Immediate management

100% oxygen. Patient flat. Stop further gas entry. Support the circulation. Call early — imaging should not delay the referral.

The immediate priorities in suspected gas embolism are to give 100% oxygen, lay the patient flat, stop further gas entry, support the circulation and refer early for hyperbaric oxygen therapy.

Stop further gas entry

Check all intravascular access devices for integrity, correct connections and valve function. Inspect sites of recently removed central lines or haemodialysis catheters for signs of patency. If the embolism occurred during surgery, notify the surgeon to identify and eliminate the source. Lower the surgical field below the level of the heart. If a body cavity is being insufflated, release the pressure.

Oxygenation

Administer 100% oxygen immediately. This is not titrated to oxygen saturations. High-flow oxygen reduces bubble size by creating a diffusion gradient that draws nitrogen out of the gas embolus, and improves oxygen delivery to ischaemic tissue in the penumbra.

Positioning

Keep the patient flat (supine). Do not elevate the head of the bed.

Trendelenburg (head-down) positioning was traditionally recommended to prevent gas reaching the cerebral circulation. Prolonged Trendelenburg worsens cerebral oedema and should be avoided. Specific manoeuvres such as left lateral decubitus (Durant's position) have limited supporting evidence. Neither should delay resuscitation or the referral call. Discuss positioning with the Hyperbaric Physician when connected.

Resuscitation

Follow standard resuscitation principles: airway, breathing, circulation. CPR is best performed with the patient supine. Chest compressions may help force gas from the pulmonary outflow tract into the smaller pulmonary vessels. Use vasopressors and inotropes early if there is haemodynamic compromise. If a central venous catheter is already in situ near the right atrium or ventricle, aspiration of gas may be attempted; inserting a new central line for this purpose alone is not recommended.

Refer early

Contact the HBOT Single Point of Access (020 4632 2377) as soon as gas embolism is suspected. Do not wait for imaging results. Do not wait for clinical improvement. Patients may show initial recovery and then relapse. The probability of a good neurological outcome declines with each hour of delay.

Chambers can take sick patients: NHS-commissioned hyperbaric units have the equipment and trained staff to treat critically unwell patients inside the chamber, including those who are intubated, ventilated and requiring vasopressor or inotrope support. Critical illness is not, in itself, a reason to delay or withhold referral.

If the patient is not immediately fit for transfer, secure the airway, ventilate and manage on ICU while discussing the case with the hyperbaric team. Review fitness for transfer regularly.

Contraindications to HBOT

There are very few absolute contraindications. Two should be identified early:

  • Untreated pneumothorax — a chest drain must be inserted before compression.
  • Severe bullous lung disease.

Most are relative: Discuss with the Hyperbaric Physician on a risk-benefit basis. The presence of a relative contraindication should not prevent or delay the referral call.

Emergency
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