Perfusion Index for Predicting Diabetic Ketoacidosis Severity in the Emergency Department

This prospective observational cohort study will evaluate whether the perfusion index measured at emergency department admission is associated with the severity of diabetic ketoacidosis in adults. The study will include 140 patients aged 18 years or older who are diagnosed with diabetic ketoacidosis in the emergency department. The perfusion index will be measured using pulse oximetry. Serum lactate measured as part of routine clinical care will also be recorded, and the lactate-to-perfusion index ratio will be calculated. The ability of the perfusion index, serum lactate, and the lactate-to-perfusion index ratio to predict diabetic ketoacidosis severity will be compared. Their associations with time to diabetic ketoacidosis resolution, intensive care unit admission, hospital and intensive care unit length of stay, mechanical ventilation, vasopressor use, and in-hospital mortality will also be evaluated. No treatment will be assigned by the investigators, and all patients will receive routine clinical care.