The Use of Near-Infrared Spectroscopy and/or Transcranial Doppler as Non-Invasive Markers of Cerebral Perfusion in Adult Sepsis Patients With Delirium: A Systematic Review

Abstract

Background: Several studies have previously reported the presence of altered cerebral perfusion during sepsis. However, the role of non-invasive neuromonitoring, and the impact of altered cerebral perfusion, in sepsis patients with delirium remains unclear. Methods: We performed a systematic review of studies that used near-infrared spectroscopy (NIRS) and/or transcranial Doppler (TCD) to assess adults (≥18 years) with sepsis and delirium. From study inception to July 28, 2020, we searched the following databases: Ovid MedLine, Embase, Cochrane Library, and Web of Science. Results: Of 1546 articles identified, 10 met our inclusion criteria. Although NIRS-derived regional cerebral oxygenation was consistently lower, this difference was only statistically significant in one study. TCD-derived cerebral blood flow velocity was inconsistent across studies. Importantly, both impaired cerebral autoregulation during sepsis and increased cerebrovascular resistance were associated with delirium during sepsis. However, the heterogeneity in NIRS and TCD devices, duration of recording (from 10 seconds to 72 hours), and delirium assessment methods (e.g., electronic medical records, confusion assessment method for the intensive care unit), precluded meta-analysis. Conclusion: The available literature demonstrates that cerebral perfusion disturbances may be associated with delirium in sepsis. However, future investigations will require consistent definitions of delirium, delirium assessment training, harmonized NIRS and TCD assessments (e.g., consistent measurement site and length of recording), as well as the quantification of secondary and tertiary variables (i.e., Cox, Mxa, MAPOPT), in order to fully assess the relationship between cerebral perfusion and delirium in patients with sepsis.

Visualization of blood-brain barrier disruption in septic mice with the new method based on in vivo imaging technology

“…Several studies have used sepsis-associated delirium (SAD) or brain dysfunction (SABD) as an indicator of BBB injury and found cerebral blood ow autoregulation impairment to be an independent risk factor for SAD and SABD. 41,[53][54][55] The statistical analysis from other studies also revealed that patients with positive Confusion Assessment Method for the ICU status and lower Richmond Agitation-Sedation Scale scores had lower brain tissue oxygen or other brain microcirculation parameters, 46,56 consistent with our ndings.…”

Near-infrared light spectroscopy and stimulation in cognitive neuroscience—the need for an integrative view?

“…The clinical relevance of Mohammadi's work resides in the fact that pulse amplitude correlates positively with age [5] and that a consistently higher pulsatility in the cerebral blood flow (CBF) could be associated with microvascular damage and cognitive decline [6]. But apart from their novel and potentially clinically-relevant findings, part of the originality of this work consists in the use that the authors make of NIRS technology to gauge cerebral pulsatility which, until now, has been traditionally provided by Transcranial Doppler (TCD) [7,8]. The measurement of such an index via optical imaging is not completely novel [4,5], but, to our knowledge, this is the first study to do it with physical activity and cognition.…”

Diffuse optical tomography for mapping cerebral hemodynamics and functional connectivity in delirium

“…Impaired cerebral oxygenation has been implicated as an independent risk factor for the subsequent development of delirium in patients with sepsis, shock, respiratory failure, and other medical illnesses. 57 , 58 , 59 There does not appear to be a consistent relationship between low peripheral oxygen and hemoglobin levels compared to cerebral values, thus suggesting a separate mechanism involved in delirium. 58 Low cerebral oxygen states are intimately correlated with progression of oxidative stress, which causes inability to maintain ionic gradients, impaired cellular depolarization, abnormal neurotransmitter metabolism, and failure to eliminate neurotoxic free radicals.…”