Acid Base Imbalance

Metabolic acidosis is one of the most common acid-base disturbances encountered in critically ill children and often reflects underlying disease severity. Despite its clinical importance, prospective epidemiological data regarding its frequency, underlying etiologies, and associated clinical outcomes among pediatric intensive care unit (PICU) admissions in Upper Egypt remain limited. The primary objective of this prospective observational cohort study is to determine the frequency of metabolic acidosis among pediatric patients admitted to the Pediatric Intensive Care Unit at Assiut University Children Hospital. Secondary objectives include identifying the common etiologies and types of metabolic acidosis, as well as evaluating its relationship with clinical outcomes such as mortality, duration of PICU stay, need for mechanical ventilation, and requirement for vasoactive support. A total of 140 eligible pediatric patients aged 1 month to 18 years admitted to the PICU will be enrolled. Eligible patients will undergo arterial blood gas (ABG) analysis and standard clinical and laboratory evaluations upon admission. Metabolic acidosis will be defined based on admission ABG criteria (serum/arterial bicarbonate \< 22 mmol/L and/or base deficit ≥ 5 mmol/L). Patients will be monitored throughout their hospital stay to assess clinical outcomes without interfering with routine medical management.

Frequent monitoring of acid-base status, ventilation, and tissue oxygenation is essential for managing critically ill patients in the intensive care unit (ICU). While arterial blood gas (ABG) analysis is considered the standard method for these evaluations, maintaining arterial catheters carries risks of complications, such as thrombosis, hematoma, and infection. Central venous blood gas (CVBG) analysis offers a safer alternative because central venous catheters are already routinely placed for patient care. Additionally, the venous-to-arterial carbon dioxide difference (CO2 gap) serves as an indicator of systemic blood flow and tissue perfusion. However, patients with diabetes mellitus often present with underlying microvascular alterations, endothelial changes, and metabolic variations that might alter tissue perfusion and peripheral gas exchange. This study aims to assess the correlation and agreement between central venous and arterial blood gas parameters, as well as evaluate the diagnostic accuracy of the CO2 gap, in diabetic versus non-diabetic critically ill patients. A total of 100 adult ICU patients (50 diabetic and 50 non-diabetic) with pre-existing central venous and arterial lines will be enrolled. Paired blood samples will be drawn simultaneously to compare blood gas values and calculate the CO2 gap without altering standard clinical treatment.

Most cardiac surgery procedures requires the use of heart-lung machine. The heart-lung machine circuit needs to be filled with a fluid before connecting it to the patients circulation. This is called priming and is accomplished by filling the circuit with a solution used for fluid replacement. The circuit in our institution requires 1100 mL to be filled. The body has several mechanisms with the purpose to maintain its state of balance. When a large amount of clear solution suddenly enters the blood stream this balance can be altered. The goal of this clinical trial is to investigate different priming solutions in the heart-lung machine circuit. The main questions it aims to answer are: How do different priming solutions alter the acid-base balance, osmolality and electrolytes which reflects the body's water balance for patients undergoing cardiac surgery with the use of heart-lung machine? There will be 4 different groups: 1. Ringer-Acetate, 1100 mL / no addition 2. Ringer-Acetate, 1100 mL + 80 mmol sodium chloride (NaCl) 3. Ringer-Acetate, 1100 mL + 160 mmol NaCl 4. Plasmalyte, 1100 mL / no addition Blood samples will be taken before, during and after surgery, post operative day 1 and 4 to analyze acid-base balance, electrolytes, and plasma osmolality. Urine output and hydration status will also be collected until post operative day 1. After 3 months, a blood sample will be taken for analysis of electrolytes and kidney function.

This randomized, double-blind, placebo-controlled crossover trial will investigate the acute effects of sodium bicarbonate supplementation on performance, stroke biomechanics, and selected physiological and perceptual responses during a simulated 200-meter Bi-Fins race in elite finswimmers.