Effects of short-term hyperoxia on sytemic hemodynamics, oxygen transport, and microcirculation: An observational study in patients with septic shock and healthy volunteers

To characterize the microvascular effects of a brief period of hyperoxia, in patients with septic shock and in healthy volunteers. In 20 patients with septic shock, we assessed systemic hemodynamics, sublingual microcirculation by SDF-videomicroscopy, and skin perfusion by capillary refill time (CRT), central-peripheral temperature (ΔT°), and perfusion index. Measurements were performed at baseline and after 5 min of inspired oxygen fraction of 1.00. Additionally, we studied 8 healthy volunteers, in whom hyperoxia was prolonged to 30 min. In septic patients, hyperoxia increased mean arterial pressure and systemic vascular resistance, but cardiac output remained unchanged. The only significant change in sublingual microcirculation was a decreased heterogeneity flow index (1.03 [1.01–1.07] vs 1.01 [0.34–1.05], P = .002). Perfused vascular density (13.1 [12.0–15.0] vs 14.0 [12.2–14.8] mm/mm2, P = .21) and the other sublingual microvascular variables were unmodified. CRT and ΔT° did not change but perfusion index slightly decreased. In healthy volunteers, sublingual microcirculation and skin perfusion were stable. Short-term hyperoxia induced systemic cardiovascular changes but was not associated with noticeable derangement in sublingual microcirculation and skin perfusion. Nevertheless, longer exposures to hyperoxia might have produced different results. •In septic shock, short-term hyperoxia increased systemic vascular resistance.•Sublingual microcirculation was unaffected by hyperoxia.•Concerning skin perfusion, only perfusion index was significantly decreased.•Since vascular resistance increased, ischemia might be present in other territories.•In volunteers, a longer hyperoxic exposure did not alter sublingual microcirculation.