Case report: intraoperative anaphylactoid reaction and hydroxyethyl starch in balanced electrolyte solution (Hextend)

To report a first case of probable anaphylactoid reaction to 6% hydroxyethyl starch reconstituted in balanced electrolyte and glucose solution (Hextend).

A 22-yr-old man was admitted for a partial nephrectomy. Near the end of the four-hour operation, an infusion of Hextend was initiated. Shortly thereafter, mechanical ventilation became difficult, peak inspiratory pressure increased to 55 cm H2O with audible wheezing over the patient's lungs. Blood pressure suddenly decreased to 68/46 mmHg. Multiple doses of phenylephrine, ephedrine and epinephrine were required to restore the patient's blood pressure. Postoperatively, a diffuse urticarial rash was apparent on his upper torso. The patient recovered uneventfully. His postoperative serum tryptase was 26.3 ng x mL(-1) (reference range, < 11.5 ng x mL(-1)) and the urine N-methyl-histamine was 2448 microg x g(-1) creatinine (reference range, 30-200 microg x g(-1) creatinine). Two months after the event, skin testing was conducted to test for possible allergy to latex, lidocaine, propofol, cisatracurium, succinylcholine, vecuronium, midazolam, fentanyl, ondansetron, neostigmine, and cephazolin, and all were negative. Hextend was also tested, starting with a 1:100,000 dilution and the results were negative.

The temporal relationship of severe hypotension, bronchospasm and skin rash within ten minutes from administration of Hextend in this patient suggests an immediate hypersensitivity reaction to hetastarch. The elevated levels of serum tryptase and urinary N-methyl-histamine suggest that this hypersensitivity was mediated from mast cell degranulation. Negative skin testing suggests that the reaction was anaphylactoid.