| Purpose:To compare different levels of blood pressure with restrictive transfusion to the effects of intraoperative blood loss, systemic oxygen metabolism and renal function in elderly patients undergoing lumbar fusion.Methods:The protocol was approved by Independent Ethics Committee for Clinical Research of Zhongda Hospital, Affiliated to Southeast University. Forty elderly patients (aged 60 to 75 years old and ASA grade ? or ?) undergoing elective lumbar fusion surgery were enrolled in the study from August 2015 to January 2016. And they were randomly divided into two groups:experimental group (Group A:Control target MAP 65mmllg, n=20) and control group (Group B:control target MAP 75mmHg, n=20). Both groups used intravenous-inhalation combined anesthesia. Infusion strategy:before anesthesia both groups were given the 1/3 fasted physiological requirements and followed by 3 ml/(kg·h) Ringer's lactate solution. Intraoperative blood loss were recycled by autologous blood recover machine, apart from the autologous recycled blood, the remaining were supplemented by hydroxyethyl starch 130/0.4 in 1:1. Strategy of blood pressure control:at the incision we began to control blood pressure. If MAP was higher than the target, we adjusted the infusion rate of nitroglycerin to maintain MAP at the target value; if MAP was below the target, we stopped nitroglycerin, and use norepinephrine to maintain MAP. Controlling MAP was ended till the operation to spinal decompression finished. Mean arterial pressure (MAP), heart rate (HR), cardiac index (CI), central venous pressure (CVP), hemoglobin (Hb), lactate (Lac), arterial oxygen partial pressure (PaO2), central venous blood oxygen partial pressure (PcvO2), arterial oxygen saturation (SaO2) and central venous oxygen saturation (ScvO2) were recorded at preoperatively(To), 1h and 2h(Ti and T2) after hypotension and out of the operating room(T3). Then calculated oxygen delvery index(DO2I), oxygen consumption index(VO2I) and oxygen extraction rate(ERO2). At To?T3 and postoperative first day(T4) measured serum Cystatin C(SCysC), creatinine(Cr) and blood urine nitrogen (BUN). Intraoperative crystalloid and colloid fluid volume, blood loss, urine output, autologous blood recovery, operation time, extubation time, exhaust time, hospitalization stay and postoperative complications were recorded.Results:1. The intake and output results:there was no significant difference between Group A and Group B in blood loss (493±294ml VS 564±311ml), urine volume, the amount of fluid and autologous blood recovery(P> 0.05),and both groups received no allogeneic blood. 2. Hemodynamic:The MAP in Group A was significantly lower than Group B at Ti and T2 (P<0.05). The CI decreased significantly at Ti-T3 than To in both groups(P<0.05), and the CI in Group A was significantly lower than Group B at Ti-T3(P<0.05).3. Systemic oxygen metabolism:Compared with To, the DO2I and VO2I decreased significantly at Ti-T3 in both groups (P<0.05). The DO2I in Group A was significantly lower than Group B at Ti and T2, so did the VO2I at Ti(P<0.05). Between the two groups, ERO2 had no significant difference(P> 0.05).3. Renal function:there was no significant difference between the two groups at each time point of renal function(P> 0.05). Comparison with To, the SCysC at Ti-T3 increased significantly in Group A, so did Group B at T2(P<0.05).4. Postoperative index:there was no significant difference between the two groups in tracheal extubation time, hospitalization time and incidence of postoperative complications (P> 0.05).Conclusion:To elderly patients undergoing lumbar fusion surgery with restrictive transfusion, controlling MAP in 65mmHg comparing with 75 mmHg had no effects on intraoperative blood loss and postoperative complications, and caused slight changes in renal function, but that might reduce oxygen delivery. |
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