Antibiotic Dosing in Pediatric Intensive Care

This study monitors how antibiotic levels in the blood change over time in critically ill children in the intensive care unit (ICU). Children's bodies process medications differently than adults, and illness can further change this. By tracking drug levels, researchers want to find the most effective and safe antibiotic dosing for very young and seriously ill patients. You may be eligible if: - You are a patient (newborn to 15 years old, weight at least 1.8 kg) admitted to a pediatric ICU - You are receiving one of the studied antibiotics (such as vancomycin, meropenem, ciprofloxacin, or others) as part of your treatment - You have an intravenous or arterial line available for blood sampling You may NOT be eligible if: - You do not have a catheter in place for blood sampling - Your parent or guardian has not given consent - You have a known allergy to the class of antibiotics being studied - You are on extracorporeal support such as dialysis or ECMO Talk to your doctor to see if this trial is right for you.