Document Detail


Measurements of optical pathlength using phase-resolved spectroscopy in patients undergoing cardiopulmonary bypass.
MedLine Citation:
PMID:  17242091     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Near infrared spectroscopy (NIRS) has been used during cardiac surgery to monitor cerebral oxygenation although the validity of this technique has yet to be established. Although optical pathlength included in the algorithm for calculating NIRS values is supposed to be constant, recent evidence has suggested that optical pathlength could be affected by acute hemodilution in animals. We conducted the present study to investigate whether optical pathlength changes during cardiopulmonary bypass (CPB), and whether these changes affect NIRS values in adult patients. METHODS: Nine patients undergoing elective cardiac surgery with CPB were enrolled in this study. Optical pathlength and cerebral NIRS values (oxyhemoglobin [DeltaO(2)Hb] and tissue oxygen index) were measured by phase-resolved spectroscopy and NIRO 100, respectively. Optical pathlength, hemoglobin concentration, and NIRS values were measured at the following points: 1) after the induction of anesthesia, 2) 10 min after the start of CPB, 3) 60 min after the start of CPB, and 4) 1 h after CPB. The associations between optical pathlength and other variables were analyzed by Pearson correlation coefficients and multiple regression analysis. RESULTS: Optical pathlength significantly increased starting at 27.7-30.8 cm at 10 min, and 31.3 cm at 60 min after the start of CPB (P < 0.0001). Hemoglobin concentrations significantly decreased (from 11.2 to 7.1 g/dL at 10 min and 7.7 g/dL at 60 min P < 0.0001). There was a significant correlation (r = 0.55, P < 0.001) between percentage changes in pathlength and hemoglobin concentration. Multiple regression analysis showed that optical pathlength was a significant determinant of DeltaO2Hb. CONCLUSION: The results indicate that optical pathlength can change during CPB and its changes may affect DeltaO2Hb.
Authors:
Kenji Yoshitani; Masahiko Kawaguchi; Takashi Okuno; Tomoko Kanoda; Yoshihiko Ohnishi; Masakazu Kuro; Mitsunori Nishizawa
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Validation Studies    
Journal Detail:
Title:  Anesthesia and analgesia     Volume:  104     ISSN:  1526-7598     ISO Abbreviation:  Anesth. Analg.     Publication Date:  2007 Feb 
Date Detail:
Created Date:  2007-01-23     Completed Date:  2007-03-15     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  1310650     Medline TA:  Anesth Analg     Country:  United States    
Other Details:
Languages:  eng     Pagination:  341-6     Citation Subset:  AIM; IM    
Affiliation:
Department of Anesthesiology, National Cardiovascular Center, Suita, Osaka, Japan. kenji.yoshitani@duke.edu
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MeSH Terms
Descriptor/Qualifier:
Aged
Cardiopulmonary Bypass*
Humans
Middle Aged
Optics and Photonics* / instrumentation
Oxyhemoglobins / analysis,  metabolism
Spectroscopy, Near-Infrared / instrumentation,  methods*
Chemical
Reg. No./Substance:
0/Oxyhemoglobins

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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