Derek Brand

Systemic Effects of Shock and Resuscitation Monitored by Visible Hyperspectral Imaging

Hyperspectral imaging (HSI) has been useful in monitoring several medical conditions, which to date have generally involved local changes in skin oxygenation of isolated regions of interest such as skin flaps or small burns. Here, by contrast, we present a study in which HSI was used to assess the local cutaneous manifestations of significant systemic events. HSI of the ventral surface of the lower jaw was used to monitor changes in skin oxygenation during hypovolemic shock induced by hemorrhage with additional pulmonary contusion injury in a porcine model, and to monitor the subsequent recovery of oxygenation with resuscitation. Quantitative and qualitative changes were observed in the level of skin oxygenation during shock and recovery. Quantitative values were obtained by fitting reference spectra of oxyhemoglobin and deoxyhemoglobin to sample spectra. Qualitative changes included changes in the observed spatial distribution or pattern of skin oxygenation. A mottled pattern of oxygen saturation was observed during hemorrhagic shock, but not observed during hypovolemic shock or following resuscitation. Historically, the assessment of skin color and mottling has been an important, albeit inexact, component of resuscitation algorithms. Now, it is possible to analyze these variables during shock and resuscitation in an objective manner. The clinical utility of these advances needs to be determined.

Visible hyperspectral imaging: monitoring the systemic effects of shock and resuscitation

Hyperspectral (HS) imaging has been useful in the monitoring of several medical conditions, which to date have generally involved changes in skin oxygenation in isolated regions of interest such as skin flaps or small burns. Here, by contrast, we present a study in which HSI was used to assess the cutaneous manifestations of significant systemic events. HS imaging of the ventral surface of the lower jaw was used to monitor changes in skin oxygenation during hypovolemic shock induced by pulmonary contusion and hemorrhage in a porcine model, and to monitor the subsequent recovery of oxygenation following resuscitation. Changes are seen both quantitatively, in the level of skin oxygenation as determined by the fitting of reference hemoglobin and deoxyhemoglobin spectra to sample spectra, and qualitatively, in the observed spatial distribution or pattern of oxygenation-related changes in the skin. Linear regression was used to correlate these changes with invasively obtained parameters to include mixed venous oxygen saturation and systemic arterial blood pressure. Historically, the assessment of skin color and mottling has been an important, albeit inexact, component of resuscitation algorithms. Now, it is possible to analyze these variables during shock and resuscitation in an objective manner. The clinical utility of these advances needs to be determined.