Hypocalcemic toxicity and atypical reactions in therapeutic plasma exchange

Hypocalcemic toxicity accounts for the most common adverse effects of therapeutic plasma exchange. The symptoms can be related to a fall in plasma ionized calcium. Citrate-based anticoagulants, notably sodium citrate and ACD formula A, have been indicated as the major cause of hypocalcemic toxicity, but colloid replacement fluids containing human serum albumin are also at fault. Recognition of the signs and symptoms of hypocalcemic toxicity is important because several clinical measures are available to deal with them and to ensure patient comfort. A typical reactions, characterized by flushing and hypotension during plasma exchange, have been attributed to the effects of angiotensin converting enzyme inhibitors. Both exchange and adsorption apheresis procedures can result in atypical reactions in patients who have been taking this class of drugs within 48 to 72 hours of an apheresis procedure. These reactions are less common than hypocalcemic toxicity, but can be prevented by paying attention to detail.