| Noninvasive autoregulation monitoring with and without intracranial pressure in the naive piglet brain. | |
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MedLine Citation:
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PMID: 20519421 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: Cerebrovascular autoregulation monitoring is often desirable for critically ill patients in whom intracranial pressure (ICP) is not measured directly. Without ICP, arterial blood pressure (ABP) is a substitute for cerebral perfusion pressure (CPP) to gauge the constraint of cerebral blood flow across pressure changes. We compared the use of ABP versus CPP to measure autoregulation in a piglet model of arterial hypotension. METHODS: Our database of neonatal piglet (5-7 days old) experiments was queried for animals with naïve ICP that were made lethally hypotensive to determine the lower limit of autoregulation (LLA). Twenty-five piglets were identified, each with continuous recordings of ICP, regional cerebral oximetry (rSo2), and cortical red cell flux (laser Doppler). Autoregulation was assessed with the cerebral oximetry index (COx) in 2 ways: linear correlation between ABP and rSo2 (COx(ABP)) and between CPP and rSo2 (COx(CPP)). The lower limits of autoregulation were determined from plots of red cell flux versus ABP. Averaged values of COx(ABP) and COx(CPP) from 5 mm Hg ABP bins were used to show receiver operating characteristics for the 2 methods. RESULTS: COx(ABP) and COx(CPP) yielded identical receiver operating characteristic curve areas of 0.91 (95% confidence interval [CI], 0.88-0.95) for determining the LLA. However, the thresholds for the 2 methods differed: a threshold COx(ABP) of 0.5 was 89% sensitive (95% CI, 81%-94%) and 81% specific (95% CI, 73%-88%) for detecting ABP below the LLA. A threshold COx(CPP) of 0.42 gave the same 89% sensitivity (95% CI, 81%-94%) with 77% specificity (95% CI, 69%-84%). CONCLUSIONS: The use of ABP instead of CPP for autoregulation monitoring in the naïve brain with COx results in a higher threshold value to discriminate ABP above from ABP below the LLA. However, accuracy was similar with the 2 methods. These findings support and refine the use of near-infrared spectroscopy to monitor autoregulation in patients without ICP monitors. |
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Authors:
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Ken M Brady; Jennifer O Mytar; Kathleen K Kibler; Charles W Hogue; Jennifer K Lee; Marek Czosnyka; Peter Smielewski; R Blaine Easley |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Review Date: 2010-06-02 |
Journal Detail:
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Title: Anesthesia and analgesia Volume: 111 ISSN: 1526-7598 ISO Abbreviation: Anesth. Analg. Publication Date: 2010 Jul |
Date Detail:
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Created Date: 2010-06-25 Completed Date: 2010-07-12 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 1310650 Medline TA: Anesth Analg Country: United States |
Other Details:
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Languages: eng Pagination: 191-5 Citation Subset: AIM; IM |
Affiliation:
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Department of Anesthesiology, Division of Pediatric Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, 600 North Wolfe St., Blalock 943, Baltimore, MD 21287, USA. Kbrady5@jhmi.edu |
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Balloon Dilatation Blood Pressure / physiology Brain / physiology* Cerebrovascular Circulation / physiology Data Interpretation, Statistical Homeostasis / physiology* Intracranial Pressure / physiology* Likelihood Functions Linear Models Monitoring, Physiologic / methods* Oximetry Oxygen / blood ROC Curve Swine |
| Chemical | |
Reg. No./Substance:
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7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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