Effect of dilutional anemia that can be treated with only one unit of red blood cell transfusion on tissue oxygenation in cardiac surgery patients

Background/aim: Cardiac surgery, especially in the presence of cardiopulmonary bypass (CPB), is associated with an inflammatory reaction that may promote microcirculatory alterations, in addition to the general impact on system hemodynamics. Anemia and transfusion make patients more susceptible to the deleterious effects of CPB. In this study, it was aimed to evaluate the effect of dilutional anemia, which is caused by CPB and can be treated with 1­2 units of red blood cell (RBC) transfusion, on global tissue oxygenation parameters in cardiac surgery patients. Materials and methods: This prospective observational study comprised 127 patients who had a relatively stable operation period without any major anesthetic or surgical complications (e.g., operation duration >5 h, bleeding or hemodilution requiring more than 1­2 units of RBCs, or unstable hemodynamics, requiring inotropic support of more than 5 µg/kg/min dopamine). Patients were observationally divided into two groups: minimally transfused (Group Tr) and nontransfused (Group NTr). Global tissue oxygenation parameters were evaluated after anesthesia induction (T1) and at the end of the operation (T3) and compared between the groups. Results: Group Tr consisted of patients who had significantly lower preoperative hemoglobin values than Group NTr patients. The dilutional anemia of all Group Tr patients could be corrected with 1 unit of RBCs. The lactate levels at T3, increment rates of lactate, and venoarterial carbon dioxide pressure difference (ΔpCO2) levels [(T3 ­ T1) : T1] in Group Tr were significantly higher than those in Group NTr. Conclusion: Dilutional anemia as a result of CPB mostly occurs in patients with borderline preoperative hemoglobin concentrations and its correction with RBC transfusion does not normalize the degree of microcirculatory and oxygenation problems, which the patients are already prone to because of the nature of CPB. Preventing dilutional anemia and transfusion, especially in patients with preoperative borderline hemoglobin levels, may therefore reduce the burden of impaired microcirculation-associated organ failure in on-pump cardiac surgery.

Which type of conditioning method protects the spinal cord from the ischemia-reperfusion injury in 24 hours?

OBJECTIVE: This study was designed to test the effects of different types of preconditioning and postconditioning methods on spinal cord protection following aortic clamping. METHODS: The animals (rabbits) were divided into sham-operated, ischemic preconditioning, remote ischemic preconditioning, simultaneous aortic and ischemic remote preconditioning, and ischemic postconditioning groups. After neurological evaluations, ultrastructural analysis and immunohistochemical staining for caspase-3 were evaluated after 24 h following ischemia. RESULTS: The neurological outcomes of the remote ischemic preconditioning (4.2 ± 0.4) and ischemic postconditioning (4.6 ± 0.8) groups were significantly improved when compared with the ischemia group (2.2 ± 04). The immunohistochemical analysis revealed that the lowest percentage of apoptosis was in-group ischemic preconditioning at 12.5 ± 30.6%. In the comparison of intracellular edema in an ultrastructural analysis, the ischemic preconditioning and ischemic postconditioning groups had significantly lower values than the ischemia group. CONCLUSION: The conditioning methods attenuate ischemia-reperfusion injury for spinal cord injury. Ischemic and remote preconditioning and also postconditioning methods are simple to perform and inexpensive.

Obesity and postoperative early complications in open heart surgery.

PURPOSE: We investigated the distribution of early clinical outcomes among normal, obese, and morbidly obese patients undergoing open heart surgery. METHODS: Medical records of 1,000 patients undergoing open heart surgery since February 2011 at our hospital were investigated retrospectively after permission was obtained from the Council of Education Planning of the hospital. The comorbidities and perioperative and discharge data were analyzed for 279 patients with a body mass index (BMI) score between 18 and <30 [non-obese reference group (NRG, n = 279)]; 166 patients with BMI between 30 and <35 [obese group (OG, n = 166); and 192 seriously obese patients with BMI ≥35 [extreme obese group (EOG, n = 192)]. Distribution of the patients according to BMI scores was found to represent the BMI distribution of the Turkish population. RESULTS: Pulmonary and infective complications were significantly higher in EOG patients compared to NRG based on crude confidence interval. Based on adjusted multiple logistic regression analysis, by adjusting the effects of age, sex, comorbidities (diabetes mellitus, hypertension, hyperlipidemia, chronic obstructive pulmonary disease), and smoking, the incidence of pulmonary and gastrointestinal complications in EOG was higher compared to NRG. Discharge with morbidity was significantly higher in OG and EOG compared to NRG. CONCLUSIONS: We found that obesity does not increase short-term mortality for open heart surgery; however, it increases the risk of postoperative pulmonary and gastrointestinal complications and discharge with morbidity.

In which period of injury is resveratrol treatment effective: ischemia or reperfusion?

The periods of ischemia and reperfusion represent different characteristics by lack of oxygen and reoxygenation. The aim of this experimental spinal cord injury model was to investigate whether resveratrol has protective effects during ischemia or reperfusion and the mechanism of the protection by using N-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthase. Rabbits were divided into seven groups according to the time of administration of resveratrol or L-NAME (RI and RR, resveratrol during ischemia or reperfusion; IL and RL, L-NAME during ischemia or reperfusion; RILR, resveratrol during ischemia and L-NAME during reperfusion; LIRR, L-NAME during ischemia and resveratrol during reperfusion; control group). After neurologic evaluation at the twenty-fourth hour of reperfusion, lumbar spinal cords were removed for electron microscopic evaluation, immunohistochemical staining for apoptosis, and malondialdehyde (MDA) and myeloperoxidase (MPO) measurements. The RILR group had the best functional recovery, with a mean 3.6 Tarlov score (P < 0.05), and showed near normal electron microscopic findings (scores of 7.6 +/- 0.9 for the control group and 3.9 +/- 2.9 for the RILR group, P < 0.05). MPO and MDA levels were decreased in all groups compared with the control group, but only the decrement in the RILR group reached statistical significance. Immunohistochemical analysis showed that the groups including resveratrol and L-NAME together had the best staining for apoptosis. Resveratrol exhibits important protection by means of neurologic outcome, histopathologic analysis, and biochemical analysis, especially when used in during ischemia followed by L-NAME administration during reperfusion. Also, resveratrol protects against apoptosis, especially when combined with L-NAME.