CO Poisoning: Treatment When Initial 100% Oxygen Has Not Normalised COHb

This protocol applies to patients with carbon monoxide poisoning who have received first-line high-concentration oxygen therapy but have not yet achieved the required treatment targets — a normalised carboxyhaemoglobin (COHb) level below 3% and full resolution of symptoms.

First-Line Treatment — Goals Not Met

Initial management of CO poisoning requires immediate administration of 100% oxygen at the highest achievable concentration — via mask CPAP (non-invasive ventilation), demand valve, high-flow mask with reservoir bag, or invasive airway protection when protective reflexes are inadequate. This approach is maintained until COHb drops below 3% and the patient becomes symptom-free, typically within a maximum of approximately five physiological half-lives of COHb at 100% oxygen breathing. This next-line protocol is triggered when those targets have not been reached.

Next-Line Approach (Partial Overview)

When the initial oxygen strategy has not met targets, the protocol escalates to hyperbaric oxygen therapy (HBOT) — a specialised, multi-session intervention that must be initiated within a defined early window following the failure of first-line treatment.

The complete treatment schedule, session parameters, timing windows, and clinical decision algorithm are available in the full protocol.

Instant Access to Structured Evidence-Based Regimens

References

HBOT should be initiated within 6 h.
HBOT should be performed three times within 24 h.
The initial HBOT session should correspond to the therapy schedule (TS) 300/90 (according to Boerema schedule).
A second and third HBOT session should be performed at a treatment pressure greater than/equal to 2.4 bar (TS 240/90).
In the European literature, the TS 300/90 (so-called Boerema schedule, 300 kPa total pressure for 90 min with oxygen breathing followed by gradual decompression) and TS 240/90 (240 kPa total pressure for 90 min with oxygen breathing) are described.

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