Relationship of physical symptoms, ECG, free calcium, and other blood chemistries in reinfusion with citrated blood.

Changes in ECG, free calcium (CaF), and other biochemical parameters were measured during reinfusion of citrate anticoagulated blood in 12 subjects undergoing plateletpheresis. Physical symptoms during the procedure were also monitored. The CaF was found to correlate best with the Q-oTc interval as compared to the Q-oT, Q-Tc, or Q-T interval. While the correlation was significant (r = 0.592, p less than .001), the Q-oTc could not predict the CaF. A number of other blood constituents were found to change during plateletpheresis, with most directly related to either citrate administration or hemodilution. Severe physical symptoms were found in one subject and no symptoms in three. In the subjects without symptoms the changes in Q-oTc, Pi, alkaline phosphatase, and glucose through the plateletpheresis procedure were different from changes in all subjects. The decrease in glucose level was the most striking single factor correlating with the lack of physical symptoms during the citrate-induced hypocalcemia associated with plateletpheresis. It is concluded that monitoring of the ECG cannot substitute for direct measurement of free calcium in citrate-induced hypocalcemia, that the physical symptoms associated with similar levels of hypocalcemia are variable, that glucose level may be a marker for the effects of citrate-induced hypocalcemia, and that lowered citrate loads during plateletpheresis appear warranted.