HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Respond to This Article Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kirkness, C. J. Articles by Mitchell, P. H. Search for Related Content PubMed PubMed Citation Articles by Kirkness, C. J. Articles by Mitchell, P. H.

Intracranial and Blood Pressure Variability and Long-Term Outcome After Aneurysmal Sub-arachnoid Hemorrhage

Corresponding author: Catherine J. Kirkness, RN, PhD, Box 357266, University of Washington, Room T620A, 1959 Pacific NE St, Seattle, WA 98195 (e-mail: kirkness{at}u.washington.edu).

Background Care of brain-injured patients in intensive care units has focused on maintaining arterial blood pressure and intracranial pressure within prescribed ranges. Research suggests, however, that the dynamic variability of these pressure signals provides additional information about physiological functioning and may reflect adaptive capacity.

Objectives To see if long-term outcomes can be predicted from variability of arterial blood pressure and intracranial pressure in patients with aneurysmal subarachnoid hemorrhage.

Methods Arterial blood pressure and intracranial pressure were monitored continuously for 4 days in 90 patients (74% women; mean age, 53 years) in an intensive care unit after subarachnoid hemorrhage. Variability of arterial blood pressure and intracranial pressure signals was calculated on 4 timescales: 24 hours, 1 hour, 5 minutes, and the difference of sequential 5-second means. The Extended Glasgow Outcome Scale was used to assess functional outcome 6 months after subarachnoid hemorrhage.

Results Pressure variability was better than mean pressure levels for predicting 6-month functional outcome. When initial neurological condition was controlled for, greater faster variability (particularly 5-second) was associated with better outcomes (typical P<.001), whereas greater 24-hour variability was associated with poorer outcomes (typical P<.001).

Conclusions The relationship between long-term functional outcome and variability of arterial blood pressure and intracranial pressure levels depends on the timescale at which the variability is measured. Because it is associated with better outcome, greater faster variability may reflect better physiological adaptive capacity.