Ionized Calcium as a Severity Marker in Septic Shock Patients

Sepsis is a serious condition where the body has an extreme, dysregulated response to an infection, often leading to life-threatening organ dysfunction. Low levels of ionized calcium (the active, free form of calcium in the blood) are common in critically ill patients admitted to intensive care units (ICUs). While established clinical scoring systems like the Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation II (APACHE II) help assess illness severity, there is a continuous need for rapid, cost-effective biological markers that can be measured immediately at the bedside using routine blood gas analyzers. The primary purpose of this observational study is to evaluate whether ionized calcium levels measured upon admission to the ICU can serve as an early marker of disease severity and outcome in adult patients diagnosed with sepsis or septic shock. Adult participants diagnosed with sepsis or septic shock who are admitted to the ICU will receive standard medical care. Routine arterial or venous blood samples will be analyzed at admission to measure ionized calcium and other standard laboratory markers. Researchers will correlate these calcium levels with baseline illness severity scores (SOFA and APACHE II) and evaluate patient outcomes, including 28-day mortality, length of ICU stay, and the need for mechanical ventilation or vasopressor medications.

Inclusion Criteria: * Adult patients aged 18 years or older * Diagnosed with sepsis or septic shock according to the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) * Admission to the intensive care unit (ICU) within 24 hours of presentation Exclusion Criteria: * Known pre-existing disorders of calcium or parathyroid metabolism (e.g., chronic hypoparathyroidism, hyperparathyroidism) * Severe chronic kidney disease (CKD stage 4 or 5) or end-stage renal disease on dialysis * Patients receiving active intravenous calcium, bisphosphonates, or vitamin D supplementation within 48 hours prior to admission * Massive blood transfusion (more than 4 units of packed red blood cells) within 6 hours of admission (due to citrate-induced hypocalcemia)