Early neurovascular uncoupling in the brain during community acquired pneumonia

Abstract

IntroductionSepsis leads to microcirculatory dysfunction and therefore a disturbed neurovascular coupling in the brain. To investigate if the dysfunction is also present in less severe inflammatory diseases we studied the neurovascular coupling in patients suffering from community acquired pneumonia.MethodsPatients were investigated in the acute phase of pneumonia and after recovery. The neurovascular coupling was investigated with a simultaneous electroencephalogram (EEG)-Doppler technique applying a visual stimulation paradigm. Resting EEG frequencies, visual evoked potentials as well as resting and stimulated hemodynamic responses were obtained. Disease severity was characterized by laboratory and cognitive parameters as well as related scoring systems. Data were compared to a control group.ResultsWhereas visually evoked potentials (VEP) remained stable a significant slowing and therefore uncoupling of the hemodynamic responses were found in the acute phase of pneumonia (Rate time: control group: 3.6 ± 2.5 vs. acute pneumonia: 1.6 ± 2.4 s; P < 0.0005). In the initial investigation, patients who deteriorated showed a decreased hemodynamic response as compared with those who recovered (gain: recovered: 15% ± 4% vs. deteriorated: 9% ± 3%, P < 0.05; control: 14% ± 5%). After recovery the coupling normalized.ConclusionsOur study underlines the role of an early microcirculatory dysfunction in inflammatory syndromes that become evident in pre-septic conditions with a gradual decline according to disease severity.

Disassociation of static and dynamic cerebral autoregulatory performance in healthy volunteers after lipopolysaccharide infusion and in patients with sepsis

“…Since recent studies suggest that neurovascular coupling is likewise slower in sepsis (29,30), impaired dynamic autoregulation may reflect a general cerebral microvascular dysfunction that involves "indolence" of cerebrovascular responses, thus exposing the brain to intermittent hypoxia both during decreases in blood pressure and upon neuronal activation. Both cerebral hypoxia due to low CaO 2 levels (anemic hypoxia) and changes in Pa CO 2 may be of importance to these changes, and may, indeed, be further augmented by cerebral microvascular dysfunction.…”

Transcranial doppler assessment of cerebral perfusion in critically ill septic patients: a pilot study

“…Transcranial Doppler (TCD) is a readily available and reproducible technique by which cerebral perfusion can be evaluated in everyday clinical practice. Indirect cerebral microcirculation assessment by testing cerebral autoregulation in response to several stimulations with TCD has been previously performed [12-17]. However, these methods are relatively complicated and not easily applicable.…”

The Anesthetic Effects on Vasopressor Modulation of Cerebral Blood Flow in an Immature Swine Model

“…2–4 Furthermore, recent investigations have reported alterations in cerebrovascular function and physiology in critically ill patients without primary brain injury. 5–8 …”