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Regulation of pH and acid–base homeostasis is vitally important to cell functions, its metabolism, and normal human physiology. The kidneys and lungs regulate acid–base balance, whereas the brain and the liver have some regulatory functions. The first part of this chapter provides comprehensive information on acid–base balance and describes its associated disorders. The interconnection between electrolytes and their neutrality are major concepts to be applied in the diagnosis of acid–base imbalance and its disorders. The second part of this chapter provides practical information regarding the cardiorenal syndrome, which is a term used to define the disorders of the kidneys and the heart, whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction of the other.

Background: Low-molecular-weight heparin (LMWH) has been suggested as an effective and safe anticoagulant for hemodialysis. The aim of our study was to investigate the effects of LMWH including minor bleeding, clotting formation in the extracorporeal dialysis circuit and their effect on the lipid profile in comparison with heparin. Methods: This randomized, crossover study with parallel design was conducted in 45 patients who required maintenance hemodialysis due to end-stage renal failure. Four patients with known bleeding disorders, receiving anticoagulant drugs and receiving drugs which could affect heparin activity were excluded. All patients were randomly assigned to receive either enoxaparin sodium (0.7 mg/kg) or standard heparin for a duration of 12 weeks, after which patients were crossed over to another therapy for a further 12 weeks. Enoxaparin sodium was administered 5 minutes before dialysis, injected into the arterial line pre- dialyser and heparin was administered 50 U/kg intravenously into the pre- dialyser arterial line followed by a maintenance dose of 1000 U per hour. Results: The mean age of the study population was of 65.18 (SD = 12.15) years. From these patients 22 (53%) were male and 19 (47%) were female. At the end of the first study phase, minor bleeding in patients receiving enoxaparin with dose of 0.25 mg/kg was significantly decreased in comparison to the patients receiving heparin (P: 0.03), although vascular compression time did not significantly differ between the heparin and enoxaparin groups. At the end of the second study phase, the enoxaparin group showed a significant increase in minor bleeding in comparison with the heparin group (P: 0. 04). In the enoxaparin arm, recurrent blood oozing from puncture sites led to the idea to reduce the dose of enoxaparin. After enoxaparin dose reduction, the frequency of minor bleeding decreased to 10% (from 19% to 10%) (P: 0.01). Vascular compression time was not statistically different in heparin and enoxaparin at the end of study (P: 0.1). There were no significant changes in serum lipids with either anticoagulant neither at the end of the 12th week nor at the end of the 24th week. Conclusions: This study suggests that a single-dose of enoxaparin is an effective and convenient alternative to standard heparin. The recommended dose of this study in Iranian patients is 0.25 mg/kg.

Background: Cardiovascular disease is the most common cause of death in patients with chronic kidney disease. Diastolic dysfunction is an important risk factor result in development of advanced cardiovascular disease. Fibroblast growth factor- 23 (FGF23) secretes in response to hypophosphatemia as a result of renal excretion of phosphate. Elevation of serum FGF23 is one of the possible causes of diastolic dysfunction. The aim of the current study was to investigate association between Serum levels of FGF23 and diastolic dysfunction in hemo dialysis patients. Methods: 100 hemodialysis patients were enrolled in the study between October 2015 and February 2016. Cardiac diastolic function was assessed by tissue Doppler imaging and ejection fraction>50% considered to be investigated. Serum FGF23, cholesterol, triglyceride, fasting blood sugar, 25(OH)vitD3, Phosphorus, calcium, alkaline phosphatase, PTH and hemoglobin were measured in all patients. Statistical analysis preformed using SPSS version 16(Chicago, USA). Results: FGF 23 was elevated in 69% (52/75) of patient and had correlation with serum levels of phosphor and PTH, while Serum levels of FGF23 was not significantly difference between patients whit diastolic dysfunction versus other cardiac problem (p=0.158). Conclusions: After elimination of secondary causes of diastolic dysfunction, no association was found between serum FGF23 levels and diastolic dysfunction among hemodialysis patients.

Background: Acute Kidney Injury (AKI) is a prevalent and important complication of cardiac surgery, which is associated with significant morbidity and mortality. Identification of risk factors associated with AKI will help it’s prevent. Objectives: The objective of the present investigation was to identify risk factors for acute kidney injury in patients who underwent coronary artery bypass graft (CABG) surgery at a tertiary care center for cardiovascular patients in Iran. Patients and Methods: From March 2014 to April 2015, 490 consecutive patients who underwent On-pump CABG at Rajaie cardiovascular medical and research center were assessed. Baseline variables and perioperative data were collected and their association with the development of AKI was evaluated. Results: Patients’ mean age was of 67.9 (SD = 12.5) years. From these patients 353 (72%) were male and 137 (28%) were female. Six deaths (1.3%) occurred among patients. Thirteen patients (2%) had AKI. The baseline serum creatinine concentrations in patients with AKI were significantly higher than other patients (P = 0.04). Volume of transfused red blood cells and hemoglobin value were different, associated with AKI (P 0.05). Mean arterial pressure (MAP) was not different in patients with AKI (P = 0.85). The mean pump time in patients with AKI was significantly higher than the other patients (P = 0.02). Postoperative Left ventricle ejection fraction (LVEF) in patients who developed AKI was significantly reduced compared with patients without AKI (P = 0.01). The in-hospital mortality of patients who developed AKI was 7.69% compared with 1.04% among those who did not (P = 0. 01). Conclusions: Acute kidney injury is the important postoperative organ dysfunction in patients who underwent CABG and preoperative elevated serum creatinine concentration, cardiopulmonary bypass time > 120 minutes, intraoperative anemia and blood transfusion were serious risk factors associated with AKI.