Abstract:

Objective To investigate the effects of intraoperative fluid therapy guided by different stroke volume variation（SVV）on tourniquet⁃related hemodynamic fluctuations in elderly patients undergoing total knee arthroplasty（TKA）. Methods Eighty⁃one elderly patients were divided into 3 groups（n = 27）randomly according to the SVV threshold after tourniquet inflated：5%～7%（group L），8%～10%（group M）and 11%～13%（group H）. Hemodynamic indexes such as invasive arterial pressure，SVVwere continuously monitored by the Lidco instru⁃ ment. The area under the curve（AUT）of the part of MAP below 20% of the baseline 10 mins after tourniquet deflated，the minimum MAP（MAPmin）and the maximum percentage of MAP decreasing from the baseline（MAP% max） were calculated. Before the tourniquet was deflated（T0），5 minutes（T1）and 10 minutes（T2）radial artery blood was collected to detect blood lactic acid（Lac）. The requirement for fluid and vasoactive drug，blood loss and urine volume were recorded. Troponin T were recorded before operation，1 day and 3 days after operation. The early post⁃ operative complications were recorded. Results AUT of hypotension showed a decreasing trend after tourniquet release in all three groups. Compared with group L，MAPmin was significantly decreased and MAP% max was signifi⁃ cantly increased in group H（P < 0.05）. The lac was significantly increased in group M and group H at T1（P < 0.05）. Compared with group M，MAPmin was significantly decreased in group H（P < 0.05）. Conclusion In elderly patients undergoing TKA，controlling SVV at 5%～7% level before tourniquet was deflated can prevent tourniquet⁃ related hypotension，improve tissue perfusion，and decrease postoperative myocardial injury.

Key words:

stroke volume variation, fluid therapy, hypotention, total knee arthroplasty, myocar? dial injury