Hypotension During General Anesthesia Induction due to Oral Administration of 5-Aminolevulic Acid and Residual Effects of Long-acting Angiotensin Receptor Blockers: A Case Report

Background<br>   Various cases of hypotension are associated with the use of general anesthesia. Here,we report a case of refractory hypotension during general anesthesia that was thought to be affected by preoperative medication.<br> Case Report<br>   A 70-year-old patient underwent brain tumor resection with the assistance of photodynamic diagnosis using 5-aminolevulinic acid (5-ALA). The patient had been taking angiotensin receptor blockers (ARB) and calcium channel blockers for hypertension. During general anesthesia induction using fentanyl (100 μg), propofol (2 μg/mL), rocuronium (40 mg), and remifentanil (0.2 μg/kg/min), hypotension occurred. Refractory hypotension persisted despite rapid dose reduction of propofol and remifentanil, repeated doses of phenylephrine (total 0.8 mg), and infusion loading. Since only adrenaline was effective against hypotension, an anaphylactic reaction was suspected, and surgery was canceled. The drug-induced lymphocyte stimulation and basophil activation tests for drug-induced anaphylactic reaction (allergy testing) yielded negative results. Therefore, an overreaction to propofol and remifentanil due to 5-ALA and/or the residual effects of ARBs was suspected. The patient was scheduled to undergo surgery without 5-ALA administration. Moreover, ARB was discontinued 72-h before surgery. Surgery was completed without hypotension.<br> Conclusion<br>   We encountered a case of refractory hypotension caused by 5-ALA and the residual effects of ARBs.