Assessing the relationship between brain tissue oxygenation and neurological dysfunction in critically ill patients: study protocol

Background: Acute and chronic neurological complications amongst survivors of critical illness is common, however, the underlying etiology of this neurological dysfunction is unknown. This is the first study to use near-infrared spectroscopy to non-invasively measure brain tissue oxygenation, as a surrogate marker of cerebral perfusion, and correlate these values with subsequent neurological dysfunction. We will test the hypothesis that poor cerebral oxygenation during the first 24 hours of critical illness is correlated with acute and chronic neurological complications.Methods: This single-centre prospective observational study will be performed in a 33-bed medical/surgical intensive care unit (ICU). Adult patients are eligible for enrolment if they are admitted to the ICU within 24 hours, require mechanical ventilation, and/or vasopressor support. For 24 hours, cerebral oxygenation levels will be measured with the FORESIGHT oximeter; vital signs and tissue oxygenation will be captured with data monitoring software. Participants will be screened daily for delirium with the confusion assessment method-ICU. Long-term neurological function will be assessed with the Repeatable Battery for the Assessment of Neuropsychological Status and the kinesiological instrument for normal and altered reaching movements (KINARM) robot.Conclusions: This study will provide novel information regarding the determinants of cerebral oxygenation during the acute phase (i.e. 24 hours) of critical illness, and its potential relationship with subsequent neurological complications. Should a relationship exist between cerebral oxygenation and neurological complications, future studies will be aimed at using brain tissue oxygenation as a therapeutic target to prevent acute and chronic neurological dysfunction. Clinical Trial Registration: This trial is registered on clinicaltrials.gov (Identifier: NCT02344043), retrospectively registered January 8, 2015.

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Brain Tissue Oxygenation in Patients with Septic Shock: a Feasibility Study

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques ◽

10.1017/cjn.2015.280 ◽

2015 ◽

Vol 43 (1) ◽

pp. 65-73 ◽

Cited By ~ 14

Author(s):

Michael Wood ◽

Andy Song ◽

David Maslove ◽

Cathy Ferri ◽

Daniel Howes ◽

...

Keyword(s):

Septic Shock ◽

Observational Study ◽

Brain Tissue ◽

Prospective Observational Study ◽

Tissue Oxygenation ◽

Physiological Parameters ◽

Neurological Dysfunction ◽

Surgical Intensive Care Unit ◽

Surgical Intensive Care ◽

Brain Tissue Oxygenation

AbstractBackground: Delirium is common in critically ill patients and its presence is associated with increased mortality and increased likelihood of poor cognitive function among survivors. However, the cause of delirium is unknown. The purpose of this study was to demonstrate the feasibility of using near-infrared spectroscopy (NIRS) to assess brain tissue oxygenation in patients with septic shock, who are at high risk of developing delirium. Methods: This prospective observational study was conducted in a 33-bed general medical surgical intensive care unit (ICU). Patients with severe sepsis or septic shock were eligible for recruitment. The FORESIGHT NIRS monitor was used to assess brain tissue oxygenation in the frontal lobes for the first 72 hours of ICU admission. Physiological data was also recorded. We used the Confusion Assessment Method-ICU to screen for delirium.Results: From March 1st 2014-September 30th 2014, 10 patients with septic shock were recruited. The NIRS monitor captured 81% of the available data. No adverse events were recorded. Brain tissue oxygenation demonstrated significant intra- and inter-individual variability in the way it correlated with physiological parameters, such as mean arterial pressure, heart rate, and peripheral oxygen saturation. Mean brain tissue oxygen levels were significantly lower in patients who were delirious for the majority of their ICU stay. Conclusion: It is feasible to record brain tissue oxygenation with NIRS in patients with septic shock. This study provides the infrastructure necessary for a larger prospective observational study to further examine the relationship between brain tissue oxygenation, physiological parameters, and acute neurological dysfunction.

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