Cerebral Blood Flow Alterations in Sepsis-Associated Encephalopathy A Prospective Observational Study

Background- The timely recognition of sepsis-associated encephalopathy (SAE) remains a challenge. This study aimed to observe the CBF changes via TCD during sepsis and explore their possible predictive value in SAE.Methods- In this prospective observational study, septic patients were enrolled and classified according to the diagnosis of SAE into two groups: SAE group and non-SAE group. Then SAE patients were further divided into subgroup A (the type with agitation) and subgroup B (the type with depressed consciousness) based on their clinical manifestations. The clinical profiles and TCD parameters within 24 hours of onset were compared between groups and subgroups.Results- Exactly 198 septic patients were enrolled including 65 patients in SAE group (36 male/29 female with a median age of 70) and 133 patients in non-SAE group (75 male/58 female with a median age of 67). Significant elevated peak-systolic velocity (VS; 107 [69-138] cm/s vs 85 [69-101] cm/s, P = .002) of the left middle cerebral artery (MCA) and pulsatility index (PI; left: 0.99 [0.81-1.34] vs 0.89 [0.76-1.00], P < .001; right: 0.99 [0.77-1.21] vs 0.88 [0.78-1.03], P = .007) of bilateral MCAs were found in SAE group compared with non-SAE group. In subgroup analysis, subgroup A (the type with agitation) showed significantly increased VS/VM/VD and lower PI/RI of bilateral MCAs compared with subgroup B (the type with depressed consciousness). The cerebral blood flow volume of subgroup A were obviously higher than subgroup B [858.7 (729.1,876.9) mL/s vs 380.9 (373.3,447.4) mL/s, P < .001].Conclusions- This study confirmed the abnormal CBF among SAE and found different types of CBF alterations were related to different clinical features. VS and PI might help clinicians to early identify different types of SAE.