Failed Oxygenation: DOPE-S

Why this matters

A low oxygen saturation (SpO₂, the sat) narrows your focus. Crews bag the same way again, turn up oxygen that is already at maximum, or change devices without fixing why oxygen is not reaching the blood.

On scene you may have seconds. Use the same spoken check every time. It covers the patient and the equipment.

Failed oxygenation is not only “cannot intubate.” It is any time the patient is not getting enough oxygen. That includes a poor bag-valve-mask (BVM) seal, a displaced tube, an empty tank, blood that is not reaching ventilated lung, tension pneumothorax, or a blocked airway.

Clinical sequence

1. If the sat is falling, or the waveform is flat or unreadable after an airway, say DOPE-S out loud.
2. Work the letters in order. D is displacement: the wrong depth, the esophagus, or a disconnected circuit. O is obstruction: suction, and look for kinks. P is pneumothorax or other physiology, including air stacked in the lungs. E is equipment. S is the seal and how you squeeze the bag, including rate and volume.
3. Fix one thing, then bag again. Do not start another look until you have given oxygen.
4. If the patient is still getting worse, place a supraglottic airway or move to a cannot-intubate-cannot-oxygenate plan per protocol. Another identical direct-laryngoscopy look is not a plan.

DOPE-S, Letter by Letter

DOPE is the Pediatric Advanced Life Support memory aid for sudden worsening in a ventilated patient. The letters are displacement, obstruction, pneumothorax, and equipment. The added S, seal and technique, is an EMS teaching step. Many field failures start as a bad mask seal or bagging too fast, not as a ventilator alarm.

When the crew says oxygen is on, but the numbers and the patient do not agree, say this check out loud.

1. D is displacement or delivery.
   • Check that oxygen is connected to the right port, the reservoir is inflated, and the tubing is not kinked under the stretcher.
   • Check that the advanced airway is still in place, at the right depth, after every move.
   • Check for a waveform for end-tidal carbon dioxide (EtCO₂), the carbon dioxide trace on the monitor. A sudden flat line after a move is a displaced tube or a disconnected circuit until you prove otherwise. If the tube is in the esophagus, take it out and oxygenate.
2. O is obstruction.
   • Look for blood, vomit, secretions, the tongue, a foreign body, severe bronchospasm, or laryngospasm.
   • Suction until you can see. Place an adjunct. If the cause is anaphylaxis or asthma, give the medicines in your protocol.
3. P is pneumothorax or physiology.
   • Look for one-sided chest findings, trauma, blast injury, high-pressure bagging, or severe asthma or chronic obstructive pulmonary disease with auto-PEEP. Auto-PEEP is air trapped in the lungs that cannot get out.
   • Look past the mask. Think about tension pneumothorax, blood that is not reaching ventilated lung, and shock that makes the sat number unreliable.
4. E is equipment.
   • Check for an empty cylinder, a closed regulator, the wrong adapter, a cracked mask, suction that does not work, or a bad sat probe.
   • Move the probe. A flat reading on a pink patient who is moving may be the probe, the site, or the signal. Look at color, alertness, and work of breathing before you trust one number.
5. S is seal and technique.
   • Check head position, a two-person seal, rate, and volume. See the BVM lesson.
   • Many failed airways start as failed basic ventilation. Fix the bag before you blame the tube.

If You Still Cannot Oxygenate

• Fix what you already have before you add another device. A third mask does not help if the position and the seal are still wrong.
• Two-person BVM, an adjunct, and suction often work better than another identical one-handed attempt.
• Place a supraglottic airway or an endotracheal tube when your protocol allows it. Confirm with waveform capnography when you have it.
• If you cannot ventilate and the patient is getting worse, follow your failed-airway pathway per protocol and training. This lesson does not teach a surgical procedure.
• Call for help early when the patient is getting worse. That may be a second unit, a supervisor, an intercept, or air medical when that is indicated.
• Write down what you tried, in what order, and what changed. The emergency department and your quality review need that record.

When the Pulse Ox Lies

• The sat lags behind what is happening now. It fails on cold fingers, in shock, with dirt, and with movement.
• A poor pulse-ox waveform means the number may be wrong.
• A flat probe reading on a pink, moving patient may be the probe or the site. Confirm with the exam and try another site. Do not treat that number as certain death, and do not turn oxygen off because of it.
• Act first on causes you can fix. Those are not breathing enough, a blocked or dirty airway, the wrong oxygen fraction, a displaced tube, and equipment failure. DOPE-S covers those before you blame bad lungs.

Teaching points

• Stay in order when you are stressed. Do not skip letters.
• Tubes move during packaging and loading. Recheck the waveform and the tube depth after every major move.
• Know your service’s difficult-airway steps before you need them in the middle of the night.

Practice

Related: Effective BVM, Waveform capnography.

Sources & Further Study

Named guidelines for further study. They are not clinical orders and do not replace your protocol or medical direction.

• NASEMSO National Model EMS Clinical Guidelines (2022) — U.S. EMS model language; follow your protocol
• AHA/AAP 2025 Part 8: Pediatric Advanced Life Support — DOPE mnemonic (Displacement, Obstruction, Pneumothorax, Equipment) for sudden deterioration in a ventilated patient
• DOPE (Displacement, Obstruction, Pneumothorax, Equipment) is the PALS memory aid for sudden worsening in a ventilated patient. Seal and technique (the “S” here) is an EMS teaching step for field bag-valve-mask work.
• Your local airway and CICO protocol.