Baseline cerebral oximetry values in elderly patients with hip fractures: A prospective observational study

SummaryAimThis study was conducted to evaluate baseline cerebral tissue regional oxygen saturation (rSO2) values and identify risk factors related to severe rSO2 reductions in elderly patients with hip fractures.Patients and methodsThis was a prospective observational single-centre study on patients undergoing scheduled or urgent operation for isolated hip fracture. The study was approved by the Institution Ethics Committee, and all patients signed informed consent before entering the study. Data were collected on factors potentially related to baseline cerebral rSO2. Data were analysed with Student's t-test, Pearson's correlation or multiple regression analysis as appropriate.ResultsSixty-nine patients, aged (mean ± standard deviation (SD)) 74 ± 13 years participated. Left baseline rSO2 was 60.09 ± 10.20 and right baseline rSO2 was 58.64 ± 9.92. Baseline rSO2 < 45 was observed in 10.1% of patients on the left and 8.7% on the right side. Correlation between left- and right-side baseline cerebral rSO2 was highly significant (r = 0.852, p < 0.001). Baseline cerebral rSO2 had a positive, highly significant correlation with preoperative haematocrit (r = 0.50, p < 0.001) and arterial haemoglobin oxygen saturation (SpO2) (r = 0.587, p < 0.001), but correlation was negative with the American Society of Anesthesiologists (ASA) physical status (r = −0.42, p < 0.001) and age (r = −0.39, p = 0.001). Linear regression showed that preoperative haematocrit accounts for 23% (R2 = 0.23) of baseline rSO2 variability, whereas preoperative haematocrit and SpO2 combined account for 43.7% of rSO2 variability (R2 = 0.437). Combined preoperative haematocrit + SpO2 + age accounted for 51.3% (R2 = 0.513) of observed rSO2 variability.ConclusionLow baseline cerebral rSO2 values are common in elderly hip fracture patients, despite normal haemodynamic and arterial saturation values. Preoperative haematocrit, SpO2 and age explain a significant portion of cerebral rSO2 variability. More studies are needed to validate our findings and assess the potential benefit of interventions aimed at improving cerebral rSO2 in elderly hip fracture patients.