Cerebral oxygen levels during a passive leg raising challenge test in patients with sepsis and septic shock: A cohort study

Background: Sepsis-related cerebral dysfunction has been underestimated in critical illness settings. Cerebral oximetry offers information relating to cerebral dysfunction. We hypothesized that cerebral oxygenation change during a passive leg raising (PLR) challenge test would reveal the pathophysiology of cerebral dysfunction in sepsis and septic shock. Methods: We selected 521 patients and 108 study patients were recruited. PLR was performed within 24 hours after diagnosis, during which we reviewed hemodynamic monitoring data. We measured forehead cerebral oxygenation at baseline and after PLR within 5 minutes and simultaneously recorded oxygen-related parameters and related data. Results: Regional saturation cerebral oxygen (rScO 2 ) levels at baseline for patients with delirium were significantly lower than nondelirious patients (59.2 ± 8.9% vs. 62.5 ± 10.8%, respectively; P = 0.001). ΔrSO 2 plr in patients with delirium were lower than those in non-delirious patients (3.4 ± 4.7% vs. 5.1 ± 6.1%; P = 0.037). Baseline rScO 2 levels were significantly higher in survivors than in nonsurvivors (55.1 ± 9.4% vs. 61.9 ± 10.2%; P = 0.003). ΔrScO 2 plr were significantly associated with episodes of delirium and mortality, with correlation coefficients of −0.586 and −0.384, respectively (both P < 0.001). The predictability of ΔrScO 2 plr for delirium was optimal, with the highest area under the curve (AUC) of 0.944 (threshold, 3%; sensitivity, 77.8%; specificity, 83.3%). Baseline rScO 2 was associated with 28-day mortality, ΔrScO 2 plr was associated with delirium. Conclusion: Baseline rScO 2 and ΔrScO 2 plr substantially correlated with 28-day mortality and delirium. Patients may benefit from strategies that optimize baseline rScO 2 and minimize fluctuations.