Ketamine-Induced Anaphylactic Shock During Prophylactic Mastectomy

Ketamine is a commonly used intravenous (IV) anesthetic and postoperative analgesic. Known side effects include sedation, hallucinations, and confusion, but anaphylaxis to ketamine is not generally known as a typical complication. We present the case of a 35-year-old woman undergoing bilateral prophylactic mastectomy that developed intraoperative anaphylaxis to first exposure of ketamine. A literature search using PubMed and key words “ketamine”, “anaphylaxis”, and “anaphylactic shock” was conducted along with a description of the clinical case. The patient enrolled in the Ketamine Analgesia for Long-lasting Pain relief After Surgery (KALPAS) study and consented to receiving ketamine in 0.9% sodium chloride vs only 0.9% sodium chloride intraoperatively. The literature search of ketamine-induced anaphylaxis yielded only 4 cases. The patient received a 0.35mg/kg bolus of study drug and began a 0.25mg/kg ketamine infusion after induction. She also received cefazolin, propofol, rocuronium, ketamine, lidocaine, and fentanyl intraoperatively. Within one hour of receiving the medications the patient developed widespread urticaria, hypercarbia, bronchospasm, and refractory hypotension, which was treated with phenylephrine, epinephrine, dexamethasone, and diphenhydramine. The surgery was aborted midway, and the patient required ICU admission overnight. Allergy testing revealed a positive intradermal test for ketamine, indicating IgE mediated anaphylaxis to ketamine. She tested negative for all other medications delivered in the OR, suggesting that ketamine infusion can result in life-threatening anaphylaxis. This trial is registered at clinicaltrials.gov (NCT05037123). Funded by National Institutes of Health (1UG3CA261067-01).