Postoperative delirium after reconstructive surgery for oral tumor: a retrospective clinical study

The aim of this study was to perform a statistical evaluation of the risk factors for postoperative delirium after oral tumor resection and reconstructive surgery. The records of 69 consecutive patients who underwent major head and neck tumor resection and reconstructive surgery, and who received postoperative management in the high care unit (HCU) or intensive care unit (ICU) of Tsukuba University Hospital between January 2013 and December 2017, were analysed retrospectively. Delirium was diagnosed in 23 patients (33.3%) after surgery. There were significant differences in age, sex, history of diabetes mellitus and chronic obstructive pulmonary disease, recent hospitalization history, sedation period, duration of ventilator use, length of ICU/HCU stay, postoperative blood tests (haemoglobin and potassium), and postoperative medication with a major tranquilizer between those with and without delirium. Logistic regression analysis of selected independent variables revealed a hazard ratio (95% confidence interval) of 1.42 (1.09-1.86) for the sedation period. Delirium was hyperactive type in 15 cases, hypoactive type in five, and mixed type in three. There was no obvious difference in postoperative day of onset or delirium period according to subtype. In conclusion, a history of diabetes and the sedation period were found to be related to postoperative delirium. However, this study was small and retrospective, so further investigation is necessary.