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      Multi-site and multi-depth near-infrared spectroscopy in a model of simulated (central) hypovolemia: lower body negative pressure

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          Abstract

          Purpose

          To test the hypothesis that the sensitivity of near-infrared spectroscopy (NIRS) in reflecting the degree of (compensated) hypovolemia would be affected by the application site and probing depth. We simultaneously applied multi-site (thenar and forearm) and multi-depth (15–2.5 and 25–2.5 mm probe distance) NIRS in a model of simulated hypovolemia: lower body negative pressure (LBNP).

          Methods

          The study group comprised 24 healthy male volunteers who were subjected to an LBNP protocol in which a baseline period of 30 min was followed by a step-wise manipulation of negative pressure in the following steps: 0, −20, −40, −60, −80 and −100 mmHg. Stroke volume and heart rate were measured using volume-clamp finger plethysmography. Two multi-depth NIRS devices were used to measure tissue oxygen saturation (StO2) and tissue hemoglobin index (THI) continuously in the thenar and the forearm. To monitor the shift of blood volume towards the lower extremities, calf THI was measured by single-depth NIRS.

          Results

          The main findings were that the application of LBNP resulted in a significant reduction in stroke volume which was accompanied by a reduction in forearm StO2 and THI.

          Conclusions

          NIRS can be used to detect changes in StO2 and THI consequent upon central hypovolemia. Forearm NIRS measurements reflect hypovolemia more sensitively than thenar NIRS measurements. The sensitivity of these NIRS measurements does not depend on NIRS probing depth. The LBNP-induced shift in blood volume is reflected by a decreased THI in the forearm and an increased THI in the calf.

          Electronic supplementary material

          The online version of this article (doi:10.1007/s00134-010-2128-6) contains supplementary material, which is available to authorized users.

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          Most cited references34

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          Noninvasive, infrared monitoring of cerebral and myocardial oxygen sufficiency and circulatory parameters.

          The relatively good transparency of biological materials in the near infrared region of the spectrum permits sufficient photon transmission through organs in situ for the monitoring of cellular events. Observations by infrared transillumination in the exposed heart and in the brain in cephalo without surgical intervention show that oxygen sufficiency for cytochrome a,a3, function, changes in tissue blood volume, and the average hemoglobin-oxyhemoglobin equilibrium can be recorded effectively and in continuous fashion for research and clinical purposes. The copper atom associated with heme a3 did not respond to anoxia and may be reduced under normoxic conditions, whereas the heme-a copper was at least partially reducible.
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            Epidemiology of trauma deaths: a reassessment.

            Recognizing the impact of the 1977 San Francisco study of trauma deaths in trauma care, our purpose was to reassess those findings in a contemporary trauma system. Cross-sectional. All trauma deaths occurring in Denver City and County during 1992 were reviewed; data were obtained by cross-referencing four databases: paramedic trip reports, trauma registries, coroner autopsy reports and police reports. There were 289 postinjury fatalities; mean age was 36.8 +/- 1.2 years and mean Injury Severity Score (ISS) was 35.7 +/- 1.2. Predominant injury mechanisms were gunshot wounds in 121 (42%), motorvehicle accidents in 75 (38%) and falls in 23 (8%) cases. Seven (2%) individuals sustained lethal burns. Ninety eight (34%) deaths occurred in the pre-hospital setting. The remaining 191 (66%) patients were transported to the hospital. Of these, 154 (81%) died in the first 48 hours (acute), 11 (6%) within three to seven days (early) and 26 (14%) after seven days (late). Central nervous system injuries were the most frequent cause of death (42%), followed by exsanguination (39%) and organ failure (7%). While acute and early deaths were mostly due to the first two causes, organ failure was the most common cause of late death (61%). In comparison with the previous report, we observed similar injury mechanisms, demographics and causes of death. However, in our experience, there was an improved access to the medical system, greater proportion of late deaths due to brain injury and lack of the classic trimodal distribution.
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              Comparison of finger and intra-arterial blood pressure monitoring at rest and during laboratory testing.

              The accuracy of blood pressure values obtained by continuous noninvasive finger blood pressure recording via the FINAPRES device was evaluated by comparison with simultaneous intraarterial monitoring both at rest and during performance of tests known to induce fast and often marked changes in blood pressure. The comparison was performed in 24 normotensive or essential hypertensive subjects. The average discrepancy between finger and intra-arterial blood pressure recorded over a 30-minute rest period was 6.5 +/- 2.6 mm Hg and 5.4 +/- 2.9 mm Hg for systolic and diastolic blood pressure, respectively; a close between-method correspondence was also demonstrated by linear regression analysis. The beat-to-beat changes in finger systolic and diastolic blood pressure were on average similar to those measured intra-arterially during tests that induced a pressor or depressor response (hand-grip, cold pressor test, diving test, Valsalva maneuver, intravenous injections of phenylephrine and trinitroglycerine) as well as during tests that caused vasomotor changes without major variations in blood pressure (application of lower body negative pressure, passive leg raising). The average between-method discrepancy in the evaluation of blood pressure changes was never greater than 4.3 and 2.0 mm Hg for systolic and diastolic blood pressure, respectively; the corresponding standard deviations ranged between 4.6 and 1.6 mm Hg. Beat-to-beat computer analysis of blood pressure variability over the 30-minute rest period provided standard deviations almost identical when calculated by separate consideration of intra-arterial and finger blood pressure tracings (3.7 and 3.8 mm Hg, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
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                Author and article information

                Contributors
                +31-20-5662140 , +31-20-6967004 , s.bartels@erasmusmc.nl
                r.bezemer@amc.uva.nl
                f.j.wallisdevries@amc.uva.nl
                d.m.milstein@amc.uva.nl
                a.pintolima@eramusmc.nl
                t.g.cherpanath@amc.uva.nl
                a.vandenmeiracker@erasmusmc.nl
                j.vanbommel@erasmusmc.nl
                m.heger@amc.uva.nl
                j.m.karemaker@amc.uva.nl
                c.ince@amc.uva.nl
                Journal
                Intensive Care Med
                Intensive Care Medicine
                Springer-Verlag (Berlin/Heidelberg )
                0342-4642
                1432-1238
                21 January 2011
                21 January 2011
                April 2011
                : 37
                : 4
                : 671-677
                Affiliations
                [1 ]Department of Intensive Care, Erasmus Medical Center, University Medical Center, ‘s-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands
                [2 ]Department of Translational Physiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
                [3 ]Division of Cardiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
                [4 ]Division of Vascular Medicine and Pharmacology, Department of Internal Medicine, Erasmus Medical Center, University Medical Center, ‘s-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands
                [5 ]Department of Experimental Surgery, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
                [6 ]Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
                [7 ]Department of Systems Physiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
                Article
                2128
                10.1007/s00134-010-2128-6
                3058331
                21253704
                db725be1-5e34-477a-948d-065048c6e406
                © The Author(s) 2011
                Categories
                Original
                Custom metadata
                © Copyright jointly held by Springer and ESICM 2011

                Emergency medicine & Trauma
                hypovolemia,tissue hemoglobin content,tissue oxygenation,lower body negative pressure,microcirculation,near-infrared spectroscopy

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