Shortness of Breath

Lungs, heart, blood, blood-gases, or plumbing?

Open full pathway

Educational first-pass aid. Reassess the patient, confirm doses and use local protocols.

1 · First minutes

Separate hypoxemic vs hypercapnic vs non-pulmonary drivers.
POCUS: B-lines, lung sliding, RV size — plus a focused history.
Gate PE (PERC if very-low gestalt; otherwise a validated Wells/age-adjusted or YEARS D-dimer pathway).

2 · Escalate now if

Silent chest, exhaustion, or falling respiratory rate in asthma/COPD
Rising CO₂ or falling pH on VBG
SpO₂ <90% despite high-flow oxygen
Hemodynamic instability or stridor at rest
Absent lung sliding with shock
New confusion or drowsiness (CO₂ narcosis)

3 · Immediate workup

SpO₂ + observation; peak flow in asthma if the patient can perform it
POCUS + ECG (RV strain, ischemia)
VBG/ABG when hypercapnia or deterioration is suspected

4 · Don’t miss

Pulmonary embolism
Sudden dyspnea with clear lungs; PERC if very-low gestalt, otherwise a validated Wells/age-adjusted or YEARS D-dimer pathway. Echo may show RV strain.
Tension pneumothorax
Trauma, COPD or PPV + hemodynamic collapse → decompress before imaging.
Acute pulmonary edema / LV failure
Orthopnea, crackles, diffuse B-lines — early NIV + nitrates if hypertensive.
Near-fatal asthma / COPD exacerbation
Silent chest, normalizing CO₂, exhaustion = pre-arrest physiology.
Anaphylaxis
IM epinephrine into the anterolateral thigh immediately — do not wait for urticaria (it may be absent).

5 · Disposition lane

Admit (ward / HDU)

Persistent hypoxia on therapy, moderate exacerbation, PE or pneumonia requiring inpatient therapy; selected low-risk PE can be treated at home after Hestia/PESI-based assessment, bleeding-risk and follow-up checks; use PSI plus clinical judgment for pneumonia.

ICU / NIV-ventilation

NIV failure or exhaustion; COPD with pH <7.25 or falling despite NIV; tension physiology; high-risk PE (shock/hypotension) — PERT/reperfusion, not RV strain alone.