IATROGENIC AIR-EMBOLISM

The incidence of iatrogenic air embolism can only be estimated since m any accidents are not recognized. Clinical manifestations, essentially neurological or cardiovascular disorders vary greatly. Air embolism m ay occur during coronary or cerebral arteriography, cardiopulmonary by pass, venous catheterism, various types of surgery or blood transfusio n among other situations. Once air has entered the arterial circulatio n, the bubble of gas follows the blood flow until it is blocked by a s maller calibre vessel. The progressive diffusion of the air reduces th e size of the embolus which then migrates on to smaller and smaller ve ssels. Subsequent pathological manifestations of air embolism result f rom mechanical obstruction leading to ischemia and inflammatory reacti ons to air acting as a foreign body. The sudden onset signs of neurolo gical impairment with or without a cardiopulmonary component in patien ts in a high-risk situation leads to clinical diagnosis. Treatment mus t be started immediately although brain CT scan or echocardiography ma y help confirm the diagnosis. The source of the air must be immediatel y identified and removed and the vital functions controlled. Mechanica l or facial mask ventilation with pure oxygen is indicated. Hyperbaric oxygen therapy should be instituted. Morbidity and mortality after ia trogenic air embolism is high but major improvements have been achieve d with oxygen therapy. Neurological sequellae have been estimated to r each 19 to 50% of the patients. A personal controlled prospective stud y revealed 14% mortality after hyperbaric oxygen therapy given within 12 hours of the accident.