Identification of risk factors for post-induction hypotension in patients receiving 5-aminolevulinic acid: a single-center retrospective study

Background: 5-Aminolevulinic acid (5-ALA) is useful as a photodynamic agent, but its use commonly leads to hypotension. Although avoiding a mean arterial pressure (MAP) < 60 mmHg is important, the incidence of MAP < 60 mmHg when using 5-ALA is unclear. Therefore, we conducted a retrospective study to assess the incidence of post-induction hypotension and identified risk factors of this phenomenon. Methods: One-hundred and seventy-two consecutive patients who underwent transurethral resection of the bladder tumor or craniotomy with the use of 5-ALA were enrolled. The primary outcome was the incidence of post-induction hypotension, defined as MAP < 60 mmHg during the first 1 h after anesthesia induction. We divided participants into the normal blood pressure group (group N) and the hypotension group (group L). Results: The incidence of post-induction hypotension was 70% (group L = 121, group N = 51). Multivariate analysis revealed that female sex was an independent factor of post-induction hypotension (odds ratio [OR] 3.95; 95% confidence interval [CI] 1.21–12.97; p = 0.02). Systolic blood pressure < 100 mmHg before anesthesia induction and general anesthesia were also identified as significant independent factors (OR 13.30; 95% CI 1.17–151.0; p = 0.04 and OR 25.84; 95% CI 9.80–68.49; p < 0.001, respectively). Conclusions: The incidence of post-induction hypotension was 70% in patients using 5-ALA. Female sex, systolic blood pressure < 100 mmHg before anesthesia induction, and general anesthesia might be independent factors of post-induction hypotension when using 5-ALA.