CT shows pneumatosis intestinalis or portal venous gas = bowel necrosis (WSES 2017)
- [LIFE_THREATENING] Lactate >4 mmol/L AND rising despite resuscitation = ongoing bowel infarction (WSES 2017)

Citations

- WSES 2017 Acute Mesenteric Ischaemia Guidelines (Bala et al, World J Emerg Surg 2017) [PMID:28794797](https://pubmed.ncbi.nlm.nih.gov/28794797/)

Last reconciled with current guidelines: 2026-05-26.
References
  • WSES 2017 Acute Mesenteric Ischaemia Guidelines (Bala et al, World J Emerg Surg 2017) — PMID:28794797