Changes in noradrenaline and dopamine levels under oxygen debt conditions in the brain of rats during experimental acute pancreatitis

This study’s aim was to assess the level of catecholamines, i.e., noradrenaline and dopamine, under oxygen debt conditions in the brain of experimental animals in which acute pancreatitis was experimentally induced. Catecholamines play the role of neurotransmitters and neuromediators. They are responsible for the regulation of motor and emotional processes, take part in the regulation of hormonal activities, sleep, wakefulness, concentration, attention, and learning processes. The experiment also determined the oxygen tension as an indicator of respiratory failure and the activity of amylase and lipase in the development of the inflammatory process. The animals on which the experiment was conducted were Wistar rats (140 animals) divided into 3 research groups: control (C) animals (n = 30), healthy (H) animals (n = 30), and operated (O) animals (n = 80). The determination of amylase, lipase, oxygen pressure, NA, and DO levels were performed at hours 2, 6, 12, 24, and 48 of the experiment. The animals in group C had an injection needle inserted to investigate only the effects of mechanical damage to the organs. On the other hand, the animals in group O had a 5% solution of sodium taurocholate introduced into the common bile-pancreatic duct. The research conducted shows that the most significant changes in NA and DO levels were observed on the first day of the experiment. The concentrations of the above catecholamines were statistically significantly correlated with the level of amylase in the blood. The peak of dopamine was observed between the 6th and 12th hours of the experiment, while the lowest concentration of noradrenaline was observed at the 6th hour of the experiment.

Justification of the choice of indicators for assessing load hypoxia in humans and laboratory animals

In a study on healthy athletes of the track and field profile, it was shown that the hypoxia of physical activity is most fully reflected by the indicator of specific oxygen debt (maximum oxygen debt divided by 1000 J of work performed). When simulating load hypoxia in laboratory animals, direct registration of the arising oxygen debt is technically difficult to implement, and its indirect signs may be a decrease in peripheral blood saturation, excessive tachycardia, and hyperlactatemia of the post-load period. Key words: hypoxia of physical activity, oxygen debt, athletes, laboratory animals, blood lactate, physical activity.

Macrocirculatory Parameters and Oxygen Debt Indices in Pigs During Propofol Or Alfaxalone Anesthesia When Subjected to Experimental Stepwise Hemorrhage

Background: Pigs are anesthetized when used for emergency procedures live tissue training (LTT) of civilian and military medical personnel or for experimental purposes, but there is a paucity in the literature regarding anesthesia of pigs for this purpose.Objective(s): The main goals of the study were to compare oxygen debt, macrocirculatory parameters, and time to cardiac arrest between pigs in hemorrhagic shock and anesthetized with propofol-ketamine-dexmedetomidine or alfaxalone-ketamine-dexmedetomidine.Design: A prospective, non-blinded randomized study design was used. Sixteen pigs were randomized in blocks of four to be anesthetized with either propofol-ketamine-dexmedetomidine (n = 8) or alfaxalone-ketamine-dexmedetomidine (n = 8) as a continuous infusion.Interventions: Premedication with ketamine 15 mg kg−1 and midazolam 1 mg kg−1 was given i.m. Anesthesia was maintained with propofol 8 mg kg−1 h−1 or alfaxalone 5 mg kg−1 h−1 combined with ketamine 5 mg kg−1 h−1 and dexmedetomidine 4 μg kg−1 h−1 i.v. A stepwise, volume-controlled model for hemorrhage was created by exsanguination.Main Outcome Measures: Indices of oxygen debt (lactate, base excess, and oxygen extraction), macrocirculatory (PR, SAP, DAP, MAP, and CI, SVI, and TPR) variables, and time to death was compared between groups.Results: Pigs in the alfaxalone group had significantly higher SAP than pigs given propofol. No difference in other macrocirculatory variables or indices of oxygen debt could be found. A blood loss of 50% of the total blood volume or more was possible in most pigs with both anesthetic regimes.Conclusions: Pigs anesthetized with propofol or alfaxalone combined with ketamine and dexmedetomidine tolerated substantial blood loss.

Patterns of oxygen debt repayment in cardiogenic shock patients sustained with extracorporeal life support: a retrospective study

Cardiogenic shock is the most frequent shock in cardiac intensive care, and cardiac dysfunction and sever hypoxia are often seen in critically ill patients. Inadequate organ and tissue perfusion and hypoxia result in anaerobic metabolism with hyperlactatemia and oxygen debt accumulation. However, the role of accumulated oxygen debt in course of cardiogenic shock and hypoxia is not clearly described. Here we first described the existence of several patterns of oxygen debt repayment in cardiogenic shock patients maintained by extracorporeal life support system. Oxygen debt was computed from the lactate concentration at five time points, covering the first 26 hours of ECLS. The patterns as the basic pathophysiological processes are independent from the cause of primary insult. The groups of patients classified to the specific patterns differed by survival rate from 51.5% to only 4.6%. It is very important that initial class does not predetermine the fate and can change in the course of treatment due to ‘between clusters migration’. We believe that our finding of patterns of oxygen debt repayment in cardiogenic shock patients may offer a new insights for a more rational, goal-directed treatment of such highly morbid conditions as hypoxia and cardiogenic shock.

A Physiologic Approach to Hemodynamic Monitoring and Optimizing Oxygen Delivery in Shock Resuscitation

The approach to shock resuscitation focuses on all components of oxygen delivery, including preload, afterload, contractility, hemoglobin, and oxygen saturation. Resuscitation focused solely on preload and fluid responsiveness minimizes other key elements, resulting in suboptimal patient care. This review will provide a physiologic and practical approach for the optimization of oxygen delivery utilizing available hemodynamic monitoring technologies. Venous oxygen saturation (SvO2) and lactate will be discussed as indicators of shock states and endpoints of resuscitation within the framework of resolving oxygen deficit and oxygen debt.

Hyperbaric oxygenation in transplantology

The ability to eliminate any form of oxygen debt by transporting oxygen to organs and tissues, by dissolving it in body fluids, brings hyperbaric oxygenation to a new level of application in transplantology. The review discusses the pathophysiological aspects of hyperbaric oxygenation during ischemia and reinfusion, especially when used in transplantology, and also investigations on the use of hyperbaric oxygenation in model experiments and in clinical practice. Analysis of the efficacy of hyperbaric oxygenation therapy at various stages of the transplantation process (preconditioning, donation, organ storage, in the early and late post-transplant periods) allows us to conclude that this method should be more widely involved in transplantation practice.Authors declare no conflict of interest.