Metabolic acidosis is a common complication of chronic kidney disease (CKD). The kidneys play a crucial role in acid–base balance, maintaining pH within the normal range (isohydria) by following mechanisms: bicarbonate reabsorption, ammogenesis, and titratable acidity. The anion gap describes the amount of unmeasured anions and is classically evaluated as the difference between the major cation (sodium) and the sum of the two major anions (chloride and bicarbonate). Metabolic acidosis can be divided into two types: normal anion gap metabolic acidosis and high anion gap metabolic acidosis. A high anion gap level is considered unfavorable in terms of prognosis as it is associated with increased mortality. Treatment of metabolic acidosis in patients with chronic kidney disease, despite available therapeutic options, is a challenge. Supplementation with bicarbonates does not improve prognosis on the one hand, and on the other hand, it may be harmful. The new KDIGO guidelines for 2024 have been significantly modified compared to 2012 after negative results of studies on bicarbonate supplementation. Bicarbonate supplementation is currently recommended only when levels are less than 18 mmol/L. This review provides an overview of the current knowledge on the pathophysiology, classification, and therapeutic options, including dietary recommendations and new pharmacology agents.

Background: Normal-anion-gap metabolic acidosis (AGMA) and high-anion-gap metabolic acidosis (HAGMA) are two forms of metabolic acidosis, which is a common complication in patients with chronic kidney disease (CKD). The aim of this study is to identify the prevalence of various acid–base disorders in patients with advanced CKD using point-of-care testing (POCT) and to determine the relationship between POCT parameters. Methods: In a group of 116 patients with CKD in stages G4 and G5, with a mean age of 62.5 ± 17 years, a sample of arterial blood was taken during the arteriovenous fistula procedure for POCT, which enables an assessment of the most important parameters of acid–base balance, including: pH, base excess (BE), bicarbonate (HCO₃⁻), chloride(Cl⁻), anion gap (AG), creatinine and urea concentration. Based on this test, patients were categorized according to the type of acidosis-base disorder. Results: Decompensate acidosis with a pH < 7.35 was found in 68 (59%) patients. Metabolic acidosis (MA), defined as the concentration of HCO₃⁻ ≤ 22 mmol/L, was found in 92 (79%) patients. In this group, significantly lower pH, BE, HCO₃⁻ and Cl⁻ concentrations were found. In group of MA patients, AGMA and HAGMA was observed in 48 (52%) and 44 (48%) of patients, respectively. The mean creatinine was significantly lower in the AGMA group compared to the HAGMA group (4.91 vs. 5.87 mg/dL, p < 0.05). The AG correlated positively with creatinine (r = 0.44, p < 0.01) and urea (r = 0.53, p < 0.01), but there was no correlation between HCO₃⁻ and both creatinine (r = −0.015, p > 0.05) and urea (r = −0.07, p > 0.05). The Cl⁻ concentrations correlated negatively with HCO₃⁻ (r = −0.8, p < 0.01). Conclusions: The most common type of acid–base disturbance in CKD patients in stages 4 and 5 is AGMA, which is observed in patients with better kidney function and is associated with compensatory hyperchloremia. The initiation of renal replacement therapy was significantly earlier for patients diagnosed with HAGMA compared to those diagnosed with AGMA. The more advanced the CKD, the higher the AG.

Background: The most common form of vascular access for hemodialysis is a native arteriovenous fistula, which connects the site of the artery to the end of the vein. The maturation process of the fistula plays a crucial role in the establishment of a functional vascular access. Radial artery stenosis is among the potential causes of maturation failure. In these cases, improving the fistula’s blood flow may be difficult, as traditional surgical reanastomosis and endovascular intervention frequently fail. Radial artery deviation and reimplantation (RADAR) is a novel and effective technique for creating primary fistulas with a high patency rate. The main disadvantage of this procedure is the ligation of the radial artery and the subsequent known consequences. Methods: To accelerate maturation, we used RADAR as a secondary approach in three patients with radial artery stenosis and maturation failure. Results: In all patients after surgery, we observed a significant increase in fistula blood flow. Two patients used fistulas for hemodialysis after surgery. We describe the image diagnosis, procedure, and benefits of this method. Conclusions: The RADAR technique may be successfully used as a secondary access in patients with maturation failure due to RA stenosis to accelerate fistula maturation.

Background: The number of senior chronic kidney disease (CKD) patients is steadily increasing worldwide. Falls are more frequent in this group than in the general population, and they are associated with a variety of complications ranging from minor (bruises) to severe (fracture, brain injury, or death). The significant burden of comorbidities, particularly cardiovascular disorders, impacts coordination. The aim of the study was to assess coordination disorders in CKD patients in the context of cardiovascular complications and vascular status. Methods: In this prospective study, 132 patients with CKD 2–5, including 40 (30%) hemodialysis patients, were enrolled. The short form physiological profile assessment (S-PPA) was used to assess coordination. Results: During a 2-year follow-up period, 49 individuals experienced 84 falls. The median S-PPA score (Z score) was 3.36. Based on this, we divided our cohort into two groups: a Z score of <3.36 and a Z score of ≥3.36. The groups with high scores (≥3.36) characterized by higher parameters of vessel stiffness, including AIx@75, augmentation pressure, and PWV, experienced considerably greater numbers of falls (41 vs. 8, p < 0.001), CV events (10 vs. 2, p < 0.05), and deaths (14 vs. 0, p < 0.001). Conclusions: Coordination impairments and the associated risk of falls in CKD patients are directly related to cardiovascular diseases and vascular conditions. Lower arterial compliance has been linked with the largest coordination disorder. Visual impairments, especially contrast sensitivity, are an independent risk factor for falls.

Metabolic acidosis is a common disorder in patients with chronic kidney disease (CKD). As eGFR decreases, a reciprocal decrease in bicarbonate (HCO₃⁻) and an increase in chloride (Cl⁻) concentration is observed. The aim of this study is to determine whether the Cl⁻/HCO₃⁻ ratio can be used to predict metabolic acidosis with pH decline. A total of 115 patients (age 63 ± 17 years), with CKD stage G4 or G5 were enrolled in this cross-sectional study. The arterial (A) and venous (V) blood samples were taken during AV fistula creation and evaluated in a point of care testing analyzer. The ratio of arterial Cl⁻ and HCO₃⁻ concentration were calculated. According to mean arterial pH (pH-A) the group was divided into group with pH-A ≤ 7.33 and with pH-A > 7.33. The group with pH-A ≤ 7.33 showed significantly lower HCO₃⁻, and higher Cl⁻, Cl⁻/HCO₃⁻-ratio than group with pH-A > 7.33. Cl⁻/HCO₃⁻-A ratio negatively correlated with pH (r=-0.77,p < 0.01). The discriminative power of Cl⁻/HCO₃⁻-A ratio for predicting pH-A ≤ 7.33 was 0.917 ([CI] = 0.87–0.97,p < 0.01) which provided 87% sensitivity and 84% specificity. The best cut-off was 6.22(mmol/l)/(mmol/l). In conclusion, a Cl⁻/HCO₃⁻ ratio higher than 6.22(mmol/l)/(mmol/l) may be used as predictor of advanced metabolic acidosis in CKD stages G4 and G5.

Background: The distal ulnar-basilic arteriovenous fistula (UBAVF) is a rarely used alternative type of vascular access for haemodialysis. The location of the vein on the back aspect of the forearm forces an extremely uncomfortable external rotation of the upper limb during surgery when the patient is in a supine position. Methods: We present a new approach towards creating UBAVF, which involves placing the patient in the prone position, thus eliminating the aforementioned inconvenience. The procedure was performed and described in a 46-year-old patient with chronic kidney disease (CKD) due to diabetic nephropathy. In the period from September 2021 to December 2021, we created an additional three UBAVFs with such modifications. Results: All fistulas were patent both immediately after the procedure and 2 weeks after surgery. Conclusions: The prone position may improve the comfort of both the operator and the patient during the procedure. On top of this, it may have a positive impact on the quality of the arteriovenous anastomosis.