CONTEXT AND OBJECTIVE: The ideal site for lactate collection has not been clearly established. This study aimed to evaluate associations between lactate levels in arterial blood (Lart), peripheral venous blood (Lper) and central venous blood (Lcen) in patients with severe sepsis or septic shock. DESIGN AND SETTING:Cross-sectional analytical study in an tertiary university hospital. METHOD:Samples from patients with a central venous catheter and from healthy volunteers (control group) were collected. Blood was drawn simultaneously for measurements of Lart, Lper and Lcen, and the first sample was collected less than 24 hours after the onset of organ dysfunction.The results were analyzed using Pearson correlation, Bland-Altman and McNemar tests. RESULTS:A total of 238 samples were collected from 32 patients. The correlation results were r = 0.79 (P < 0.0001) for Lart/Lper and r = 0.84 (P < 0.0001) for Lart/Lcen. Bland-Altman showed large limits of agreement: -3.2 ± 4.9 (-12.8 to 6.4) and -0.8 ± 5.9 (-12.5 to 10.8), for Lper and Lcen respectively. In the control group, there was greater correlation (r = 0.9009, P = 0.0004) and agreement: -0.7 ± 1.2 (-3.1 to 1.7). Regarding clinical intervention, there was good agreement between Lart/Lcen (96.3%; three disagreements), with worst results for Lart/Lper (87.0%) with 10 cases of disagreement (P = 0.04). In eight patients (80.0%) Lper was higher than Lart. RESULTADOS: Um total de 238 amostras foi coletado em 32 pacientes. Resultados da correlação: r = 0.79 (P < 0,0001) para Lart/Lper e r = 0.84 (P < 0,0001) para Lart/Lcen. Bland-Altman mostrou largos limites de concordância, -3.2 ± 4.9 (-12.8 to 6.4) and -0.8 ± 5.9 (-12.5 to 10.8), para Lper e Lcen, respectivamente. No grupo controle, houve uma maior correlação (r = 0.9009, P = 0,0004) e concordância: -0.7 ± 1.2 (-3.1 to 1.7).No que se refere à intervenção clínica, houve boa concordância Lart/Lcen (96.3%, três não concordantes), com resultados piores encontrados para Lart/Lper (87.0%) com 10 casos não concordantes (P = 0,04). Em oito pacientes (80.0%) Lper foi mais elevado que Lart. CONCLUSÃO:Lcen, e não Lper, pode substituir Lart com boa correlação e concordância clínica. Lper tende a superestimar Lart, assim levando a intervenções terapêuticas desnecessárias.

Hydrogen sulfide is produced endogenously by a variety of enzymes involved in cysteine metabolism. Clinical data indicate that endogenous levels of hydrogen sulfide are diminished in various forms of cardiovascular diseases. The aim of the current study was to investigate the effects of hydrogen sulfide supplementation on cardiac function during reperfusion in a clinically relevant experimental model of cardiopulmonary bypass. Twelve anesthetized dogs underwent hypothermic cardiopulmonary bypass. After 60 minutes of hypothermic cardiac arrest, reperfusion was started after application of either saline vehicle (control, n = 6), or the sodium sulfide infusion (1 mg/kg/hour, n = 6). Biventricular hemodynamic variables were measured by combined pressure-volume-conductance catheters. Coronary and pulmonary blood flow, vasodilator responses to acetylcholine and sodiumnitroprusside and pulmonary function were also determined. Administration of sodium sulfide led to a significantly better recovery of left and right ventricular systolic function (P < 0.05) after 60 minutes of reperfusion. Coronary blood flow was also significantly higher in the sodium sulfide-treated group (P < 0.05). Sodium sulfide treatment improved coronary blood flow, and preserved the acetylcholine-induced increases in coronary and pulmonary blood (P < 0.05). Myocardial ATP levels were markedly improved in the sulfide-treated group. Thus, supplementation of sulfide improves the recovery of myocardial and endothelial function and energetic status after hypothermic cardiac arrest during cardiopulmonary bypass. These beneficial effects occurred without any detectable adverse hemodynamic or cardiovascular effects of sulfide at the dose used in the current study. The aim of the current study was to test potential cytoprotective and anti-inflammatory effects of the novel biological mediator hydrogen sulfide in murine models. Murine J774 macrophages were grown in culture and exposed to cytotoxic concentrations of nitrosoglutathione, or peroxynitrite (a reactive species formed from the reaction of nitric oxide and superoxide). Pretreatment of the cells with sodium sulfide (60-300 µM) reduced the loss of cell viability elicited by the nitric oxide donor compound (3 mM) or by peroxynitrite (3 mM), as measured by the MTT method. Sodium sulfide did not affect cell viability in the concentration range tested. In mice subjected to bacterial lipopolysaccharide (LPS, 5 mg/kg i.p.), treatment of the animals with sodium sulfide (0.2 mg/kg/hour for 4 hours, administered in Alzet minipumps) reduced the LPSinduced increase in plasma IL-1β and TNFα levels. These responses were attenuated when animals were pretreated with the heme oxygenase inhibitor tin-protoporphyrin IX (6 mg/kg). The current results point to the cytoprotective and anti-inflammatory effects of hydrogen sulfide, in cells exposed to nitrosative stress, and in animals subjected to endotoxemia. Introduction It has been previously shown that the two forms of acute cholecystitis, acute acalculous cholecystiti...

We really appreciate your interest in our study published in the last issue of Sao Paulo Medical Journal. We would like to thank you for your comments.We would like to clarify that the aim of our work was exactly to test whether the lactate levels in arterial and venous blood could replace each other. Our results did show that venous peripheral lactate, drawn by venipuncture and not from capillary blood, cannot replace arterial lactate. However, the concordance between central venous and arterial levels was reasonable.This suggests that, in clinical practice, both can be used.