The Effect Of Single Lung Ventilation Time On Postoperative Cognitive Dysfunction And Serum Hypoxic Inducible Factor-1? In Elderly Patients

Objective: The single lung ventilation is a non-physiological ventilation mode,which can increase intrapulmonary shunt and cause the imbalance of ventilation and blood flow.Now,the relevant studies have shown that single lung ventilation is a risk factor for postoperative postoperative congnitive dysfunction(POCD),however,the effect of single lung ventilation time on POCD is not clear.Therefore,in this study,we investigated the effect of single lung ventilation time on POCD and serum hypoxic inducible factor-1?(HIF-1?)in elderly patients undergoing thoracic surgery by recording the time of single lung ventilation during operation,so as to provide more understanding for POCD.Methods: This study prospectively included 202 elderly patients with thoracic surgery patients,according to the time of one lung ventilation were divided into less than 1 hours,1-2 hours,2-3 hours,3 hours more than 4 groups,namely M1,M2,M3,M4 group,the HIF-1? was determined by enzyme linked immunosorbent assay(ELISA)in these patients at preoperative(T1),1th hour after surgery(T2),12 th hour after surgery(T3),1th day after surgery(T4),3th days after surgery(T5),7th days after surgery(T6)and the neuropsychological tests were used to assess incidence of POCD in these patients,the relationship among single lung ventilation time,neuropsychological test and serum HIF-1? was analyzed.Results:(1)168 patients were included in this study,there were 38 patients in M1 group,52 patients in M2 group,54 patients in M3 group and 24 patients in M4 group,and there was no significant difference in general data in four groups(P>0.05).(2)There was no significant difference in neuropsychological tests in the four groups before surgery(P>0.05),however,at 7th days surgery,there was significant difference in neuropsychological tests in the four groups,compared with M1 and M2 group,mental state scale,digit span test,digit symbol test and word fluency test score was lower in M3 and M4 group(P<0.05).(3)There was no significant difference in the serum HIF-1? in the four groups at T1(P>0.05),however,at T2~T4 period,compared with T1,serum HIF-1? levels were increased in four groups,and compared with M1,M2 group,serum HIF-1? levels were more significantly increased in M3 and M4 group(P<0.05),however,at T5~T6 period,there was no significant difference in the serum HIF-1? in the four groups(P>0.05).(4)The 53 patients have developed POCD at the 7th days after surgery and the incidence of POCD was 31.5%,among these patients,there were 4 patients in M1 group,12 patients in M2 group,24 patients in M3 group and 13 patients in M4 group,there was significant difference in the incidence of POCD in four groups,compared with M1 and M2 group,the incidence of POCD was increased in M3 and M4 group(P<0.05).(5)The Pearson correlation analysis showed that single lung ventilation time was negatively correlated with MMSE and vocabulary fluency test score(P<0.05).(6)The Pearson correlation analysis also showed single lung ventilation time was positively correlated with serum HIF-1? levels(P<0.05).(7)The logistic regression analysis showed that longer single lung ventilation time is a risk factor for the occurrence of POCD,in addition,the higher serum HIF-1? is an important predictor of the risk of POCD.Conclusions: During the operation of thoracic surgery,the single lung ventilation time was longer and the serum HIF-1? levels were higher,the incidence of POCD was higher.The longer single lung ventilation time and the higher serum HIF-1? levels were risk factors for POCD in patients undergoing thoracic surgery.