Hyperspectral Imaging: A New Approach to the Diagnosis of Hemorrhagic Shock

Abstract

Background: Skin color changes and mottling are frequently described signs of hemorrhagic shock (HEM). Based on this, we developed a noninvasive, noncontact hyperspectral imaging system (HSI), which quantifies and depicts the surface tissue saturation of oxygen (SHSIO2) for each pixel in a region of interest (ROI). Our purpose was to assess HSI in a porcine HEM model. We hypothesized that HEM would cause decreases in S HSIO2 of the skin. Methods: The HyperMed HSI system employs a spectral separator to vary the wavelength of light admitted to a digital camera. During image acquisition, a hypercube of images, each at a separate wavelength, is generated (at 5-nm intervals, from 500 to 600 nm). Then, the visible light spectrum for each pixel in the hypercube is compared by linear regression to standard spectra for oxyhemoglobin (OxyHb) and deoxyhemoglobin (DeoxyHb). The resulting fit coefficients for OxyHb and DeoxyHb are used to calculate SHSIO2 values for each pixel in the ROI. The mean values for OxyHb, DeoxyHb, and SHSIO2 across the ROI are calculated. Grayscale SHSIO2 pictures of the ROI are also generated, in which the brightness of each pixel is proportional to its value. Seventeen pigs, 36.4 + or - 0.11 kg, underwent standard prep- aration, and were maintained on ketamine and isoflurane. Normothermia was maintained (37 C to 39 C). The hemorrhage group (HEM, n = 9) underwent three blood withdrawals, each 10 mL/kg, with 15 minutes between withdrawals. After the third withdrawal, animals were resuscitated with lactated Ringer's and then shed blood. The control group (CTRL, n = 8) received intravenous fluids at 100 mL/h. HSI images were obtained of the inner hindlimb throughout. Results: All HEM animals showed linear decreases in both mean SHSIO2 and OxyHb values with blood loss, which were reversed by resuscitation.

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Document Details

Document Type
Technical Report
Publication Date
May 01, 2006
Accession Number
ADA627973

Entities

People

  • Andriy I Batchinsky
  • Brian Tracey
  • Bryan S. Jordan
  • David Martini
  • James R. Mansfield
  • Jenny E. Freeman
  • Katherine Hetz
  • Leopoldo C. Cancio
  • Svetlana Panasyuk

Organizations

  • United States Army Institute of Surgical Research

Tags

Communities of Interest

  • Biomedical

DTIC Thesaurus Topics

  • Anesthesia
  • Arteries
  • Blood
  • Blood Transfusions
  • Cardiovascular Physiological Phenomena
  • Charge Coupled Devices
  • Hemorrhage
  • Hemorrhagic Shock
  • Hyperspectral Imagery
  • Oxygenation
  • Patient Care
  • Spectra
  • Spectroscopy
  • Statistical Analysis
  • Tissues
  • Veins
  • Visible Spectra

Fields of Study

  • Medicine

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