Nailfold Capillaroscopy Reveals Peripheral Microcirculatory Trajectories in Septic Shock

BackgroundSepsis-induced microcirculatory dysfunction may persist despite systemic hemodynamic stabilization, yet longitudinal changes in peripheral microvascular structure and flow during recovery remain insufficiently characterized. We used nailfold capillaroscopy (NFC) to characterize these changes during recovery from septic shock.MethodsIn this prospective two-center study, patients with Sepsis-3 septic shock underwent NFC during shock and after clinician-confirmed hemodynamic stabilization. Baseline NFC analyses required analyzable initial recordings; longitudinal analyses required paired assessments and survival to reassessment. Mortality was prespecified as the primary outcome. Longitudinal NFC changes and the association between change in red blood cell (RBC) velocity and lactate clearance were prespecified; outcome-stratified analyses were post hoc and exploratory.ResultsOf 25 patients meeting clinical eligibility criteria, 21 were enrolled, 19 had analyzable baseline NFC recordings, and 15 had paired assessments; four died before reassessment. Baseline RBC velocity was 0.268 mm/s in survivors and 0.290 mm/s in non-survivors (P = 0.653). In the paired cohort, RBC velocity increased from 0.295 to 0.550 mm/s; median within-patient change was 0.167 mm/s (95% CI, 0.067 to 0.609; P = 0.1531). The median within-patient change in capillary length was 42.1 μm (95% CI, -7.3 to 65.3; P = 0.0125). Median ΔRBC velocity was 0.393 mm/s in survivors and -0.127 mm/s in non-survivors; the between-group median difference was 0.520 mm/s (95% CI, -0.042 to 1.368; P = 0.0256). The prespecified association between ΔRBC velocity and lactate clearance was positive but imprecise (Spearman's rho = 0.41; 95% CI, -0.15 to 0.77; P = 0.133).ConclusionsNFC captured dynamic and heterogeneous peripheral microcirculatory changes despite systemic hemodynamic stabilization. Increased RBC velocity among survivors suggests that serial NFC may complement conventional macrocirculatory assessment by providing information on microcirculatory recovery. These findings support further prospective evaluation of NFC as a feasible bedside tool for longitudinal microcirculatory monitoring.