Comparison of preoperative neutrophil-percentage-to-albumin ratio, systemic immune-inflammatory index, and neutrophil-to-lymphocyte ratio for predicting postoperative delirium in patients undergoing head and neck free-flap reconstruction surgery: a retrospective observational study.

[PURPOSE] Reports on postoperative delirium (POD), neutrophil-percentage-to-albumin ratio (NPAR), and systemic immune-inflammatory index (SII) are limited. We aimed to compare the accuracy of preoperative NPAR, SII, and neutrophil-to-lymphocyte ratio (NLR) in predicting POD in patients undergoing head and neck free-flap reconstruction.

[METHODS] This single-center, observational, retrospective study in Japan included 184 patients who underwent head and neck free-flap reconstruction. POD was diagnosed using the Intensive Care Delirium Screening Checklist. Multivariable logistic regression analyses were conducted to evaluate the association of preoperative NPAR, SII, and NLR with POD. Receiver operating characteristic (ROC) curves were used to compare the accuracy of each inflammatory marker in predicting POD.

[RESULTS] Seven patients were excluded, leaving 177 patients (52 females, 125 males). Of these, 38 (21.5%) were diagnosed with POD. Multivariable logistic regression showed that preoperative NPAR, SII, and NLR were significantly associated with POD in patients undergoing head and neck free-flap reconstruction surgery. The areas under the ROC curve of NPAR, SII, and NLR were 0.78 (95% confidence interval: 0.69-0.86), 0.72 (0.62-0.82), and 0.75 (0.66-0.84), respectively.

[CONCLUSION] The Preoperative NPAR and SII were significantly correlated with POD in patients undergoing head and neck reconstruction, similar to NLR. Preoperative NPAR might serve as an established marker in predicting POD in patients undergoing head and neck free-flap reconstruction.