Clinical Disease

critical-care

High-impact pattern

TTM Prognostication After Cardiac Arrest

Multimodal neurologic prognostication after targeted temperature management — when and how to predict neurologic recovery

After cardiac arrest, TTM sedates and pharmacologically paralyzes for 24-48h to provide cerebral neuroprotection; valid neurologic prognostication requires deferring any withdrawal-of-care discussion until ≥72h after rewarming and using a MULTIMODAL approach (exam + NSE + SSEP + EEG + imaging) — never a single finding.

If you forget

Prognostication timing: NEVER before 72h post-rewarming — TTM masks every exam finding

Board trap

Junior resident wants to prognosticate at 24h because the patient is off sedation with GCS 3 — but AHA 2025 post-arrest pathway requires waiting ≥72h after rewarming AND using MULTIMODAL findings (no single test, including absent SSEP, is sufficient in isolation) before any WLST discussion.

Key numbers

TTM target: 32-36°C × 24h (TTM-2 trial; equivalent outcomes)
Earliest valid prognostication: ≥72h AFTER return to normothermia
NSE cutoff: >33 μg/L (Abbott) — peak/trend over 72h, not a single value
SSEP bilaterally absent N20 cortical response: FPR <1% for awakening
Pupillary light reflex absent at 72h: FPR ~2-5% (NOT zero)
pH <7.2 or lactate >7 mmol/L on presentation: low survival likelihood
Time to ROSC >30 minutes: low survival likelihood

Reviewed Sep 24, 2026 for clinical accuracy by BoardsBridge Editorial Process

Uri Rozen, MD — Licensed Physician, Israel

Source guidelines: AHA Adult ALS 2025 · AHA MCS Cardiogenic Shock 2023 · Scai Shock Classification 2022 · AHA NRP 2020

Re-review cadence: 12 months from reviewed date.

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Card ID: ttm-prognostication · Path: aba.critical-care.post-cardiac-arrest-targeted-temperature.ttm-prognostication