Failed Oxygenation: DOPE-S

Why This Is Hard

Low SpO₂ creates tunnel vision. Crews re-bag the same way, turn up O₂ already at max, or jump devices without fixing why oxygen is not reaching the blood. On scene you may have seconds, not a textbook chapter — so you need a repeatable mental pass that covers patient and equipment.

Failed oxygenation is not only “can’t intubate.” It is any situation where the patient is not getting adequate oxygen delivery despite your efforts: bad BVM, displaced tube, empty tank, severe shunt, tension physiology, or obstruction.

Framework: DOPE-S

When “we’re oxygenating” but numbers and the patient disagree, run this pass out loud:

1. D — Displacement / delivery
   • O₂ source connected to the right port? Reservoir inflated? Tubing kinked under the stretcher?
   • Advanced airway still in place and at correct depth after every move?
   • Waveform EtCO₂ present? Sudden flat line after a move screams displacement until proven otherwise.
2. O — Obstruction
   • Blood, vomit, secretions, tongue, foreign body, severe bronchospasm, laryngospasm context.
   • Suction aggressively; use adjuncts; consider etiology (anaphylaxis, asthma) for meds per protocol.
3. P — Pneumothorax / physiology
   • Unilateral findings, trauma, blast, high-pressure bagging, severe asthma/COPD auto-PEEP.
   • Think beyond the mask: tension pneumothorax pathway, medical causes of shunt/dead space, profound shock with poor SpO₂ signal.
4. E — Equipment
   • Empty cylinder, closed regulator, wrong adapter, cracked mask, failed suction, bad SpO₂ probe.
   • Try another probe site; look at the patient (color, mentation, work of breathing) before trusting a single number.
5. S — Seal & technique
   • BVM position, two-person seal, rate, volume (see BVM lesson).
   • Many “failed airways” start as failed basic ventilation.

Escalation Thinking (Prehospital)

• Optimize what you have before stacking devices blindly (third mask type without fixing position/seal).
• Two-person BVM + adjuncts + suction often beats another identical one-handed attempt.
• Supraglottic / ETT when indicated and authorized — confirm with waveform capnography when available.
• If ventilation is impossible and the patient is crashing, follow your failed airway / CICO (cannot intubate, cannot oxygenate) pathway per protocol and training — this lesson does not teach a surgical procedure.
• Call for help early (second unit, supervisor, intercept, air medical when indicated) when trajectory is bad.
• Document what you tried, in what order, and what changed — critical for ED and QA.

SpO₂ vs the Patient

• SpO₂ lags behind real-time changes and fails on cold, shocky, dirty, or moving fingers.
• Poor waveform on the pulse ox means the number may be fiction.
• Hypoxia causes: hypoventilation, V/Q mismatch/shunt, low FiO₂, diffusion problems, equipment failure — DOPE-S covers the field-actionable ones first.

Key Points

• Stay systematic under stress; do not skip DOPE-S.
• Fix basics (delivery, obstruction, seal) before only blaming “bad lungs.”
• Displacement after packaging and loading is a classic EMS failure mode — recheck EtCO₂ and tube depth after every major move.
• Know your service’s difficult airway algorithm before you need it at 02:00.

Practice

Run a tabletop: SpO₂ 78% after intubation. Partner names a failure mode; you walk DOPE-S in order and state the immediate action for each letter. Related: BVM that actually works and waveform capnography.

Sources & Further Study

• Difficult airway / failed airway educational frameworks (DOPE and variants).
• Your local airway and CICO protocol.