RN Basics

First five minutes

New Hypoxemia Algorithm

Probe, position and oxygen first; then DOPE or the bedside clues

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 Look at the patient: is the low SpO₂ real?

  • Not breathing or no pulse: call a code, open the airway, bag-mask with 100% O₂; CPR if pulseless
  • Look at color, work of breathing, RR and mental status; distressed or cyanotic: raise the O₂ now
  • Check the probe: clear pleth wave, warm finger, probe seated; try an ear or forehead probe
  • Real or unsure: call the respiratory therapist and the provider now; rapid response team outside the ICU

Poor waveform, patient comfortable → step 2Real, not intubated → step 3Real, on a ventilator (tube or tracheostomy) → step 4

2 Probe problem: fix it and recheck

  • Warm the hand, reseat the probe, limit motion, remove dark nail polish; ear or forehead probe for poor perfusion
  • Cold, vasoconstricted or on high-dose pressors: a weak signal can still hide real hypoxemia
  • Still unsure: ABG with co-oximetry; methylene blue dye and methemoglobin distort SpO₂
  • Recheck with a good waveform; tell the provider if it stays low

End of this path.

3 Sit up and raise the oxygen

  • Sit upright, head of bed 45° or more, unless hypotensive or on spine precautions
  • Raise O₂ to SpO₂ 92–96% (88–92% if at risk of CO₂ retention): nasal cannula up to 6 L/min, then nonrebreather 15 L/min
  • Listen to both sides; count the RR; look for secretions, wheeze, crackles, swelling and the fluid balance
  • Ask for an ABG and a portable chest x-ray

Next: treat what you find → step 5

4 On the ventilator: 100% O₂, then DOPE

  • FiO₂ to 100%; look at chest rise, exhaled Vt, peak pressure and the EtCO₂ waveform
  • Distressed or still falling: disconnect and bag with 100% O₂ and a PEEP valve; feel how easy it is
  • Displacement: tube depth at the teeth, EtCO₂ waveform. Obstruction: kinks, biting, secretions; pass a suction catheter
  • Pneumothorax: one side silent, high peak and plateau, falling BP. Equipment: circuit, O₂ supply, settings

Tube out, no EtCO₂ waveform, or catheter will not pass → step 6Signs of tension pneumothorax → step 7Better when bagged: equipment or settings → step 8DOPE clear: the lungs are worse → step 9

5 Not intubated: treat what you find

  • Secretions, weak cough or aspiration: stop tube feeds, suction (nasotracheal if needed), cough and chest physiotherapy with RT
  • Wheeze: albuterol 2.5–5 mg nebulized, plus ipratropium 0.5 mg in asthma or COPD
  • Crackles, JVD or overload: furosemide IV per order (40–80 mg, more if on a home dose); early NIV; nitroglycerin if SBP is high
  • Slow, shallow breathing and pinpoint pupils: naloxone 0.04–0.4 mg IV, titrated to breathing

One side silent with falling BP: tension pneumothorax → step 7Still under target on 15 L/min, or working hard → step 10Improving → step 11

6 Tube out or blocked

  • Tube out or no EtCO₂ waveform: deflate the cuff, remove the tube, bag-mask with 100% O₂ (oral airway, two hands)
  • Catheter will not pass: biting (bite block, sedation) or a plug; still blocked: remove the tube and bag-mask
  • Call anesthesia or the airway team to reintubate; airway cart, suction and RSI drugs to the bedside
  • Tracheostomy: remove a speaking valve or cap and the inner cannula, then suction; still blocked: deflate the cuff, then remove the tube
  • Tracheostomy out: O₂ to face and stoma; follow the Tracheostomy Emergency algorithm

End of this path.

7 Tension pneumothorax: decompress now

  • Clues: one side silent, falling SpO₂ and BP, high peak and plateau on the ventilator; tracheal shift is late
  • The provider decompresses now: needle or finger at the 4th–5th intercostal space, just anterior to the mid-axillary line
  • Do not wait for an x-ray; 100% O₂; chest tube tray to the bedside
  • A chest tube follows, then an x-ray and a blood gas

End of this path.

8 Better off the ventilator: equipment or settings

  • Keep bagging with 100% O₂ and PEEP while RT checks or replaces the circuit or ventilator
  • Look for leaks, disconnects, water in the circuit, the O₂ supply, and a wrong FiO₂, PEEP or Vt
  • Fighting the ventilator: treat pain and agitation; adjust flow, trigger or mode with RT

End of this path.

9 DOPE clear: lung or circulation problem

  • After suctioning or a disconnect: lung units may have collapsed; ask RT about re-recruiting and more PEEP
  • Sudden one-sided collapse: mucus plug; suction, chest physiotherapy, bronchoscopy
  • Crackles and a positive balance: diuresis per order. High peak, normal plateau: suction, bite block or bronchodilator
  • Falling EtCO₂ with hypotension: think PE or low cardiac output. Severe ARDS (P/F under 150): proning

Next: ABG and imaging → step 11

10 Escalate: high-flow or NIV

  • High-flow nasal cannula 40–60 L/min, FiO₂ to the SpO₂ target: first choice for most hypoxemic failure
  • NIV (CPAP or BiPAP) instead for cardiogenic pulmonary edema, or COPD with pH 7.35 or less and a high PaCO₂
  • BiPAP start: EPAP 5, IPAP 10–15 cm H₂O; only if awake, protecting the airway and not vomiting
  • Reassess within 1 hour: SpO₂, RR, effort; ABG at 1–2 h on NIV; ROX (SpO₂ ÷ FiO₂ ÷ RR) under 3.85 at 12 h predicts HFNC failure

Improving → step 11Failing or tiring → step 12

11 Find the cause: ABG and imaging

  • ABG: PaO₂ and P/F ratio; PaCO₂ and pH for hypoventilation or CO₂ retention; lactate
  • Portable chest x-ray; bedside ultrasound for lung sliding, B-lines, effusion and heart function
  • 12-lead ECG; sudden hypoxemia, tachycardia and clear lungs: ask about PE (CT angiography when safe to travel)
  • Common causes: edema, pneumonia or aspiration, plug or collapse, bronchospasm, pneumothorax, PE, ARDS, oversedation

Next: report → step 13

12 When to intubate

  • SpO₂ under 88–90% on maximal HFNC or NIV, or RR over 35 with exhaustion or paradoxical breathing
  • GCS 8 or less, cannot protect the airway or clear secretions, vomiting, or NIV not tolerated
  • Hypercapnia worsening on NIV: pH still under 7.25 after 1–2 hours, or falling; shock
  • Call anesthesia or the airway team; RSI checklist; preoxygenate on NIV or HFNC; push-dose pressor drawn up

End of this path.

13 Report (SBAR) and keep watching

  • S: SpO₂ on what support (device and L/min, or FiO₂ and PEEP), RR, HR, BP, when it started
  • B: diagnosis, recent procedures, fluid balance, opioids or sedatives, last chest x-ray, code status
  • A: work of breathing, mental status, breath sounds, ABG (pH, PaCO₂, PaO₂), P/F, the cause you suspect
  • R: bedside review; orders for imaging, ABG, HFNC or NIV, diuretic or nebulizer; ICU or airway team if failing
  • Recheck SpO₂, RR and work of breathing every 15 minutes until stable

End of this path.

Drugs in this algorithm

Related one-pagers

Practice free in your browser2,150+ exam-style questions with rationales. No account, no ads. Also free on the App Store and Google Play.

For education and exam preparation only. Follow your institution’s protocols. Study aid with typical adult values; follow your institution's protocols and current AHA guidelines.