Gas embolism is when a bubble enters the circulation and blocks blood flow cause damage to the surrounding tissues. The commonest example in our work is that of arterial gas embolism, which we see in divers. Air gets into the arterial circulation due to pressure damage to the lungs, normally following a rapid ascent.
Gas can unintentionally enter the circulation due to other reasons. It can be an unfortunate and unintended complication of a medical procedure. For example, chest surgery, chest drain insertion or insertion of large lines into big veins for administration of fluids or drugs in hospital.
Both groups of patients are treated with Hyperbaric Oxygen (HBO) at our chamber under discussion with our duty doctor. The course of treatment varies depending on the individual case.
The vast majority of individuals with gas embolism that we treat are divers with arterial gas embolism (AGE), following pulmonary barotrauma during a dive. The vast majority of individuals with gas embolism that we treat are divers with arterial gas embolism (AGE), following pulmonary barotrauma during a dive. Of course arterial or venous gas embolism can occur for many other reasons, mostly iatrogenic.
AGE can be seen as a result of
- Mechanical ventilation
- Penetrating chest trauma
- Chest tube insertion
- Bronchoscopy
The venous system is also often exposed to the possibility of excess gas being injected iatrogenically as well. For example,
- Accidental IV injection
- Bypass accidents
- During haemodialysis
- CV line insertion/disconnection
- GIendoscopy/arthroscopy
- Laparoscopy/TURP
- Surgical wounds higher than the heart, e.g. sitting craniotomy.
An individual can tolerate up to 20ml/min IV of gas, whereas volumes tolerated directly into arterial system are much lower. There is limited data on the exact volume.
Air within the circulation will create different pathology depending on its location and volume. Air within the heart can lead to a “vapour lock” resulting in circulatory compromise thus hypotension and cardiac arrest. It could also cause arrhythmias and or ischaemia if passes into the cardiac vessels.
Bubbles may pass into the cerebral circulation and manifest as general reduction in GCS or focal neurology depending on their location.
If you think your patient has a gas embolism please ring the emergency line on 07831 151 523 (24 hrs) in England and Wales or 0345 408 6008 in Scotland.
References
Blanc P, Boussuges A, Henriette K, Sainty JM, Deleflie M. Iatrogenic cerebral air embolism: importance of an early hyperbaric oxygenation. Intensive Care Med. 2002 May;28(5):559-63. doi: 10.1007/s00134-002-1255-0. Epub 2002 Mar 21. PMID: 12029402.
Mitchell SJ, Bennett MH, Moon RE. Decompression Sickness and Arterial Gas Embolism. N Engl J Med. 2022 Mar 31;386(13):1254-1264. doi: 10.1056/NEJMra2116554. PMID: 35353963.
Mathieu D, Marroni A, Kot J. Tenth European Consensus Conference on Hyperbaric Medicine: recommendations for accepted and non-accepted clinical indications and practice of hyperbaric oxygen treatment. Diving Hyperb Med. 2017 Mar;47(1):24-32. doi: 10.28920/dhm47.1.24-32. Erratum in: Diving Hyperb Med. 2017 Jun;47(2):131-132. doi: 10.28920/dhm47.2.131-132. PMID: 28357821; PMCID: PMC6147240.