During massive transfusion many blood constituents may decline, including serum magnesium. Ho and Leonard identified factors that can help to identify a patient with hypomagnesemia. The authors are from Royal Perth Hospital and the University of Western Australia.


The authors found that about 60% of patients develop hypomagnesemia.


Mechanisms of hypomagnesemia: dilution and citrate toxicity


Risk for hypomagnesemia correlates with:

(1) hypocalcemia: The OR is 1.67 per 0.1 mmol drop

(2) hypofibrinogenemia: The OR is 1.05 per 10 mg/dL (or 100 mg/L) drop.


total OR for each =

= (OR)^(number of intervals)


Since hypocalcemia and hypofibrinogemia have the same cause then they are not completely independent. This may preclude a cumulative odds ratio based on the two parameters.



(1) is common in massive blood transfusion

(2) correlates with ionized calcium levels

(3) does not appear to impact mortality


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