Impaired cerebral autoregulation is associated with brain dysfunction in patients with sepsis

Abstract

BackgroundSepsis-associated brain dysfunction (SABD) is associated with high morbidity and mortality. The pathophysiology of SABD is multifactorial. One hypothesis is that impaired cerebral autoregulation (CAR) may result in brain hypoperfusion and neuronal damage leading to SABD.MethodsWe studied 100 adult patients with sepsis (July 2012–March 2017) (age = 62 [52–71] years; Acute Physiology and Chronic Health Evaluation II score on admission = 21 [15–26]). Exclusion criteria were acute or chronic intracranial disease, arrhythmias, extracorporeal membrane oxygenation, and known intra- or extracranial supra-aortic vessel disease. The site of infection was predominantly abdominal (46%) or pulmonary (28%). Transcranial Doppler was performed, insonating the left middle cerebral artery with a 2-MHz probe. Middle cerebral artery blood flow velocity (FV) and arterial blood pressure (ABP) signals were recorded simultaneously; Pearson’s correlation coefficient (mean flow index [Mxa]) between ABP and FV was calculated using MATLAB. Impaired CAR was defined as Mxa > 0.3.ResultsMxa was 0.29 [0.05–0.62]. CAR was impaired in 50 patients (50%). In a multiple linear regression analysis, low mean arterial pressure, history of chronic kidney disease and fungal infection were associated with high Mxa. SABD was diagnosed in 57 patients (57%). In a multivariable analysis, altered cerebral autoregulation, mechanical ventilation and history of vascular disease were independent predictors of SABD.ConclusionsCerebral autoregulation was altered in half of the patients with sepsis and was associated with the development of SABD. These findings support the concept that cerebral hypoxia could contribute to the development of SABD.Electronic supplementary materialThe online version of this article (10.1186/s13054-018-2258-8) contains supplementary material, which is available to authorized users.

Dynamic Cerebral Autoregulation and Critical Closing Pressure in Experimental Human Endotoxemia and Sepsis Patients

“…Under healthy circumstances, spontaneous fluctuations in ABP are damped to preserve a constant CBF, in order to maintain cerebrovascular homeostasis. However, this so-called dynamic cerebral autoregulation is frequently impaired in sepsis, especially in the first few days [3][4][5]. A disturbed cerebral autoregulation may represent an important mechanism in the pathophysiology of SAE, rendering the brain more vulnerable to changes in perfusion pressure [4].…”

Sepsis-Associated Encephalopathy: From Delirium to Dementia?

“…Endothelial dysfunction during sepsis leads to inconsistent cerebral blood flow, especially during blood pressure fluctuations. A disturbed autoregulation was present in almost 50% of sepsis patients with SAE [38]. However, this study was limited to evaluation of blood perfusion in large intra-cranial arteries, whereas dysfunction in the microcirculation was not analyzed [38].…”

“…A disturbed autoregulation was present in almost 50% of sepsis patients with SAE [38]. However, this study was limited to evaluation of blood perfusion in large intra-cranial arteries, whereas dysfunction in the microcirculation was not analyzed [38]. Recent animal experiments in sheep revealed impaired cerebral microcirculation during septic shock resulting in decreased cerebral oxygenation [39].…”

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“…Such a decrease may be secondary to hyperventilation rather than the consequences of endotoxinemia/sepsis on cerebral hemodynamics. Sepsis also impairs cerebral autoregulation (54)(55)(56)(57). Interestingly, decreased cerebral autoregulation in sepsis was found to be associated with delirium (58).…”