Discussion
bleeding, intraoperative bleeding, intraoperative blood loss, ischemia, blood loss, postoperative bleeding, knee arthroplasty, TKA, hypotension
BLEEDING, BLOOD LOSS, ISCHEMIA, POSTOPERATIVE BLEEDING, HYPOXIC, ADVERSE EFFECTS, INTRAOPERATIVE BLOOD LOSS, INTRAOPERATIVE BLEEDING
Tourniquets and controlled hypotension techniques are commonly used in total knee arthroplasty to control bone surface bleeding and maintain a clear surgical field. However, Morelli et al. [We verified the effectiveness of the intravenous infusion of low-dose norepinephrine in reducing bleeding during surgery from two aspects: intraoperative blood loss and the surgeon's visual perception. In this study, the average intraoperative blood loss in the NE group and C group was 294.50 ± 113.71 ml and 480.92 ± 132.05 ml, respectively, with a 38.8% reduction in the NE group compared to the C group. At the same time, the median bone-cutting surface bleeding score in the NE group was 2 (1, 2), while in the C group it was 3 (3, 4), highlighting a significant decrease in the NE group. This indicates that compared with placebo, intravenous infusion of low-dose norepinephrine during TKA without a hemostatic band can significantly reduce intraoperative bleeding and bone-cutting surface bleeding, providing a satisfactory clear bone-cutting surface. De Backer et al. [Another advantage of using a low dose of norepinephrine via a venous pump is that it can appropriately increase intraoperative blood pressure. Vallée et al. [The greatest risk of intravenous infusion of norepinephrine is excessive vasoconstriction, which leads to inadequate organ perfusion and tissue ischemia. Therefore, the benefits and adverse effects of intravenous infusion of low-dose norepinephrine must be evaluated. To further understand the effect of the intravenous infusion of low-dose norepinephrine on systemic organ perfusion, we compared the differences in arterial blood lactate concentrations between the two groups before and after norepinephrine administration. Lactate is a metabolic product of cells under anaerobic and hypoxic conditions. When the balance between oxygen supply and demand is disrupted, lactate increases due to anaerobic metabolism, and its value directly reflects systemic tissue perfusion and microcirculation [Several studies have investigated the optimal dose of intravenously administered norepinephrine. Several animal models of general anesthesia have shown that after appropriate fluid supplementation, intravenous infusion of norepinephrine at 0.3–1 mg/(kg·min) does not affect the blood flow and oxygenation of visceral organs such as the heart, kidneys, liver, and intestines [There was no significant difference in transfusion rates between the two patient groups during hospitalization; however, the overall transfusion rate in our study population was very low (5%), with two patients (3.3%) in the NE group and four patients (6.7%) in the C group receiving transfusions. In this study, both groups of patients received a dose of tranexamic acid (15 mg/kg) via intravenous infusion before and 3 h after the surgery. Although tranexamic acid cannot reduce intraoperative blood loss, numerous randomized controlled trials have shown that intravenous infusion of tranexamic acid without a tourniquet during TKA can effectively and safely reduce postoperative bleeding and transfusion requirements [This study was conducted in patients receiving routine general anesthesia, which is the standard anesthetic method for TKA at our center. While certain studies have indicated that general anesthesia results in greater blood loss when compared to spinal anesthesia [This study has several limitations. First, some studies have shown that norepinephrine can promote platelet release and activation by activating α-2 and β-2 adrenergic receptors, which stimulates the release of various coagulation factors to achieve hemostasis [In summary, venous infusion of low-dose norepinephrine can effectively reduce intraoperative bleeding and provide a clearer bone-cutting surface while ensuring that the MAP is not low. Simultaneously, venous infusion of low-dose norepinephrine did not affect the blood lactate concentration indicators of systemic organ perfusion during surgery and did not increase the transfusion rate during hospitalization, indicating high safety. These are the unique advantages of venous infusion of low-dose norepinephrine that other known intraoperative hemostasis methods do not have. This study proposes a novel and feasible approach for optimizing intraoperative bleeding management and increasing surgical safety.