We acknowledge the support by the S&#227;o Paulo Research Foundation (FAPESP) through Proc. 2012/02500-8 (RM), 2014/25486-6 (RF) and 2013/07559-3. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

The protocol was approved by the local committee of the University of Campinas (protocol number 56602516.2.0000.5404). Written informed consent was obtained from the patient or a legal representative prior to the measurements. We monitored patients that were admitted to the Clinics Hospital at the University of Campinas with a diagnosis of either ischemic stroke or a subarachnoid hemorrhage affecting the anterior circulation. Patients with ischemic strokes affecting the posterior circulation, patients with decompressive craniectomies due to elevated intracranial pressure and patients with other neurodegenerative diseases (dementia, Parkinson&#39;s or any other disease that can be associated with cortical atrophy) were excluded from the study protocol.
1. Preparations before moving the system to the ICU
<ol>
	<li>Connect all the fibers to the relevant lasers and detectors, and make sure they are properly attached to the optical probe (Figure 1B).</li>
	<li>Check that the optical probe is covered with a black cloth to avoid the lasers shining in the room.</li>
	<li>Turn the system power switch to the &#8216;ON&#8217; position. After powering the system, wait 30s and then turn the DCS laser key switch to the &#8216;ON&#8217; position. The FD-DOS lasers are automatically turned on when the system is powered.</li>
	<li>While the system is being prepared, obtain consent from either the participant or a legal representative. After obtaining consent, bring the cart to the patient&#8217;s room. 
	NOTE: Since the hybrid system has a built-in battery that lasts up to 45 min, it does not need to be turned off during transport.</li>
</ol>
2. Calibration and gain settings of the DOS system
<ol>
	<li>Upon arrival at the ICU, turn off the DCS laser by switching the key to the &#8216;OFF&#8217; position.</li>
	<li>Starting with the solid phantom marked &#8216;Calibrate&#8217;, run the calibration process on the FD-DOS software (BOXY, ISS) by following the steps below.
	<ol>
		<li>On the &#8216;File&#8217; menu, load the appropriate settings file for the probe being used by clicking on the &#8216;Load settings file&#8217; option.</li>
		<li>Place the probe on the curved side of the phantom, ensuring a good contact with the surface and then optimize the PMT bias voltage by clicking on the &#8216;Optimize All Detectors&#8217; button in the FD-DOS software.</li>
		<li>Run the calibration for multiple source-detector separations by clicking on the option &#8216;Calc. Waveform Calib. Values for Optical Props. and Multiple Distances&#8217; from the &#8216;Calibrate&#8217; menu.</li>
		<li>Open the &#8216;User-defined Calculations&#8217; option from the &#8216;Text-Mon&#8217; menu to check that the measured optical properties match the prespecified values (written in the solid phantom), and that the fitting R2 is close to one.</li>
	</ol>
	</li>
	<li>Repeat the steps above (except step 2.2.3) to measure the optical properties of the phantom marked as &#8216;Check&#8217; to ensure the calibration was adequate. The measured optical properties should match, within 10%, the values specified in the phantoms. 
	CAUTION: Make sure to turn off PMTs (by clicking on the &#8216;All Detectors OFF&#8217; button) every time the probe is moved to avoid damaging PMTs due to direct illumination from ambient light.</li>
	<li>If the calibration is not adequate, re-run the calibration process (steps 2.2 and 2.3). Ensuring a good calibration of the FD-DOS system is essential to the validity of the FD-DOS measurements.</li>
</ol>
3. Preparation of the participant at the bedside
<ol>
	<li>Use sanitizing wipes to clean both the probe and patient forehead.</li>
	<li>Place the double-sided tape on the probe (Figure 1B), ensuring the tape is not in direct contact with the optical fiber tips.</li>
	<li>Place a laser safety googles on the subject.</li>
	<li>Place the probes over the region-of-interest (ROI) and wrap the elastic straps around the subject&#8217;s head. Although not strictly necessary for FD-DOS and DCS, it is advisable to cover the optical probe with a black cloth or black bandage to reduce noise due to ambient light. 
	NOTE: It is important to assure that the elastic strap is neither too tight&#160;nor too loose. If the strap is too tight it may cause significant discomfort to the patient, and if the strap is too loose it may lead to poor data quality as the double-sided tape is not strong enough to keep the probes in place.</li>
	<li>After the probe is properly secured to the patient&#39;s forehead, turn on the DCS laser by switching the key to the &#8216;ON&#8217; position. 
	CAUTION: The DCS system uses a Class 3B laser which is hazardous for eye exposure. It is very important to only turn on the lasers when the probe is properly attached to the patient&#8217;s forehead.</li>
</ol>
4. Data quality assessment
<ol>
	<li>Before starting to acquire data with the GUI, write the DCS source-detector separations in the &#8216;Settings&#8217; tab of the GUI. 
	NOTE: The DCS system does not require a calibration step, but the proper input of the source-detector separations is necessary for the real-time analysis (see Supplementary Material for details).</li>
	<li>Start the acquisition software by pressing the &#8216;Start&#8217; button in the GUI and check the DOS signal in the FD-DOS software:
	<ol>
		<li>Click on the &#8216;Optimize All Detectors&#8217; button in the FD-DOS software to optimize the PMT bias voltage.</li>
		<li>Check the optical properties and the R2 of the DOS fitting in the &#8216;User Defined Calculation&#8217; option from the &#8216;Text-Mon&#8217; menu. The R2 coefficient should be close to unity and, as a rule of thumb, the absorption coefficient of human patients should be within 0.05 and 0.2 cm-1, while the scattering coefficient should be within 6 and 13 cm-113.</li>
	</ol>
	</li>
	<li>Check the DCS signal in the &#8216;Correlation curves&#8217; tab of the GUI.
	<ol>
		<li>Turn on the DCS detectors by turning the switches to the &#8216;ON&#8217; position.</li>
		<li>Ensure that each DCS detector is measuring an adequate light intensity. As a rule of thumb, more than 10 kHz is required.</li>
		<li>If the measured intensity is higher than 800 kHz, use a neutral density filter to reduce the photon counts to avoid damaging the detectors. This is typically a problem for shorter (&#60; 1 cm) source-detector separations. 
		NOTE: Apart from potentially damaging the DCS detectors, photon counts higher than 800 kHz may also bring errors due to non-linear effects in the detector.</li>
		<li>Check the autocorrelation curves to ensure a good skin coupling (see the Representative Results and Figure 2) and reposition the optical probe if necessary.</li>
		<li>If the repositioning of the probe was necessary in the previous step, repeat Steps 4.2 and 4.3. These steps may need to be repeated multiple times. 
		NOTE: The DCS and the FD-DOS detectors must be turned off each time the probe is moved. To turn the DCS detectors off, manually move the switches to the &#8216;OFF&#8217; position. The FD-DOS detector is turned off by clicking the &#8216;All Detectors OFF&#8217; button in the FD-DOS software.</li>
	</ol>
	</li>
	<li>When a good contact between the probe and the skin is achieved, stop the data collection by clicking the &#8216;Stop&#8217; button in the GUI. Then, set the experiment and patient identifiers in the &#8216;Folder&#8217; textbox and write the ROI name in the &#8216;File name&#8217; textbox.</li>
	<li>Start the data acquisition by pressing the &#8216;Start&#8217; button in the GUI.</li>
	<li>Collect data in the first ROI for as long as required by the protocol. If necessary, move the probe to the other ROIs and repeat the measurement. 
	NOTE: The monitoring period may vary depending on the study goals.</li>
</ol>
5. Considerations for the experimenter during the measurement
<ol>
	<li>After starting the measurement, write in the &#8216;Experiment Info&#8217; tab of the GUI the relevant patient information (e.g., type and location of the injury, drugs being administered, age, sex, etc.).</li>
	<li>Ensure that any relevant event that occurred during the monitoring period is marked by clicking the &#8216;Mark&#8217; button on the GUI. After each mark, make sure to write the event description in the &#8216;Experiment Info&#8217; tab of the GUI.</li>
</ol>
6. Stop data collection
<ol>
	<li>Stop the data collection by pressing the &#8216;Stop&#8217; button in the GUI.</li>
	<li>Stop the FD-DOS software by pressing the stop data acquisition and recording button represented as two red squares in the FD-DOS software.</li>
	<li>Turn off the DCS detectors by flipping the switches to the &#8216;OFF&#8217; position and turn off the DCS laser by turning the key to the &#8216;OFF&#8217; position.</li>
	<li>Turn off the PMTs of the FD-DOS module by clicking the &#8216;All Detectors OFF&#8217; button.</li>
	<li>Remove the probe from the patient&#39;s head and remove the double-sided tape from the probe. Then, clean the probe with sanitizing wipes.</li>
	<li>Repeat the measurement of the optical properties of each solid phantom as soon as possible to ensure the calibration remained adequate throughout the monitoring session (see step 4.2.2). 
	NOTE: Ideally, the calibration step should be done right after removing the optical probes from the patient&#39;s head (step 6.6). However, due to timing issues, in the examples presented in the next section this was done in the storage facility.</li>
	<li>Clean the system and its accessories with sanitizing wipes.</li>
	<li>Wheel the cart back to the storage room.</li>
</ol>

The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: RC Mesquita has one pending patent application and two other patents relevant to this work (United States patents 10,342,488 and 10,064,554). No author currently receives royalties or payments from these patents.
&#160; &#160;

This paper presented a hybrid optical system that can provide real-time information about cerebral blood flow, cerebral oxygenation, and cerebral oxygen metabolism of neurocritical patients at the beside. The use of diffuse optical techniques had been previously addressed as a potential marker for non-invasive, bedside monitoring in clinical scenarios. A previous study focused on the clinical aspects and the feasibility of optical monitoring during hospitalization in the neuro-ICU through a case report9...

An erratum was issued for:&#160;<a href="https://www.jove.com/t/61608">Real-Time Monitoring of Neurocritical Patients with Diffuse Optical Spectroscopies</a>. The Authors section was updated from:
Rodrigo Menezes Forti1,2 
Marilise Katsurayama2,3 
Lenise Valler2,3 
Andr&#233;s Quiroga1,2 
Luiz Simioni1 
Julien Menko4 
Antonio L. E. Falc&#227;o3 
Li Min Li2,5 
Rickson C. Mesquita1,2 
1Institute of Physics, University of Campinas 
2Brazilian Institute of Neuroscience and Neurotechnology 
3Clinical Hospital, University of Campinas 
4Department of Emergency Medicine, Albert Einstein College of Medicine 
5School of Medical Sciences, University of Campinas
to:
Rodrigo Menezes Forti1,2 
Marilise Katsurayama2,3 
Giovani Grisotti Martins1 
Lenise Valler2,3 
Andr&#233;s Quiroga1,2 
Luiz Simioni1 
Julien Menko4 
Antonio L. E. Falc&#227;o3 
Li Min Li2,5 
Rickson C. Mesquita1,2 
1Institute of Physics, University of Campinas 
2Brazilian Institute of Neuroscience and Neurotechnology 
3Clinical Hospital, University of Campinas 
4Department of Emergency Medicine, Albert Einstein College of Medicine 
5School of Medical Sciences, University of Campinas

An erratum was issued for:&#160;<a href="https://www.jove.com/t/61608">Real-Time Monitoring of Neurocritical Patients with Diffuse Optical Spectroscopies</a>. The Authors section was updated.

Erratum: Real-Time Monitoring of Neurocritical Patients with Diffuse Optical Spectroscopies

Most of the complications that lead to poor outcomes for critically ill neurologic patients are related to secondary injuries caused by cerebral hemodynamic impairments. Therefore, monitoring cerebral physiology of these patients may directly impact morbidity and mortality rates1,2,3,4,5,6,7. Currently, however, there is no established clinical tool for the continuous real-time noninvasive monitoring of cerebral physiology in&#160;neurocritical patients at the bedside. Among the potential candidates, diffuse optical techniques have recently been proposed as a promising tool to fill in this gap8,9,10,11. By measuring the slow changes (i.e., on the order of tens to hundreds of ms) of the diffusively scattered near-infrared light (~650-900 nm) from the scalp, diffuse optical spectroscopy (DOS) can measure concentrations of the main chromophores in the brain, such as cerebral oxy- (HbO) and deoxy-hemoglobin (HbR)12,13. Additionally, it is possible to measure cerebral blood flow (CBF) with diffuse correlation spectroscopy (DCS)10,14,15,16,17 by quantifying the rapid fluctuations in light intensity (i.e., from a few &#181;s to a few ms). When combined, DOS and DCS can also provide an estimate of the cerebral metabolic rate of oxygen (CMRO2)18,19,20.
The combination of DOS and DCS has been explored to monitor patients in several pre-clinical and clinical scenarios. For example, diffuse optics has been shown to provide relevant clinical information for critically-ill neonates21,22,23,24, including during cardiac surgeries to treat heart defects23,25,26,27,28. In addition, several authors have explored the use of diffuse optics to assess cerebral hemodynamics during different cerebrovascular interventions, such as carotid endarterectomy29,30,31, thrombolytic treatments for stroke32, head-of-bed manipulations33,34,35, cardiopulmonary resuscitation36, and others37,38,39. When continuous blood pressure monitoring is also available, diffuse optics can be used to monitor cerebral autoregulation, both in healthy and in critically ill subjects11,40,41,42, as well to assess the critical closing pressure of the cerebral circulation43. Several authors have validated CBF measurements with DCS against different gold standard CBF measures18, while CMRO2 measured with diffuse optics has been shown to be a useful parameter for neurocritical monitoring8,18,23,24,28,43,44,45. In addition, previous studies have validated the optically-derived cerebral hemodynamic parameters for long-term monitoring of neurocritical patients8,9,10,11, including for the prediction of hypoxic46,47,48 and ischemic events8.
The reliability of the diffuse optical techniques to provide valuable real-time information during longitudinal measurements as well as during clinical interventions remains largely unaddressed. The use of a standalone DOS system was previously compared to invasive brain tissue oxygen tension monitors, and DOS was deemed to not have a sufficient sensibility to replace the invasive monitors. However, apart from using relatively small populations, the direct comparison of the invasive and non-invasive monitors may be misguided as each technique probe different volumes containing different parts of the cerebral vasculature. Even though these studies ultimately concluded that diffuse optics is not a replacement for the invasive monitors, in both studies DOS achieved a moderate-to-good accuracy, which may be sufficient for cases and/or places wherein invasive monitors are not available.
Relative to other approaches, the key advantage of diffuse optics is its ability to simultaneously measure blood flow and tissue blood oxygenation non-invasively (and continuously) at the bedside using portable instrumentation. Compared to Transcranial Doppler ultrasound (TCD), DCS has an additional advantage: it measures perfusion at the tissue level, whereas TCD measures cerebral blood flow velocity in large arteries at the base of the brain. This distinction may be particularly important when evaluating steno-occlusive diseases in which both proximal large artery flow and leptomeningeal collaterals contribute to perfusion. Optical techniques also have advantages when compared to other traditional imaging modalities, such as Positron-Emission Tomography (PET) and Magnetic Resonance Imaging (MRI). In addition to simultaneously providing direct measures of both CBF and HbO/HbR concentrations, which is not possible with MRI or PET alone, optical monitoring also provides significantly better temporal resolution, allowing, for example, the assessment of dynamic cerebral autoregulation40,41,42 and the assessment dynamically evolving hemodynamical changes. Moreover, diffuse optical instrumentation is inexpensive and portable in comparison to PET and MRI, which is a critical advantage given the high burden of vascular disease in lower- and middle-income countries.
The protocol proposed here is an environment for real-time bedside neuromonitoring of patients at the intensive care unit (ICU). The protocol uses a hybrid optical device together with a clinical-friendly graphical user interface (GUI) and customized optical sensors to probe the patients (Figure 1). The hybrid system employed for showcasing this protocol combines two diffuse optical spectroscopies from independent modules: a commercial frequency-domain (FD-) DOS module and a homemade DCS module (Figure 1A). The FD-DOS module49,50 consists of 4 photomultiplier tubes (PMTs) and 32 laser diodes emitting at four different wavelengths (690, 704, 750 and 850 nm). The DCS module consists of a long-coherence laser emitting at 785 nm, 16 single-photon counters as detectors and a correlator board. The sampling frequency for the FD-DOS module is 10 Hz, and the maximum sampling frequency for the DCS module is 3 Hz. To integrate the FD-DOS and DCS modules, a microcontroller was programmed inside our control software to automatically switch between each module. The microcontroller is responsible for turning the FD-DOS and DCS lasers on and off, as well as the FD-DOS detectors to allow interleaved measurements of each module. In total, the proposed system can collect one combined FD-DOS and DCS sample every 0.5 to 5s, depending on the signal-to-noise ratio (SNR) requirements (longer collection times leads to better SNR). To couple the light to the forehead, we developed a 3D-printed optical probe that can be customized for each patient (Figure 1B), with source-detector separations varying between 0.8 and 4.0 cm. The standard source-detector separations used in the examples presented here are 2.5 cm for DCS and 1.5, 2.0, 2.5 and 3.0 cm for FD-DOS.
The main feature of the protocol presented in this study is the development of a real-time interface that can both control the hardware with a friendly GUI and display the main cerebral physiology parameters in real-time under different temporal windows (Figure 1C). The real-time analysis pipeline developed within the proposed GUI is fast and takes less than 50 ms to compute the optical parameters (see the Supplementary Material for more details). The GUI was inspired by current clinical instruments already available at the neuro-ICU, and it was adapted through extensive feedback by clinical users during the translation of the system to the neuro-ICU. Consequently, the real-time GUI can facilitate&#160;the adoption of the optical system by regular hospital staff, such as neurointensivists and nurses. The wide adoption of diffuse optics as a clinical research tool has the potential to enhance its ability to monitor physiologically meaningful data and can ultimately demonstrate that diffuse optics is a good option for non-invasively monitoring neurocritical patients in real-time.

<table>
	<tbody>
		<tr>
			<td>3D Printer</td>
			<td>Sethi3D</td>
			<td>S2</td>
			<td>3D-printer used to print the customizable probes</td>
		</tr>
		<tr>
			<td>Arduino UNO</td>
			<td>Arduino</td>
			<td>UNO REV3</td>
			<td>Microcontroller responsible to interleave the DCS and FD-DOS measurements</td>
		</tr>
		<tr>
			<td>DCS Correlator</td>
			<td>Correlator.com</td>
			<td>Flex11-16ch</td>
			<td>Component of the DCS module</td>
		</tr>
		<tr>
			<td>DCS Dectectors IO Boards</td>
			<td>Excelitas Technology</td>
			<td>SPCM-AQ4C-IO</td>
			<td>Component of the DCS module</td>
		</tr>
		<tr>
			<td>DCS Detectors</td>
			<td>Excelitas Technology</td>
			<td>SPCM-AQ4C</td>
			<td>Component of the DCS module</td>
		</tr>
		<tr>
			<td>DCS Laser</td>
			<td>CrystaLaser</td>
			<td>DL785-120-SO</td>
			<td>Component of the DCS module</td>
		</tr>
		<tr>
			<td>DCS Power supply</td>
			<td>Artesyn</td>
			<td>UMP10T-S2A-S2A-S2A-S2A-IES-00-A</td>
			<td>Component of the DCS module (power supply for the DCS detecto; 2, 5 and 30V)</td>
		</tr>
		<tr>
			<td>FD-DOS fibers</td>
			<td>ISS</td>
			<td>Imagent supplies</td>
			<td>The fibers used for FD-DOS detection and illumination are provived by ISS</td>
		</tr>
		<tr>
			<td>Flexible 3D printer material</td>
			<td>Sethi3D</td>
			<td>NinjaFlex</td>
			<td>Material used to print the flexible customizable probes</td>
		</tr>
		<tr>
			<td>Imagent</td>
			<td>ISS</td>
			<td>Imagent</td>
			<td>FD-DOS module</td>
		</tr>
		<tr>
			<td>Laser safety googles</td>
			<td>Thorlabs</td>
			<td>LG9</td>
			<td></td>
		</tr>
		<tr>
			<td>Multi-mode fiber</td>
			<td>Thorlabs</td>
			<td>FT400EMT</td>
			<td>Multi-mode fiber used for DCS illumination</td>
		</tr>
		<tr>
			<td>Neutral density filter 1.0 OD</td>
			<td>Edmund Optics</td>
			<td>53-705</td>
			<td>Neutral density filter for the short source detector separations</td>
		</tr>
		<tr>
			<td>Single-mode optical fiber</td>
			<td>Thorlabs</td>
			<td>780HP</td>
			<td>Single-mode optical fiber used for the DCS detectors</td>
		</tr>
		<tr>
			<td>System battery</td>
			<td>SMS</td>
			<td>NET4</td>
			<td>System battery used for transportation</td>
		</tr>
	</tbody>
</table>

real-time monitoring of neurocritical patients with diffuse optical spectroscopies

Neurophysiological monitoring is an important goal in the treatment of neurocritical patients, as it may prevent secondary damage and directly impact morbidity and mortality rates. However, there is currently a lack of suitable non-invasive, real-time technologies for continuous monitoring of cerebral physiology at the bedside. Diffuse optical techniques have been proposed as a potential tool for bedside measurements of cerebral blood flow and cerebral oxygenation in case of neurocritical patients. Diffuse optical spectroscopies have been previously explored to monitor patients in several clinical scenarios ranging from neonatal monitoring to cerebrovascular interventions in adults. However, the feasibility of the technique to aid clinicians by providing real-time information at the bedside remains largely unaddressed. Here, we report the translation of a diffuse optical system for continuous real-time monitoring of cerebral blood flow, cerebral oxygenation, and cerebral oxygen metabolism during intensive care. The real-time feature of the instrument could enable treatment strategies based on patient-specific cerebral physiology rather than relying on surrogate metrics, such as arterial blood pressure. By providing real-time information on the cerebral circulation at different time scales with relatively cheap and portable instrumentation, this approach may be especially useful in low-budget hospitals, in remote areas and for&#160;monitoring in open fields (e.g., defense and sports).

Ideally, the normalized autocorrelation curves obtained with the DCS module should be approximately 1.5 at the zero delay-time extrapolation (when using single-mode fibers14), and the curves should decay to 1 at longer delay times. The curve should be smooth, and it should have a faster decay for the longer source-detector separations. An example of a good autocorrelation is shown in Figure 2A. Figure 2B shows an example of a bad auto-cor...

Watch this Scientific Journal Video about Real-Time Monitoring of Neurocritical Patients with Diffuse Optical Spectroscopies at JoVE.com

Real-Time Monitoring of Neurocritical Patients with Diffuse Optical Spectroscopies

Presented here is a protocol for non-invasively monitoring cerebral hemodynamics of neurocritical patients in real-time and at the bedside using diffuse optics. Specifically, the proposed protocol uses a hybrid diffuse optical systems to detect and display real-time information on cerebral oxygenation, cerebral blood flow and cerebral metabolism.

Neurophysiological monitoring is an important goal in the treatment of neurocritical patients, as it may prevent secondary damage and directly impact ...

real-time-monitoring-neurocritical-patients-with-diffuse-optical

Research

JoVE Journal

Medicine

2.0K Views.  University of Campinas. Presented here is a protocol for non-invasively monitoring cerebral hemodynamics of neurocritical patients in real-time and at the bedside using diffuse optics. Specifically, the proposed protocol uses a hybrid diffuse optical systems to detect and display real-time information on cerebral oxygenation, cerebral blood flow and cerebral metabolism.

Video: Real-Time Monitoring of Neurocritical Patients with Diffuse Optical Spectroscopies

Movement Retraining using Real-time Feedback of Performance

Any modification of movement - especially movement patterns that have been honed over a number of years - requires re-organization of the neuromuscular patterns responsible for governing the movement performance. This motor learning can be enhanced through a number of methods that are utilized in research and clinical settings alike. In general, verbal feedback of performance in real-time or knowledge of results following movement is commonly used clinically as a preliminary means of instilling motor learning. Depending on patient preference and learning style, visual feedback (e.g. through use of a mirror or different types of video) or proprioceptive guidance utilizing therapist touch, are used to supplement verbal instructions from the therapist. Indeed, a combination of these forms of feedback is commonplace in the clinical setting to facilitate motor learning and optimize outcomes.
Laboratory-based, quantitative motion analysis has been a mainstay in research settings to provide accurate and objective analysis of a variety of movements in healthy and injured populations. While the actual mechanisms of capturing the movements may differ, all current motion analysis systems rely on the ability to track the movement of body segments and joints and to use established equations of motion to quantify key movement patterns. Due to limitations in acquisition and processing speed, analysis and description of the movements has traditionally occurred offline after completion of a given testing session.
This paper will highlight a new supplement to standard motion analysis techniques that relies on the near instantaneous assessment and quantification of movement patterns and the display of specific movement characteristics to the patient during a movement analysis session. As a result, this novel technique can provide a new method of feedback delivery that has advantages over currently used feedback methods.

Retraining abnormal movement patterns following injury or disease is a key component of physical rehabilitation. Recent advances in technology have permitted accurate assessment of movement during a variety of tasks, with near instantaneous quantification of results. This provides new opportunities for modification of faulty movement patterns in real time.

Any modification of movement - especially movement patterns that have been honed over a number of years - requires re-organization of the neuromuscular ...

Real-time Cytotoxicity Assays in Human Whole Blood

A live cell-based whole blood cytotoxicity assay (WCA) that allows access to temporal information of the overall cell cytotoxicity is developed with high-throughput cell positioning technology. The targeted tumor cell populations are first preprogrammed to immobilization into an array format, and labeled with green fluorescent cytosolic dyes. Following the cell array formation, antibody drugs are added in combination with human whole blood. Propidium iodide (PI) is then added to assess cell death. The cell array is analyzed with an automatic imaging system. While cytosolic dye labels the targeted tumor cell populations, PI labels the dead tumor cell populations. Thus, the percentage of target cancer cell killing can be quantified by calculating the number of surviving targeted cells to the number of dead targeted cells. With this method, researchers are able to access time-dependent and dose-dependent cell cytotoxicity information. Remarkably, no hazardous radiochemicals are used. The WCA presented here has been tested with lymphoma, leukemia, and solid tumor cell lines. Therefore, WCA allows researchers to assess drug efficacy in a highly relevant ex&#160;vivo condition.

The whole blood cytotoxicity assay (WCA) is a cytotoxicity assay developed by incorporating high-throughput cell positioning technology with fluorescence microscopy and automated image processing. Here, we describe how lymphoma cells treated with an anti-CD20 antibody can be analyzed real-time in human whole blood to provide quantitative cellular cytotoxicity analysis.

A live cell-based whole blood cytotoxicity assay (WCA) that allows access to temporal information of the overall cell cytotoxicity is developed with ...

Diffuse Optical Spectroscopy for the Quantitative Assessment of Acute Ionizing Radiation Induced Skin Toxicity Using a Mouse Model

Acute skin toxicities from ionizing radiation (IR) are a common side effect from therapeutic courses of external beam radiation therapy (RT) and negatively impact patient quality of life and long term survival. Advances in the understanding of the biological pathways associated with normal tissue toxicities have allowed for the development of interventional drugs, however, current response studies are limited by a lack of quantitative metrics for assessing the severity of skin reactions. Here we present a diffuse optical spectroscopic (DOS) approach that provides quantitative optical biomarkers of skin response to radiation. We describe the instrumentation design of the DOS system as well as the inversion algorithm for extracting the optical parameters. Finally, to demonstrate clinical utility, we present representative data from a pre-clinical mouse model of radiation induced erythema and compare the results with a commonly employed visual scoring. The described DOS method offers an objective, high through-put evaluation of skin toxicity via functional response that is translatable to the clinical setting.

We present a diffuse optical spectroscopic (DOS) approach that provides quantitative optical biomarkers of skin response to radiation. We describe DOS instrumentation design, optical parameters extraction algorithms and the animal handling procedures required to yield representative data from a pre-clinical mouse model of radiation induced erythema.

Acute skin toxicities from ionizing radiation (IR) are a common side effect from therapeutic courses of external beam radiation therapy (RT) and ...

Uncontrolled Hemorrhagic Shock Modeled via Liver Laceration in Mice with Real Time Hemodynamic Monitoring

Uncontrolled hemorrhage is an important cause of preventable deaths among trauma patients. We have developed a murine model of uncontrolled hemorrhage via a liver laceration that results in consistent blood loss, hemodynamic alterations, and survival.
Mice undergo a standardized resection of the left-middle lobe of the liver. They are allowed to bleed without mechanical intervention. Hemostatic agents can be administered as pre-treatment or rescue therapy depending on the interest of the investigator. During the time of hemorrhage, real-time hemodynamic monitoring via a left femoral arterial line is performed. Mice are then sacrificed, blood loss is quantified, blood is collected for further analysis, and organs are harvested for analysis of injury. Experimental design is described to allow for simultaneous testing of multiple animals.
Liver hemorrhage as a model of uncontrolled hemorrhage exists in the literature, primarily in rat and porcine models. Some of these models utilize hemodynamic monitoring or quantify blood loss but lack consistency. The present model incorporates quantification of blood loss, real-time hemodynamic monitoring in a murine model that offers the advantage of using transgenic lines and a high-throughput mechanism to further investigate the pathophysiologic mechanisms in uncontrolled hemorrhage.

Uncontrolled hemorrhage, an important cause of mortality among trauma patients, can be modeled using a standard liver laceration in a murine model. This model results in consistent blood loss, survival, and allows for testing hemostatic agents. This article provides the step-by-step process to perform this valuable model.

Uncontrolled hemorrhage is an important cause of preventable deaths among trauma patients. We have developed a murine model of uncontrolled hemorrhage via ...

Real-time Pressure-volume Analysis of Acute Myocardial Infarction in Mice

Acute myocardial infarction can lead to acute heart failure and cardiogenic shock. The evaluation of hemodynamics is critical for the evaluation of any potential therapeutic approach directed against acute left ventricular (LV) dysfunction. Current imaging modalities (e.g., echocardiography and magnetic resonance imaging) have several limitations since data on LV pressure cannot directly be measured. LV catheterization in mice undergoing coronary artery occlusion could serve as a novel method for a real-time evaluation of LV function.
At the beginning of the procedure, mice were anesthetized followed by endotracheal intubation. For LV catheterization, the right carotid artery was exposed via middle-neck incision. The catheter was introduced and placed into the LV cavity. Left thoracotomy was conducted and the left main coronary artery (LCA) was ligated. To induce reperfusion, the suture was released after 45 min. Pressure-volume data was recorded at all times.
Ligation of the LCA caused a decrease in LV systolic function as evidenced by a 30% reduction in stroke volume, LV ejection fraction (EF), and cardiac output. Maximum dP/dt as a parameter for LV contractility was also significantly reduced and diastolic function was severely impaired (minimum dP/dt -40%). Reperfusion over a period of 20 min did not lead to a complete recovery of LV function.
Real-time pressure-volume analysis served as a valid procedure for monitoring cardiac function during acute myocardial infarction in mice. Maintaining stable anesthesia and a standardized surgical approach was crucial to ensure valid results. As the early phase of acute myocardial infarction is critical for morbidity and mortality, the delineated method could be beneficial for preclinical evaluation of new strategies for cardioprotection.

Acute myocardial infarction in mice induces acute but incompletely characterized changes in left ventricular (LV) function. LV catheterization in mice undergoing coronary artery occlusion serves as a novel method for a real-time evaluation of LV function.

Acute myocardial infarction can lead to acute heart failure and cardiogenic shock. The evaluation of hemodynamics is critical for the evaluation of any ...

Integration of Brain Tissue Saturation Monitoring in Cardiopulmonary Exercise Testing in Patients with Heart Failure

Cerebral hypo-oxygenation during rest or exercise negatively impacts the exercise capacity of patients with heart failure with reduced ejection fraction (HF). However, in clinical cardiopulmonary exercise testing (CPET), cerebral hemodynamics is not assessed. NIRS is used to measure cerebral tissue oxygen saturation (SctO2) in the frontal lobe. This method is reliable and valid and has been utilized in several studies. SctO2 is lower during both rest and peak exercise in patients with HF than in healthy controls (66.3 &#177; 13.3% and 63.4 &#177; 13.8% vs. 73.1 &#177; 2.8% and 72 &#177; 3.2%). SctO2 at rest is significantly linearly correlated with peak VO2 (r = 0.602), oxygen uptake efficiency slope (r = 0.501), and brain natriuretic peptide (r = -0.492), all of which are recognized prognostic and disease severity markers, indicating its potential prognostic value. SctO2 is determined mainly by end-tidal CO2 pressure, mean arterial pressure, and hemoglobin in the HF population. This article demonstrates a protocol that integrates SctO2 using NIRS into incremental CPET on a calibrated bicycle ergometer.

This protocol integrated near-infrared spectroscopy into conventional cardiopulmonary exercise testing to identify the involvement of the cerebral hemodynamic response in exercise intolerance in patients with heart failure.

Cerebral hypo-oxygenation during rest or exercise negatively impacts the exercise capacity of patients with heart failure with reduced ejection fraction ...

Digital Home-Monitoring of Patients after Kidney Transplantation: The MACCS Platform

The MACCS (Medical Assistant for Chronic Care Service) platform enables secure sharing of key medical information between patients after kidney transplantation and physicians. Patients provide information such as vital signs, well-being, and medication intake via smartphone apps. The information is transferred directly into a database and electronic health record at the kidney transplant center, which is used for routine patient care and research. Physicians can send an updated medication plan and laboratory data directly to the patient app via this secure platform. Other features of the app are medical messages and video consultations. Consequently, the patient is better-informed, and self-management is facilitated. In addition, the transplant center and the patient's local nephrologist automatically exchange notes, medical reports, laboratory values, and medication data via the platform. A telemedicine team reviews all incoming data on a dashboard and takes action, if necessary. Tools to identify patients at risk for complications are under development. The platform exchanges data via a standardized secure interface (Health Level 7 (HL7), Fast Healthcare Interoperability Resources (FHIR)). The standardized data exchange based on HL7 FHIR guarantees interoperability with other eHealth solutions and allows rapid scalability to other chronic diseases. The underlying data protection concept is in concordance with the latest European General Data Protection Regulation. Enrollment started in February 2020, and 131 kidney transplant recipients are actively participating as of July 2020. Two large German health insurance companies are currently funding the telemedicine services of the project. The deployment for other chronic kidney diseases and solid organ transplant recipients is planned. In conclusion, the platform is designed to enable home monitoring and automatic data exchange, empower patients, reduce hospitalizations, and improve adherence, and outcomes after kidney transplantation.

The MACCS platform&#160;is a comprehensive telemedicine concept aiming at better outcomes after kidney transplantation by sharing key medical information between patients and physicians. A telemedicine team reviews incoming data to detect potential complications and to improve adherence in kidney transplant recipients to achieve better long-term outcomes.

The MACCS (Medical Assistant for Chronic Care Service) platform enables secure sharing of key medical information between patients after kidney ...

Real-Time Electrocardiogram Monitoring During Treadmill Training in Mice

Regular physical exercise is a major contributor to cardiovascular health, influencing various metabolic as well as electrophysiological processes. However, in certain cardiac diseases such as inherited arrhythmia syndromes, e.g., arrhythmogenic cardiomyopathy (ACM) or myocarditis, physical exercise may have negative effects on the heart leading to a proarrhythmogenic substrate production. Currently, the underlying molecular mechanisms of exercise-related proarrhythmogenic remodeling are largely unknown, thus it remains unclear which frequency, duration, and intensity of exercise can be considered safe in the context of disease(s).
The proposed method allows to study proarrhythmic/antiarrhythmic effects of physical exercise by combining treadmill training with real-time monitoring of the ECG. Implantable telemetry devices are used to continuously record the ECG of freely moving mice over a period of up to 3 months both at rest and during treadmill training. Data acquisition software with its analysis modules is used to analyze basic ECG parameters such as heart rate, P wave duration, PR interval, QRS interval, or QT duration at rest, during and after training. Furthermore, heart rate variability (HRV) parameters and occurrence of arrhythmias are evaluated. In brief, this manuscript describes a step-by-step approach to experimentally explore exercise induced effects on cardiac electrophysiology, including potential proarrhythmogenic remodeling in mouse models.

Electrocardiogram (ECG) is the key variable to understanding cardiac electrophysiology. Physical exercise has beneficial effects but may also be harmful in the context of cardiovascular diseases. This manuscript provides a method of recording real-time ECG during exercise, which can serve to investigate its effects on cardiac electrophysiology in mice.

Regular physical exercise is a major contributor to cardiovascular health, influencing various metabolic as well as electrophysiological processes. ...

Real-Time Monitoring and Modulation of Blood Pressure in a Rabbit Model of Ischemic Stroke

Control of blood pressure, in terms of both absolute values and its variability, affects outcomes in ischemic stroke patients. However, it remains challenging to identify the mechanisms that lead to poor outcomes or evaluate measures by which these effects can be mitigated because of the prohibitive limitations inherent to human data. In such cases, animal models can be utilized to conduct rigorous and reproducible evaluations of diseases. Here we report refinement of a previously described model of ischemic stroke in rabbits that is augmented with continuous blood pressure recording to assess the impacts of modulation on blood pressure. Under general anesthesia, femoral arteries are exposed through surgical cutdowns to place arterial sheaths bilaterally. Under fluoroscopic visualization and roadmap guidance, a microcatheter is advanced into an artery of the posterior circulation of the brain. An angiogram is performed by injecting the contralateral vertebral artery to confirm occlusion of the target artery. With the occlusive catheter remaining in position for a fixed duration, blood pressure is continuously recorded to allow for tight titration of blood pressure manipulations, whether through mechanical or pharmacological means. At the completion of the occlusion interval, the microcatheter is removed, and the animal is maintained under general anesthesia for a prescribed length of reperfusion. For acute studies, the animal is then euthanized and decapitated. The brain is harvested and processed to measure the infarct volume under light microscopy and further assessed with various histopathological stains or spatial transcriptomic analysis. This protocol provides a reproducible model that can be utilized for more thorough preclinical studies on the effects of blood pressure parameters during ischemic stroke. It also facilitates effective preclinical evaluation of novel neuroprotective interventions that might improve care for ischemic stroke patients.

Continuous arterial blood pressure recording allows the investigation of impacts of various hemodynamic parameters. This report demonstrates the application of continuous arterial blood pressure monitoring in a large animal model of ischemic stroke for determination of stroke pathophysiology, impact of different hemodynamic factors, and the assessment of novel treatment approaches.

Control of blood pressure, in terms of both absolute values and its variability, affects outcomes in ischemic stroke patients. However, it remains ...

Non-Invasive Monitoring of Microvascular Oxygenation and Reactive Hyperemia using Hybrid, Near-Infrared Diffuse Optical Spectroscopy for Critical Care

The detection of levels of impairment in microvascular oxygen consumption and reactive hyperemia is vital in critical care. However, there are no practical means for a robust and quantitative evaluation. This paper describes a protocol to evaluate these impairments using a hybrid near-infrared diffuse optical device. The device contains modules for near-infrared time-resolved and diffuse correlation spectroscopies and pulse-oximetry. These modules allow the non-invasive, continuous, and real-time measurement of the absolute, microvascular blood/tissue oxygen saturation (StO2) and the blood flow index (BFI) along with the peripheral arterial oxygen saturation (SpO2). This device uses an integrated, computer-controlled tourniquet system to execute a standardized protocol with optical data acquisition from the brachioradialis muscle. The standardized vascular occlusion test (VOT) takes care of the variations in the occlusion duration and pressure reported in the literature, while the automation minimizes inter-operator differences. The protocol we describe focuses on a 3-min occlusion period but the details described in this paper can readily be adapted to other durations and cuff pressures, as well as other muscles. The inclusion of an extended baseline and post-occlusion recovery period measurement allows the quantification of the baseline values for all the parameters and the blood/tissue deoxygenation rate that corresponds to the metabolic rate of oxygen consumption. Once the cuff is released, we characterize the tissue reoxygenation rate, magnitude, and duration of the hyperemic response in BFI and StO2. These latter parameters correspond to the quantification of the reactive hyperemia, which provides information about the endothelial function. Furthermore, the above-mentioned measurements of the absolute concentration of oxygenated and deoxygenated hemoglobin, BFI, the derived metabolic rate of oxygen consumption, StO2, and SpO2 provide a yet-to-be-explored rich data set that can exhibit disease severity, personalized therapeutics, and management interventions.

We describe a protocol to non-invasively and continuously measure absolute microvascular blood flow index and blood oxygen saturation using a multi-modal device based on near-infrared diffuse optics. We then evaluate the metabolic rate of oxygen consumption and reactive hyperemia utilizing a vascular occlusion test.