Document Detail


Continuous measurement of cerebral oxygen saturation (rSO₂) for assessment of cardiovascular status during hemorrhagic shock in a swine model.
MedLine Citation:
PMID:  22847085     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Early trauma care is dependent on subjective assessments and sporadic vital sign assessments. We hypothesized that near-infrared spectroscopy-measured cerebral oxygenation (regional oxygen saturation [rSO₂]) would provide a tool to detect cardiovascular compromise during active hemorrhage. We compared rSO₂ with invasively measured mixed venous oxygen saturation (SvO₂), mean arterial pressure (MAP), cardiac output, heart rate, and calculated pulse pressure.
METHODS: Six propofol-anesthetized instrumented swine were subjected to a fixed-rate hemorrhage until cardiovascular collapse. rSO₂ was monitored with noninvasively measured cerebral oximetry; SvO₂ was measured with a fiber optic pulmonary arterial catheter. As an assessment of the time responsiveness of each variable, we recorded minutes from start of the hemorrhage for each variable achieving a 5%, 10%, 15%, and 20% change compared with baseline.
RESULTS: Mean time to cardiovascular collapse was 35 minutes ± 11 minutes (54 ± 17% total blood volume). Cerebral rSO₂ began a steady decline at an average MAP of 78 mm Hg ± 17 mm Hg, well above the expected autoregulatory threshold of cerebral blood flow. The 5%, 10%, and 15% decreases in rSO₂ during hemorrhage occurred at a similar times to SvO₂, but rSO₂ lagged 6 minutes behind the equivalent percentage decreases in MAP. There was a higher correlation between rSO₂ versus MAP (R² =0.72) than SvO₂ versus MAP (R² =0.55).
CONCLUSIONS: Near-infrared spectroscopy-measured rSO₂ provided reproducible decreases during hemorrhage that were similar in time course to invasively measured cardiac output and SvO₂ but delayed 5 to 9 minutes compared with MAP and pulse pressure. rSO₂ may provide an earlier warning of worsening hemorrhagic shock for prompt interventions in patients with trauma when continuous arterial BP measurements are unavailable.
Authors:
Lais Helena Camacho Navarro; Rodrigo M Lima; Muzna Khan; Wendy G Dominguez; Richard B Voigt; Michael P Kinsky; William J Mileski; George C Kramer
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  The journal of trauma and acute care surgery     Volume:  73     ISSN:  2163-0763     ISO Abbreviation:  J Trauma Acute Care Surg     Publication Date:  2012 Aug 
Date Detail:
Created Date:  2012-07-31     Completed Date:  2012-10-15     Revised Date:  2013-09-25    
Medline Journal Info:
Nlm Unique ID:  101570622     Medline TA:  J Trauma Acute Care Surg     Country:  United States    
Other Details:
Languages:  eng     Pagination:  S140-6     Citation Subset:  AIM; IM    
Affiliation:
Department of Anesthesiology, Botucatu Medical School, University of São Paulo State, São Paulo, Brazil. laishnavarro@uol.com.br
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MeSH Terms
Descriptor/Qualifier:
Animals
Brain / blood supply*
Brain Chemistry
Cardiac Output / physiology
Cardiovascular System / physiopathology*
Cerebrovascular Circulation / physiology
Female
Monitoring, Physiologic
Oximetry
Oxygen / analysis
Shock, Hemorrhagic / physiopathology*
Spectroscopy, Near-Infrared
Swine
Chemical
Reg. No./Substance:
7782-44-7/Oxygen

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


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