Prospective observational cohort study of cerebrovascular CO2 reactivity in patients with inflammatory CNS diseases

Abstract

Word count of the text: 3089Word count of the abstract: 258 Conflict of interest: noneThere was no financial support for this study. 2 ABSTRACT PURPOSEThe purpose of this study was to evaluate the significance of cerebrovascular CO 2 reactivity (CO 2 R) in the course and outcome of inflammatory CNS diseases. METHODSSixty eight patients with inflammatory CNS diseases and thirty healthy volunteers were included in this prospective observational cohort study. The observational period was between January 2005 and May 2009. CO 2 reactivity was measured by Transcranial Doppler ultrasound (TCD) using the breath-holding method. We compared patients with normal CO 2 R (BHI m ≥ 1.18 = BHI N group) with patients who showed impaired CO 2 R (BHI m < 1.18 = BHI R group). We also analyzed the association of impaired CO 2 R with the etiology, severity and outcome of disease. RESULTSWhen compared to BHI N group, the patients from BHI R group were older, had a heavier consciousness disturbance, experienced more frequent respiratory failure, and subsequently had worse outcomes. There were no fatalities among the 28 patients in the BHI N group. The comparison of subjects with bacterial and non-bacterial meningitis revealed no significant differences. The unfavorable outcome of disease (GOS 1-3) was significantly more common in subjects with impaired CO 2 reactivity (62.5% vs. 10.7%).Logistic regression analysis was performed in order to establish the prognostic value of BHI m . The outcome variable was unfavorable outcome (GOS 1-3), while the independent variables were age, GCS and BHI m . The age and BHI m showed the strongest influence on disease outcome. A decrease of BHI m for each 0,1 unit increased the risk of unfavorable outcome for 17%. CONCLUSIONSOur study emphasizes the importance of CO 2 reactivity assessment in patients with inflammatory CNS diseases.

Critical Cerebral Perfusion Pressure at High Intracranial Pressure Measured by Induced Cerebrovascular and Intracranial Pressure Reactivity

“…Two additional aspects of our study should be emphasized. First, the loss of CBF autoregulation that occurs in traumatized or ischemic brain with MVS differs from the loss of CBF autoregulation observed with cerebrovascular dilation by high CO 2 (20, 21) or Diamox (22–24). Pharmacologically induced cerebrovascular dilation occurs by vasodilation of arteries, and arterioles, and high flow through capillaries resulting in a pressure passive relationship between CBF and CPP (1).…”

“…CBF autoregulation defined by lowering MAP to measure the critical CPP would require manipulation of blood pressure to unacceptably low levels and therefore cannot be studied in patients (19) and has historically been measured in animals (1, 2). Alternative methods of evaluating CBF autoregulation include the cerebrovascular response to a vasodilatory stimulus such as Co 2 (20, 21) and acetazolamide (22–24). CBF autoregulatory status is also evaluated by induced changes in arterial pressure and the CBF response as the cerebrovascular reactivity (CVRx) (3, 25).…”

Therapeutic hypothermia for severe adult Herpes simplex virus encephalitis

“…Furthermore, in traumatic brain injury and central nervous system infections reduction in CO 2 R was a single most accurate predictor variable for poor outcome [2,3]. Consequently, in patients with HSE, reduced CO 2 R and severe focal or diffuse brain edema the useful treatment option are still lacking while the death and brain herniation may ensue rapidly.…”

Can a combination of ultrasonographic parameters accurately evaluate concussion and guide return-to-play decisions?

“…(19,20) It also uses an expected mean breath holding index of 1.8 with a standard deviation of 0.5, which too are based on values obtained from healthy controls. (24,25)…”