Glucose anhydrous 20g / Sodium chloride 3.5g / Sodium citrate 2.9g oral powder sachets

IntroductionIntravenous crystalloid fluid infusion is a mandatory nutritional intervention received by surgical patients. Crystalloids vary in the pH value and electrolyte balance when administered; these effects directly alter plasma and urine compositions and can considerably affect the patient's intraoperative metabolism.MethodsThis randomized controlled study compared 0.9% saline solution and lactated Ringer's solution in terms of intraoperative metabolism among 56 patients undergoing lumbar spinal surgery. Blood and urine samples were obtained before and after surgery for arterial blood gas analysis and untargeted metabolomic analysis using liquid chromatography-mass spectrometry.ResultsPatients receiving 0.9% saline developed hyperchloremic acidosis and exhibited higher postoperative plasma concentrations of sodium (interaction P = 0.008) and glucose (interaction P = 0.034). They also required higher intraoperative norepinephrine doses (18 [0-43] μg vs. 0 [0-5] μg; P P = .051); significantly higher oxaloacetate concentrations (interaction P = .015), which may indicate less intraoperative gluconeogenesis (interaction P = .015); lower leucine degradation metabolite concentration, namely hydroxyisocaproic acid (interaction P = .055); and an attenuated decline in anti-inflammatory phospholipid breakdown metabolite, namely 15-ketoeicosatetraenoic acid (interaction P = .063). By contrast, patients receiving 0.9% saline solution exhibited unfavorable metabolism in urine indicated by reduced excretion of citric acid and creatine, which correlated with reduced glomerular filtration rates.ConclusionsThe administration of lactated Ringer's solution may facilitate more favorable intraoperative metabolic profiles than the administration of 0.9% saline solution during lumbar spinal surgery.

Abstract licence: CC BY-NC

Intravenous fluid administration is an important part of the management of the surgical patient. Fluid can be used to compensate for the normal turnover of fluid and electrolytes (maintenance), to replace losses, to expand the extracellular fluid space to maintain adequate circulation (resuscitation), and to provide nutrition. Too little fluid and too much fluid both increase the number of postoperative complications. Balanced crystalloid solutions, such as buffered Ringer's, Plasma-Lyte®, and Sterofundin®, are the most widely used fluids. Isotonic (0.9%) sodium chloride should be reserved for alkalotic and/or hyponatremic patients. Small amounts of these fluids (3 L). Maintenance fluids contain glucose and are indicated during the postoperative period before oral hydration is possible. Glucose might also be provided when awaiting surgery. The choice of replacement fluid is governed by the type of losses that have occurred. The goal of infusion fluids during hemorrhage or serious disease changes over time and might be described in the four phases resuscitation, optimization, stabilization, and de-resuscitation. Nutrition fluids are indicated after 1 week without adequate oral nutrition. Fluid therapy during surgery is performed according to the fluid balance approach (minor surgery), the outcome-oriented approach (intermediate-size surgery), or the goal-directed approach (major surgery). Children tolerate prolonged fasting poorly and preoperative fasting for clear fluids should not exceed 1 h. They have a greater tendency to develop hypoglycemia and hyponatremia than adults and, therefore, isotonic crystalloids that minimize these risks should be used during pediatric surgery. The basal daily need for fluid is children is usually taken according to the "4-2-1" rule to which additions can be made depending on the extent of the surgery. Intravenous fluid administration should be continued during the postoperative phase until enteral hydration is feasible.

Abstract licence: CC BY

The tricarboxylic acid (TCA) cycle couples nutrient oxidation with the generation of reducing equivalents that power oxidative phosphorylation. Nevertheless, the requirement for components of the TCA cycle is context-specific, raising the question of which TCA cycle outputs support cell fitness. Here, we demonstrate that citrate clearance is an essential function of the TCA cycle. As citrate production increases, so do TCA cycle activity and dependence upon aconitase 2 (ACO2), the enzyme that initiates citrate catabolism in the TCA cycle. Disrupting citrate catabolism activates the integrated stress response and impairs cell fitness, and these effects are reversed by preventing citrate production or promoting mitochondrial citrate efflux. In vivo, ACO2 deficiency induces citrate accumulation and triggers tubular degeneration in the kidney, a tissue that physiologically takes up circulating citrate. Thus, intracellular citrate accumulation can be a metabolic liability, and citrate clearance is a major function of ACO2 in the TCA cycle.

Abstract licence: CC BY-NC-ND

There is a widespread belief that organic sodium salts included in intravenous solutions serve as bicarbonate precursors, and that this mechanism explains their effects on plasma pH. We aimed to explain why the effect of organic anions, such as citrate, acetate, gluconate, and lactate on the acid-base balance is independent of bicarbonate generation. For this purpose, we mainly focused on regional citrate anticoagulation (RCA). The sodium load provided with these buffers and its contribution to the plasma strong ion difference is a more suitable model for explaining and predicting their alkalinizing effect. Moreover, the bicarbonate generated from the metabolization of these buffers via the Krebs cycle results from CO2 dissolution in water, and thus yields bicarbonate together with a proton (H+). As such, metabolization of these buffers does not cause alkalosis per se.

Abstract licence: CC BY-NC-ND