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Issue: Issue 1 (2014) – Supplement 1


Original Article

Impaired autoregulation is associated with mortality in severe cerebral diseases

Author(s):
Bernhard Schmidt, Jens J. Schwarze, Marco Weinhold, Vesna Lezaic, Marek Czosnyka, and Jürgen Klingelhöfer
Abstract:
Background: Small cerebral vessels respond to variations of cerebral perfusion pressure (CPP) by changes of vessel diameter inducing changes of blood flow resistance and keeping cerebral blood flow constant. This mechanism is called cerebral autoregulation (CA). An index Mx, observing correlation between cerebral blood flow velocity (CBFV) and CPP has been recently introduced for assessment of state of CA during spontaneous changes of CPP. In the current study, the relationship between lethal outcome during hospitalization and Mx index was investigated.

Methods: Thirty patients (18-77 years, mean 53±16 years) with severe cerebral diseases were studied. CBFV, arterial blood pressure (ABP,) and intracranial pressure (ICP) were simultaneously recorded. Assessments were repeated at days 2, 4 and 7. Mx was calculated retrospectively, as averaged correlation between CBFV and CPP (=ABP-ICP). Positive values of Mx indicated impairment of CA.

Results: Six of the patients died in-hospital. In this group Mx was significantly higher than in the group of survivors (0.28±0.40 versus 0.03±0.21; p<0.05). Changes of Mx during days of monitoring (Mx last day - Mx first day) were not significantly related to mortality. Nine patients showed an Mx >0.2, four of them died, whereas from the 21 patients with Mx <0.2 only two died . The association between increased Mx and death was significant (p<0.05, Fisher’s exact test). Mx correlated significantly with Glasgow Outcome Score (GOS) in the subgroup of patients with known GOS (N=21; R=-0.56, p<0.05).

Conclusion: Increased Mx indicates impairment of CA and is associated with risk of death in patients with severe cerebral diseases.

Keywords: Cerebral autoregulation, Cerebral perfusion pressure, Intracranial pressure, Cerebral disease.

International Journal of Clinical Neurosciences and Mental Health 2014; 1(Suppl. 1):S18

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