Extrarenal Effects of Aldosterone on Potassium Homeostasis

The role of aldosterone in regulating K+ excretion in the distal nephron is well established in kidney physiology. In addition to effects on the kidney, aldosterone modulates K+ and Na+ transport in salivary fluid, sweat, airway epithelia, and colonic fluid. More controversial and less well defined is the role of aldosterone in determining the internal distribution of K+ across cell membranes in non-transporting epithelia. In vivo studies have been limited by the difficulty in accurately measuring overall K+ balance and factoring in both variability and secondary changes in acid-base balance, systemic hemodynamics, and other K+-regulatory factors such as hormones and adrenergic activity. Despite these limitations, the aggregate data support a contributory role of aldosterone along with insulin and catecholamines in the normal physiologic regulation of internal K+ distribution. The authors speculate differences in tissue sensitivity to aldosterone may also contribute to differential tissue response of cardiac and skeletal muscle to conditions of total body K+ depletion.

Acid-base balance at high altitude in lowlanders and indigenous highlanders

High-altitude exposure results in a hyperventilatory-induced respiratory alkalosis followed by renal compensation (bicarbonaturia) to return arterial blood pH(a) toward sea-level values. However, acid-base balance has not been comprehensively examined in both lowlanders and indigenous populations - where the latter are thought to be fully adapted to high-altitude. The purpose of this investigation was to compare acid-base balance between acclimatizing lowlanders, and Andean and Sherpa highlanders at various altitudes (~3,800, ~4,300, and ~5,000 m). We compiled data collected across five independent high-altitude expeditions and report the following novel findings: 1) at 3,800 m, Andeans (n=7) had elevated pHa compared to Sherpas (n=12; P<0.01), but not to lowlanders (n=16; nine days acclimatized; P=0.09); 2) at 4,300 m, lowlanders (n=16; 21 days acclimatized) had elevated pHa compared to Andeans (n=32) and Sherpas (n=11; both P<0.01), and Andeans had elevated pHa compared to Sherpas (P=0.01); and 3) at 5,000 m, lowlanders (n=16; 14 days acclimatized) had higher pHa compared to both Andeans (n=66) and Sherpas (n=18; P<0.01, and P=0.03, respectively), and Andean and Sherpa highlanders had similar blood pHa (P=0.65). These novel data characterize acid-base balance acclimatization and adaptation to various altitudes in lowlanders and indigenous highlanders.

Effects of Short-Term Phosphate Loading on Aerobic Capacity under Acute Hypoxia in Cyclists: A Randomized, Placebo-Controlled, Crossover Study

The aim of this study was to evaluate the effects of sodium phosphate (SP) supplementation on aerobic capacity in hypoxia. Twenty-four trained male cyclists received SP (50 mg·kg−1 of FFM/day) or placebo for six days in a randomized, crossover study, with a three-week washout period between supplementation phases. Before and after each supplementation phase, the subjects performed an incremental exercise test to exhaustion in hypoxia (FiO2 = 16%). Additionally, the levels of 2,3-diphosphoglycerate (2,3-DPG), hypoxia-inducible factor 1 alpha (HIF-1α), inorganic phosphate (Pi), calcium (Ca), parathyroid hormone (PTH) and acid-base balance were determined. The results showed that phosphate loading significantly increased the Pi level by 9.0%, whereas 2,3-DPG levels, hemoglobin oxygen affinity, buffering capacity and myocardial efficiency remained unchanged. The aerobic capacity in hypoxia was not improved following SP. Additionally, our data revealed high inter-individual variability in response to SP. Therefore, the participants were grouped as Responders and Non-Responders. In the Responders, a significant increase in aerobic performance in the range of 3–5% was observed. In conclusion, SP supplementation is not an ergogenic aid for aerobic capacity in hypoxia. However, in certain individuals, some benefits can be expected, but mainly in athletes with less training-induced central and/or peripheral adaptation.

Clinical Characteristics of 10 Pregnant and Postpartum Women With Extracorporeal Membrane Oxygenation: A Retrospective Study

Background: The aim of study was to summarize the clinical characteristics and experience of extracorporeal membrane oxygenation (ECMO) in pregnant and postpartum patients.Methods and Results: We retrospectively reviewed 131 consecutive ECMO patients at our center from May 2015 to May 2021. A total of 10 Chinese patients were pregnant or postpartum at the time of ECMO initiation. Patients ranged in age from 25 to 36 years (median age 30.5 years). The ECMO duration ranged from 3 to 31 days (median duration 8 days). There was a stabilizing trend of acid-base balance and decreasing lactic acid over the 3 days following ECMO initiation. Seven (70%) patients survived at least 48 h after weaning from ECMO. Four (40%) patients survived until discharge, and four (40%) fetuses survived until discharge.Conclusion: ECMO provides a suitable temporary cardiopulmonary support for pregnant and postpartum patients. ECMO shows a favorable effect on short-term stability in critical obstetric patients.

Acid–Base Balance, Blood Gases Saturation, and Technical Tactical Skills in Kickboxing Bouts According to K1 Rules

Background: Acid–base balance (ABB) is a major component of homeostasis, which is determined by the efficient functioning of many organs, including the lungs, kidneys, and liver, and the proper water and electrolyte exchange between these components. The efforts made during competitions by combat sports athletes such as kickboxers require a very good anaerobic capacity, which, as research has shown, can be improved by administering sodium bicarbonate. Combat sports are also characterized by an open task structure, which means that cognitive and executive functions must be maintained at an appropriate level during a fight. The aim of our study was to analyze the changes in ABB in capillary blood, measuring levels of H+, pCO2, pO2, HCO3−, BE and total molar CO2 concentration (TCO2), which were recorded 3 and 20 min after a three-round kickboxing bout, and the level of technical and tactical skills presented during the fight. Methods: The study involved 14 kickboxers with the highest skill level (champion level). Statistical comparison of mentioned variables recorded prior to and after a bout was done with the use of Friedman’s ANOVA. Results: 3 min after a bout, H+ and pO2 were higher by 41% and 11.9%, respectively, while pCO2, HCO3−, BE and TO2 were lower by 14.5%, 39.4%, 45.4% and 34.4%, respectively. Furthermore, 20 min after the bout all variables tended to normalization and they did not differ significantly compared to the baseline values. Scores in activeness of the attack significantly correlated (r = 0.64) with pre–post changes in TCO2. Conclusions: The disturbances in ABB and changes in blood oxygen and carbon dioxide saturation observed immediately after a bout indicate that anaerobic metabolism plays a large part in kickboxing fights. Anaerobic training should be included in strength and conditioning programs for kickboxers to prepare the athletes for the physiological requirements of sports combat.

Use of enteral electrolyte solutions with different sodium acetate concentrations in weaned foals: the effects on acid-base balance, blood glucose, lactate, and urine ph

ABSTRACT: The effects of acetate as an alkalinizing agent in maintenance enteral electrolyte solutions administered by nasogastric route in a continuous flow have not been previously described in weaned foals. This is the second part of a study that evaluated the effects of two electrolyte solutions of enteral therapy fluid in weaned foals. In this part, will be considered the effects of enteral electrolyte solutions containing different acetate concentrations on acid-base balance, blood glucose, lactate and urine pH of weaned foals. This was a controlled trial in a cross-over design performed in six foals with a mean age of 7.3 ± 1.4 months. After 12 h of water and food deprivation, each animal received the following two treatments by nasogastric route in a continuous flow of 15 ml/kg/h during 12 h: HighAcetate (acetate 52 mmol/l) and LowAcetate (acetate 22.6 mmol/l). The HighAcetate treatment was effective in generating a slight increase in blood pH, blood bicarbonate concentration, base excess and urinary pH.

Post craniotomy and electrocardiographic monitoring

Background: Post craniotomy management mainly emphasizes monitoring complications that occur. Close supervision and monitoring are needed in post craniotomy patients, especially in the first 48 hours so that the patient is placed in the intensive care unit (ICU). Various studies have identified various complications that arise from mild complications to severe complications, namely the death of patients after craniotomy, so that hemodynamic monitoring tool are needed. Electrocardiography is one of the hemodynamic monitoring tools in the intensive care room which is very useful in monitoring heart rhythm abnormalities in post-craniotomy patients.Methods: This descriptive study was conducted on 30 respondents post craniotomy and were treated in the Intensive Care Unit (ICU) for 1-3 days of treatment. An electrocardiographic monitoring analysis was performed on 30 respondents, then confirmed by examination of blood electrolytes and blood gas analysis.Results: In this study 90% of respondents experienced electrocardiographic rhythm abnormalities, 50% sinus arrhythmia, 33.3% sinus tachycardia, 6.7% sinus bardycardia. The results of electrolyte examination 18 respondents experienced electrolyte balance disorders where 4 respondents experienced hyponatremia, 7 respondents experienced hypernatremia+hyperchloremia, 1 respondent experienced hyponatremia+hypochloremia, 5 respondents experienced hyperchloremia and 1 respondent experienced hypokalemia. There are 7 respondents experiencing acid-base balance disorders.Conclusions: in this study showed that most of the patients after craniotomy had heart rhythm abnormalities. The most common arrhythmia is sinus arrhythmia. The pathological conditions that accompany these rhythm disturbances are mostly caused by electrolyte balance disorders, acid-base balance disorders or a combination of the two disorders.