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Vishwanath K, Gurjar R, Wolf D, Riccardi S, Duggan M, King D. Diffuse optical monitoring of peripheral tissues during uncontrolled internal hemorrhage in a porcine model. BIOMEDICAL OPTICS EXPRESS 2018; 9:569-580. [PMID: 29552394 PMCID: PMC5854059 DOI: 10.1364/boe.9.000569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 12/11/2017] [Accepted: 12/22/2017] [Indexed: 05/06/2023]
Abstract
Reliable, continuous and noninvasive blood flow and hemoglobin monitoring in trauma patients remains a critical, but generally unachieved goal. Two optical sensing methods - diffuse correlation spectroscopy (DCS) and diffuse reflectance spectroscopy (DRS) - are used to monitor and detect internal hemorrhage. Specifically, we investigate if cutaneous perfusion measurements acquired using DCS and DRS in peripheral (thighs and ear-lobe) tissues could detect severe hemorrhagic shock in a porcine model. Four animals underwent high-grade hepato-portal injury in a closed abdomen, to induce uncontrolled hemorrhage and were subsequently allowed to bleed for 10 minutes before fluid resuscitation. DRS and DCS measurements of cutaneous blood flow were acquired using fiber optical probes placed on the thigh and earlobe of the animals and were obtained repeatedly starting from 1 to 5 minutes pre-injury, up to several minutes post shock. Clear changes were observed in measured optical spectra across all animals at both sites. DCS-derived cutaneous blood flow decreased sharply during hemorrhage, while DRS-derived vascular saturation and hemoglobin paralleled cardiac output. All derived optical parameters had the steepest changes during the rapid initial hemorrhage unambiguously. This suggests that a combined DCS and DRS based device might provide an easy-to-use, non-invasive, internal-hemorrhage detection system that can be used across a wide array of clinical settings.
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Affiliation(s)
- Karthik Vishwanath
- Department of Physics, Miami University, Oxford, OH 45056, USA
- Affiliations of authors when experiments were conducted: Radiation Monitoring Devices Inc., 44 Hunt Street, Watertown, MA 02472, USA
| | - Rajan Gurjar
- MIT Lincoln Laboratory, 244 Wood Street, Lexington, MA 02420, USA
- Affiliations of authors when experiments were conducted: Radiation Monitoring Devices Inc., 44 Hunt Street, Watertown, MA 02472, USA
| | - David Wolf
- Warner Babcock Institute for Green Chemistry, 100 Research Drive, Wilmington, MA 01887, USA
- Affiliations of authors when experiments were conducted: Radiation Monitoring Devices Inc., 44 Hunt Street, Watertown, MA 02472, USA
| | - Suzannah Riccardi
- MIT Lincoln Laboratory, 244 Wood Street, Lexington, MA 02420, USA
- Affiliations of authors when experiments were conducted: Radiation Monitoring Devices Inc., 44 Hunt Street, Watertown, MA 02472, USA
| | - Michael Duggan
- Division of Trauma, Emergency Surgery, and Surgical Critical Care, Massachusetts General Hospital, 165 Cambridge Street, Suite 810 Boston, MA 02114, USA
| | - David King
- Division of Trauma, Emergency Surgery, and Surgical Critical Care, Massachusetts General Hospital, 165 Cambridge Street, Suite 810 Boston, MA 02114, USA
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Farkas DL, Kolodziejski NJ, Stapels CJ, McAdams DR, Fernandez DE, Podolsky MJ, Christian JF, Ward BB, Vartarian M, Feinberg SE, Lee SY, Parikh U, Mycek MA, Joyner MJ, Johnson CP, Paradis NA. A disposable, flexible skin patch for clinical optical perfusion monitoring at multiple depths. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2016; 9715:97151H. [PMID: 29056813 PMCID: PMC5647776 DOI: 10.1117/12.2230988] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Stable, relative localization of source and detection fibers is necessary for clinical implementation of quantitative optical perfusion monitoring methods such as diffuse correlation spectroscopy (DCS) and diffuse reflectance spectroscopy (DRS). A flexible and compact device design is presented as a platform for simultaneous monitoring of perfusion at a range of depths, enabled by precise location of optical fibers in a robust and secure adhesive patch. We will discuss preliminary data collected on human subjects in a lower body negative pressure model for hypovolemic shock. These data indicate that this method facilitates simple and stable simultaneous monitoring of perfusion at multiple depths and within multiple physiological compartments.
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Affiliation(s)
- Dana L Farkas
- Northeastern University, Boston, MA 02115
- Radiation Monitoring Devices, 44 Hunt Street, Watertown, MA, USA 02472
| | | | | | - Daniel R McAdams
- Radiation Monitoring Devices, 44 Hunt Street, Watertown, MA, USA 02472
| | | | | | - James F Christian
- Radiation Monitoring Devices, 44 Hunt Street, Watertown, MA, USA 02472
| | - Brent B Ward
- Dept. of Oral and Maxillofacial Surgery, University of Michigan, Ann Arbor, MI 48109
| | - Mark Vartarian
- Dept. of Oral and Maxillofacial Surgery, University of Michigan, Ann Arbor, MI 48109
| | - Stephen E Feinberg
- Dept. of Oral and Maxillofacial Surgery, University of Michigan, Ann Arbor, MI 48109
| | - Seung Yup Lee
- Dept. of Oral and Maxillofacial Surgery, University of Michigan, Ann Arbor, MI 48109
| | - Urmi Parikh
- Dept. of Oral and Maxillofacial Surgery, University of Michigan, Ann Arbor, MI 48109
| | - Mary-Ann Mycek
- Dept. of Oral and Maxillofacial Surgery, University of Michigan, Ann Arbor, MI 48109
| | | | | | - Norman A Paradis
- Department of Emergency Medicine, Dartmouth-Hitchcock Medical, Lebanon, NH 03766
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Blood pressure regulation X: what happens when the muscle pump is lost? Post-exercise hypotension and syncope. Eur J Appl Physiol 2013; 114:561-78. [PMID: 24197081 DOI: 10.1007/s00421-013-2761-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 10/22/2013] [Indexed: 01/19/2023]
Abstract
Syncope which occurs suddenly in the setting of recovery from exercise, known as post-exercise syncope, represents a failure of integrative physiology during recovery from exercise. We estimate that between 50 and 80% of healthy individuals will develop pre-syncopal signs and symptoms if subjected to a 15-min head-up tilt following exercise. Post-exercise syncope is most often neurally mediated syncope during recovery from exercise, with a combination of factors associated with post-exercise hypotension and loss of the muscle pump contributing to the onset of the event. One can consider the initiating reduction in blood pressure as the tip of the proverbial iceberg. What is needed is a clear model of what lies under the surface; a model that puts the observational variations in context and provides a rational framework for developing strategic physical or pharmacological countermeasures to ultimately protect cerebral perfusion and avert loss of consciousness. This review summarizes the current mechanistic understanding of post-exercise syncope and attempts to categorize the variation of the physiological processes that arise in multiple exercise settings. Newer investigations into the basic integrative physiology of recovery from exercise provide insight into the mechanisms and potential interventions that could be developed as countermeasures against post-exercise syncope. While physical counter maneuvers designed to engage the muscle pump and augment venous return are often found to be beneficial in preventing a significant drop in blood pressure after exercise, countermeasures that target the respiratory pump and pharmacological countermeasures based on the involvement of histamine receptors show promise.
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Lacewell AN, Buck TM, Romero SA, Halliwill JR. Postexercise syncope: Wingate syncope test and effective countermeasure. Exp Physiol 2013; 99:172-86. [PMID: 24078670 DOI: 10.1113/expphysiol.2013.075333] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Altered systemic haemodynamics following exercise can compromise cerebral perfusion and result in syncope. As the Wingate anaerobic test often induces presyncope, we hypothesized that a modified Wingate test could form the basis of a novel model for the study of postexercise syncope and a test bed for potential countermeasures. Along these lines, breathing through an impedance threshold device has been shown to increase tolerance to hypovolaemia, and could prove beneficial in the setting of postexercise syncope. Therefore, we hypothesized that a modified Wingate test followed by head-up tilt would produce postexercise syncope, and that breathing through an impedance threshold device (countermeasure) would prevent postexercise syncope in healthy individuals. Nineteen recreationally active men and women underwent a 60 deg head-up tilt during recovery from the Wingate test while arterial pressure, heart rate, end-tidal CO2 and cerebral tissue oxygenation were measured on a control day and a countermeasure day. The duration of tolerable tilt was increased by a median time of 3 min 48 s with countermeasure in comparison to the control (P < 0.05), and completion of the tilt test increased from 42 to 67% with the countermeasure. During the tilt, mean arterial pressure was greater (108.0 ± 4.1 versus 100.4 ± 2.4 mmHg; P < 0.05) with the countermeasure in comparison to the control. These data suggest that the Wingate syncope test produces a high incidence of presyncope, which is sensitive to countermeasures such as inspiratory impedance.
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Affiliation(s)
- Alisha N Lacewell
- J. R. Halliwill: 122 Esslinger Hall, 1240 University of Oregon, Eugene, OR 97403-1240, USA.
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Jeong SM, Shibata S, Levine BD, Zhang R. Exercise plus volume loading prevents orthostatic intolerance but not reduction in cerebral blood flow velocity after bed rest. Am J Physiol Heart Circ Physiol 2011; 302:H489-97. [PMID: 22081705 DOI: 10.1152/ajpheart.00427.2011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study tested the hypothesis that reduction in cerebral blood flow (CBF) during orthostatic stress after bed rest can be ameliorated with volume loading, exercise, or both. Transcranial Doppler was used to measure changes in CBF velocity during lower body negative pressure (LBNP) before and after an 18-day bed rest in 33 healthy subjects. Subjects were assigned into four groups with similar age and sex: 1) supine cycling during bed rest (Exercise group; n = 7), 2) volume loading with Dextran infusion after bed rest to restore reduced left ventricular filling pressure (Dextran group; n = 7), 3) exercise combined with volume loading to prevent orthostatic intolerance (Ex-Dex group; n = 7), and 4) a control group (n = 12). LBNP tolerance was measured using a cumulative stress index (CSI). After bed rest, CBF velocity was reduced at a lower level of LBNP in the Control group, and the magnitude of reduction was greater in the Ex-Dex group. However, reduction in orthostatic tolerance was prevented in the Ex-Dex group. Notably, volume loading alone prevented greater reductions in CBF velocity after bed rest, but CSI was reduced still by 25%. Finally, decreases in CBF velocity during LBNP were correlated with reduction in cardiac output under all conditions (r(2) = 0.86; P = < 0.001). Taken together, these findings demonstrate that volume loading alone can ameliorate reductions in CBF during LBNP. However, the lack of associations between changes in CBF velocity and orthostatic tolerance suggests that reductions in CBF during LBNP under steady-state conditions by itself are unlikely to be a primary factor leading to orthostatic intolerance.
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Affiliation(s)
- Sung-Moon Jeong
- Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, and University of Texas Southwestern Medical Center at Dallas, TX 75231, USA
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Ainslie PN, Willie CK, Tzeng YC. Role of SNA in the pathophysiology of cardiovascular collapse during syncope: muscle vs. brain. J Physiol 2009; 587:5795-6. [PMID: 19959554 DOI: 10.1113/jphysiol.2009.182667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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