To the Editor:—
Eight years ago I wrote a letter to the editor1in response to a Meeting Abstracts Article published in Anesthesiology on air embolism (AE).2My letter said, “one totally preventable and recurring cause of potentially fatal venous air embolism that was not mentioned in the article … is externally pressurizing a reinfusion blood bag that has been filled with blood from a surgical field scavenging-blood processing system.” I was dismayed and astounded that the recent review article published in Anesthesiology on AE3also did not mention the predictable, preventable, often fatal AE that occurs from externally pressurizing reinfusion bags filled with surgical field-scavenged/processed/salvaged blood. In the majority of multiple models made by multiple manufacturers (e.g ., Cobe Cardiovascular Inc. [Arvada, CO] and Hemonetics [Braintree, MA]), the processing unit (centrifuge bowl wherein the scavenged cells are washed) must send a 70- to 80-ml column of air into the reinfusion bag before any blood from the processing unit can enter the reinfusion bag. In addition, there are a number of processing blood circumstances that will cause the reinfusion bag to contain multiples of 70–80 ml of air. If the dead space volume of the infusion line to the patient is less than 70–80 ml, venous AE due to external pressurization of a scavenged/processed/salvaged blood reinfusion bag is a 100% physical certainty. Because the AE bolus is introduced into a sizable vein over 1–2 s, there is a significant probability that significant compromise of the circulation will ensue.
Indeed, Linden reported five cases of fatal AE due to administration of recovered blood under pressure in New York State alone from January 1990 to June 1995,4and the American Society of Anesthesiologists Closed Claims database contains “several” fatalities “from air in the blood from the cell saver.”5In my own medical–legal experience, I have reviewed two fatalities in the past 3 yr and six fatalities in the past 10–12 yr due to pressurizing recovered blood. All of the cases I reviewed had the same horrific story: Multiple bowls of salvaged blood were processed without purging the air from the reinfusion bag, the reinfusion bag was externally pressurized, there was a sudden cardiac arrest within 1 min of the reinfusion bag being emptied of blood, there was a failed resuscitation (including aspiration of air from central veins), and then the autopsy showed a heart filled with air. The obvious, but lifesaving take-home message of these considerations is that reinfusion blood bags that have been filled with blood that has been scavenged and processed by an autotransfusion system should never be externally pressurized.
University of California San Diego Medical Center, San Diego, California. jbenumof@ucsd.edu
