ICU Basics

Cardiac arrest and ACLS

Flash Pulmonary Edema (SCAPE) Algorithm

Sympathetic crashing pulmonary edema: NIV and high-dose nitroglycerin

Reviewed by Alex G, BSN, RN, CEN, CCRN, CMC, NREMT-P · From the Reference tab of the app

Each step lists what to do, then the choices that lead on. In the app the algorithm is tapped through one decision at a time.

1 Recognize it and call for help

  • Sudden severe breathlessness over minutes to hours, crackles, frothy sputum, sweating, falling SpO₂; SBP often over 180
  • Call the provider and respiratory therapy for NIV; rapid response or ICU team if the patient is failing
  • Sit the patient fully upright; oxygen by non-rebreather while NIV is set up
  • Monitor, IV access, BP every 3–5 min (arterial line when possible), 12-lead ECG within 10 minutes

SBP 160 or more: SCAPE → step 2SBP 100–159 → step 3SBP under 100 or signs of shock → step 4

2 CPAP or BiPAP now

  • Start at once; do not wait for an x-ray or labs
  • CPAP 5–10 cm H₂O, or BiPAP IPAP 10–15 and EPAP 5–8 cm H₂O; FiO₂ to keep SpO₂ 92–96%
  • Respiratory therapist at the bedside; good mask seal; coach the patient through the first minutes

Next: safe to give nitrates? → step 5

3 Pulmonary edema without severe hypertension

  • CPAP or BiPAP for distress or low SpO₂, as above
  • IV loop diuretic early: furosemide 40 mg IV, or 1–2 times the daily home dose IV (CAEP 2025)
  • Nitroglycerin if SBP stays 100 or more and nothing rules it out: start 5–10 mcg/min, raise every 3–5 min

Next: find the trigger → step 6

4 Pulmonary edema with shock

  • No nitrates; hold diuretics until perfusion improves
  • Norepinephrine for hypotension, plus an inotrope (dobutamine or milrinone) for low output
  • 12-lead: STEMI → cath lab; echo for LV and RV function, valves and tamponade
  • NIV with care, or intubate with norepinephrine running
  • Cardiology and the shock team: mechanical support (Impella, VA-ECMO) if drugs fail

End of this path.

5 Any reason to avoid nitrates?

  • PDE-5 inhibitor: sildenafil or vardenafil within 24 h, tadalafil within 48 h
  • Inferior STEMI with right ventricular infarction (ST elevation in V4R), severe aortic stenosis or LVOT obstruction

None: give high-dose nitroglycerin → step 7Yes: one of these → step 8

6 Find the trigger, then wean

  • 12-lead and troponin: STEMI or ongoing ischemia → cardiology and the cath lab; a small troponin rise is common (trend it)
  • Echo: LV function, wall motion, a new or severe valve leak (acute MR)
  • Other triggers: AF or other arrhythmia, missed medicines or salt load, AKI, renal artery stenosis, stimulants
  • Wean nitroglycerin, then NIV, as breathing and SBP settle; start oral therapy; ICU or step-down

End of this path.

7 High-dose nitroglycerin

  • Sublingual 0.4–0.8 mg (1–2 sprays or tablets), repeated every 5 min until the IV is running
  • IV bolus 400–1,000 mcg as a slow push; repeat once after 5 min if SBP is still over 160
  • Infusion: start at 100 mcg/min, raise every 3–5 min toward 200, maximum 400 mcg/min
  • Turn it down as breathing and BP improve; ESC 2019 aims for SBP under 140 at once; do not overshoot into hypotension

Next: diuretic and other treatments → step 9

8 Nitrates unsafe: other options

  • Keep NIV but watch BP closely: it lowers preload too
  • PDE-5 inhibitor: no nitrates or nitroprusside; the provider may use clevidipine, nicardipine or enalaprilat
  • RV infarction: no nitrates; cardiology and the cath lab (STEMI algorithm)
  • Severe aortic stenosis or LVOT obstruction: vasodilators only with an arterial line and cardiology at the bedside

Next: diuretic and other treatments → step 9

9 Diuretic, ACE inhibitor and what to avoid

  • Volume overloaded (edema, weight gain, home diuretic): furosemide 40 mg IV, or 1–2 times the daily home dose IV (CAEP 2025)
  • SBP still high: captopril 12.5–25 mg sublingual or enalaprilat 1.25 mg IV over 5 min (not with AKI, high K⁺, angioedema or pregnancy)
  • Still high at 400 mcg/min: the provider adds nitroprusside or clevidipine, with an arterial line
  • No morphine (linked to more intubation and ICU admission) and no beta-blocker in the acute phase

Next: reassess every 15 minutes → step 10

10 Is the patient improving?

  • Better: slower breathing, rising SpO₂, less effort, SBP coming down
  • Blood gas if drowsy or tiring

Improving → step 6Worse, tiring or drowsy on NIV → step 11SBP under 100 or lightheaded → step 12

11 NIV failing: intubate

  • Signs: worsening SpO₂ or work of breathing, rising CO₂, drowsiness, vomiting, cannot keep the mask on
  • Call the airway team; preoxygenate on the NIV mask
  • BP often crashes at induction: cut or stop the nitroglycerin first; push-dose pressor and norepinephrine ready
  • After the tube: PEEP 8–10 cm H₂O to start, 6–8 mL/kg PBW; restart nitroglycerin as BP allows

Next: find the trigger → step 6

12 BP fell too far

  • Stop the nitroglycerin; the effect fades within minutes
  • Lower the NIV pressure if BP stays low
  • Look for RV infarction, aortic stenosis, a new arrhythmia or ischemia (12-lead, echo)

BP recovers → step 10Stays low with poor perfusion → step 4

Drugs in this algorithm

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