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Acanfora D, Casucci G, Ciccone MM, Scicchitano P, Lonobile T, Chiariello L, Maestri R, Pedone C, Provitera V, Nolano M, Incalzi RA. Biomechanical and neuroautonomic adaptation to acute blood volume displacement in ischemic dilated cardiomyopathy: the predictive value of the CD25 test. J Appl Physiol (1985) 2020; 129:1173-1182. [PMID: 32940562 DOI: 10.1152/japplphysiol.00514.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The adaptation to volume displacement induced by tilt test was assessed in patients with heart failure and previous inferoapical/inferolateral or basal/apical septal myocardial infarction. The responsiveness of cardiac muscle to sympathetic nervous system stimulation predicts the mortality in patients with ischemic heart failure and may represent a useful tool for clinicians in the general assessment of this kind of patients.
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Affiliation(s)
- Domenico Acanfora
- San Francesco Hospital, Telese Terme, Benevento, Italy
- Maugeri Scientific Clinical Institutes, SpA SB, Institute of Care and Scientific Research, Rehabilitation Institute of Telese Terme, Telese Terme, , Italy
| | | | - Marco Matteo Ciccone
- Section of Cardiovascular Diseases, Department of Emergency and Organ Transplantation, University of Bari School of Medicine, Bari, Italy
| | - Pietro Scicchitano
- Section of Cardiovascular Diseases, Department of Emergency and Organ Transplantation, University of Bari School of Medicine, Bari, Italy
| | | | | | - Roberto Maestri
- Maugeri Scientific Clinical Institutes, SpA SB, Institute of Care and Scientific Research, Rehabilitation Institute of Montescano, Pavia, Italy
| | - Claudio Pedone
- Unit of Geriatrics, Policlinico Universitario, Campus Bio-Medico di Roma, Rome, Italy
| | - Vincenzo Provitera
- Maugeri Scientific Clinical Institutes, SpA SB, Institute of Care and Scientific Research, Rehabilitation Institute of Telese Terme, Telese Terme, , Italy
| | - Maria Nolano
- Maugeri Scientific Clinical Institutes, SpA SB, Institute of Care and Scientific Research, Rehabilitation Institute of Telese Terme, Telese Terme, , Italy
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Goswami N, Blaber AP, Hinghofer-Szalkay H, Convertino VA. Lower Body Negative Pressure: Physiological Effects, Applications, and Implementation. Physiol Rev 2019; 99:807-851. [PMID: 30540225 DOI: 10.1152/physrev.00006.2018] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
This review presents lower body negative pressure (LBNP) as a unique tool to investigate the physiology of integrated systemic compensatory responses to altered hemodynamic patterns during conditions of central hypovolemia in humans. An early review published in Physiological Reviews over 40 yr ago (Wolthuis et al. Physiol Rev 54: 566-595, 1974) focused on the use of LBNP as a tool to study effects of central hypovolemia, while more than a decade ago a review appeared that focused on LBNP as a model of hemorrhagic shock (Cooke et al. J Appl Physiol (1985) 96: 1249-1261, 2004). Since then there has been a great deal of new research that has applied LBNP to investigate complex physiological responses to a variety of challenges including orthostasis, hemorrhage, and other important stressors seen in humans such as microgravity encountered during spaceflight. The LBNP stimulus has provided novel insights into the physiology underlying areas such as intolerance to reduced central blood volume, sex differences concerning blood pressure regulation, autonomic dysfunctions, adaptations to exercise training, and effects of space flight. Furthermore, approaching cardiovascular assessment using prediction models for orthostatic capacity in healthy populations, derived from LBNP tolerance protocols, has provided important insights into the mechanisms of orthostatic hypotension and central hypovolemia, especially in some patient populations as well as in healthy subjects. This review also presents a concise discussion of mathematical modeling regarding compensatory responses induced by LBNP. Given the diverse applications of LBNP, it is to be expected that new and innovative applications of LBNP will be developed to explore the complex physiological mechanisms that underline health and disease.
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Affiliation(s)
- Nandu Goswami
- Physiology Section, Otto Loewi Research Center for Vascular Biology, Immunology and Inflammation, Medical University of Graz , Graz , Austria ; Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada ; Battlefield Health & Trauma Center for Human Integrative Physiology, Combat Casualty Care Research Program, US Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas
| | - Andrew Philip Blaber
- Physiology Section, Otto Loewi Research Center for Vascular Biology, Immunology and Inflammation, Medical University of Graz , Graz , Austria ; Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada ; Battlefield Health & Trauma Center for Human Integrative Physiology, Combat Casualty Care Research Program, US Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas
| | - Helmut Hinghofer-Szalkay
- Physiology Section, Otto Loewi Research Center for Vascular Biology, Immunology and Inflammation, Medical University of Graz , Graz , Austria ; Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada ; Battlefield Health & Trauma Center for Human Integrative Physiology, Combat Casualty Care Research Program, US Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas
| | - Victor A Convertino
- Physiology Section, Otto Loewi Research Center for Vascular Biology, Immunology and Inflammation, Medical University of Graz , Graz , Austria ; Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada ; Battlefield Health & Trauma Center for Human Integrative Physiology, Combat Casualty Care Research Program, US Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas
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Goswami N, Batzel JJ, Loeppky JA, Hinghofer-Szalkay H. Teaching fluid shifts during orthostasis using a classic paper by Foux et al. ADVANCES IN PHYSIOLOGY EDUCATION 2011; 35:330-335. [PMID: 22139766 DOI: 10.1152/advan.00071.2011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Hypovolemic and orthostatic challenge can be simulated in humans by the application of lower body negative pressure (LBNP), because this perturbation leads to peripheral blood pooling and, consequently, central hypovolemia. The classic paper by Foux and colleagues clearly shows the effects of orthostasis simulated by LBNP on fluid shifts and homeostatic mechanisms. The carefully carried out experiments reported in this paper show the interplay between different physiological control systems to ensure blood pressure regulation, failure of which could lead to critical decreases in cerebral blood flow and syncope. Here, a teaching seminar for graduate students is described that is designed in the context of this paper and aimed at allowing students to learn how Foux and colleagues have advanced this field by addressing important aspects of blood regulation. This seminar is also designed to put their research into perspective by including important components of LBNP testing and protocols developed in subsequent research in the field. Learning about comprehensive protocols and carefully controlled studies can reduce confounding variables and allow for an optimal analysis and elucidation of the physiological responses that are being investigated. Finally, in collaboration with researchers in mathematical modeling, in the future, we will incorporate the concepts of applicable mathematical models into our curriculum.
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Affiliation(s)
- Nandu Goswami
- Institute of Physiology, Center of Physiological Medicine, Medical University of Graz, Austria.
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FADEL PAULJ. Arterial Baroreflex Control of the Peripheral Vasculature in Humans. Med Sci Sports Exerc 2008; 40:2055-62. [DOI: 10.1249/mss.0b013e318180bc80] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hinghofer-Szalkay HG, Goswami N, Rössler A, Grasser E, Schneditz D. Reactive hyperemia in the human liver. Am J Physiol Gastrointest Liver Physiol 2008; 295:G332-7. [PMID: 18535294 DOI: 10.1152/ajpgi.00042.2008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We tested whether hepatic blood flow is altered following central hypovolemia caused by simulated orthostatic stress. After 30 min of supine rest, hemodynamic, plasma density, and indocyanine green (ICG) clearance responses were determined during and after release of a 15-min 40 mmHg lower body negative pressure (LBNP) stimulus. Plasma density shifts and the time course of plasma ICG concentration were used to assess intravascular volume and hepatic perfusion changes. Plasma volume decreased during LBNP (-10%) as did cardiac output (-15%), whereas heart rate (+14%) and peripheral resistance (+17%) increased, as expected. On the basis of ICG elimination, hepatic perfusion decreased from 1.67 +/- 0.32 (pre-LBNP control) to 1.29 +/- 0.26 l/min (-22%) during LBNP. Immediately after LBNP release, we found hepatic perfusion 25% above control levels (to 2.08 +/- 0.48 l/min, P = 0.0001). Hepatic vascular conductance after LBNP was also significantly higher than during pre-LBNP control (21.4 +/- 5.4 vs. 17.1 +/- 3.1 ml.min(-1).mmHg(-1), P < 0.0001). This indicates autoregulatory vasodilatation in response to relative ischemia during a stimulus that has cardiovascular effects similar to normal orthostasis. We present evidence for physiological post-LBNP reactive hyperemia in the human liver. Further studies are needed to quantify the intensity of this response in relation to stimulus duration and magnitude, and clarify its mechanism.
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Affiliation(s)
- Helmut G Hinghofer-Szalkay
- Institute of Physiology, Center for Physiological Medicine, Medical Univ. Graz, Harrachgasse 21, A-8010 Graz, Austria.
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Kitano A, Shoemaker JK, Ichinose M, Wada H, Nishiyasu T. Comparison of cardiovascular responses between lower body negative pressure and head-up tilt. J Appl Physiol (1985) 2005; 98:2081-6. [PMID: 15761089 DOI: 10.1152/japplphysiol.00563.2004] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To investigate local blood-flow regulation during orthostatic maneuvers, 10 healthy subjects were exposed to −20 and −40 mmHg lower body negative pressure (LBNP; each for 3 min) and to 60° head-up tilt (HUT; for 5 min). Measurements were made of blood flow in the brachial (BFbrachial) and femoral arteries (BFfemoral) (both by the ultrasound Doppler method), heart rate (HR), mean arterial pressure (MAP), cardiac stroke volume (SV; by echocardiography), and left ventricular end-diastolic volume (LVEDV; by echocardiography). Comparable central cardiovascular responses (changes in LVEDV, SV, and MAP) were seen during LBNP and HUT. During −20 mmHg LBNP, −40 mmHg LBNP, and HUT, the following results were observed: 1) BFbrachial decreased by 51, 57, and 41%, and BFfemoral decreased by 40, 53, and 62%, respectively, 2) vascular resistance increased in the upper limb by 110, 147, and 85%, and in the lower limb by 76, 153, and 250%, respectively. The increases in vascular resistance were not different between the upper and lower limbs during LBNP. However, during HUT, the increase in the lower limb was much greater than that in the upper limb. These results suggest that, during orthostatic stimulation, the vascular responses in the limbs due to the cardiopulmonary and arterial baroreflexes can be strongly modulated by local mechanisms (presumably induced by gravitational effects).
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Affiliation(s)
- Asami Kitano
- Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Ibaraki 305-8574, Japan
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Pricher MP, Holowatz LA, Williams JT, Lockwood JM, Halliwill JR. Regional hemodynamics during postexercise hypotension. I. Splanchnic and renal circulations. J Appl Physiol (1985) 2004; 97:2065-70. [PMID: 15310744 DOI: 10.1152/japplphysiol.00465.2004] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Moderate exercise elicits a relative postexercise hypotension that is caused by an increase in systemic vascular conductance. Previous studies have shown that skeletal muscle vascular conductance is increased postexercise. It is unclear whether these hemodynamic changes are limited to skeletal muscle vascular beds. The aim of this study was to determine whether the splanchnic and/or renal vascular beds also contribute to the rise in systemic vascular conductance during postexercise hypotension. A companion study aims to determine whether the cutaneous vascular bed is involved in postexercise hypotension (Wilkins BW, Minson CT, and Halliwill JR. J Appl Physiol 97: 2071-2076, 2004). Heart rate, arterial pressure, cardiac output, leg blood flow, splanchnic blood flow, and renal blood flow were measured in 13 men and 3 women before and through 120 min after a 60-min bout of exercise at 60% of peak oxygen uptake. Vascular conductances of leg, splanchnic, and renal vascular beds were calculated. One hour postexercise, mean arterial pressure was reduced (79.1 +/- 1.7 vs. 83.4 +/- 1.8 mmHg; P < 0.05), systemic vascular conductance was increased by approximately 10%, leg vascular conductance was increased by approximately 65%, whereas splanchnic (16.0 +/- 1.8 vs. 18.5 +/- 2.4 ml.min(-1).mmHg(-1); P = 0.13) and renal (20.4 +/- 3.3 vs. 17.6 +/- 2.6 ml.min(-1).mmHg(-1); P = 0.14) vascular conductances were unchanged compared with preexercise. This suggests there is neither vasoconstriction nor vasodilation in the splanchnic and renal vasculature during postexercise hypotension. Thus the splanchnic and renal vascular beds neither directly contribute to nor attenuate postexercise hypotension.
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Affiliation(s)
- Mollie P Pricher
- Department of Human Physiology, University of Oregon, Eugene, OR 97403-1240, USA
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Howden R, Lightfoot JT, Turner MJ, Brown SJ, Swaine IL. A wide range of baroreflex stimulation does not alter forearm blood flow. Eur J Appl Physiol 2004; 93:124-9. [PMID: 15278354 DOI: 10.1007/s00421-004-1181-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2004] [Indexed: 11/26/2022]
Abstract
The contribution to the regulation of forearm blood flow (FBF) by different baroreceptor populations has previously only been studied over a limited range of stimuli. Therefore, FBF and R-R interval were recorded during neck suctions and neck pressures ranging from -60 to +40 mmHg. The change in R-R interval (DeltaR-R) during neck suction was significantly increased at each stage when compared to the control ( P<0.05). DeltaR-R did not show any significant change during any of the neck pressure stages ( P>0.05). Suction or pressure applied to the neck did not elicit any significant changes in FBF when compared to the control ( P>0.05). These data show that widening the range of applied stimuli to carotid sinus baroreceptors does not induce a change in FBF. However, the small transient changes reported previously cannot be discounted.
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Affiliation(s)
- Reuben Howden
- Physiology of Exercise, De Montfort University, Lansdowne Road, Bedford, UK.
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Taylor JA, Halliwill JR, Brown TE, Hayano J, Eckberg DL. 'Non-hypotensive' hypovolaemia reduces ascending aortic dimensions in humans. J Physiol 1995; 483 ( Pt 1):289-98. [PMID: 7776239 PMCID: PMC1157889 DOI: 10.1113/jphysiol.1995.sp020585] [Citation(s) in RCA: 112] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
1. The notion that small, 'non-hypotensive' reductions of effective blood volume alter neither arterial pressure nor arterial baroreceptor activity is pervasive in the experimental literature. We tested two hypotheses: (a) that minute arterial pressure and cardiac autonomic outflow changes during hypovolaemia induced by lower body suction in humans are masked by alterations in breathing, and (b) that evidence for arterial baroreflex engagement might be obtained from measurements of thoracic aorta dimensions. 2. In two studies, responses to graded lower body suction at 0 (control), 5, 10, 15, 20 and 40 mmHg were examined in twelve and ten healthy young men, respectively. In the first, arterial pressure (photoplethysmograph), R-R interval, and respiratory sinus arrhythmia amplitude (complex demodulation) were measured during uncontrolled and controlled breathing (constant breathing frequency and tidal volume). In the second, cross-sectional areas of the ascending thoracic aorta were calculated from nuclear magnetic resonance images. 3. Lower body suction with controlled breathing resulted in an increased arterial pulse pressure at mild levels (5-20 mmHg; ANOVA, P < 0.05) and a decreased arterial pulse pressure at moderate levels (40 mmHg; ANOVA, P < 0.05). Both R-R intervals and respiratory sinus arrhythmia were negatively related to lower body suction level, whether group averages (general linear regression, r > 0.92) or individual subjects (orthogonal polynomials, 12 of 12 subjects) were assessed. 4. Aortic pulse area decreased progressively and significantly during mild lower body suction, with 47% of the total decline occurring by 5 mmHg. 5. These results suggest that small reductions of effective blood volume reduce aortic baroreceptive areas and trigger haemodynamic adjustments which are so efficient that alterations in arterial pressure escape detection by conventional means.
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Affiliation(s)
- J A Taylor
- Department of Medicine, Hunter Holmes McGuire Department of Veterans Affairs Medical Center, Richmond, VA, USA
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