Cerebral Oximetry and Cognitive Dysfunction in Elderly Patients Undergoing Surgery for Hip Fractures: A Prospective Observational Study

This study was conducted to examine perioperative cerebral oximetry changes in elderly patients undergoing hip fracture repair and evaluate the correlation between regional oxygen saturation (rSO₂) values, postoperative cognitive dysfunction (POCD) and hospital stay.

This prospective observational study included 69 patients. Data recorded included demographic information, rSO₂ values from baseline until the second postoperative hour and Mini Mental State Examination (MMSE) scores preoperatively and on postoperative day 7. MMSE score ≤23 was considered evidence of cognitive dysfunction. Postoperative confusion or agitation, medications administered for postoperative agitation, and hospital length of stay were also recorded. Data were analyzed with Student’s t-test, Pearson’s correlation or multiple regression analysis as appropriate.

Patient age was 74±13 years. Baseline left sided rSO₂ values were 60±10 and increased significantly after intubation. Baseline rSO₂ L<50 and <45 was observed in 11.6% and 10.1% of patients respectively. Perioperative cerebral desaturation occurred in 40% of patients. MMSE score was 26.23 ± 2.77 before surgery and 25.94 ± 2.52 on postoperative day 7 (p=0.326). MMSE scores ≤ 23 were observed preoperatively in 6 and postoperatively in 9 patients. Patients with cognitive dysfunction had lower preoperative hematocrit, hemoglobin, SpO₂ and rSO₂ values at all times, compared to patients who did not. There was no correlation between rSO₂ or POCD and hospital stay. Patients with baseline rSO₂ <5 required more medications for postoperative agitation.

Cognitive dysfunction occurs preoperatively and postoperatively in elderly patients with hip fractures, and is associated with low cerebral rSO₂ values.