Clinical use of autologous blood pressure-controlled tourniquets: a single-center retrospective study

Background Conventional pneumatic tourniquets rely on fixed empirical pressures that disregard patient-specific vascular characteristics and dynamic hemodynamic variability, exposing tissues to avoidable mechanical and ischemic stress. Physiologic approaches such as limb occlusion pressure (LOP) improve individualization but remain static, operator-dependent, and poorly suited to real-time blood-pressure fluctuations. Fully automated systolic blood pressure (SBP)–responsive systems offer a dynamic, closed-loop solution, yet clinical evidence supporting their real-world performance is lacking. Methods This single-center retrospective cohort study evaluated 203 consecutive adults (January 2023–September 2024) undergoing upper-extremity surgery with an autologous SBP-controlled tourniquet. Continuous or high-frequency systolic blood pressure measurements were time-aligned with the cuff-pressure waveforms to characterize real-time modulation by the closed-loop system. Primary outcomes were hemostatic effectiveness and breakthrough bleeding. Secondary outcomes included pressure behavior, SBP–cuff correlation, perioperative hemodynamic stability, and postoperative neurologic or cutaneous complications. Results The closed-loop system maintained physiologically minimal occlusion pressure (mean ≈ 167 mmHg) with seamless moment-to-moment modulation, demonstrating a strong SBP–cuff correlation (r = 0.82; p < 0.001). Hemostasis was uniformly reliable, with 0% breakthrough bleeding (95% CI 0–1.8%). Perioperative SBP and DBP exhibited only modest, expected fluctuations under anesthesia, indicating that automated modulation did not destabilize systemic hemodynamics. No neurologic deficits, paresthesia, skin injury, or distal perfusion abnormalities were observed postoperatively. Conclusions This study provides the first real-world clinical evidence that a fully automated SBP-responsive tourniquet can deliver stable hemostasis, maintain physiologically appropriate occlusion pressures, and achieve an excellent safety profile without Doppler-based calibration or manual adjustment. By continuously harmonizing cuff pressure with beat-to-beat systolic variability, the system overcomes the inherent limitations of fixed-pressure and static LOP-guided strategies. Automated, physiology-driven pressure control represents a promising next-generation paradigm for safer, individualized, and workflow-efficient tourniquet practice.