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Orbegozo D, Su F, Xie K, Rahmania L, Taccone FS, De Backer D, Vincent JL, Creteur J. Peripheral Muscle Near-Infrared Spectroscopy Variables are Altered Early in Septic Shock. Shock 2018; 50:87-95. [PMID: 28930916 DOI: 10.1097/SHK.0000000000000991] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Noninvasive evaluation of muscle perfusion using near-infrared spectroscopy (NIRS) coupled with a vascular occlusion test (VOT) may provide an early and simple marker of altered perfusion and microcirculatory function in sepsis. OBJECTIVE The aim of the study was to compare the time-course of NIRS-derived variables with systemic measures of perfusion in an experimental model of peritonitis. METHODS Peritonitis was induced in eight anesthetized, mechanically ventilated, adult sheep (24-34 kg), by injecting autologous feces into the peritoneal cavity. Animals were followed until death or for a maximum of 30 h. Muscle tissue oxygen saturation (StO2) was determined using NIRS on the right posterior leg and arterial VOTs were performed by intermittent intra-aortic balloon inflation. Microdialysis was used to measure muscle lactate and pyruvate levels. RESULTS Muscle StO2 was significantly lower than baseline values from 8 h after sepsis induction, but with considerable intersubject variability. The NIRS VOT ascending (Asc) slope decreased to values <120%/min in most animals from 12 h after sepsis induction. Muscle lactate/pyruvate ratios were higher than baseline from 16 h after sepsis induction. Mixed venous oxygen saturation (SvO2) decreased to <70% and blood lactate levels increased to >2 mmol/L in most of the animals only 24 and 28 h after sepsis induction, respectively. Muscle NIRS StO2 correlated strongly with femoral venous oxygen saturation (r = 0.820) and moderately with SvO2 (r = 0.436). CONCLUSIONS The muscle NIRS Asc slope after a VOT is altered earlier than global markers of tissue hypoperfusion during sepsis. This simple noninvasive test can detect early changes in peripheral perfusion in sepsis.
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Pavlisko ND, Killos M, Henao-Guerrero N, Riccó CH, Werre S. Evaluation of tissue hemoglobin saturation (StO 2 ) using near-infrared spectroscopy during hypoxemia and hyperoxemia in Beagle dogs. Vet Anaesth Analg 2016; 43:18-26. [DOI: 10.1111/vaa.12258] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 10/22/2014] [Indexed: 11/27/2022]
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Torres Filho I, Nguyen NM, Jivani R, Terner J, Romfh P, Vakhshoori D, Ward KR. Oxygen saturation monitoring using resonance Raman spectroscopy. J Surg Res 2015; 201:425-31. [PMID: 27020828 DOI: 10.1016/j.jss.2015.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/02/2015] [Accepted: 12/04/2015] [Indexed: 11/13/2022]
Abstract
BACKGROUND The knowledge of hemoglobin oxygen saturation (SO2) and tissue oxygenation is critical to identify the presence of shock and therapeutic options. The resonance vibrational enhancement of hemoglobin allows measurement of oxy- and deoxy species of hemoglobin and resonance Raman spectroscopy (RRS-StO2) has been successfully used to measure aggregate microvascular oxygenation. We tested the hypothesis that noninvasive oxygen saturation measured by RRS-StO2 could serve as surrogate of systemic central venous SO2. METHODS In anesthetized rats, measurements of RRS-StO2 made in oral mucosa, skin, muscle, and liver were compared with measurements of central venous SO2 using traditional multi-wavelength oximetry. Various oxygenation levels were obtained using a stepwise hemorrhage while over 100 paired blood samples and Raman-based measurements were performed. The relationships between RRS-StO2 and clinically important systemic blood parameters were also evaluated. RRS-StO2 measurements were made in 3-mm diameter tissue areas using a microvascular oximeter and a handheld probe. RESULTS Significant correlations were found between venous SO2 and RRS-StO2 measurements made in the oral mucosa (r = 0.913, P < 0.001), skin (r = 0.499, P < 0.01), and liver (r = 0.611, P < 0.05). The mean difference between sublingual RRS-StO2 and blood sample SO2 values was 5.4 ± 1.6%. Sublingual RRS-StO2 also correlated with lactate (r = 0.909, P < 0.01), potassium (r = 0.757, P < 0.01), and pH (r = 0.703, P < 0.05). CONCLUSIONS Raman-based oxygen saturation is a promising technique for the noninvasive evaluation of oxygenation in skin, thin tissues, and solid organs. Under certain conditions, sublingual RRS-StO2 measurements correlate with central venous SO2.
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Affiliation(s)
- Ivo Torres Filho
- Department of Anesthesiology, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Science Center, Richmond, Virginia; Department of Emergency Medicine, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Science Center, Richmond, Virginia; Damage Control Resuscitation, U.S. Army Institute of Surgical Research, Fort Sam Houston, Texas.
| | - Nguyen M Nguyen
- Department of Anesthesiology, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Science Center, Richmond, Virginia
| | - Rizwan Jivani
- Department of Anesthesiology, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Science Center, Richmond, Virginia
| | - James Terner
- Department of Chemistry, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Science Center, Richmond, Virginia
| | | | | | - Kevin R Ward
- Department of Emergency Medicine and the Michigan Center for Integrative Research in Critical Care, University of Michigan, Ann Arbor, Michigan
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Orbegozo Cortés D, Puflea F, De Backer D, Creteur J, Vincent JL. Near infrared spectroscopy (NIRS) to assess the effects of local ischemic preconditioning in the muscle of healthy volunteers and critically ill patients. Microvasc Res 2015; 102:25-32. [PMID: 26265192 DOI: 10.1016/j.mvr.2015.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 07/12/2015] [Accepted: 08/06/2015] [Indexed: 12/28/2022]
Abstract
Near-infrared spectroscopy (NIRS) permits non-invasive evaluation of tissue oxygen saturation (StO2). A vascular occlusion test (VOT) produces transient controlled ischemia similar to that used in ischemic preconditioning. We hypothesized that we could evaluate local responses to ischemic preconditioning by performing repeated VOTs and observing the changes in different NIRS VOT-derived variables. In healthy volunteers (n=20), four VOTs were performed at 30-min intervals on one day and, in a second group (n=21), two VOTs with time intervals of 5, 15 or 30min were performed on 3 separate days. Two cohorts of patients, one with circulatory shock (n=23) and a hemodynamically stable group (n=20), were also studied, repeating the VOT twice with a 5-min interval. In the 1-day volunteers, there was a median decrease of 15 (6-21)% in the Desc slope (StO2 decrease during VOT) after the second VOT, but no significant change in the Asc slope (StO2 increase after VOT). In the 3-day volunteers, the Desc slope also decreased, regardless of the time interval between VOTs. There was no overall decrease in the Desc slope in either patient cohort with repeated VOTs but there was marked individual patient variability. Patients in whom the Desc slope decreased had less organ dysfunction at admission, required less norepinephrine (0.00 vs 0.08mcg/kg/min, p=0.02), less frequently had sepsis (12 vs 50%, p=0.02) and had a lower mortality (6 vs 39%, p=0.03) compared to those in whom it did not decrease. Repeated NIRS VOT can non-invasively assess the local effects of ischemic preconditioning in the muscle.
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Affiliation(s)
- Diego Orbegozo Cortés
- Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Florin Puflea
- Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Daniel De Backer
- Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Jacques Creteur
- Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Jean-Louis Vincent
- Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium.
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Ellerby GEC, Smith CP, Zou F, Scott P, Soller BR. Validation of a spectroscopic sensor for the continuous, noninvasive measurement of muscle oxygen saturation and pH. Physiol Meas 2013; 34:859-71. [PMID: 23859848 DOI: 10.1088/0967-3334/34/8/859] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
New patient monitoring technologies can noninvasively and directly provide an assessment of the adequacy of tissue perfusion through the simultaneous determination of muscle oxygen saturation (SmO2) and muscle pH (pHm). Non-pulsatile near infrared spectroscopy is used to determine these microvascular parameters. Two separate studies were conducted using an isolated perfused swine limb preparation to widely vary venous blood oxygen saturation (SviO2) and pH (pHvi) to assess the accuracy of a noninvasive sensor with the capability to simultaneously measure both parameters. The isolated limb model is necessary to establish equilibrium between the venous output of the perfusion circuit and the venule measurement of the spectroscopic sensor. The average absolute difference between SmO2 and SviO2 determined over 50 conditions of SviO2 between 13% and 83% on 3 pig limbs was 3.8% and the coefficient of determination (R(2)) was 0.95. The average absolute difference between pHm and pHvi determined over 69 conditions of pHvi between pHvi 6.9 and pHvi 7.5 on 3 pig limbs was 0.045 pH units with an R(2) of 0.92. Measured accuracy was acceptable to support clinically relevant decision making for the assessment of impaired tissue perfusion and acidosis. Sensors were also evaluated on human subjects. There was no statistical difference in SmO2 by gender or location when multiple sensors were evaluated on the right and left calf, deltoid, and thigh of resting men and women (N = 33). SmO2 precision for subjects at rest was 5.6% over the six locations with four different sensors.
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Affiliation(s)
- G E C Ellerby
- Reflectance Medical Inc., 116 Flanders Road, Suite 1000, Westborough, MA 01581, USA
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Lu M, Zhao L, Wang Y, You G, Kan X, Zhang Y, Zhang N, Wang B, Guo YJ, Zhou H. Measurement of the methemoglobin concentration using Raman spectroscopy. Artificial Cells, Nanomedicine, and Biotechnology 2013; 42:63-9. [DOI: 10.3109/21691401.2013.775577] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Shadgan B, Macnab AJ. Using near-infrared spectroscopy (NIRS) technology in a clinical setting to address an important issue. ACTA ACUST UNITED AC 2008; 65:1205; author reply 1205-6. [PMID: 19002000 DOI: 10.1097/TA.0b013e318188b946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ward KR, Barbee RW, Reynolds PS, Torres Filho IP, Tiba MH, Torres L, Pittman RN, James T. Oxygenation monitoring of tissue vasculature by resonance Raman spectroscopy. Anal Chem 2007; 79:1514-8. [PMID: 17297949 PMCID: PMC2515598 DOI: 10.1021/ac061072x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Resonance Raman spectroscopy offers a mechanism for the noninvasive measurement of in vivo and in situ hemoglobin oxygen saturation (HbO(2)Sat) in living tissue. Clinically informative signals can be provided by resonance enhancement with deep violet excitation. It is notable that fluorescence does not significantly degrade the quality of the signals. During the controlled hemorrhage and resuscitation of rats, signal intensity ratios of oxy- vs. deoxyhemoglobin from sublingual mucosa correlated with co-oximetry values of blood withdrawn from a central venous catheter. The spectroscopic application described here has potential as a noninvasive method for the diagnosis of clinical shock and guidance of its therapy.
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Affiliation(s)
- Kevin R. Ward
- Dept of Emergency Medicine, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Shock Center (VCURES); Richmond, VA 23298 USA
- Dept of Physiology, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Shock Center (VCURES); Richmond, VA 23298 USA
| | - R. Wayne Barbee
- Dept of Emergency Medicine, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Shock Center (VCURES); Richmond, VA 23298 USA
- Dept of Physiology, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Shock Center (VCURES); Richmond, VA 23298 USA
| | - Penny S. Reynolds
- Dept of Emergency Medicine, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Shock Center (VCURES); Richmond, VA 23298 USA
| | - Ivo P. Torres Filho
- Dept of Anesthesiology, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Shock Center (VCURES); Richmond, VA 23298 USA
- Dept of Emergency Medicine, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Shock Center (VCURES); Richmond, VA 23298 USA
| | - M. Hakam Tiba
- Dept of Emergency Medicine, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Shock Center (VCURES); Richmond, VA 23298 USA
| | - Luciana Torres
- Dept of Emergency Medicine, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Shock Center (VCURES); Richmond, VA 23298 USA
- Dept of Physiology, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Shock Center (VCURES); Richmond, VA 23298 USA
| | - Roland N. Pittman
- Dept of Emergency Medicine, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Shock Center (VCURES); Richmond, VA 23298 USA
- Dept of Physiology, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Shock Center (VCURES); Richmond, VA 23298 USA
| | - Terner James
- Dept of Chemistry, Virginia Commonwealth University and the Virginia Commonwealth University Reanimation Engineering Shock Center (VCURES); Richmond, VA 23298 USA
- * Corresponding author: e-mail , tel. 804-828-7500, Dept. of Chemistry, VCU Box 842006, Richmond, VA 23284-2006
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Cancio LC, Batchinsky AI, Mansfield JR, Panasyuk S, Hetz K, Martini D, Jordan BS, Tracey B, Freeman JE. Hyperspectral imaging: a new approach to the diagnosis of hemorrhagic shock. ACTA ACUST UNITED AC 2006; 60:1087-95. [PMID: 16688075 DOI: 10.1097/01.ta.0000217357.10617.3d] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Skin color changes and mottling are frequently described signs of hemorrhagic shock (HEM). Based on this, we developed a noninvasive, noncontact hyperspectral imaging system (HSI), which quantifies and depicts the surface tissue saturation of oxygen (SHSIO2) for each pixel in a region of interest (ROI). Our purpose was to assess HSI in a porcine HEM model. We hypothesized that HEM would cause decreases in SHSIO2 of the skin. METHODS The HyperMed HSI system employs a spectral separator to vary the wavelength of light admitted to a digital camera. During image acquisition, a "hypercube" of images, each at a separate wavelength, is generated (at 5-nm intervals, from 500 to 600 nm). Then, the visible light spectrum for each pixel in the hypercube is compared by linear regression to standard spectra for oxyhemoglobin (OxyHb) and deoxyhemoglobin (DeoxyHb). The resulting fit coefficients for OxyHb and DeoxyHb are used to calculate SHSIO2 values for each pixel in the ROI. The mean values for OxyHb, DeoxyHb, and SHSIO2 across the ROI are calculated. Grayscale SHSIO2 pictures of the ROI are also generated, in which the brightness of each pixel is proportional to its value. Seventeen pigs, 36.4 +/- 0.11 kg, underwent standard preparation, and were maintained on ketamine and isoflurane. Normothermia was maintained (37 degrees C to 39 degrees C). The hemorrhage group (HEM, n = 9) underwent three blood withdrawals, each 10 mL/kg, with 15 minutes between withdrawals. After the third withdrawal, animals were resuscitated with lactated Ringer's and then shed blood. The control group (CTRL, n = 8) received intravenous fluids at 100 mL/h. HSI images were obtained of the inner hindlimb throughout. RESULTS All HEM animals showed linear decreases in both mean SHSIO2 and OxyHb values with blood loss, which were reversed by resuscitation. These changes were evident on the grayscale SHSIO2 pictures, but not to the naked eye, and paralleled those of invasively obtained arterial base excess and mixed venous oxygen saturation. CONCLUSIONS HSI is a promising noninvasive and noncontact tool for quantifying changes in skin oxygenation during HEM and resuscitation.
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Affiliation(s)
- Leopoldo C Cancio
- US Army Institute of Surgical Research, Fort Sam Houston, Texas 78234-6315, USA.
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Ward KR, Ivatury RR, Barbee RW, Terner J, Pittman R, Torres Filho IP, Spiess B. Near infrared spectroscopy for evaluation of the trauma patient: a technology review. Resuscitation 2005; 68:27-44. [PMID: 16325319 DOI: 10.1016/j.resuscitation.2005.06.022] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2005] [Revised: 06/06/2005] [Accepted: 06/06/2005] [Indexed: 12/22/2022]
Abstract
Clinicians now realize the limitations of the physical examination in detecting compensated shock states, the severity of uncompensated states, and in determining the adequacy of resuscitation in order to prevent subsequent post-traumatic multisystem organ failure and death. A renewed interest has developed in interrogating the state of oxygen transport at the end-organ level in the trauma patient. Although used as a research tool and now clinically to monitor cerebral oxygenation during complex cardiovascular and neurosurgery, near infrared absorption spectroscopy (NIRS) is being more aggressively investigated and now marketed clinically as a noninvasive means to assess tissue oxygenation in the trauma patient at the end organ level. This paper will describe the principles of NIRS and the basis for its proposed use in the trauma patient to assess tissue oxygenation. This includes its known limitations, current controversies, and what will be needed in the future to make this technology a part of the initial and ongoing assessment of the trauma patient. The ultimate goal of such techniques is to prevent misassessment of patients and inadequate resuscitation, which are believed to be major initiators in the development of multisystem organ failure and death.
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Affiliation(s)
- Kevin R Ward
- Virginia Commonwealth University Reanimation Engineering Shock Center, VCURES, Department of Emergency Medicine, Virginia Commonwealth University, P.O. Box 980401, Richmond VA 23298, USA.
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Abstract
BACKGROUND Early hemodynamic assessment of global parameters in critically ill patients fails to provide adequate information on tissue perfusion. It requires invasive monitoring and may represent a late intervention initiated mainly in the intensive care unit. Noninvasive monitoring of peripheral perfusion can be a complementary approach that allows very early application throughout the hospital. In addition, as peripheral tissues are sensitive to alterations in perfusion, monitoring of the periphery could be an early marker of tissue hypoperfusion. This review discusses noninvasive methods for monitoring perfusion in peripheral tissues based on clinical signs, body temperature gradient, optical monitoring, transcutaneous oximetry, and sublingual capnometry. DISCUSSION Clinical signs of poor peripheral perfusion consist of a cold, pale, clammy, and mottled skin, associated with an increase in capillary refill time. The temperature gradients peripheral-to-ambient, central-to-peripheral and forearm-to-fingertip skin are validated methods to estimate dynamic variations in skin blood flow. Commonly used optical methods for peripheral monitoring are perfusion index, near-infrared spectroscopy, laser Doppler flowmetry and orthogonal polarization spectroscopy. Continuous noninvasive transcutaneous measurement of oxygen and carbon dioxide tensions can be used to estimate cutaneous blood flow. Sublingual capnometry is a noninvasive alternative for gastric tonometry.
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Affiliation(s)
- Alexandre Lima
- Department of Intensive Care, Erasmus MC, University Medical Center Rotterdam, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands
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Abstract
BACKGROUND In field situations, patient triage may require early determination of patients progressing to irreversible shock. We investigated the utility of near-infrared spectroscopy (NIRS) in early detection of irreversible hemorrhagic shock. METHODS Twenty instrumented pigs were treated with a protocol involving 35% blood volume hemorrhage, 90 minutes of shock, and stepwise resuscitation with lactated Ringer's. Hemodynamics and NIRS measurements of skeletal muscle (leg), stomach, and liver tissue oxyhemoglobin saturation (StO2) were measured at baseline, every 30 minutes during shock, and after each resuscitative step. Measurements were compared between animals that expired during resuscitation (unresuscitatable) and animals that survived all resuscitative steps (resuscitatable). RESULTS Neither global oxygen delivery, oxygen consumption, nor lactate distinguished resuscitatable from unresuscitatable animals. Invasive measurements of SvO2 did distinguish resuscitatable from unresuscitatable animals. After the first fluid bolus, both stomach and leg StO2 differed significantly between resuscitatable and unresuscitatable animals. Regression analysis revealed skeletal muscle (leg) StO2 obtained after the first resuscitative step was a significant mortality predictor despite resuscitation (r2=0.45) (p = 0.005). CONCLUSIONS Non-invasive NIRS monitoring of leg and stomach StO2 differentiates resuscitatable from unresuscitatable animals after the initial resuscitative bolus. Use of this non-invasive tool may guide appropriate use of resuscitative fluids and has possible point-of-care applications.
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Affiliation(s)
- Jodie H Taylor
- Department of Surgery, University of Minnesota, Minneapolis, MN, USA
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Myers DE, Anderson LD, Seifert RP, Ortner JP, Cooper CE, Beilman GJ, Mowlem JD. Noninvasive method for measuring local hemoglobin oxygen saturation in tissue using wide gap second derivative near-infrared spectroscopy. J Biomed Opt 2005; 10:034017. [PMID: 16229661 DOI: 10.1117/1.1925250] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A simple continuous wave near-infrared algorithm for estimating local hemoglobin oxygen saturation in tissue (%StO2) is described using single depth attenuation measurements at 680, 720, 760, and 800 nm. Second derivative spectroscopy was used to reduce light scattering effects, chromophores with constant absorption, baseline/instrumentation drift, and movement artifacts. Unlike previous second derivative methods which focused primarily on measuring deoxyhemoglobin concentration; a wide 40 nm wavelength gap used for calculating second derivative attenuation significantly improved sensitivity to oxyhemoglobin absorption. Scaled second derivative attenuation at 720 nm was correlated to in vitro hemoglobin oxygen saturation to generate a %StO2 calibration curve. The calibration curve was insensitive to total hemoglobin, optical path length, and optical scattering. Measurement error due to normal levels of carboxyhemoglobin, methemoglobin, and water absorption were less than 10 %StO2 units. Severe methemoglobinemia or edema combined with low blood volume could cause StO2 errors to exceed 10 StO2 units. Both a broadband and commercial four-wavelength spectrometer (InSpectra) measured %StO2. The InSpectra tissue spectrometer readily detected limb ischemia on 26 human volunteers for hand, forearm, and leg muscles. A strong linear correlation, r2>0.93, between StO2 and microvascular %SO2 was observed for isolated animal hind limb, kidney, and heart.
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Affiliation(s)
- Dean E Myers
- Hutchinson Technology Inc., Hutchinson, Minnesota 55350, USA.
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Abstract
AIMS Mitochondria are responsible for meeting the majority of the energetic demand of most tissues. They also play a major role in regulating cell survival. These dual roles of mitochondria place them at the centre of many pathologies leading to tissue degeneration and disruption of energy balance. The prominent role of mitochondria in ageing and disease has led to a tremendous growth in mitochondrial research at the cellular and molecular level. We describe below a new non-invasive approach to measure mitochondrial function that will bridge the gap between our understanding of mitochondrial function in vitro and that in the intact organism. METHODS AND RESULTS This approach uses optical and magnetic resonance spectroscopy to measure in vivo O2 consumption and ATP synthesis rates, respectively, from skeletal muscle. These values lead to a quantitative assessment of the mitochondrial ATP/O2 or P/O. The P/O represents the efficiency of coupling between phosphorylation and oxygen consumption in the mitochondria, which is a measure of mitochondrial dysfunction. CONCLUSIONS This work represents a significant advance in research on the role of mitochondria in degenerative disease and ageing because it allows a quantitative measure of mitochondrial pathology in vivo. The non-invasive nature of this approach also enables repeated measures of mitochondrial function on the same individual, thereby making this a potentially useful diagnostic technique. The results from this work have led to insights into the coupling of ATP synthesis to oxidation and the regulation of oxidative phosphorylation by intracellular PO2.
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Affiliation(s)
- D J Marcinek
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195, USA
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Taylor JH, Beilman GJ, Conroy MJ, Mulier KE, Myers D, Gruessner A, Hammer BE. Tissue energetics as measured by nuclear magnetic resonance spectroscopy during hemorrhagic shock. Shock 2004; 21:58-64. [PMID: 14676685 DOI: 10.1097/01.shk.0000101674.49265.93] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The defect in energy production in an organism during shock states may be related to the impairment of mitochondrial respiration early in shock. The aim of this study was to investigate the timing and degree of cellular energetic changes during hemorrhagic shock in real time. Instrumented, splenectomized swine were randomized to undergo hemorrhagic shock, induced by a 35% blood volume bleed, for 90 min with (n = 10) or without (n = 9) subsequent resuscitation. Resuscitated animals received shed blood in two increments followed by two normal saline boluses (20 mL/kg/bolus). Throughout experimentation, tissue phosphoenergetics of liver and skeletal muscle were monitored using 31P nuclear magnetic resonance (NMR) spectroscopy via NMR coils on the liver and hindlimb. Near-infrared spectroscopy probes were used to measure liver, stomach, and skeletal muscle oxyhemoglobin saturation (StO2). Hemorrhagic shock induced an increase in phosphomonoesters in skeletal muscle (baseline: 7.09%, 90 min: 9.94% (P < 0.05); expressed as percent total phosphorus). This increase resolved in animals receiving resuscitation (n = 10) but remained elevated in those in unresuscitated shock (n = 9). Inorganic phosphate levels increased and betaATP levels decreased significantly in the liver of animals in shock as compared with baseline. StO2 in skeletal muscle, stomach, and liver correlated with whole organism oxygen delivery (r2 = 0.356, 0.368, and 0.432, respectively). We conclude that hemorrhagic shock induces early elevation of phosphomonoesters in skeletal muscle, which correlates with the severity of shock. This implies an early transition to anaerobic glycolysis during hemorrhagic shock, which may be indicative of early mitochondrial dysfunction.
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Affiliation(s)
- Jodie H Taylor
- Department of Surgery, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Abstract
The coupling of mitochondrial ATP synthesis and oxygen consumption (ratio of ATP and oxygen fluxes, P/O) plays a central role in cellular bioenergetics. Reduced P/O values are associated with mitochondrial pathologies that can lead to reduced capacity for ATP synthesis and tissue degeneration. Previous work found a wide range of values for P/O in normal mitochondria. To measure mitochondrial coupling under physiological conditions, we have developed a procedure for determining the P/O of skeletal muscle in vivo. This technique measures ATPase and oxygen consumption rates during ischemia with31P magnetic resonance and optical spectroscopy, respectively. This novel approach allows the independent quantitative measurement of ATPase and oxygen flux rates in intact tissue. The quantitative measurement of oxygen consumption is made possible by our ability to independently measure the saturations of hemoglobin (Hb) and myoglobin (Mb) from optical spectra. Our results indicate that the P/O in skeletal muscle of the mouse hindlimb measured in vivo is 2.16 ± 0.24. The theoretical P/O for resting muscle is 2.33. Systemic treatment with 2,4-dinitrophenol to partially uncouple mitochondria does not affect the ATPase rate in the mouse hindlimb but nearly doubles the rate of oxygen consumption, reducing in vivo P/O to 1.37 ± 0.22. These results indicate that only a small fraction of the oxygen consumption in resting mouse skeletal muscle is nonphosphorylating under physiological conditions, suggesting that mitochondria are more tightly coupled than previously thought.
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Affiliation(s)
- David J Marcinek
- Department of Radiology, University of Washington Medical Center, Seattle, WA 98195, USA.
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Abstract
BACKGROUND Hemodynamic, laboratory, and tissue energetics were measured in a porcine model of hemorrhagic shock to evaluate variables as predictors of early mortality from shock. We hypothesized that elevated phosphomonoesters would predict early mortality in hemorrhagic shock. METHODS Pigs (n = 36) were subjected to 35% hemorrhage for 90 minutes in a 1.5-T nuclear magnetic resonance (NMR) magnet. Measurements included base deficit (BD); lactate; oxygen consumption/delivery; near-infrared spectroscopy of liver, stomach, and skeletal muscle tissue oxyhemoglobin saturation; and NMR spectroscopic measurements of high-energy phosphates of liver and skeletal muscle. Variables were compared between nonsurvivors and survivors to resuscitation after 90-minute measurements. RESULTS Ninety-minute mortality was 25%. Muscle phosphomonoesters (PMEs) and oxygen consumption differed significantly between survivors and nonsurvivors at baseline. Regression analysis identified baseline muscle PME levels, baseline BD, and 30-minute BD as early predictors of mortality before resuscitation (r2 = 0.304). CONCLUSION Baseline elevation in muscle PME levels predicts mortality in an animal model of severe hemorrhagic shock.
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Affiliation(s)
- Jodie H Taylor
- Department of Surgery, University of Minnesota, Minneapolis, MN 55455, USA
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Affiliation(s)
- Stephen M Cohn
- Daugherty Family Department of Surgery, University of Miami School of Medicine, Ryder Trauma Center, Florida 33101, USA.
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