In-silico and in-vitro investigation of a photonic monitor for intestinal perfusion and oxygenation

Robinson, Mitchell B.; Butcher, Ryan J.; Wilson, Mark A.; Ericson, M.N.; Coté, Gerard L.

doi:10.1364/boe.8.003714

Cited by 1 publication

(4 citation statements)

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“…The sensor boards utilized were modified ADPD103Z boards from Analog Devices. 26 As mentioned above, conventional optical perfusion and oxygenation measurements utilize long visible and NIR wavelengths, which enable increased penetration depth for dense tissues. For the thin intestinal tissues, the photon penetration is too deep at these long wavelengths, resulting in high background signals and motion artifact.…”

Section: Optical Perfusion and Oxygenation Monitorsmentioning

confidence: 99%

“…The decrease in nonpulsatile signal intensity for the red signal results from the decrease in blood velocity, reducing both the alignment of the orientation of the red blood cells that increase reflected light as well as the expansion of the vessels. The effects seen with wavelength in vivo were also validated using the previously described optofluidic phantom 26 by altering the scattering properties of the blood phantom used. Comparing the blood phantom to the same phantom with the addition of aluminum oxide particles with an increasing flow rate yielded the signals in Fig.…”

Section: Perfusionmentioning

confidence: 99%

“…To confirm that higher absorbance of blood at short wavelengths drives the signal generation, comparison of the flow in the vasculature was performed with the optofluidic phantom system, which mimics the flow through the small intestine. 26 While a comparison of the flow velocity through the cranial mesenteric artery to the optical signals would be ideal, it is difficult to correctly match pulses between the artery and the sensor, given the unknown vascular path length between the two points. The use of the in vitro system provided a defined path of fluid flow and a more reliable comparison of the flow to Fig.…”

Section: Perfusionmentioning

confidence: 99%

“…Taking advantage of visible wavelengths and short source-todetector separations, a photoplethysmographic sensor has been designed, built, and validated in vitro to separate perfusion and oxygenation information acquired from the intestinal wall. 22,26 The use of visible wavelengths, with the increased scattering associated with shorter wavelengths and the increased absorbance of hemoglobin, confines photons within the perfused tissue and increases the hemoglobin signature in the collected optical signal. It is hypothesized that this sensor may be used to directly inform the physician on the resuscitation status via intestinal perfusion and oxygenation.…”

Section: Introductionmentioning

confidence: 99%

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In vivo performance of a visible wavelength optical sensor for monitoring intestinal perfusion and oxygenation

et al. 2018

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Traumatic injury resulting in hemorrhage is a prevalent cause of death worldwide. The current standard of care for trauma patients is to restore hemostasis by controlling bleeding and administering intravenous volume resuscitation. Adequate resuscitation to restore tissue blood flow and oxygenation is critical within the first hours following admission to assess severity and avoid complications. However, current clinical methods for guiding resuscitation are not sensitive or specific enough to adequately understand the patient condition. To better address the shortcomings of the current methods, an approach to monitor intestinal perfusion and oxygenation using a multiwavelength (470, 560, and 630 nm) optical sensor has been developed based on photoplethysmography and reflectance spectroscopy. Specifically, two sensors were developed using three wavelengths to measure relative changes in the small intestine. Using vessel occlusion, systemic changes in oxygenation input, and induction of hemorrhagic shock, the capabilities and sensitivity of the sensor were explored in vivo. Pulsatile and nonpulsatile components of the red, blue, and green wavelength signals were analyzed for all three protocols (occlusion, systemic oxygenation changes, and shock) and were shown to differentiate perfusion and oxygenation changes in the jejunum. The blue and green signals produced better correlation to perfusion changes during occlusion and shock, while the red and blue signals, using a new correlation algorithm, produced better data for assessing changes in oxygenation induced both systemically and locally during shock. The conventional modulation ratio method was found to be an ineffective measure of oxygenation in the intestine due to noise and an algorithm was developed based on the Pearson correlation coefficient. The method utilized the difference in phase between two different wavelength signals to assess oxygen content. A combination of measures from the three wavelengths provided verification of oxygenation and perfusion states, and showed promise for the development of a clinical monitor.

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Section: Optical Perfusion and Oxygenation Monitorsmentioning

confidence: 99%

Section: Perfusionmentioning

confidence: 99%

Section: Perfusionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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