Correlation analysis of postoperative blood volume changes and delirium in elderly patients undergoing surgery for hip fracture

Abstract

Objective To explore the relationship of blood volume changes and postoperative delirium in elderly patients undergoing surgery for hip fracture.Methods One hundred and fifty elderly patients who underwent surgery for hip fracture were enrolled in the study.Delirium was diagnosed by Confusion Assessment Method(CAM).Preoperative,intraoperative and postoperative data were collected,and the correlation of postoperative delirium and blood volume changes were analyzed by logistic regression analysis.Results A total of 59 patients(28 males and 31 females)had delirium after surgery and the occurrence rate of postoperative delirium was 39.3％ (59/150).The average age in delirium group was significantly older than that in the control group[ (77.71 ±6.63)years old vs(73.79 ±5.42) years old,t =-3.958,P ＜0.001 ].The average hemoglobin concentration and hematocrit in delirium group were both less than that in control group whether before surgery or at 7 days after surgery( before surgery:average hemoglobin concentration:[ ( 117.80 ± 16.59)g/L vs( 123.92 ±14.61 ) g/L,t =2.378,P =0.019; hematocrit:(0.355 ± 0.154) vs(0.372 ± 0.210),t =2.291,P =0.023 ;7days after surgery:average hemoglobin concentration:(98.15 ± 11.51 ) g/L vs ( 102.33 ± 9.88 ) g/L,t =2.369,P =0.019; hematocrit:(0.296 ± 0.040 ) vs (0.306 ± 0.030),t =-3.958,P ＜ 0.001 ].There was no significant difference on gender,fracture type,surgical approach,operative time,blood loss and hemoglobin concentration at 1,3 days after surgery between the two groups( P ＞0.05 ).Logistic regression analysis showed that age ( OR 3.280 ),education ( OR 0.389 ),and hemoglobin concentration at 7 days after operration ( OR 1.097) were significantly related to the occurrence of postoperative delirium ( P ＜ 0.05 ).Conclusion Our findings suggest that the risk for postoperative delirium is the result of more than one factor.Older age,continued postoperative low hemoglobin concentration and low degree of education present high risk of delirium in patients underwent surgery for hip fractures. Key words: Postoperative delirium; Hip fracture; Blood volume changes; Logistic regression analysis