Accidental administration of the remifentanil formulation Ultiva™ into the epidural space and the complete time course of its consequences: a case report

Kota Nishimoto, Sachiyo Sakamoto, Makiko Mikami, Kiichi Hirota, Koh Shingu

Ultiva™ contains the potent short-acting μ-opioid receptor agonist remifentanil hydrochloride, and it is commonly administered intravenously during general anesthesia. It is not approved for epidural or intrathecal use in clinical practice because it contains glycine as an acidic buffer. However, at this moment, very limited information is available on epidural administration of Ultiva™. We report the accidental administration of 300 μg of remifentanil and 2.25 mg of glycine into the epidural space after emergence from general anesthesia for distal pancreatectomy and the complete time course of its consequences. The respiratory depression occurred at 5 min after the administration, and complete loss of consciousness was observed at 8 min. The patient was re-intubated and underwent mechanical respiration. At 45 min (33 min after re-intubation), spontaneous respiration resumed, she was responsive to commands, and her orientation returned. She was extubated successfully. These consequences might have resulted from the diffusion of the components of Ultiva™ into not only systemic circulation but also the cerebrospinal fluid. Moreover, the complex pathophysiology might be associated with remifentanil, as well as glycine present in Ultiva™.