This single-arm, open-label clinical study evaluates the efficacy and safety of a standardized empirical anti-infective escalation protocol for patients with hematological malignancies complicated by febrile neutropenia. The treatment algorithm follows a sequential strategy: initial carbapenem monotherapy (2 days) → if ineffective, combination with vancomycin/linezolid (3 days) → if no response, escalation to antifungal therapy (7 days). For patients demonstrating persistent or recurrent fever with uncontrolled infection parameters after 12-14 days of prior empirical anti-infective therapy, switching to ceftazidime-avibactam combined with aztreonam is implemented. Therapeutic efficacy is assessed through comprehensive evaluation of clinical manifestations, inflammatory biomarkers, radiographic imaging, and microbiological findings. Comprehensive safety surveillance includes continuous monitoring of adverse events and all-cause mortality throughout the treatment course.