Feasibility and bedside visual evaluation of lymphatic dysfunction in sepsis using indocyanine green lymphography

Previous studies have suggested that lymphatic dysfunction contributes to organ injury during sepsis, yet clinical features of peripheral lymphatic drainage remain poorly characterized among septic patients. We performed a prospective observational cohort study enrolling adult patients fulfilling Sepsis‑3 diagnostic criteria and non‑septic critically‑ill controls. Subcutaneous indocyanine green (ICG) injection was delivered to intact upper extremities within 24 h of diagnosis. A portable laser lymphatic imager was used for image acquisition and calculation of lymphatic flow velocity. Clinical data and 28‑day survival outcomes were collected. We enrolled 47 participants, including 34 patients with sepsis (28‑day all‑cause mortality 35.3%) and 13 non‑septic controls. Lymphatic flow velocity was 0.24 cm/s (IQR, 0.14‑0.36 cm/s) in non‑septic patients, 0.08 cm/s (IQR, 0.01‑0.25 cm/s) in sepsis survivors, and 0.02 cm/s (IQR, 0.00‑0.14 cm/s) in sepsis non‑survivors; overall between‑group difference was statistically significant ( P = 0.014). Among patients with sepsis, 9 participants had zero lymphatic flow velocity, of whom 55.6% died within 28 days. The complete examination was finished within 10 min, with no hypersensitivity, local infection or other adverse events reported. Bedside ICG lymphography enables safe and rapid visual and quantitative assessment of peripheral lymphatic drainage in adults with sepsis. Reduced peripheral lymphatic flow velocity is associated with poor prognosis, which may serve as a potential prognostic biomarker for sepsis. These findings require validation in larger‑sample cohorts.