1
|
Bjerkan J, Kobal J, Lancaster G, Šešok S, Meglič B, McClintock PVE, Budohoski KP, Kirkpatrick PJ, Stefanovska A. The phase coherence of the neurovascular unit is reduced in Huntington's disease. Brain Commun 2024; 6:fcae166. [PMID: 38938620 PMCID: PMC11210076 DOI: 10.1093/braincomms/fcae166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 03/07/2024] [Accepted: 05/09/2024] [Indexed: 06/29/2024] Open
Abstract
Huntington's disease is a neurodegenerative disorder in which neuronal death leads to chorea and cognitive decline. Individuals with ≥40 cytosine-adenine-guanine repeats on the interesting transcript 15 gene develop Huntington's disease due to a mutated huntingtin protein. While the associated structural and molecular changes are well characterized, the alterations in neurovascular function that lead to the symptoms are not yet fully understood. Recently, the neurovascular unit has gained attention as a key player in neurodegenerative diseases. The mutant huntingtin protein is known to be present in the major parts of the neurovascular unit in individuals with Huntington's disease. However, a non-invasive assessment of neurovascular unit function in Huntington's disease has not yet been performed. Here, we investigate neurovascular interactions in presymptomatic (N = 13) and symptomatic (N = 15) Huntington's disease participants compared to healthy controls (N = 36). To assess the dynamics of oxygen transport to the brain, functional near-infrared spectroscopy, ECG and respiration effort were recorded. Simultaneously, neuronal activity was assessed using EEG. The resultant time series were analysed using methods for discerning time-resolved multiscale dynamics, such as wavelet transform power and wavelet phase coherence. Neurovascular phase coherence in the interval around 0.1 Hz is significantly reduced in both Huntington's disease groups. The presymptomatic Huntington's disease group has a lower power of oxygenation oscillations compared to controls. The spatial coherence of the oxygenation oscillations is lower in the symptomatic Huntington's disease group compared to the controls. The EEG phase coherence, especially in the α band, is reduced in both Huntington's disease groups and, to a significantly greater extent, in the symptomatic group. Our results show a reduced efficiency of the neurovascular unit in Huntington's disease both in the presymptomatic and symptomatic stages of the disease. The vasculature is already significantly impaired in the presymptomatic stage of the disease, resulting in reduced cerebral blood flow control. The results indicate vascular remodelling, which is most likely a compensatory mechanism. In contrast, the declines in α and γ coherence indicate a gradual deterioration of neuronal activity. The results raise the question of whether functional changes in the vasculature precede the functional changes in neuronal activity, which requires further investigation. The observation of altered dynamics paves the way for a simple method to monitor the progression of Huntington's disease non-invasively and evaluate the efficacy of treatments.
Collapse
Affiliation(s)
- Juliane Bjerkan
- Department of Physics, Lancaster University, Lancaster LA1 4YB, UK
| | - Jan Kobal
- Department of Neurology, University Medical Centre, 1525 Ljubljana, Slovenia
| | - Gemma Lancaster
- Department of Physics, Lancaster University, Lancaster LA1 4YB, UK
| | - Sanja Šešok
- Department of Neurology, University Medical Centre, 1525 Ljubljana, Slovenia
| | - Bernard Meglič
- Department of Neurology, University Medical Centre, 1525 Ljubljana, Slovenia
| | | | - Karol P Budohoski
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Peter J Kirkpatrick
- Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, UK
| | | |
Collapse
|
2
|
Huang SJY, Wang X, Halvorson BD, Bao Y, Frisbee SJ, Frisbee JC, Goldman D. Laser Doppler Fluximetry in Cutaneous Vasculature: Methods for Data Analyses. J Vasc Res 2024; 61:197-211. [PMID: 38749406 DOI: 10.1159/000538718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 03/27/2024] [Indexed: 08/09/2024] Open
Abstract
INTRODUCTION Acquisition of a deeper understanding of microvascular function across physiological and pathological conditions can be complicated by poor accessibility of the vascular networks and the necessary sophistication or intrusiveness of the equipment needed to acquire meaningful data. Laser Doppler fluximetry (LDF) provides a mechanism wherein investigators can readily acquire large amounts of data with minor inconvenience for the subject. However, beyond fairly basic analyses of erythrocyte perfusion (fluximetry) data within the cutaneous microcirculation (i.e., perfusion at rest and following imposed challenges), a deeper understanding of microvascular perfusion requires a more sophisticated approach that can be challenging for many investigators. METHODS This manuscript provides investigators with clear guidance for data acquisition from human subjects for full analysis of fluximetry data, including levels of perfusion, single- and multiscale Lempel-Ziv complexity (LZC) and sample entropy (SampEn), and wavelet-based analyses for the major physiological components of the signal. Representative data and responses are presented from a recruited cohort of healthy volunteers, and computer codes for full data analysis (MATLAB) are provided to facilitate efforts by interested investigators. CONCLUSION It is anticipated that these materials can reduce the challenge to investigators integrating these approaches into their research programs and facilitate translational research in cardiovascular science.
Collapse
Affiliation(s)
- Sophie J Y Huang
- Departments of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Xuan Wang
- Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Brayden D Halvorson
- Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Yuki Bao
- Biomedical Engineering, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Stephanie J Frisbee
- Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
- Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
- Lawson Health Research Institute, London, Ontario, Canada
| | - Jefferson C Frisbee
- Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Daniel Goldman
- Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
- Biomedical Engineering, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
3
|
Nietvelt F, Van Herreweghe I, Godschalx V, Soetens F. Extravascular injection of neuromuscular blocking drugs: A systematic review of current evidence and management. Eur J Anaesthesiol 2024; 41:367-373. [PMID: 38410855 PMCID: PMC10990036 DOI: 10.1097/eja.0000000000001967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Extravascular injection of neuromuscular blocking drugs (NMBDs) can cause a neuromuscular block because of systemic absorption. Currently, there are no guidelines available on managing extravasation of NMBDs. This article reviews the available literature on extravasation of NMBDs. Medline and Embase databases were searched for studies concerning the paravenous or subcutaneous injection of NMBDs. Nine articles were included consisting of seven case reports, one case series and one clinical trial. Rocuronium was used as primary NMBD in nine cases, vecuronium in two cases and pancuronium in one case. Although there exists significant heterogeneity between the reported information in the included studies, the majority of the case reports describe a slower onset, with a median delay of 20 min and prolonged duration of the neuromuscular block. Nine patients had a residual neuromuscular block at the end of the surgery. Postoperative monitoring in the recovery room was prolonged (median time 4 h). Most studies suggest that the delay in NMBD onset and recovery is caused by the formation of a subcutaneous depot, from which the NMBD is slowly absorbed into the systemic circulation. According to the current literature, extravasation of NMBDs results in an unpredictable neuromuscular block. Strategies to prevent potentially harmful side effects, such as frequent train-of-four (TOF) monitoring, the use of NMBD reversal agents and prolonged length of stay in the postanaesthesia care unit (PACU), should be considered. This article suggests a clinical pathway that can be used after extravascular injection of NMBDs.
Collapse
Affiliation(s)
- Frederik Nietvelt
- From the Department of Anaesthesiology, UZ Leuven, Leuven, Belgium (FN, VG), Department of Anaesthesiology, Ziekenhuis Oost-Limburg, Genk, Belgium (IVH) and Department of Anaesthesiology, AZ Turnhout, Turnhout, Belgium (FS)
| | | | | | | |
Collapse
|
4
|
Amendola C, Buttafava M, Carteano T, Contini L, Cortese L, Durduran T, Frabasile L, Guadagno CN, Karadeinz U, Lacerenza M, Mesquida J, Parsa S, Re R, Sanoja Garcia D, Konugolu Venkata Sekar S, Spinelli L, Torricelli A, Tosi A, Weigel UM, Yaqub MA, Zanoletti M, Contini D. Assessment of power spectral density of microvascular hemodynamics in skeletal muscles at very low and low-frequency via near-infrared diffuse optical spectroscopies. BIOMEDICAL OPTICS EXPRESS 2023; 14:5994-6015. [PMID: 38021143 PMCID: PMC10659778 DOI: 10.1364/boe.502618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/10/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023]
Abstract
In this work, we used a hybrid time domain near-infrared spectroscopy (TD-NIRS) and diffuse correlation spectroscopy (DCS) device to retrieve hemoglobin and blood flow oscillations of skeletal muscle microvasculature. We focused on very low (VLF) and low-frequency (LF) oscillations (i.e., frequency lower than 0.145 Hz), that are related to myogenic, neurogenic and endothelial activities. We measured power spectral density (PSD) of blood flow and hemoglobin concentration in four muscles (thenar eminence, plantar fascia, sternocleidomastoid and forearm) of 14 healthy volunteers to highlight possible differences in microvascular hemodynamic oscillations. We observed larger PSDs for blood flow compared to hemoglobin concentration, in particular in case of distal muscles (i.e., thenar eminence and plantar fascia). Finally, we compared the PSDs measured on the thenar eminence of healthy subjects with the ones measured on a septic patient in the intensive care unit: lower power in the endothelial-dependent frequency band, and larger power in the myogenic ones were observed in the septic patient, in accordance with previous works based on laser doppler flowmetry.
Collapse
Affiliation(s)
| | | | | | | | - Lorenzo Cortese
- ICFO - Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
| | - Turgut Durduran
- ICFO - Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | | | - Claudia Nunzia Guadagno
- BioPixS Ltd – Biophotonics Standards, IPIC, Tyndall National Institute, Lee Maltings Complex, Cork, Ireland
| | - Umut Karadeinz
- ICFO - Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
| | | | - Jaume Mesquida
- Critical Care Department, Parc Taulí Hospital Universitari. Institut D’Investigació i Innovació Parc Taulí I3PT, Sabadell, Spain
| | | | - Rebecca Re
- Dipartimento di Fisica, Politecnico di Milano, Milan, Italy
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Milano, Italy
| | | | | | - Lorenzo Spinelli
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Milano, Italy
| | - Alessandro Torricelli
- Dipartimento di Fisica, Politecnico di Milano, Milan, Italy
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Milano, Italy
| | - Alberto Tosi
- Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milan, Italy
| | - Udo M. Weigel
- HemoPhotonics S.L., Castelldefels, (Barcelona), Spain
| | - M. Atif Yaqub
- ICFO - Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
| | - Marta Zanoletti
- ICFO - Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
| | - Davide Contini
- Dipartimento di Fisica, Politecnico di Milano, Milan, Italy
| |
Collapse
|
5
|
Bjerkan J, Lancaster G, Meglič B, Kobal J, Crawford TJ, McClintock PVE, Stefanovska A. Aging affects the phase coherence between spontaneous oscillations in brain oxygenation and neural activity. Brain Res Bull 2023; 201:110704. [PMID: 37451471 DOI: 10.1016/j.brainresbull.2023.110704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 07/03/2023] [Accepted: 07/11/2023] [Indexed: 07/18/2023]
Abstract
The risk of neurodegenerative disorders increases with age, due to reduced vascular nutrition and impaired neural function. However, the interactions between cardiovascular dynamics and neural activity, and how these interactions evolve in healthy aging, are not well understood. Here, the interactions are studied by assessment of the phase coherence between spontaneous oscillations in cerebral oxygenation measured by fNIRS, the electrical activity of the brain measured by EEG, and cardiovascular functions extracted from ECG and respiration effort, all simultaneously recorded. Signals measured at rest in 21 younger participants (31.1 ± 6.9 years) and 24 older participants (64.9 ± 6.9 years) were analysed by wavelet transform, wavelet phase coherence and ridge extraction for frequencies between 0.007 and 4 Hz. Coherence between the neural and oxygenation oscillations at ∼ 0.1 Hz is significantly reduced in the older adults in 46/176 fNIRS-EEG probe combinations. This reduction in coherence cannot be accounted for in terms of reduced power, thus indicating that neurovascular interactions change with age. The approach presented promises a noninvasive means of evaluating the efficiency of the neurovascular unit in aging and disease.
Collapse
Affiliation(s)
- Juliane Bjerkan
- Lancaster University, Department of Physics, LA1 4YB, Lancaster, United Kingdom
| | - Gemma Lancaster
- Lancaster University, Department of Physics, LA1 4YB, Lancaster, United Kingdom
| | - Bernard Meglič
- University of Ljubljana Medical Centre, Department of Neurology, 1525, Ljubljana, Slovenia
| | - Jan Kobal
- University of Ljubljana Medical Centre, Department of Neurology, 1525, Ljubljana, Slovenia
| | - Trevor J Crawford
- Lancaster University, Department of Psychology, LA1 4YF, Lancaster, United Kingdom
| | | | - Aneta Stefanovska
- Lancaster University, Department of Physics, LA1 4YB, Lancaster, United Kingdom.
| |
Collapse
|
6
|
Kralj L, Lenasi H. Wavelet analysis of laser Doppler microcirculatory signals: Current applications and limitations. Front Physiol 2023; 13:1076445. [PMID: 36741808 PMCID: PMC9895103 DOI: 10.3389/fphys.2022.1076445] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 12/28/2022] [Indexed: 01/21/2023] Open
Abstract
Laser Doppler flowmetry (LDF) has long been considered a gold standard for non-invasive assessment of skin microvascular function. Due to the laser Doppler (LD) microcirculatory signal's complex biological and physiological context, using spectral analysis is advisable to extract as many of the signal's properties as feasible. Spectral analysis can be performed using either a classical Fourier transform (FT) technique, which has the disadvantage of not being able to localize a signal in time, or wavelet analysis (WA), which provides both the time and frequency localization of the inspected signal. So far, WA of LD microcirculatory signals has revealed five characteristic frequency intervals, ranging from 0.005 to 2 Hz, each of which being related to a specific physiological influence modulating skin microcirculatory response, providing for a more thorough analysis of the signals measured in healthy and diseased individuals. Even though WA is a valuable tool for analyzing and evaluating LDF-measured microcirculatory signals, limitations remain, resulting in a lack of analytical standardization. As a more accurate assessment of human skin microcirculation may better enhance the prognosis of diseases marked by microvascular dysfunction, searching for improvements to the WA method is crucial from the clinical point of view. Accordingly, we have summarized and discussed WA application and its limitations when evaluating LD microcirculatory signals, and presented insight into possible future improvements. We adopted a novel strategy when presenting the findings of recent studies using WA by focusing on frequency intervals to contrast the findings of the various studies undertaken thus far and highlight their disparities.
Collapse
Affiliation(s)
- Lana Kralj
- Institute of Physiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Helena Lenasi
- Institute of Physiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia,*Correspondence: Helena Lenasi,
| |
Collapse
|
7
|
Multiple blood flow surges during intermittent pneumatic compression: The origins and their implications. J Biomech 2022; 143:111264. [PMID: 36055052 DOI: 10.1016/j.jbiomech.2022.111264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 08/07/2022] [Accepted: 08/15/2022] [Indexed: 11/23/2022]
Abstract
Intermittent pneumatic compression (IPC) therapy has been used to enhance peripheral blood flow for prevention and rehabilitation of ischemic-related vascular diseases. A novel phenomenon has been reported that multiple blood flow surges appeared in the skin blood flow signal during each compression, but its mechanism has not been fully revealed. This study aimed to gain insights into the origins of these blood flow surges through experiment and biomechanical modeling methods. Foot skin blood flow (SBF) signals of 13 healthy adults (23.8 ± 0.5 yr old, 7 males) and air cuff pressure signals were recorded during IPC. Lumped parameter modeling and wavelet analysis were adopted to investigate the multiple blood flow surges (named as Peak1, Peak2 and Peak3). The results of the simulated Peak1 and Peak2 were in good agreements with the experiment results, suggesting that IPC could enhance foot SBF not only by deflation, but also by inflation. Statistical analysis demonstrated that high frequency compression with more frequent occurrence of Peak1 and Peak2 lead to significantly higher (Friedman test, p < 0.001) time-averaged SBF enhancement than the traditional mode. In addition, wavelet analysis showed that the major frequency component of the Peak3 (0.059 Hz) was within the range of the vascular myogenic activity, suggesting a vascular regulation process triggered by intravascular pressure changes. Our study provide new insights into the mechanism of how IPC enhance foot SBF.
Collapse
|
8
|
Huang W, Li X, Xie H, Qiao T, Zheng Y, Su L, Tang ZM, Dou Z. Different Cortex Activation and Functional Connectivity in Executive Function Between Young and Elder People During Stroop Test: An fNIRS Study. Front Aging Neurosci 2022; 14:864662. [PMID: 35992592 PMCID: PMC9382234 DOI: 10.3389/fnagi.2022.864662] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 06/20/2022] [Indexed: 11/23/2022] Open
Abstract
Objective The objective of this study was to examine the activation and functional connectivity of the prefrontal and temporal lobe in young and elder people during the Stroop test using functional near-infrared spectroscopy (fNIRS). Methods A total of 33 healthy volunteers (20 young people, mean age: 23.7 ± 3.9 years; 13 elder people, mean age: 63.9 ± 4.0 years) participated in the study. All subjects were asked to finish the Stroop Color Word Test. The oxygenated hemoglobin concentration (Delta [HbO2]) signals and the deoxygenated hemoglobin (Delta [HbR]) signals were recorded from temporopolar area (TA), pars triangularis Broca's area (Broca), dorsolateral prefrontal cortex (DLPFC), and frontopolar area (FA) by fNIRS. The coherence between the left and right frontotemporal lobe delta [HbO2] oscillations in four frequency intervals (I, 0.6–2 Hz; II, 0.145–0.6 Hz; III, 0.052–0.145 Hz; and IV, 0.021–0.052 Hz) was analyzed using wavelet coherence analysis and wavelet phase coherent. Results In the Stroop test, the young group was significantly better than the elder group at the responses time, whether at congruent tasks or at incongruent tasks (congruent: F = 250.295, p < 0.001; incongruent: p < 0.001). The accuracy of the two groups differed significantly when performing incongruent tasks but not when performing congruent tasks (incongruent: F = 9.498, p = 0.001; congruent: p = 0.254). Besides, only elders show significant activation in DLPFC, Broca, FA, and TA (p < 0.05) during the Stroop test, but young people did not show significant differences. In the functional connectivity of task states, younger people had stronger connections between different brain regions in both the left and right brain compared with the elderly (p < 0.05). In particular, the left and right DLPFC showed stronger connection strength in most of the brain areas. The result suggested that younger people had stronger functional connectivity of brain areas than older people when completing the task. Conclusion According to these results, although the cortical activation in the elder people was higher than the young people, the young showed stronger connectivity in most of the brain areas than the elders. Both sides of DLPFC and right Broca area were the most significant cortical activation in Stroop test. It was suggested that the decrease in functional connectivity in the elder people resulted in the atrophy of white matter, to which we should pay more attention.
Collapse
Affiliation(s)
- Wenhao Huang
- Department of Rehabilitation Medicine, The Third Affiliated Hospital of Sun Yat- sen University, Guangzhou, China
| | - Xin Li
- Department of Rehabilitation Medicine, The Third Affiliated Hospital of Sun Yat- sen University, Guangzhou, China
| | - Hui Xie
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Tong Qiao
- Affiliated Hospital of Inner Mongolia Medical University, Hohhot, China
| | - Yadan Zheng
- Department of Rehabilitation Medicine, The Third Affiliated Hospital of Sun Yat- sen University, Guangzhou, China
| | - Liujie Su
- Department of Rehabilitation Medicine, The Third Affiliated Hospital of Sun Yat- sen University, Guangzhou, China
| | - Zhi-Ming Tang
- Department of Rehabilitation Medicine, The Third Affiliated Hospital of Sun Yat- sen University, Guangzhou, China
- *Correspondence: Zhi-Ming Tang
| | - Zulin Dou
- Department of Rehabilitation Medicine, The Third Affiliated Hospital of Sun Yat- sen University, Guangzhou, China
- Zulin Dou
| |
Collapse
|
9
|
Successful continuous positive airway pressure treatment reduces skin sympathetic nerve activity in patients with obstructive sleep apnea. Heart Rhythm 2022; 19:127-136. [PMID: 34562644 PMCID: PMC8742760 DOI: 10.1016/j.hrthm.2021.09.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 08/27/2021] [Accepted: 09/15/2021] [Indexed: 01/03/2023]
Abstract
BACKGROUND Obstructive sleep apnea (OSA) is associated with cardiovascular diseases and increased sympathetic tone. We previously demonstrated that patients with OSA have increased skin sympathetic nerve activity (SKNA). OBJECTIVE The purpose of this study was to test the hypothesis that continuous positive airway pressure (CPAP) treatment reduces SKNA. METHODS The electrocardiogram, SKNA, and polysomnographic recording were recorded simultaneously in 9 patients with OSA. After baseline recording, CPAP titration was performed and the pressure was adjusted gradually for the optimal treatment, defined by reducing the apnea-hypopnea index (AHI) to ≤5/h. Otherwise the treatment was considered suboptimal (AHI > 5/h). Fast Fourier transform analyses were performed to investigate the frequency spectrum of SKNA. RESULTS There were very low frequency (VLF), low frequency (LF), and high frequency (HF) oscillations in SKNA. The HF oscillation matched the frequency of respiration. OSA episodes were more frequently associated with the VLF and LF than with the HF oscillations of SKNA. Compared with baseline, CPAP significantly decreased the arousal index and AHI and increased the minimal and mean oxyhemoglobin levels. Optimal treatment significantly increased the dominant frequency and reduced the heart rate, average SKNA (aSKNA), SKNA burst duration, and total burst area. The dominant frequency negatively correlated with aSKNA. CONCLUSION VLF, LF, and HF oscillations are observed in human SKNA recordings. Among them, VLF and LF oscillations are associated with OSA while HF oscillations are associated with normal breathing. CPAP therapy reduces aSKNA and shifts the frequency of SKNA oscillation from VLF or LF to HF.
Collapse
|
10
|
Fredriksson I, Larsson M, Strömberg T, Iredahl F. Vasomotion analysis of speed resolved perfusion, oxygen saturation, red blood cell tissue fraction, and vessel diameter: Novel microvascular perspectives. Skin Res Technol 2021; 28:142-152. [PMID: 34758168 PMCID: PMC9907591 DOI: 10.1111/srt.13106] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 08/21/2021] [Indexed: 12/17/2022]
Abstract
BACKGROUND Vasomotion is the spontaneous oscillation in vascular tone in the microcirculation and is believed to be a physiological mechanism facilitating the transport of blood gases and nutrients to and from tissues. So far, Laser Doppler flowmetry has constituted the gold standard for in vivo vasomotion analysis. MATERIALS AND METHODS We applied vasomotion analysis to speed-resolved perfusion, oxygen saturation, red blood cell tissue (RBC) tissue fraction, and average vessel diameter from five healthy individuals at rest measured by the newly developed Periflux 6000 EPOS system over 10 minutes. Magnitude scalogram and the time-averaged wavelet spectra were divided into frequency intervals reflecting endothelial, neurogenic, myogenic, respiratory, and cardiac function. RESULTS Recurrent high-intensity periods of the myogenic, neurogenic, and endothelial frequency intervals were found. The neurogenic activity was considerably more pronounced for the oxygen saturation, RBC tissue fraction, and vessel diameter signals, than for the perfusion signals. In a correlation analysis we found that changes in perfusion in the myogenic, neurogenic, and endothelial frequency intervals precede changes in the other signals. Furthermore, changes in average vessel diameter were in general negatively correlated to the other signals in the same frequency intervals, indicating the importance of capillary recruitment. CONCLUSION We conclude that vasomotion can be observed in signals reflecting speed resolved perfusion, oxygen saturation, RBC tissue fraction, and vessel diameter. The new parameters enable new aspects of the microcirculation to be observed.
Collapse
Affiliation(s)
- Ingemar Fredriksson
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Marcus Larsson
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Tomas Strömberg
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Fredrik Iredahl
- Department of Health, Medicine and Caring Sciences, Linköping University, Division of Community Medicine, Linköping, Sweden.,Department of Primary health care, Region Östergötland, Linköping, Sweden
| |
Collapse
|
11
|
Coutrot M, Dudoignon E, Joachim J, Gayat E, Vallée F, Dépret F. Perfusion index: Physical principles, physiological meanings and clinical implications in anaesthesia and critical care. Anaesth Crit Care Pain Med 2021; 40:100964. [PMID: 34687923 DOI: 10.1016/j.accpm.2021.100964] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/01/2021] [Accepted: 09/03/2021] [Indexed: 10/20/2022]
Abstract
Photoplethysmography (PPG) has been extensively used for pulse oximetry monitoring in anaesthesia, perioperative and intensive care. However, some components of PPG signal have been employed for other purposes, such as non-invasive haemodynamic monitoring. Perfusion index (PI) is derived from PPG signal and represents the ratio of pulsatile on non-pulsatile light absorbance or reflectance of the PPG signal. PI determinants are complex and interlinked, involving and reflecting the interaction between peripheral and central haemodynamic characteristics, such as vascular tone and stroke volume. Recently, several studies have shed light on the interesting performances of this variable, especially assessing regional or neuraxial block success, and haemodynamic monitoring in anaesthesia, perioperative and intensive care. Nevertheless, no review has yet been published concerning the interest of PI in these fields. In this narrative review will be exposed first the physiological and pathophysiological determinants of PI, and then the mean to measure this value as well as its potential limitations. In the second part, the existing data concerning usefulness of PI in different clinical settings such as operating theatres, intensive care units and emergency departments will be presented and discussed. Finally, the perspectives concerning the use of PI and mentioned aspects that should be explored regarding this tool will be underlined.
Collapse
Affiliation(s)
- Maxime Coutrot
- AP-HP, GH St-Louis-Lariboisière, Department of Anaesthesiology and Critical Care and Burn Unit, Paris, France; FHU PROMICE, Paris, France.
| | - Emmanuel Dudoignon
- AP-HP, GH St-Louis-Lariboisière, Department of Anaesthesiology and Critical Care and Burn Unit, Paris, France; University Paris Diderot, France.
| | - Jona Joachim
- AP-HP, GH St-Louis-Lariboisière, Department of Anaesthesiology and Critical Care and Burn Unit, Paris, France
| | - Etienne Gayat
- AP-HP, GH St-Louis-Lariboisière, Department of Anaesthesiology and Critical Care and Burn Unit, Paris, France; University Paris Diderot, France; UMR INSERM 942, Institut National de la Santé et de la Recherche Médicale (INSERM), France; FHU PROMICE, Paris, France
| | - Fabrice Vallée
- AP-HP, GH St-Louis-Lariboisière, Department of Anaesthesiology and Critical Care and Burn Unit, Paris, France; University Paris Diderot, France; UMR INSERM 942, Institut National de la Santé et de la Recherche Médicale (INSERM), France; FHU PROMICE, Paris, France; Inria, France; LMS, Ecole Polytechnique, CNRS, Institut Polytechnique de Paris, France
| | - François Dépret
- AP-HP, GH St-Louis-Lariboisière, Department of Anaesthesiology and Critical Care and Burn Unit, Paris, France; University Paris Diderot, France; UMR INSERM 942, Institut National de la Santé et de la Recherche Médicale (INSERM), France; FHU PROMICE, Paris, France; F-CRIN INICRCT network, Paris, France
| |
Collapse
|
12
|
Oral Glucose Load and Human Cutaneous Microcirculation: An Insight into Flowmotion Assessed by Wavelet Transform. BIOLOGY 2021; 10:biology10100953. [PMID: 34681052 PMCID: PMC8533385 DOI: 10.3390/biology10100953] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/31/2021] [Accepted: 09/10/2021] [Indexed: 01/10/2023]
Abstract
Simple Summary There is increasing evidence to suggest that microcirculation becomes dysfunctional earlier than large blood vessels or the heart in several diseases. In diabetes mellitus, a disease characterized by chronic hyperglycemia, microvascular impairment is well-established; on the contrary, the effect of acute hyperglycemia in microcirculation remains unclarified. Our aim was to investigate the microvascular effect of an oral glucose load (OGL) using laser Doppler flowmetry (LDF) as a perfusion quantification technique, coupled with wavelet transform (WT) to perform a spectral decomposition of the LDF signal. On two distinct occasions (pre-load and post-load), sixteen healthy subjects drank either a standard glucose solution or water. Perfusion was assessed by LDF and WT while resting and during post-occlusive reactive hyperemia (PORH), evoked by a transient three-min occlusion of the brachial artery, in the forearm and the finger pulp. The OGL affected microcirculation in both sites compared to water, significantly blunting the PORH response in the forearm. The WT revealed significant differences in the cardiac and sympathetic components after OGL between the pre-load and post-load periods. These results suggest that an OGL induces a short-term subtle microvascular impairment, probably involving a modulation of the sympathetic nervous system. Abstract Microcirculation in vivo has been assessed using non-invasive technologies such as laser Doppler flowmetry (LDF). In contrast to chronic hyperglycemia, known to induce microvascular dysfunction, the effects of short-term elevations in blood glucose on microcirculation are controversial. We aimed to assess the impact of an oral glucose load (OGL) on the cutaneous microcirculation of healthy subjects, quantified by LDF and coupled with wavelet transform (WT) as an interpretation tool. On two separate occasions, sixteen subjects drank either a glucose solution (75 g in 250 mL water) or water (equal volume). LDF signals were obtained in two anatomical sites (forearm and finger pulp) before and after each load (pre-load and post-load, respectively), in resting conditions and during post-occlusive reactive hyperemia (PORH). The WT allowed decomposition of the LDF signals into their spectral components (cardiac, respiratory, myogenic, sympathetic, endothelial NO-dependent). The OGL blunted the PORH response in the forearm, which was not observed with the water load. Significant differences were found for the cardiac and sympathetic components in the glucose and water groups between the pre-load and post-load periods. These results suggest that an OGL induces a short-term subtle microvascular impairment, probably involving a modulation of the sympathetic nervous system.
Collapse
|
13
|
Xiong L, Liu D, Wang Y, Wong KS, Fan Y. An Index From Transcranial Doppler Signals for Evaluation of Stroke Rehabilitation Using External Counterpulsation. IEEE Trans Neural Syst Rehabil Eng 2021; 29:1487-1493. [PMID: 34310311 DOI: 10.1109/tnsre.2021.3099203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This study aimed to develop a sensitive index from transcranial Doppler (TCD) signals for quantitatively evaluating the effects of long-term external counterpulsation (ECP) treatment on stroke rehabilitation. We recruited 27 patients with unilateral ischemic stroke and a good acoustic window within 7 days of stroke onset. 15 of them received 35 daily 1-hour ECP treatment (ECP group) and the others underwent conventional therapy without ECP treatment (No-ECP group). We monitored blood flow in middle cerebral arteries on both sides by TCD, and analyzed them via discrete wavelet analysis method. The overall changes of National Institutes of Health Stroke Scale (NIHSS) and Barthel Index were assessed. A 'big-wave' phenomenon was observed in TCD signals of patients in ECP group after 35 days' treatment, with significant fluctuation in frequency interval from 0.010 to 0.034 Hz as main feature. A new index, which was denoted as I , was derived from this phenomenon. The I was significantly higher for patients in ECP group than that for patients in No-ECP group after 35-days' treatment ( 0.01). And the I was positively correlated with NIHSS change in ECP group ( ). The new index could be used as an effective indicator for evaluating enhancement of endothelial metabolism and neurogenic activity after long-term ECP treatment.
Collapse
|
14
|
Guerrero F, Lambrechts K, Wang Q, Mazur A, Théron M, Marroni A. Endothelial function may be enhanced in the cutaneous microcirculation after a single air dive. Diving Hyperb Med 2020; 50:214-219. [PMID: 32957122 DOI: 10.28920/dhm50.3.214-219] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 05/17/2020] [Indexed: 11/05/2022]
Abstract
INTRODUCTION The effects of scuba diving on the vessel wall have been studied mainly at the level of large conduit arteries. Data regarding the microcirculation are scarce and indicate that these two vascular beds are affected differently by diving. METHODS We assessed the changes in cutaneous microcirculation before an air scuba dive, then 30 min and 24 h after surfacing. Endothelium-dependent and independent vasomotion were successively elicited by iontophoretic administration of acetylcholine and sodium nitroprusside respectively, and cutaneous blood flux was monitored by laser Doppler flowmetry. RESULTS The response to sodium nitroprusside was significantly lower 30 min after surfacing than before diving (50 (SEM 6)% of the pre-dive values, P = 0.0003) and returned to normal values 24 h post-dive (102 (29)% of the pre-dive values, P = 0.113). When compared to pre-dive values, acetylcholine elicited a hyperaemia which was not statistically different 30 min after surfacing (123 (17)% of the pre-dive values, P = 0.230), but significantly increased 24 h post-dive (148 (10)% of the pre-dive values, P = 0.005). CONCLUSION Microvascular smooth muscle function is transiently impaired after diving. On the contrary, microvascular endothelial function is enhanced for up to 24 h after diving. This further suggests that the microcirculation reacts differently than large conduit arteries to scuba diving. The impact of modifications occurring in the microvascular bed on the physiological effects of diving merits further study.
Collapse
Affiliation(s)
- François Guerrero
- Univ Brest, ORPHY EA4324, IBSAM, 6 avenue Le Gorgeu, 29200 Brest, France.,Corresponding author: François Guerrero, EA4324 ORPHY, 6 Av. Le Gorgeu CS 93837, 29238 BREST Cedex 3, France,
| | - Kate Lambrechts
- Univ Brest, ORPHY EA4324, IBSAM, 6 avenue Le Gorgeu, 29200 Brest, France
| | - Qiong Wang
- Univ Brest, ORPHY EA4324, IBSAM, 6 avenue Le Gorgeu, 29200 Brest, France
| | - Aleksandra Mazur
- Univ Brest, ORPHY EA4324, IBSAM, 6 avenue Le Gorgeu, 29200 Brest, France
| | - Michael Théron
- Univ Brest, ORPHY EA4324, IBSAM, 6 avenue Le Gorgeu, 29200 Brest, France
| | | |
Collapse
|
15
|
Tikhonova IV, Grinevich AA, Guseva IE, Tankanag AV. Effect of orthostasis on the regulation of skin blood flow in upper and lower extremities in human. Microcirculation 2020; 28:e12655. [PMID: 32860464 DOI: 10.1111/micc.12655] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 07/08/2020] [Accepted: 08/13/2020] [Indexed: 12/18/2022]
Abstract
OBJECTIVE The research is aimed to investigate interactions between cardiovascular signals and to assess contributions of central and local mechanisms to skin blood flow regulation in upper and lower extremities at rest and under orthostasis. METHODS Heart rate variability, respiration, forearm, and foot skin blood flow were assessed at rest and during postural test in 25 healthy volunteers. Spectral analysis was performed. Phase synchronization degree of analyzed signals was determined by group phase wavelet coherence function. RESULTS Skin blood flow was lower on foot at rest and during postural test than on forearm. High-frequency component of heart rate variability was higher at ~0.3 Hz during postural test versus rest. Blood flow oscillation amplitudes on the foot were lower in frequency range including respiratory interval at rest than on forearm. Postural exposure increased amplitude of foot blood flow oscillations in respiratory interval and decreased amplitudes in cardiac interval versus rest. Orthostasis increased group wavelet phase coherence between foot blood flow and heart rate variability or respiration, as well as between forearm and foot blood flow at 0.3 Hz corresponding to respiration. CONCLUSIONS The contribution of central mechanisms associated with respiration to blood flow regulation increased in lower extremities during orthostasis.
Collapse
Affiliation(s)
- Irina V Tikhonova
- Institute of Cell Biophysics of Russian Academy of Sciences, Pushchino, Russia
| | - Andrey A Grinevich
- Institute of Cell Biophysics of Russian Academy of Sciences, Pushchino, Russia
| | - Irina E Guseva
- Hospital of Pushchino Scientific Centre of Russian Academy of Sciences, Pushchino, Russia
| | - Arina V Tankanag
- Institute of Cell Biophysics of Russian Academy of Sciences, Pushchino, Russia
| |
Collapse
|
16
|
|
17
|
In-vivo correlations between skin metabolic oscillations and vasomotion in wild-type mice and in a model of oxidative stress. Sci Rep 2019; 9:186. [PMID: 30655574 PMCID: PMC6336806 DOI: 10.1038/s41598-018-36970-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 11/27/2018] [Indexed: 12/17/2022] Open
Abstract
Arterioles in the cutaneous microcirculation frequently display an oscillatory phenomenon defined vasomotion, consistent with periodic diameter variations in the micro-vessels associated with particular physiological or abnormal conditions. The cellular mechanisms underlying vasomotion and its physiological role have not been completely elucidated. Various mechanisms were demonstrated, based on cell Ca2+ oscillations determined by the activity of channels in the plasma membrane or sarcoplasmic reticulum of vascular cells. However, the possible engagement in vasomotion of cell metabolic oscillations of mitochondrial or glycolytic origin has been poorly explored. Metabolic oscillations associated with the production of ATP energy were previously described in cells, while limited studies have investigated these fluctuations in-vivo. Here, we characterised a low-frequency metabolic oscillator (MO-1) in skin from live wild-type and Nrf2−/− mice, by combination of fluorescence spectroscopy and wavelet transform processing technique. Furthermore, the relationships between metabolic and microvascular oscillators were examined during phenylephrine-induced vasoconstriction. We found a significant interaction between MO-1 and the endothelial EDHF vasomotor mechanism that was reduced in the presence of oxidative stress (Nrf2−/− mice). Our findings suggest indirectly that metabolic oscillations may be involved in the mechanisms underlying endothelium-mediated skin vasomotion, which might be altered in the presence of metabolic disturbance.
Collapse
|
18
|
Martini R, Bagno A. The wavelet analysis for the assessment of microvascular function with the laser Doppler fluxmetry over the last 20 years. Looking for hidden informations. Clin Hemorheol Microcirc 2018; 70:213-229. [DOI: 10.3233/ch-189903] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Romeo Martini
- Department of Cardio-Thorax and Vascular Sciences, Unit of Angiology, Azienda Ospedaliera Universitaria di Padova, Italy
| | - Andrea Bagno
- Department of Industrial Engineering, Università di Padova, Italy
| |
Collapse
|
19
|
Shokri-Kojori E, Tomasi D, Volkow ND. An Autonomic Network: Synchrony Between Slow Rhythms of Pulse and Brain Resting State Is Associated with Personality and Emotions. Cereb Cortex 2018; 28:3356-3371. [PMID: 29955858 PMCID: PMC6095212 DOI: 10.1093/cercor/bhy144] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 05/15/2018] [Accepted: 05/18/2018] [Indexed: 12/14/2022] Open
Abstract
The sympathetic system's role in modulating vasculature and its influence on emotions and personality led us to test the hypothesis that interactions between brain resting-state networks (RSNs) and pulse amplitude (indexing sympathetic activity) would be associated with emotions and personality. In 203 participants, we characterized RSN spatiotemporal characteristics, and phase-amplitude associations of RSN fluctuations with pulse and respiratory recordings. We found that RSNs are spatially reproducible within participants and were temporally associated with low frequencies (LFs < 0.1 Hz) in physiological signals. LF fluctuations in pulse amplitude were not related to cardiac electrical activity and preceded LF fluctuations in RSNs, while LF respiratory amplitude fluctuations followed LF fluctuations in RSNs. LF phase dispersion (PD) (lack of synchrony) between RSNs and pulse (PDpulse) (not respiratory) correlated with the common variability in measures of personality and emotions, with more synchrony being associated with more positive temperamental characteristics. Voxel-level PDpulse mapping revealed an "autonomic brain network," including sensory cortices and dorsal attention stream, with significant interactions with peripheral signals. Here, we uncover associations between pulse signal amplitude (presumably of sympathetic origin) and brain resting state, suggesting that interactions between central and autonomic nervous systems are important for characterizing personality and emotions.
Collapse
Affiliation(s)
- Ehsan Shokri-Kojori
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Dardo Tomasi
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Nora D Volkow
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
20
|
Silva H, Ferreira HA, da Silva HP, Monteiro Rodrigues L. The Venoarteriolar Reflex Significantly Reduces Contralateral Perfusion as Part of the Lower Limb Circulatory Homeostasis in vivo. Front Physiol 2018; 9:1123. [PMID: 30174614 PMCID: PMC6107688 DOI: 10.3389/fphys.2018.01123] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 07/27/2018] [Indexed: 12/31/2022] Open
Abstract
Perfusion at microvascular level involves the contribution of both local and central regulators, under a complex vascular signaling frame. The venoarteriolar reflex (VAR) is one of such regulatory responses, of particular relevance in the lower limb to prevent edema. Although known for quite some time, many of the complex interactions involving all of these regulatory mechanisms still need clarification. Our objective was to look deeper into VAR through modern photoplethymography (PPG). Twelve healthy subjects (both sexes, 26.0 ± 5.0 y.o.) were enrolled in this study after informed written consent. Subjects were submitted to a leg lowering maneuver while lying supine to evoke the VAR, involving three phases-10 min baseline register, both legs extended, 10 min challenge, with one randomly chosen leg (test) pending 50 cm below heart level, while the contralateral (control) remained in place, and 10 minutes recovery, resuming the initial position. PPG signals were collected from both feet and treated by the wavelet transform (WT) revealing six spectral bands in frequency intervals comprising the cardiac [1.6-0.7 Hz], respiratory [0.4-0.26 Hz], myogenic [0.26-0.1 Hz], neurogenic/sympathetic [0.1-0.045 Hz], endothelial NO-dependent (NOd) [0.045-0.015 Hz], and NO-independent (NOi) [0.015-0.007 Hz] activities. For the first time, this approach revealed that, with VAR, perfusion significantly decreased in both limbs, although the change was more pronounced in the test foot. Here, a significant decrease in myogenic, neurogenic and NOd, were noted, while the control foot recorded a decrease in neurogenic and an increase in NOd. These results confirm the utility of WT spectral analysis for flowmotion. Further, it strongly suggests that VAR results from a complex cooperation between local myogenic-endothelial responses, where a central neurogenic reflex might also be involved.
Collapse
Affiliation(s)
- Henrique Silva
- Research Center for Biosciences and Health Technologies, Universidade Lusófona's CBiOS, Lisbon, Portugal
- Pharmacological Sciences Department, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - Hugo A. Ferreira
- Faculty of Sciences, Institute of Biophysics and Biomedical Engineering, Universidade de Lisboa, Lisbon, Portugal
| | - Hugo P. da Silva
- IT - Instituto de Telecomunicações, Lisbon, Portugal
- School of Technology, Polytechnic Institute of Setúbal, Setúbal, Portugal
| | - L. Monteiro Rodrigues
- Research Center for Biosciences and Health Technologies, Universidade Lusófona's CBiOS, Lisbon, Portugal
- Pharmacological Sciences Department, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| |
Collapse
|
21
|
Astashev ME, Serov DA, Tankanag AV. Anesthesia effects on the low frequency blood flow oscillations in mouse skin. Skin Res Technol 2018; 25:40-46. [PMID: 29790611 DOI: 10.1111/srt.12593] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2018] [Indexed: 11/30/2022]
Abstract
BACKGROUND When laboratory animals are used one needs to anesthetize them before recording. However, the influence of anesthesia on animal blood flow oscillations has not been studied. The effects of two ways of anesthesia, zoletil-xylazine, and zoletil-nitrous oxide mixtures, on mouse skin perfusion using laser Doppler flowmetry (LDF) technique were studied. METHODS BALB/c mice were used. LDF probe was placed on the ventral surface of the left hind paw. Spectral analysis of LDF signals was performed with continuous adaptive wavelet transform to identify and describe peripheral blood flow oscillations in mouse skin. RESULTS Low-frequency oscillation interval boundaries (myogenic, neurogenic, and endothelial) for mice were shown to coincide with the boundaries determined for human and rats, that demonstrate their independence from the body size. Zoletil-xylazine anesthesia significantly decreased neurogenic and endothelial oscillation amplitudes by 29% and 50% respectively and increased the amplitude of cardiac oscillations by 23% compared to zoletyl-nitrous oxide anesthesia. There were no significant changes of the amplitudes of myogenic and respiratory oscillations with zoletil-nitrous oxide anesthesia compared to the zoletil-xylazine mixture. CONCLUSION We suggest that the different influence of anesthesia modes on the amplitudes of skin blood flow oscillations is associated with sympathetic activity suppressed by zoletil-xylazine anesthesia.
Collapse
Affiliation(s)
- M E Astashev
- Institute of Cell Biophysics, Russian Academy of Science, Pushchino, Moscow region, Russia
| | - D A Serov
- Institute of Fundamental Problems of Biology, Russian Academy of Science, Pushchino, Moscow region, Russia
| | - A V Tankanag
- Institute of Cell Biophysics, Russian Academy of Science, Pushchino, Moscow region, Russia
| |
Collapse
|
22
|
Zhang X, Qian X, Tao C, Liu X. In Vivo Imaging of Microvasculature during Anesthesia with High-Resolution Photoacoustic Microscopy. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:1110-1118. [PMID: 29499917 DOI: 10.1016/j.ultrasmedbio.2018.01.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 01/18/2018] [Accepted: 01/23/2018] [Indexed: 05/22/2023]
Abstract
Anesthesia monitoring is extremely important in improving the quality of anesthesia and ensuring the safety of patients in operation. Photoacoustic microscopy (PAM) is proposed to in vivo image the skin microvasculature of 10 nude mice undergoing general anesthesia by using the isoflurane gas with a concentration of 3%. Benefiting from strong optical absorption of hemoglobin, PAM has good contrast and high resolution in mapping of microvasculature. A series of high quality images can clearly reveal the subtle changes of capillaries in morphology over time. Two indices, vessel intensity and vessel density, are extracted from these images to measure the microvasculature quantitatively. The imaging results show that the vessel intensity and density are increased over time. After 65 min, the vessel intensity increased 42.7 ± 8.6% and the density increased 28.6 ± 12.2%. These indices extracted from photoacoustic images accurately reflect the greater blood perfusion undergoing general anesthesia. Additionally, abnormal reductions of vessel intensity and density are also observed as overtime anesthesia. This preclinical study suggests that PAM holds potential to monitor anesthesia by imaging the skin microvasculature.
Collapse
Affiliation(s)
- Xiang Zhang
- MOE Key Laboratory of Modern Acoustics, Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Xiaoqin Qian
- Department of Ultrasound, Affiliated People's Hospital of Jiangsu University, Zhenjiang, Jiangsu, China
| | - Chao Tao
- MOE Key Laboratory of Modern Acoustics, Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China.
| | - Xiaojun Liu
- MOE Key Laboratory of Modern Acoustics, Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| |
Collapse
|
23
|
Ticcinelli V, Stankovski T, Iatsenko D, Bernjak A, Bradbury AE, Gallagher AR, Clarkson PBM, McClintock PVE, Stefanovska A. Coherence and Coupling Functions Reveal Microvascular Impairment in Treated Hypertension. Front Physiol 2017; 8:749. [PMID: 29081750 PMCID: PMC5645539 DOI: 10.3389/fphys.2017.00749] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 09/14/2017] [Indexed: 01/02/2023] Open
Abstract
The complex interactions that give rise to heart rate variability (HRV) involve coupled physiological oscillators operating over a wide range of different frequencies and length-scales. Based on the premise that interactions are key to the functioning of complex systems, the time-dependent deterministic coupling parameters underlying cardiac, respiratory and vascular regulation have been investigated at both the central and microvascular levels. Hypertension was considered as an example of a globally altered state of the complex dynamics of the cardiovascular system. Its effects were established through analysis of simultaneous recordings of the electrocardiogram (ECG), respiratory effort, and microvascular blood flow [by laser Doppler flowmetry (LDF)]. The signals were analyzed by methods developed to capture time-dependent dynamics, including the wavelet transform, wavelet-based phase coherence, non-linear mode decomposition, and dynamical Bayesian inference, all of which can encompass the inherent frequency and coupling variability of living systems. Phases of oscillatory modes corresponding to the cardiac (around 1.0 Hz), respiratory (around 0.25 Hz), and vascular myogenic activities (around 0.1 Hz) were extracted and combined into two coupled networks describing the central and peripheral systems, respectively. The corresponding spectral powers and coupling functions were computed. The same measurements and analyses were performed for three groups of subjects: healthy young (Y group, 24.4 ± 3.4 y), healthy aged (A group, 71.1 ± 6.6 y), and aged treated hypertensive patients (ATH group, 70.3 ± 6.7 y). It was established that the degree of coherence between low-frequency oscillations near 0.1 Hz in blood flow and in HRV time series differs markedly between the groups, declining with age and nearly disappearing in treated hypertension. Comparing the two healthy groups it was found that the couplings to the cardiac rhythm from both respiration and vascular myogenic activity decrease significantly in aging. Comparing the data from A and ATH groups it was found that the coupling from the vascular myogenic activity is significantly weaker in treated hypertension subjects, implying that the mechanisms of microcirculation are not completely restored by current anti-hypertension medications.
Collapse
Affiliation(s)
| | - Tomislav Stankovski
- Physics Department, Lancaster University, Lancaster, United Kingdom
- Faculty of Medicine, Saints Cyril and Methodius University of Skopje, Skopje, Macedonia
| | - Dmytro Iatsenko
- Physics Department, Lancaster University, Lancaster, United Kingdom
- Deutsche Bank AG, London, United Kingdom
| | - Alan Bernjak
- Physics Department, Lancaster University, Lancaster, United Kingdom
- Department of Oncology & Metabolism, University of Sheffield, Sheffield, United Kingdom
| | - Adam E. Bradbury
- Physics Department, Lancaster University, Lancaster, United Kingdom
| | | | | | | | | |
Collapse
|
24
|
Tankanag AV, Grinevich AA, Tikhonova IV, Chaplygina AV, Chemeris NK. Phase synchronization of skin blood flow oscillations in humans under asymmetric local heating. Biophysics (Nagoya-shi) 2017. [DOI: 10.1134/s0006350917040212] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
25
|
Sorelli M, Stoyneva Z, Mizeva I, Bocchi L. Spatial heterogeneity in the time and frequency properties of skin perfusion. Physiol Meas 2017; 38:860-876. [DOI: 10.1088/1361-6579/aa5909] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
26
|
Flower RW, Kling R. Observation and characterization of microvascular vasomotion using erythrocyte mediated ICG angiography (EM-ICG-A). Microvasc Res 2017; 113:78-87. [PMID: 28390895 DOI: 10.1016/j.mvr.2017.02.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 02/23/2017] [Accepted: 02/25/2017] [Indexed: 10/19/2022]
Abstract
A clinical method for characterizing the state of micro-vasculature vasomotion is demonstrated, based on observing in capillaries the dynamics of autologously re-injected erythrocytes containing ICG dye. Since a manifestation of vasomotion is transient erythrocyte pausing, vasomotion state within a field of capillaries is characterized by an histogram plot of the number of paused erythrocytes as a function of pause duration during a fixed period of observation, then the ratio of long-pausing to short-pausing erythrocytes was calculated. The method was first applied to the posterior pole retinal vasculatures of anesthetized-monkey eyes, and normal vasomotion state during air-breathing was compared to the state induced by O2-breathing, known to cause mild arteriolar vasoconstriction in the mature eye. Subsequently, the effects of other antagonists to normal arteriolarvasotonia state (long-standing experimentally-induced ocular hypertension and branch-vein occlusion, as well as tissue edema) were similarly characterized and the results compared to those obtained during baseline air-breathing. The feasibility of applying the histogram characterization of vasomotion state to human eyes and skin was also preliminarily explored.
Collapse
Affiliation(s)
- Robert W Flower
- New York University School of Medicine, USA; University of Maryland School of Medicine, USA.
| | | |
Collapse
|
27
|
Bumstead JR, Bauer AQ, Wright PW, Culver JP. Cerebral functional connectivity and Mayer waves in mice: Phenomena and separability. J Cereb Blood Flow Metab 2017; 37:471-484. [PMID: 26868180 PMCID: PMC5381445 DOI: 10.1177/0271678x16629977] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Resting-state functional connectivity is a growing neuroimaging approach that analyses the spatiotemporal structure of spontaneous brain activity, often using low-frequency (<0.08 Hz) hemodynamics. In addition to these fluctuations, there are two other low-frequency hemodynamic oscillations in a nearby spectral region (0.1-0.4 Hz) that have been reported in the brain: vasomotion and Mayer waves. Despite how close in frequency these phenomena exist, there is little research on how vasomotion and Mayer waves are related to or affect resting-state functional connectivity. In this study, we analyze spontaneous hemodynamic fluctuations over the mouse cortex using optical intrinsic signal imaging. We found spontaneous occurrence of oscillatory hemodynamics ∼0.2 Hz consistent with the properties of Mayer waves reported in the literature. Across a group of mice (n = 19), there was a large variability in the magnitude of Mayer waves. However, regardless of the magnitude of Mayer waves, functional connectivity patterns could be recovered from hemodynamic signals when filtered to the lower frequency band, 0.01-0.08 Hz. Our results demonstrate that both Mayer waves and resting-state functional connectivity patterns can co-exist simultaneously, and that they can be separated by applying bandpass filters.
Collapse
Affiliation(s)
- Jonathan R Bumstead
- 1 Department of Biomedical Engineering, Washington University in St Louis, St Louis, Missouri, USA
| | - Adam Q Bauer
- 2 Department of Radiology, Washington University in St Louis, St Louis, Missouri, USA
| | - Patrick W Wright
- 1 Department of Biomedical Engineering, Washington University in St Louis, St Louis, Missouri, USA.,2 Department of Radiology, Washington University in St Louis, St Louis, Missouri, USA
| | - Joseph P Culver
- 1 Department of Biomedical Engineering, Washington University in St Louis, St Louis, Missouri, USA.,2 Department of Radiology, Washington University in St Louis, St Louis, Missouri, USA.,3 Department of Physics, Washington University in St Louis, St Louis, Missouri, USA
| |
Collapse
|
28
|
Kenwright DA, Bernjak A, Draegni T, Dzeroski S, Entwistle M, Horvat M, Kvandal P, Landsverk SA, McClintock PVE, Musizza B, Petrovčič J, Raeder J, Sheppard LW, Smith AF, Stankovski T, Stefanovska A. The discriminatory value of cardiorespiratory interactions in distinguishing awake from anaesthetised states: a randomised observational study. Anaesthesia 2015; 70:1356-68. [PMID: 26350998 PMCID: PMC4989441 DOI: 10.1111/anae.13208] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2015] [Indexed: 12/20/2022]
Abstract
Depth of anaesthesia monitors usually analyse cerebral function with or without other physiological signals; non‐invasive monitoring of the measured cardiorespiratory signals alone would offer a simple, practical alternative. We aimed to investigate whether such signals, analysed with novel, non‐linear dynamic methods, would distinguish between the awake and anaesthetised states. We recorded ECG, respiration, skin temperature, pulse and skin conductivity before and during general anaesthesia in 27 subjects in good cardiovascular health, randomly allocated to receive propofol or sevoflurane. Mean values, variability and dynamic interactions were determined. Respiratory rate (p = 0.0002), skin conductivity (p = 0.03) and skin temperature (p = 0.00006) changed with sevoflurane, and skin temperature (p = 0.0005) with propofol. Pulse transit time increased by 17% with sevoflurane (p = 0.02) and 11% with propofol (p = 0.007). Sevoflurane reduced the wavelet energy of heart (p = 0.0004) and respiratory (p = 0.02) rate variability at all frequencies, whereas propofol decreased only the heart rate variability below 0.021 Hz (p < 0.05). The phase coherence was reduced by both agents at frequencies below 0.145 Hz (p < 0.05), whereas the cardiorespiratory synchronisation time was increased (p < 0.05). A classification analysis based on an optimal set of discriminatory parameters distinguished with 95% success between the awake and anaesthetised states. We suggest that these results can contribute to the design of new monitors of anaesthetic depth based on cardiovascular signals alone.
Collapse
Affiliation(s)
| | | | - T Draegni
- Oslo University Hospital, Ullevaal, Norway
| | - S Dzeroski
- Jožef Stefan Institute, Ljubljana, Slovenia
| | | | - M Horvat
- Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
| | - P Kvandal
- Oslo University Hospital, Ullevaal, Norway
| | | | | | - B Musizza
- Jožef Stefan Institute, Ljubljana, Slovenia
| | | | - J Raeder
- Oslo University Hospital, Ullevaal, Norway
| | | | - A F Smith
- Royal Lancaster Infirmary, Lancaster, UK
| | | | | |
Collapse
|
29
|
Abstract
Intrarenal autoregulatory mechanisms maintain renal blood flow (RBF) and glomerular filtration rate (GFR) independent of renal perfusion pressure (RPP) over a defined range (80-180 mmHg). Such autoregulation is mediated largely by the myogenic and the macula densa-tubuloglomerular feedback (MD-TGF) responses that regulate preglomerular vasomotor tone primarily of the afferent arteriole. Differences in response times allow separation of these mechanisms in the time and frequency domains. Mechanotransduction initiating the myogenic response requires a sensing mechanism activated by stretch of vascular smooth muscle cells (VSMCs) and coupled to intracellular signaling pathways eliciting plasma membrane depolarization and a rise in cytosolic free calcium concentration ([Ca(2+)]i). Proposed mechanosensors include epithelial sodium channels (ENaC), integrins, and/or transient receptor potential (TRP) channels. Increased [Ca(2+)]i occurs predominantly by Ca(2+) influx through L-type voltage-operated Ca(2+) channels (VOCC). Increased [Ca(2+)]i activates inositol trisphosphate receptors (IP3R) and ryanodine receptors (RyR) to mobilize Ca(2+) from sarcoplasmic reticular stores. Myogenic vasoconstriction is sustained by increased Ca(2+) sensitivity, mediated by protein kinase C and Rho/Rho-kinase that favors a positive balance between myosin light-chain kinase and phosphatase. Increased RPP activates MD-TGF by transducing a signal of epithelial MD salt reabsorption to adjust afferent arteriolar vasoconstriction. A combination of vascular and tubular mechanisms, novel to the kidney, provides for high autoregulatory efficiency that maintains RBF and GFR, stabilizes sodium excretion, and buffers transmission of RPP to sensitive glomerular capillaries, thereby protecting against hypertensive barotrauma. A unique aspect of the myogenic response in the renal vasculature is modulation of its strength and speed by the MD-TGF and by a connecting tubule glomerular feedback (CT-GF) mechanism. Reactive oxygen species and nitric oxide are modulators of myogenic and MD-TGF mechanisms. Attenuated renal autoregulation contributes to renal damage in many, but not all, models of renal, diabetic, and hypertensive diseases. This review provides a summary of our current knowledge regarding underlying mechanisms enabling renal autoregulation in health and disease and methods used for its study.
Collapse
Affiliation(s)
- Mattias Carlström
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Christopher S Wilcox
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - William J Arendshorst
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| |
Collapse
|
30
|
Tankanag AV, Grinevich AA, Kirilina TV, Krasnikov GV, Piskunova GM, Chemeris NK. Wavelet phase coherence analysis of the skin blood flow oscillations in human. Microvasc Res 2014; 95:53-9. [DOI: 10.1016/j.mvr.2014.07.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 07/04/2014] [Accepted: 07/05/2014] [Indexed: 11/25/2022]
|
31
|
de Boer MP, Meijer RI, Newman J, Stehouwer CD, Eringa EC, Smulders YM, Serné EH. Insulin-Induced Changes in Microvascular Vasomotion and Capillary Recruitment are Associated in Humans. Microcirculation 2014; 21:380-7. [DOI: 10.1111/micc.12114] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 01/13/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Michiel P. de Boer
- Department of Internal Medicine; Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center; Amsterdam The Netherlands
| | - Rick I. Meijer
- Department of Internal Medicine; Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center; Amsterdam The Netherlands
| | - John Newman
- Menzies Research Institute; University of Tasmania; Hobart Tasmania Australia
| | - Coen D.A. Stehouwer
- Department of Internal Medicine and the Cardiovascular Research Institute Maastricht (CARIM); University Hospital Maastricht; Maastricht The Netherlands
| | - Etto C. Eringa
- Laboratory for Physiology; Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center; Amsterdam The Netherlands
| | - Yvo M. Smulders
- Department of Internal Medicine; Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center; Amsterdam The Netherlands
| | - Erik H. Serné
- Department of Internal Medicine; Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center; Amsterdam The Netherlands
| |
Collapse
|
32
|
Jan YK, Anderson M, Soltani J, Burns S, Foreman RD. Comparison of changes in heart rate variability and sacral skin perfusion in response to postural changes in people with spinal cord injury. ACTA ACUST UNITED AC 2014; 50:203-14. [PMID: 23761001 DOI: 10.1682/jrrd.2011.08.0138] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The current clinical practice has established guidelines to assess influences of severity of autonomic injury on the control of heart and blood pressure following spinal cord injury (SCI). However, the influences of SCI-induced autonomic impairment on microvascular dysfunction have not yet been established. Heart rate variability (HRV) has been shown to be a potential tool for quantifying residual sympathovagal regulation of the cardiovascular system following SCI and may be used to assess the effect of autonomic injury on skin microvascular dysfunction. A total of 26 people were recruited into the study, including 12 people with SCI and 14 nondisabled controls. HRV and sacral skin intervals and sacral skin perfusion were continually recorded during 10 min upright and 10 min prone postures. The sympathovagal balance was defined as the ratio of the power of the low frequency to the high frequency of HRV. The results showed that postural changes of nondisabled people produced significant changes in the sympathovagal balance; lower sympathovagal balance was associated with higher skin perfusion (p < 0.05). People with SCI did not show a significant change of HRV and skin perfusion in response to postural changes. In this study, we have demonstrated that the sympathovagal balance assessed by HRV was associated with the skin vasoconstrictive response to postural changes.
Collapse
Affiliation(s)
- Yih-Kuen Jan
- Rehabilitation Research Laboratory, Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, 1206 S Forth St, Champaign, IL 61820, USA.
| | | | | | | | | |
Collapse
|
33
|
Gargiulo S, Gramanzini M, Liuzzi R, Greco A, Brunetti A, Vesce G. Effects of some anesthetic agents on skin microcirculation evaluated by laser Doppler perfusion imaging in mice. BMC Vet Res 2013; 9:255. [PMID: 24341447 PMCID: PMC3878498 DOI: 10.1186/1746-6148-9-255] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 12/02/2013] [Indexed: 11/30/2022] Open
Abstract
Background Anesthetic agents alter microcirculation, influencing tissue oxygenation and delivery of vital substrates. Laser Doppler perfusion imaging is a widespread technique in the field of microvascular research that can evaluate noninvasively and in real time the effects of environmental conditions, physical manipulations, diseases and treatments on peripheral perfusion. This study aims to evaluate laser Doppler perfusion imaging as a means to detect changes in skin microcirculation induced by some popular anesthetic agents in a murine model. Twenty-four age- and gender-matched healthy CD1 mice were examined by laser Doppler perfusion imaging. The skin microcirculatory response was measured at the level of plantar surfaces during isoflurane anesthesia with or without subsequent dexmedetomidine or acepromazine. At the end of the procedure, dexmedetomidine was reversed by atipamezole administration. Results In all mice, skin blood flow under isoflurane anesthesia did not show significant differences over time (P = 0.1). The serial perfusion pattern and values following acepromazine or dexmedetomidine administration differed significantly (P < 0.05). Conclusions We standardized a reliable laser Doppler perfusion imaging protocol to non-invasively assess changes in skin microcirculation induced by anesthesia in mice, considering the advantages and drawbacks of this technique and its translational value.
Collapse
Affiliation(s)
- Sara Gargiulo
- Institute of Biostructures and Bioimages of the National Council of Research, Via T, De Amicis 95, Naples 80145, Italy.
| | | | | | | | | | | |
Collapse
|
34
|
Smirnova E, Podtaev S, Mizeva I, Loran E. Assessment of endothelial dysfunction in patients with impaired glucose tolerance during a cold pressor test. Diab Vasc Dis Res 2013; 10:489-97. [PMID: 23975726 DOI: 10.1177/1479164113494881] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The objective of this study is to explore changes in microvascular tone during a contralateral cold pressor test and to compare the results obtained in healthy subjects and in patients with impaired glucose tolerance (IGT) and type 2 diabetes. Low-amplitude fluctuations of skin temperature in the appropriate frequency ranges were used as a characteristic for the mechanism for vascular tone regulation. In total, 13 adults with type 2 diabetes aged 40-67 years and 18 adults with IGT aged 31-60 years participated in this pilot study. The control group included 12 healthy men and women aged 39-60 years. The response to the cold pressor test in patients with type 2 diabetes and with IGT differs essentially from that of healthy subjects in the endothelial frequency range. Endothelial dysfunction occurs in the preclinical stage of diabetes and manifests, in particular, as a disturbance of the endothelial part of vascular tone regulation.
Collapse
|
35
|
Papaioannou VE, Chouvarda IG, Maglaveras NK, Baltopoulos GI, Pneumatikos IA. Temperature multiscale entropy analysis: a promising marker for early prediction of mortality in septic patients. Physiol Meas 2013; 34:1449-66. [PMID: 24149496 DOI: 10.1088/0967-3334/34/11/1449] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A few studies estimating temperature complexity have found decreased Shannon entropy, during severe stress. In this study, we measured both Shannon and Tsallis entropy of temperature signals in a cohort of critically ill patients and compared these measures with the sequential organ failure assessment (SOFA) score, in terms of intensive care unit (ICU) mortality. Skin temperature was recorded in 21 mechanically ventilated patients, who developed sepsis and septic shock during the first 24 h of an ICU-acquired infection. Shannon and Tsallis entropies were calculated in wavelet-based decompositions of the temperature signal. Statistically significant differences of entropy features were tested between survivors and non-survivors and classification models were built, for predicting final outcome. Significantly reduced Tsallis and Shannon entropies were found in non-survivors (seven patients, 33%) as compared to survivors. Wavelet measurements of both entropy metrics were found to predict ICU mortality better than SOFA, according to a combination of area under the curve, sensitivity and specificity values. Both entropies exhibited similar prognostic accuracy. Combination of SOFA and entropy presented improved the outcome of univariate models. We suggest that reduced wavelet Shannon and Tsallis entropies of temperature signals may complement SOFA in mortality prediction, during the first 24 h of an ICU-acquired infection.
Collapse
Affiliation(s)
- V E Papaioannou
- Democritus University of Thrace, Alexandroupolis University Hospital, Intensive Care Unit, Dragana 68100, Greece
| | | | | | | | | |
Collapse
|
36
|
Iatsenko D, Bernjak A, Stankovski T, Shiogai Y, Owen-Lynch PJ, Clarkson PBM, McClintock PVE, Stefanovska A. Evolution of cardiorespiratory interactions with age. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2013; 371:20110622. [PMID: 23858485 PMCID: PMC4042892 DOI: 10.1098/rsta.2011.0622] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We describe an analysis of cardiac and respiratory time series recorded from 189 subjects of both genders aged 16-90. By application of the synchrosqueezed wavelet transform, we extract the respiratory and cardiac frequencies and phases with better time resolution than is possible with the marked events procedure. By treating the heart and respiration as coupled oscillators, we then apply a method based on Bayesian inference to find the underlying coupling parameters and their time dependence, deriving from them measures such as synchronization, coupling directionality and the relative contributions of different mechanisms. We report a detailed analysis of the reconstructed cardiorespiratory coupling function, its time evolution and age dependence. We show that the direct and indirect respiratory modulations of the heart rate both decrease with age, and that the cardiorespiratory coupling becomes less stable and more time-variable.
Collapse
Affiliation(s)
- D. Iatsenko
- Department of Physics, Lancaster University, Lancaster LA1 4YB, UK
- e-mail:
| | - A. Bernjak
- Department of Physics, Lancaster University, Lancaster LA1 4YB, UK
- Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - T. Stankovski
- Department of Physics, Lancaster University, Lancaster LA1 4YB, UK
| | - Y. Shiogai
- Department of Physics, Lancaster University, Lancaster LA1 4YB, UK
| | - P. J. Owen-Lynch
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK
| | - P. B. M. Clarkson
- Cardiology Department, Raigmore Hospital, Old Perth Road, Inverness IV2 3UJ, UK
| | | | - A. Stefanovska
- Department of Physics, Lancaster University, Lancaster LA1 4YB, UK
- Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| |
Collapse
|
37
|
Papaioannou VE, Chouvarda IG, Maglaveras NK, Pneumatikos IA. Temperature variability analysis using wavelets and multiscale entropy in patients with systemic inflammatory response syndrome, sepsis, and septic shock. Crit Care 2012; 16:R51. [PMID: 22424316 PMCID: PMC3681376 DOI: 10.1186/cc11255] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 03/18/2012] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Even though temperature is a continuous quantitative variable, its measurement has been considered a snapshot of a process, indicating whether a patient is febrile or afebrile. Recently, other diagnostic techniques have been proposed for the association between different properties of the temperature curve with severity of illness in the Intensive Care Unit (ICU), based on complexity analysis of continuously monitored body temperature. In this study, we tried to assess temperature complexity in patients with systemic inflammation during a suspected ICU-acquired infection, by using wavelets transformation and multiscale entropy of temperature signals, in a cohort of mixed critically ill patients. METHODS Twenty-two patients were enrolled in the study. In five, systemic inflammatory response syndrome (SIRS, group 1) developed, 10 had sepsis (group 2), and seven had septic shock (group 3). All temperature curves were studied during the first 24 hours of an inflammatory state. A wavelet transformation was applied, decomposing the signal in different frequency components (scales) that have been found to reflect neurogenic and metabolic inputs on temperature oscillations. Wavelet energy and entropy per different scales associated with complexity in specific frequency bands and multiscale entropy of the whole signal were calculated. Moreover, a clustering technique and a linear discriminant analysis (LDA) were applied for permitting pattern recognition in data sets and assessing diagnostic accuracy of different wavelet features among the three classes of patients. RESULTS Statistically significant differences were found in wavelet entropy between patients with SIRS and groups 2 and 3, and in specific ultradian bands between SIRS and group 3, with decreased entropy in sepsis. Cluster analysis using wavelet features in specific bands revealed concrete clusters closely related with the groups in focus. LDA after wrapper-based feature selection was able to classify with an accuracy of more than 80% SIRS from the two sepsis groups, based on multiparametric patterns of entropy values in the very low frequencies and indicating reduced metabolic inputs on local thermoregulation, probably associated with extensive vasodilatation. CONCLUSIONS We suggest that complexity analysis of temperature signals can assess inherent thermoregulatory dynamics during systemic inflammation and has increased discriminating value in patients with infectious versus noninfectious conditions, probably associated with severity of illness.
Collapse
Affiliation(s)
- Vasilios E Papaioannou
- Alexandroupolis University Hospital, Intensive Care Unit, Democritus University of Thrace, Dragana 68100, Greece
| | - Ioanna G Chouvarda
- Laboratory of Medical Informatics, School of Medicine, Aristotle University of Thessaloniki, 54124, Greece
| | - Nikos K Maglaveras
- Laboratory of Medical Informatics, School of Medicine, Aristotle University of Thessaloniki, 54124, Greece
| | - Ioannis A Pneumatikos
- Alexandroupolis University Hospital, Intensive Care Unit, Democritus University of Thrace, Dragana 68100, Greece
| |
Collapse
|
38
|
Krasnikov GV, Tyurina MY, Tankanag AV, Piskunova GM, Chemeris NK. Analysis of heart rate variability and skin blood flow oscillations under deep controlled breathing. Respir Physiol Neurobiol 2012; 185:562-70. [PMID: 23174619 DOI: 10.1016/j.resp.2012.11.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 11/08/2012] [Accepted: 11/12/2012] [Indexed: 10/27/2022]
Abstract
The effect of deep breathing controlled in both rate (0.25, 0.16, 0.1, 0.07, 0.05 and 0.03 Hz) and amplitude on the heart rate variability (HRV) and respiration-dependent oscillations of forearm/finger skin blood flow (SBF) has been studied in 29 young healthy volunteers. The influence of sympathovagal balance on the respiratory sinus arrhythmia (RSA) amplitude and respiratory SBF oscillations has been studied. The subjects with predominant parasympathetic tonus had statistically significant higher RSA amplitudes in the breathing rate region of 0.03-0.07 Hz than the subjects with predominant sympathetic tonus. In the finger-cushion zone, having a well-developed sympathetic vascular innervations, the amplitudes of respiratory SBF oscillations at breathing rates 0.05 and 0.07 Hz were higher in the group of subjects with predominant parasympathetic tonus. In the forearm skin, where the density of sympathetic innervations is low comparatively to that in the finger skin, no statistically significant differences in the amplitude of respiratory SBF oscillations were found concerning the two groups of subjects.
Collapse
Affiliation(s)
- Gennady V Krasnikov
- Tula State Lev Tolstoy Pedagogical University, Prospekt Lenina, 125, Tula 300026, Russia
| | | | | | | | | |
Collapse
|
39
|
Tikhonova IV, Tankanag AV, Chemeris NK. Age-related changes of skin blood flow during postocclusive reactive hyperemia in human. Skin Res Technol 2012; 19:e174-81. [DOI: 10.1111/j.1600-0846.2012.00624.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/26/2012] [Indexed: 12/01/2022]
Affiliation(s)
- Irina V. Tikhonova
- Institute of Cell Biophysics; Russian Academy of Sciences; Institutskaya st. 3; Pushchino; Moscow Region; 142290; Russia
| | - Arina V. Tankanag
- Institute of Cell Biophysics; Russian Academy of Sciences; Institutskaya st. 3; Pushchino; Moscow Region; 142290; Russia
| | - Nikolay K. Chemeris
- Institute of Cell Biophysics; Russian Academy of Sciences; Institutskaya st. 3; Pushchino; Moscow Region; 142290; Russia
| |
Collapse
|
40
|
Cannesson M, de Backer D, Hofer CK. Using arterial pressure waveform analysis for the assessment of fluid responsiveness. Expert Rev Med Devices 2012; 8:635-46. [PMID: 22026628 DOI: 10.1586/erd.11.30] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Predicting the effects of volume expansion on cardiac output and oxygen delivery is of major importance in different clinical scenarios. Functional hemodynamic parameters based on pulse waveform analysis, which are relying on the effects of mechanical ventilation on stroke volume and its surrogates, have been shown to be reliable predictors of fluid responsiveness during anesthesia and intensive care unit treatment, as demonstrated by several clinical studies and meta-analyses. However, different limitations of these parameters have to be considered when they are used in clinical practice. Today, they can be continuously and automatically monitored by a variety of commercially available devices. These parameters have been introduced into the concept of perioperative fluid management and hemodynamic optimization - an approach that may positively impact postoperative patients' outcomes. In this article, technical aspects of the assessment of the functional hemodynamic parameters derived from pulse waveform analysis are summarized, emphasizing their advantages, limitations and potential applications, primarily in a perioperative setting in order to improve patient outcome.
Collapse
Affiliation(s)
- Maxime Cannesson
- Department of Anesthesiology & Perioperative Care, School of Medicine, University of California, Irvine, CA, USA.
| | | | | |
Collapse
|
41
|
Deep and surface hemodynamic signal from functional time resolved transcranial near infrared spectroscopy compared to skin flowmotion. Comput Biol Med 2012; 42:282-9. [DOI: 10.1016/j.compbiomed.2011.06.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 04/18/2011] [Accepted: 06/01/2011] [Indexed: 11/20/2022]
|
42
|
Evaluation of fluid responsiveness: is photoplethysmography a noninvasive alternative? Anesthesiol Res Pract 2012; 2012:617380. [PMID: 22611386 PMCID: PMC3353145 DOI: 10.1155/2012/617380] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 11/29/2011] [Accepted: 12/21/2011] [Indexed: 11/18/2022] Open
Abstract
Background. Goal-directed fluid therapy reduces morbidity and mortality in various clinical settings. Respiratory variations in photoplethysmography are proposed as a noninvasive alternative to predict fluid responsiveness during mechanical ventilation. This paper aims to critically evaluate current data on the ability of photoplethysmography to predict fluid responsiveness. Method. Primary searches were performed in PubMed, Medline, and Embase on November 10, 2011. Results. 14 papers evaluating photoplethysmography and fluid responsiveness were found. Nine studies calculated areas under the receiver operating characteristic curves for ΔPOP (>0.85 in four, 0.75–0.85 in one, and <0.75 in four studies) and seven for PVI (values ranging from 0.54 to 0.98). Correlations between ΔPOP/PVI and ΔPP/other dynamic variables vary substantially. Conclusion. Although photoplethysmography is a promising technique, predictive values and correlations with other hemodynamic variables indicating fluid responsiveness vary substantially. Presently, it is not documented that photoplethysmography is adequately valid and reliable to be included in clinical practice for evaluation of fluid responsiveness.
Collapse
|
43
|
Rinehart J, Liu N, Alexander B, Cannesson M. Review article: closed-loop systems in anesthesia: is there a potential for closed-loop fluid management and hemodynamic optimization? Anesth Analg 2011; 114:130-43. [PMID: 21965362 DOI: 10.1213/ane.0b013e318230e9e0] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Closed-loop (automated) controllers are encountered in all aspects of modern life in applications ranging from air-conditioning to spaceflight. Although these systems are virtually ubiquitous, they are infrequently used in anesthesiology because of the complexity of physiologic systems and the difficulty in obtaining reliable and valid feedback data from the patient. Despite these challenges, closed-loop systems are being increasingly studied and improved for medical use. Two recent developments have made fluid administration a candidate for closed-loop control. First, the further description and development of dynamic predictors of fluid responsiveness provides a strong parameter for use as a control variable to guide fluid administration. Second, rapid advances in noninvasive monitoring of cardiac output and other hemodynamic variables make goal-directed therapy applicable for a wide range of patients in a variety of clinical care settings. In this article, we review the history of closed-loop controllers in clinical care, discuss the current understanding and limitations of the dynamic predictors of fluid responsiveness, and examine how these variables might be incorporated into a closed-loop fluid administration system.
Collapse
Affiliation(s)
- Joseph Rinehart
- Department of Anesthesiology & Perioperative Care, University of California, Irvine, USA
| | | | | | | |
Collapse
|
44
|
The impact of induction of general anesthesia and a vascular occlusion test on tissue oxygen saturation derived parameters in high-risk surgical patients. J Clin Monit Comput 2011; 25:237-44. [PMID: 21948067 DOI: 10.1007/s10877-011-9301-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 08/29/2011] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Tissue oxygen saturation (StO(2)) assessed using Near Infrared Spectroscopy and its derived parameters during a vascular occlusion test (VOT) can detect microvascular changes in septic shock patients. General anesthesia (GA) impacts microcirculation. Our aim was to study the effects of general anesthesia on StO(2) and StO(2) derived parameters obtained during VOT in patients referred for cardiac surgery. METHODS We studied 15 patients referred for cardiac surgery before and after induction of GA. Before GA induction, we also studied 15 healthy volunteers (non patients) in order to compare baseline physiological data between patients and healthy subjects. Hemodynamic and microcirculatory (StO(2), ischemic slope, reperfusion slope, and hyperemic response) data were recorded at each step. We used the Inspectra StO(2) system (Hutchinson Inc, MN, USA) with a sensor placed on the thenar eminence. StO(2) values were obtained at baseline and during a VOT. A sphyngomanometer was placed on the forearm above the StO(2) probe and the cuff was then rapidly inflated 30 mmHg above systolic pressure and was maintained inflated until the StO(2) value reached 40%. It was then rapidly deflated. RESULTS Healthy volunteers had significantly higher reperfusion slope than patients (348 [251-393] vs. 261 [185-279] %/min; P < 0.05). GA induction induced no significant change in StO(2) value compared to baseline (79 [75-85] vs. 80 [76-86]%; P = 0.57). We observed a significant decrease in ischemic slope (from -12 [-16--8] to -8 [-10--6] %/min; P = 0.004) and in reperfusion slope (from 261 [185-279] %/min to 164 [151-222] %/min; P = 0.008) suggesting a decrease in local metabolic rate and a negative impact on reperfusion reserve induced by anesthesia. CONCLUSION StO(2) derived parameters during a VOT are impacted by GA induction. These parameters may have potential for microcirculation assessment in patients undergoing surgery.
Collapse
|
45
|
Cannesson M, Aboy M, Hofer CK, Rehman M. Pulse pressure variation: where are we today? J Clin Monit Comput 2011; 25:45-56. [PMID: 20390324 DOI: 10.1007/s10877-010-9229-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 03/09/2010] [Indexed: 12/19/2022]
Abstract
In the present review we will describe and discuss the physiological and technological background necessary in understanding the dynamic parameters of fluid responsiveness and how they relate to recent softwares and algorithms' applications. We will also discuss the potential clinical applications of these parameters in the management of patients under general anesthesia and mechanical ventilation along with the potential improvements in the computational algorithms.
Collapse
Affiliation(s)
- Maxime Cannesson
- Department of Anesthesiology & Perioperative Care, University of California, Irvine, 333 City Boulevard West Side, Orange, CA 92868-3301, USA
| | | | | | | |
Collapse
|
46
|
Physiologic and Clinical Principles behind Noninvasive Resuscitation Techniques and Cardiac Output Monitoring. Cardiol Res Pract 2011; 2012:531908. [PMID: 21860802 PMCID: PMC3157155 DOI: 10.1155/2012/531908] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 05/13/2011] [Accepted: 05/15/2011] [Indexed: 01/20/2023] Open
Abstract
Clinical assessment and vital signs are poor predictors of the overall hemodynamic state. Optimal measurement of the response to fluid resuscitation and hemodynamics has previously required invasive measurement with radial and pulmonary artery catheterization. Newer noninvasive resuscitation technology offers the hope of more accurately and safely monitoring a broader range of critically ill patients while using fewer resources. Fluid responsiveness, the cardiac response to volume loading, represents a dynamic method of improving upon the assessment of preload when compared to static measures like central venous pressure. Multiple new hemodynamic monitors now exist that can noninvasively report cardiac output and oxygen delivery in a continuous manner. Proper assessment of the potential future role of these techniques in resuscitation requires understanding the underlying physiologic and clinical principles, reviewing the most recent literature examining their clinical validity, and evaluating their respective advantages and limitations.
Collapse
|
47
|
Desgranges FP, Desebbe O, Ghazouani A, Gilbert K, Keller G, Chiari P, Robin J, Bastien O, Lehot JJ, Cannesson M. Influence of the site of measurement on the ability of plethysmographic variability index to predict fluid responsiveness. Br J Anaesth 2011; 107:329-35. [PMID: 21680600 DOI: 10.1093/bja/aer165] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Plethysmographic variability index (PVI) is an accurate predictor of fluid responsiveness in mechanically ventilated patients. However, the site of measurement of the plethysmographic waveform impacts its morphology and its respiratory variation. The goal of this study was to investigate the ability of PVI to predict fluid responsiveness at three sites of measurement (the forehead, ear, and finger) in mechanically ventilated patients under general anaesthesia. METHODS We studied 28 subjects after induction of general anaesthesia. Subjects were monitored with a pulmonary artery catheter and three pulse oximeter sensors (the finger, ear, and forehead). Pulse pressure variation, central venous pressure, cardiac index (CI), and PVI measured at the forehead, ear, and finger (PVI(forehead), PVI(ear), and PVI(finger)) were recorded before and after fluid loading (FL). Subjects were responders to volume expansion if CI increased >15% after FL. RESULTS Areas under the receiver-operating curves to predict fluid responsiveness were 0.906, 0.880, and 0.836 for PVI(forehead), PVI(ear), and PVI(finger), respectively (P<0.05). PVI(forehead), PVI(ear), and PVI(finger) had a threshold value to predict fluid responsiveness of 15%, 16%, and 12% with sensitivities of 89%, 74%, and 74% and specificities of 78%, 74%, and 67%, respectively. CONCLUSIONS PVI can predict fluid responsiveness in anaesthetized and ventilated subjects at all three sites of measurement. However, the threshold values for predicting fluid responsiveness differ with the site of measurement. These results support the use of this plethysmographic dynamic index in the cephalic region when the finger is inaccessible or during states of low peripheral perfusion.
Collapse
Affiliation(s)
- F-P Desgranges
- Hospices Civils de Lyon, Department of Anesthesiology and Intensive Care, Louis Pradel Hospital, Claude Bernard Lyon 1 University, INSERM ERI 22, Lyon, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Awan Z, Häggblad E, Wester T, Kvernebo M, Halvorsen P, Kvernebo K. Diffuse reflectance spectroscopy: Systemic and microvascular oxygen saturation is linearly correlated and hypoxia leads to increased spatial heterogeneity of microvascular saturation. Microvasc Res 2011; 81:245-51. [DOI: 10.1016/j.mvr.2011.02.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2010] [Revised: 02/24/2011] [Accepted: 02/24/2011] [Indexed: 11/30/2022]
|
49
|
Multifractal analysis of nonlinear complexity of sacral skin blood flow oscillations in older adults. Med Biol Eng Comput 2011; 49:925-34. [PMID: 21487818 DOI: 10.1007/s11517-011-0775-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 04/01/2011] [Indexed: 10/18/2022]
Abstract
The objective of this study was to investigate the relationship between cutaneous vasodilatory function and nonlinear complexity of blood flow oscillations (BFO) in older people. A non-painful fast local heating protocol was applied to the sacral skin in 20 older subjects with various vasodilatory functions. Laser Doppler flowmetry was used to measure skin blood oscillations. The complexity of the characteristic frequencies (i.e., metabolic (0.0095-0.02 Hz), neurogenic (0.02-0.05 Hz), myogenic (0.05-0.15 Hz), respiratory (0.15-0.4 Hz), and cardiac (0.4-2 Hz)) of BFO was quantified using the multifractal detrended fluctuation analysis. Compared with the 65-75 years group, the complexity of metabolic BFO in the 75-85 years group was significantly lower at the baseline (P < 0.05) and the second peak (P < 0.001). Compared with baseline BFO, subjects in the 65-75 years group had a significant increase in the complexity of metabolic BFO (P < 0.01) in response to local heating; while subjects in the 75-85 years group did not. Our findings support the use of multifractal analysis to assess aging-related microvascular dysfunction.
Collapse
|
50
|
Maurer K, Wacker J, Vastani N, Seifert B, Spahn DR. Changes in axonal excitability of primary sensory afferents with general anaesthesia in humans. Br J Anaesth 2010; 105:648-56. [PMID: 20729532 DOI: 10.1093/bja/aeq218] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Intraoperative monitoring of neuronal function is important in a variety of surgeries. The type of general anaesthetic used can affect the interpretation and quality of such recordings. Although the principal effects of general anaesthetics are synaptically mediated, the extent to which they affect excitability of the peripheral afferent nervous system is unclear. METHODS Forty subjects were randomized in a stratified manner into two groups, anaesthetized with either propofol or sevoflurane. The threshold tracking technique (QTRAC(®)) was used to measure nerve excitability parameters of the sensory action potential of the median nerve before and after induction of general anaesthesia. RESULTS Several parameters of peripheral sensory afferent nerve excitability changed after induction of general anaesthesia, which were similar for both propofol and sevoflurane. The maximum amplitude of the sensory nerve action potential decreased in both groups (propofol: 25.3%; sevoflurane: 29.5%; both P<0.01). The relative refractory period [mean (sd)] also decreased similarly in both groups [propofol: -0.6 (0.7) ms; sevoflurane: -0.3 (0.5) ms; both P<0.01]. Skin temperature at the stimulation site increased significantly in both groups [propofol: +1.2 (1.0)°C; sevoflurane: +1.7 (1.4)°C; both P<0.01]. CONCLUSIONS Small changes in excitability of primary sensory afferents after the induction of anaesthesia with propofol or sevoflurane were detected. These effects, which were non-specific and are possibly explained by changes observed in temperature, demonstrate possible anaesthetic effects on intraoperative neuromonitoring.
Collapse
Affiliation(s)
- K Maurer
- Pain Research Unit, Institute of Anaesthesiology, University Hospital Zurich, Rämistrasse 100, 8091 Zurich, Switzerland.
| | | | | | | | | |
Collapse
|