Perfusion Efficiency-Guided MAP De-escalation in Elderly Septic Shock

This is a single-center, prospective, randomized crossover physiological trial conducted in elderly patients (≥65 years) with septic shock in the intensive care unit (ICU). All enrolled patients receive sequential titration of mean arterial pressure (MAP) to three predefined target ranges (60-65 mmHg, 65-70 mmHg, and 70-75 mmHg) in randomized order. The primary objective is to compare tissue perfusion pressure (TPP) between the low and intermediate MAP targets, and to test the non-inferiority hypothesis that the lower MAP target is non-inferior to the intermediate target. Multiple secondary microcirculatory, systemic perfusion, and safety indicators are collected during steady-state hemodynamic periods under each MAP target stage. Researchers will adopt linear mixed-effects models to analyze intra-individual differences across blood pressure targets and explore the MAP threshold for optimal peripheral perfusion. Safety outcomes including adverse hemodynamic events and long-term clinical follow-up data will also be assessed.

Inclusion Criteria: 1. Elderly patients (≥65 years) admitted to ICU with septic shock requiring invasive arterial blood pressure monitoring and vasopressor support. 2. Clinically indicated target mean arterial pressure (MAP) range covering 60-75 mmHg. 3. Expected duration of stable hemodynamic status ≥ 150 minutes to complete the crossover titration protocol. 4. Attending intensivist agrees to participate; written informed consent obtained from patient or legally authorized representative. Exclusion Criteria: 1. Age \< 65 years. 2. Severe aortic stenosis, aortic dissection, or uncontrolled intracranial hypertension requiring fixed high MAP target. 3. Known irreversible terminal condition with expected survival \< 72 hours. 4. Severe active bleeding requiring massive transfusion with ongoing hemodynamic instability. 5. Previously enrolled in this trial. 6. Investigator judges that sequential MAP titration carries unacceptable clinical risk.