Risk factors for postoperative delirium in patients undergoing major head and neck cancer surgery: a meta-analysis

Objective: Postoperative delirium is common after extensive surgery. This study aimed to collate and synthesize published literature on risk factors for delirium in patients with head and neck cancer surgery. Methods: Three databases were searched (MEDLINE, Embase, and Cochrane Library) between January 1987 and July 2016. The Newcastle Ottawa Scale (NOS) was adopted to evaluate the study quality. Pooled odds ratios or mean differences for individual risk factors were estimated using the Mantel-Haenszel and inverse-variance methods. Results: They provided a total of 1940 patients (286 with delirium and 1654 without), and predominantly included patients undergoing head and neck cancer surgery. The incidence of postoperative delirium ranged from 11.50% to 36.11%. Ten statistically significant risk factors were identified in pooled analysis. Old age, age >70 years, male sex, duration of surgery, history of hypertension, blood transfusions, tracheotomy, American Society of Anesthesiologists physical status grade at least III, flap reconstruction and neck dissection were more likely to sustain delirium after head and neck cancer surgery. Conclusion: Delirium is common in patients undergoing major head neck cancer surgery. Several risk factors were consistently associated with postoperative delirium. These factors help to highlight patients at risk of developing delirium and are suitable for preventive action.