Time-varying effect of venous hemodynamics in intensive care via neuromuscular electrical stimulation: a prospective‚ single-center‚ self-controlled study

This study aimed to investigate the temporal changes in hemodynamic indices during and after neuromuscular electrical stimulation (NMES) in intensive care unit (ICU) patients. Forty ICU inpatients at Affiliated Hospital of Shandong First Medical University received NMES between January 8 and March 1, 2025. Hemodynamic indices of the popliteal vein were collected using Doppler ultrasound, including peak flow velocity, peak blood flow and vessel diameter. Collection time points were as follows: before NMES intervention; during the intervention (at 0.5, 1, 1.5, and 2 h); and after NMES discontinuation (at 0.5 and 1 h) to analyse hemodynamic indices over time. PFV (χ² = 179.767, p < 0.001) and BFV (χ² = 174.264, p < 0.001) significantly increased during NMES compared to baseline. Popliteal vein diameter showed a statistically significant increase after 0.5 h of intervention (p < 0.05). During the initial phase (0-1 h), hemodynamic parameters increased progressively. No significant changes occurred between 1 and 2 h (p > 0.05), suggesting a plateau response. At 1 h after NMES discontinuation, the peak flow velocity, diameter, and blood flow volume in the popliteal vein showed no statistically significant differences compared to pre-intervention values (p > 0.05). NMES accelerates lower-extremity venous blood flow in ICU patients and demonstrates feasibility and safety in the absence of conventional physical interventions. Hemodynamic parameters plateaued after 1 h of NMES application and returned to baseline within 1 h of cessation, providing new insights for future research on the clinical utilization of NMES.