Name: diffuse reflectance spectroscopy: getting the capillary refill test under one's thumb
Uploaded: 2017-12-02T14:00:00
Description: Watch this Scientific Journal Video about Diffuse Reflectance Spectroscopy: Getting the Capillary Refill Test Under One's Thumb at JoVE.com

We would like to extend our gratitude to the Link&#246;ping staff of The Swedish Defense Agency (FOI) and the Center for disaster medicine and Traumatology (KMC) for their kind support.

The study described here followed the local ethic guidelines and was approved by the regional ethical review board in Link&#246;ping (permit number 2015/99-31).
1. Informed Consent and Screening
<ol>
	<li>Obtain informed consent from the subject.</li>
	<li>Screen according to inclusion/exclusion criteria. 
	NOTE: Inclusion criteria were: (i) Healthy adult &#62;18 years of age, (ii) Able to understand written and oral information, and (iii) Provides oral and written consent. Exclusion cr...

<ol>
	<li>Strehlow, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+identification+of+shock+in+critically+ill+patients.">Early identification of shock in critically ill patients.</a> Emerg Med Clin North Am. 28 (1), 57-66 (2010).</li><li>Advanced Life Support, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Acute Medical Emergencies. , 67-84 (2010).</li><li>Brasel, K. J., Guse, C., Gentilello, L. M., Nirula, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heart+rate:+is+it+truly+a+vital+sign?.">Heart rate: is it truly a vital sign?.</a> J Trauma. 62 (4), 812-817 (2007).</li><li>De Backer, D., Ortiz, J. A., Salgado, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coupling+microcirculation+to+systemic+hemodynamics.">Coupling microcirculation to systemic hemodynamics.</a> Curr Opin Crit Care. 16 (3), 250-254 (2010).</li><li>Mrgan, M., Rytter, D., Brabrand, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Capillary+refill+time+is+a+predictor+of+short-term+mortality+for+adult+patients+admitted+to+a+medical+department:+an+observational+cohort+study.">Capillary refill time is a predictor of short-term mortality for adult patients admitted to a medical department: an observational cohort study.</a> Emerg Med J. 31 (12), 954-958 (2014).</li><li>Advanced Life Support, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Acute Medical Emergencies. , 55-65 (2010).</li><li>Lewin, J., Maconochie, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Capillary+refill+time+in+adults.">Capillary refill time in adults.</a> Emerg Med J. 25 (6), 325-326 (2008).</li><li>Lobos, A. T., Menon, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+multidisciplinary+survey+on+capillary+refill+time:+Inconsistent+performance+and+interpretation+of+a+common+clinical+test.">A multidisciplinary survey on capillary refill time: Inconsistent performance and interpretation of a common clinical test.</a> Pediatr Crit Care Med. 9 (4), 386-391 (2008).</li><li>Otieno, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Are+bedside+features+of+shock+reproducible+between+different+observers?.">Are bedside features of shock reproducible between different observers?.</a> Arch Dis Child. 89 (10), 977-979 (2004).</li><li>Raju, N. V., Maisels, M. J., Kring, E., Schwarz-Warner, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Capillary+refill+time+in+the+hands+and+feet+of+normal+newborn+infants.">Capillary refill time in the hands and feet of normal newborn infants.</a> Clin Pediatr (Phila). 38 (3), 139-144 (1999).</li><li>Klupp, N. L., Keenan, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+evaluation+of+the+reliability+and+validity+of+capillary+refill+time+test.">An evaluation of the reliability and validity of capillary refill time test.</a> The Foot. 17, 15-20 (2007).</li><li>Gorelick, M. H., Shaw, K. N., Baker, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+ambient+temperature+on+capillary+refill+in+healthy+children.">Effect of ambient temperature on capillary refill in healthy children.</a> Pediatrics. 92 (5), 699-702 (1993).</li><li>Schriger, D. L., Baraff, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Defining+normal+capillary+refill:+variation+with+age,+sex,+and+temperature.">Defining normal capillary refill: variation with age, sex, and temperature.</a> Ann Emerg Med. 17 (9), 932-935 (1988).</li><li>Pandey, A., John, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Capillary+refill+time.+Is+it+time+to+fill+the+gaps?.">Capillary refill time. Is it time to fill the gaps?.</a> Med J Armed Forces India. 69 (1), 97-98 (2013).</li><li>Strozik, K. S., Pieper, C. H., Roller, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Capillary+refilling+time+in+newborn+babies:+normal+values.">Capillary refilling time in newborn babies: normal values.</a> Arch Dis Child Fetal Neonatal Ed. 76 (3), F193-F196 (1997).</li><li>Doherty, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sub-epidermal+imaging+using+polarized+light+spectroscopy+for+assessment+of+skin+microcirculation.">Sub-epidermal imaging using polarized light spectroscopy for assessment of skin microcirculation.</a> Skin Res Technol. 13 (4), 472-484 (2007).</li><li>Noguchi, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+caffeine+contained+in+a+cup+of+coffee+on+microvascular+function+in+healthy+subjects.">Effect of caffeine contained in a cup of coffee on microvascular function in healthy subjects.</a> J Pharmacol Sci. 127 (2), 217-222 (2015).</li><li>Reus, W. F., Robson, M. C., Zachary, L., Heggers, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acute+effects+of+tobacco+smoking+on+blood+flow+in+the+cutaneous+micro-circulation.">Acute effects of tobacco smoking on blood flow in the cutaneous micro-circulation.</a> Br J Plast Surg. 37 (2), 213-215 (1984).</li><li>Lenasi, H., Strucl, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+regular+physical+training+on+cutaneous+microvascular+reactivity.">Effect of regular physical training on cutaneous microvascular reactivity.</a> Med Sci Sports Exerc. 36 (4), 606-612 (2004).</li><li>Anderson, B., Kelly, A. M., Kerr, D., Clooney, M., Jolley, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+patient+and+environmental+factors+on+capillary+refill+time+in+adults.">Impact of patient and environmental factors on capillary refill time in adults.</a> Am J Emerg Med. 26 (1), 62-65 (2008).</li><li>John, R. T., Henricson, J., Nilsson, G. E., Wilhelms, D., Anderson, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reflectance+spectroscopy:+to+shed+new+light+on+the+capillary+refill+test.">Reflectance spectroscopy: to shed new light on the capillary refill test.</a> J Biophotonics. , (2017).</li><li>Blaxter, L. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+automated+quasi-continuous+capillary+refill+timing+device.">An automated quasi-continuous capillary refill timing device.</a> Physiological measurement. 37, 83-99 (2016).</li><li>Bordoley, A., Irwin, R., Kalyani, V., MacDonald, C., Standish, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> D1GIT: Automated, temperature-calibrated measurement of capillary refill time. , (2012).</li><li>Kviesis-Kipge, E., Curkste, E., Spigulis, J., Eihvalde, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real-time+analysis+of+skin+capillary-refill+processes+using+blue+LED.">Real-time analysis of skin capillary-refill processes using blue LED.</a> Proc. of SPIE. 771523, (2010).</li><li>Shavit, I., Brant, R., Nijssen-Jordan, C., Galbraith, R., Johnson, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+imaging+technique+to+measure+capillary-refill+time:+improving+diagnostic+accuracy+for+dehydration+in+young+children+with+gastroenteritis.">A novel imaging technique to measure capillary-refill time: improving diagnostic accuracy for dehydration in young children with gastroenteritis.</a> Pediatrics. 118 (6), 2402-2408 (2006).</li><li>Cohen, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monitor+to+Measure+Dermal+Blood+Flow+in+Critically+Ill+Patients:+Study.">Monitor to Measure Dermal Blood Flow in Critically Ill Patients: Study.</a> International Scholarly Research Notices. 578316, e578316 (2013).</li></ol>

In order to get the best results with the system, variability caused by environmental factors must be controlled. All ambient light must be turned off. The camera must be positioned in vertical alignment with the measurement area. In order to ensure a constant measurement area, subjects should not move or talk during measurement. For the same reason, the camera is preferably mounted on a stand to avoid movement and to maintain a constant distance to the measurement area. Test subjects should avoid caffeine<sup class="xre...

Assessment and triage of the critically ill patient centers on the classical vital signs blood pressure (BP), heart rate (HR), respiratory rate (RR), oxygen saturation, and body temperature1. Changes in these parameters appear relatively late in the course of circulatory deterioration. For instance, in hemorrhage, a decrease in BP will not occur until blood loss becomes moderate to severe2, and HR increase can also be an insensitive and unspecific marker3.
The capillary refill test (CR test) may offer an earlier indication of incipient circulatory collapse, as the refill time is believed to change prior to the vital signs as well as clinical appearance of cold, clammy, and mottled skin1,4,5. The capillary refill test is typically performed by application and then release of a firm blanching pressure to the skin with timing (in seconds) of the return of blood to the blanched area. According to guidelines, refill should occur within 2 seconds after release of 5 seconds of firm pressure (e.g., by the physician&#39;s finger) in the normal healthy supine patient6. The rationale for the test is that a slower refill time would indicate poor skin perfusion, possible caused by one of a number of critical events such as sepsis, blood loss, acute heart failure, or hypothermia.
At present, there is no consensus on a state of the art method for performing the CR test6,7,8,9,10. Contentious issues include lack of standardization of the actual blanching maneuver and the dependence on subjective (i.e., naked eye) assessments of the refill endpoint7,9,11. Furthermore, there are indications that gender influences CR time12,13. The temperature, both ambient and skin, is known to affect the capillary refill time, but to what extent is not clear. Lastly, the use of different measurement sites, peripheral or central, is probably a further cause of variability in results with few studies in this area14,15.
In the present work, we used an optical bioengineering system to record the course of return of blood and the subsequent hyperemic response seen during the CR test. The system utilizes diffuse polarization spectroscopy to quantify and describe, in more detail than possible with the naked eye, the time and course of the capillary refill. The system comprises a standard digital camera, fitted with an external light ring with 92 white LEDs, and specially developed software. The lens and the two polarization filters, attached orthogonally in front of the LEDs, block light that has been directly reflected from the skin surface allowing only light that has become depolarized in the tissue to reach the camera. This generates a &#34;sub-epidermal&#34; image of the tissue to a depth of approximately 0.5 mm. The image is divided into its color planes and the red and green content for every pixel is calculated, generating a value which corresponds to the tissue concentration of red blood cells16. In video mode, the temporal resolution of the system is 0.02 s.

<table>
	<tbody>
		<tr>
			<td>TiVi701 Camera</td>
			<td>WheelsBridge AB</td>
			<td>TiVi701 Camera, version 1.5.1</td>
			<td>Software</td>
		</tr>
		<tr>
			<td>TiVi700</td>
			<td>WheelsBridge AB</td>
			<td>TiVi700 Analysis, version 1.2.9</td>
			<td>Software</td>
		</tr>
		<tr>
			<td>Canon EOS 700D</td>
			<td>Canon U.S.A., inc.</td>
			<td>Canon EOS 700D</td>
			<td>Digital SLR Camera</td>
		</tr>
		<tr>
			<td>Camera stand</td>
			<td>Manfrotto</td>
			<td>681B</td>
			<td>Modified camera stand to hold the digital camera in position</td>
		</tr>
		<tr>
			<td>Camera stand</td>
			<td>Disa Denmark</td>
			<td>9020B</td>
			<td>Modified camera stand to hold the digital camera in position</td>
		</tr>
	</tbody>
</table>

diffuse reflectance spectroscopy: getting the capillary refill test under one's thumb

The capillary refill test was introduced in 1947 to help estimate circulatory status in critically ill patients. Guidelines commonly state that refill should occur within 2 s after releasing 5 s of firm pressure (e.g., by the physician&#39;s finger) in the normal healthy supine patient. A slower refill time indicates poor skin perfusion, which can be caused by conditions including sepsis, blood loss, hypoperfusion, and hypothermia. Since its introduction, the clinical usefulness of the test has been debated. Advocates point out its feasibility and simplicity and claim that it can indicate changes in vascular status earlier than changes in vital signs such as heart rate. Critics, on the other hand, stress that the lack of standardization in how the test is performed and the highly subjective nature of the naked eye assessment, as well as the test&#39;s susceptibility to ambient factors, markedly lowers the clinical value. The aim of the present work is to describe in detail the course of the refill event and to suggest potentially more objective and exact endpoint values for the capillary refill test using diffuse polarization spectroscopy.

Filming the course of the capillary refilling generates vast amounts of data not possible to obtain by naked eye assessment. We suggest here new endpoints to further improve the usability of the CR test as an early indicator of deterioration in circulatory status. We call these endpoints: &#34;Baseline,&#34;&#160;&#34;Blood Zero&#34; (or &#34;BZ&#34;), &#34;Time to Return to Baseline 1&#34; (or &#34;tRtB1&#34;), &#34;Time to Peak&#34; or &#34;Tpk.&#34;&#160;The &#34;Baseline&#34; value is...

Watch this Scientific Journal Video about Diffuse Reflectance Spectroscopy: Getting the Capillary Refill Test Under One's Thumb at JoVE.com

Diffuse Reflectance Spectroscopy: Getting the Capillary Refill Test Under One's Thumb

This protocol describes how the use of diffuse polarization spectroscopy can improve the clinical usefulness of the capillary refill test. We suggest a more detailed analysis of the course of the capillary refill in healthy volunteers using diffuse reflectance spectroscopy videos and new informatic endpoints.

The capillary refill test was introduced in 1947 to help estimate circulatory status in critically ill patients. Guidelines commonly state that refill ...

The overall goal of this assessment is to quantify capillary refill time using reflectance spectroscopy in digital video to enable fast and objective detection of incipient circulatory change. Quantified objective assessment of capillary refill time using reflectance spectroscopy may provide an early warning to incipient circulatory change and facilitate triage and continuous monitoring of critically ill patients. The main advantage of this technique is that it, compared to naked eye assessment, offers a very exact and objective way to measure capillary refill time.The implications of this technique extend toward early triage of trauma patients at an accident site or at the emergency or continuous supervision of critically ill patients. To begin, connect the camera and the computer using a USB cable, and set the camera to video mode. Then, turn on the camera and make sure that it connects to the computer.Next, start the remote-controlled camera software. Also, remove any ambient light sources, and turn the computer screen away from the measurement area. To begin, bring in the test subject, and let them acclimate to the surroundings for at least 20 minutes in a supine position.Then, click the Life View button and press Start. Switch between video mode and TV mode by clicking the radio buttons. Ensure that a live video stream of the subject's forehead is visible on the display of the camera and on the computer screen.Next, adjust the camera to a height of approximately 15 centimeters directly above the subject's forehead, and make sure that the focus of the camera is set to autofocus. Ask the subject to keep their head still for the duration of the test and to refrain from talking. Then, inform the subject to place their head on a pillow and to keep it still for the duration of the test.Ask them not to talk during the 20 seconds that the test will last. They may keep their eyes closed for the whole time if they find the light too bright. In the Life View window, find and click on HD Record to start a continuous recording for 20 seconds.Do not move the camera during the duration of the test. At the end of the initial five seconds of baseline recording, apply a firm blanching pressure to the measurement area for five seconds using a plastic teaspoon for pressure equalization and temperature insulation. Then, release the pressure and quickly withdraw the plastic teaspoon from the measurement area.Continue recording for another 10 seconds in order to capture the subsequent hyperemic response. At the end of the 20 seconds, stop the recording by clicking Stop in the Life View window. Once the recording has stopped, a window will open to save the video file.Name the video and save it in mov format. Disconnect the camera from the computer once the video has downloaded to its designated folder on the computer. Start the analysis software by double-clicking on the desktop icon.Once the software has started, on the main screen, select Movie Page. In the Movie Page window, click Load Movie. Wait for the software to upload and analyze the movie.Once the upload and analysis of the movie is finished, click Save As Images and wait for the software to analyze the video and divide it into individual JPEG images. Then, find and select Crop Images Page in the main screen window. In the Crop Images Page menu, click First Photo and navigate to the folder that contains the JPEG photos from the video.Select the first photo to be analyzed. The software will automatically select the following photos of that batch. Click the Edit menu and choose between circular or rectangular markers for the region of interest.Then, in the Select Photos window, find the actual photo box and type in the name of the first photo in the batch, where the investigator's fingers fully retracted from the measurement area. To find this photo, look through the folder containing the individual photos from the video. Select a region of interest by clicking and holding the left mouse button, and draw a circle or rectangle in the photo window that is within the borders of the blanched area.The selected region of interest is automatically applied to all photos of the batch. Next, click on the File menu and choose Save ROI to save the location of the selected region of interest for future reference. Then, click on the Curve Tracker and wait for the software to analyze the region of interest.Once the Curve Tracker window opens, the change in red blood cell concentration for the selected region of interest over the duration of the test is displayed as a curve. Finally, click Export Data and save the raw data transcript for further analysis. Using this method, the capillary refilling response can be presented as the change in red blood cell concentration over time.During the first five seconds of the test, the baseline values are collected. Then, pressure is applied to reach the blood zero point. Once the pressure is relieved, the blood begins to return to the area and will peak after a few seconds.This representative graph is for a healthy male volunteer. A slower refill time would indicate poor skin perfusion, and can be indicative of adverse conditions. The use of reflectance spectroscopy videos gives more detailed data on changes in capillary refill time compared to naked eye assessment.The presented method needs further development but clearly shows the potential of the technique in measuring capillary refill events.

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