Postoperative delirium is common after hip fracture surgery in elderly patients and is associated with poor outcome (higher risk of mortality, institutionalization and length of stay). The relationship between modifiable intra-operative risk factors, such as intra-operative hypotension, and postoperative delirium is unclear. The main objective of this study was to evaluate the association between intra-operative hypotension and the development of a postoperative delirium in older patients with hip fracture. A secondary aim was to assess the impact of other pre- and intra-operative predisposing factors (anaesthetic approaches or specific anaesthetic drugs, surgery duration, timing of surgery, type of implants used as primary treatment, intra-operative blood loss) on developing postoperative delirium in this elderly population. This retrospective monocentric study included 100 consecutive hip fracture patients, aged 75 years and older, admitted to a dedicated ortho-geriatric unit. All patients were screened for post-operative delirium using the confusion assessment method performed by a geriatrician. Intra-operative hypotension was defined as a decrease of more than 30% below the preoperative baseline for systolic blood pressure or a decrease in mean arterial pressure (MAP) below 60 mmHg. Post-operative delirium (n = 37; 37.8%) and intra-operative hypotension (n = 80; 81.6%) are both common in old patients but we did not demonstrate a significant association regardless of the chosen definition. The following risk factors were significantly associated with postoperative delirium: surgical delay (OR 1.47[1.01-2.02]; p = 0.02), institutionalisation (OR 2.25[1.33-3.8]; p = 0.02) and postoperative acute kidney injury (OR 2.34[1.32-4.15]; p = 0.02). Postoperative delirium is common in old patients with hip fracture and is associated with postoperative complications, institutionalisation and surgical delay but not with intra-operative risk factors.
