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Lindinger MI, Waller AP. Physicochemical Analysis of Mixed Venous and Arterial Blood Acid-Base State in Horses at Core Temperature during and after Moderate-Intensity Exercise. Animals (Basel) 2022; 12:ani12151875. [PMID: 35892525 PMCID: PMC9332600 DOI: 10.3390/ani12151875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 07/13/2022] [Accepted: 07/15/2022] [Indexed: 11/16/2022] Open
Abstract
The present study determined the independent contributions of temperature, strong ion difference ([SID]), total weak acid concentration ([Atot]) and PCO2 to changes in arterial and mixed venous [H+] and total carbon dioxide concentration ([TCO2]) during 37 min of moderate intensity exercise (~50% of heart rate max) and the first 60 min of recovery. Six horses were fitted with indwelling carotid and pulmonary artery (PA) catheters, had PA temperature measured, and had blood samples withdrawn for immediate analysis of plasma ion and gas concentrations. The increase in core temperature during exercise (+4.5 °C; p < 0.001) significantly (p < 0.05) increased PO2, PCO2, and [H+], but without a significant effect on [TCO2] (p > 0.01). The physicochemical acid-base approach was used to determine contributions of independent variables (except temperature) to the changes in [H+] and [TCO2]. In both arterial and venous blood, there was no acidosis during exercise and recovery despite significant (p < 0.05) increases in [lactate] and in venous PCO2. In arterial blood plasma, a mild alkalosis with exercise was due to primarily to a decrease in PCO2 (p < 0.05) and an increase in [SID] (p < 0.1). In venous blood plasma, a near absence of change in [H+] was due to the acidifying effects of increased PCO2 (p < 0.01) being offset by the alkalizing effects of increased [SID] (p < 0.05). The effect of temperature on PO2 (p < 0.001) resulted in an increased arterio-venous PO2 difference (p < 0.001) that would facilitate O2 transfer to contracting muscle. The simultaneous changes in the PCO2 and the concentrations of the other independent acid-base variables (contributions from individual strong and weak ions as manifest in [SID] and [Atot]) show complex, multilevel control of acid-base states in horses performing even moderate intensity exercise. Correction of acid-base variables to core body temperature presents a markedly different physiological response to exercise than that provided by variables measured and presented at an instrument temperature of 37 °C.
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Affiliation(s)
- Michael I. Lindinger
- Research and Development, The Nutraceutical Alliance Inc., Guelph, ON N1E 2G7, Canada
- Correspondence: or ; Tel.: +1-289-812-6176
| | - Amanda P. Waller
- Center for Clinical & Translational Research, Nationwide Children’s Hospital, Columbus, OH 43205, USA;
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2
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Lo Feudo CM, Stucchi L, Stancari G, Alberti E, Conturba B, Zucca E, Ferrucci F. Associations between Exercise-Induced Pulmonary Hemorrhage (EIPH) and Fitness Parameters Measured by Incremental Treadmill Test in Standardbred Racehorses. Animals (Basel) 2022; 12:ani12040449. [PMID: 35203157 PMCID: PMC8868235 DOI: 10.3390/ani12040449] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/09/2022] [Accepted: 02/10/2022] [Indexed: 12/13/2022] Open
Abstract
Simple Summary Exercise-induced pulmonary hemorrhage (EIPH) frequently affects racehorses worldwide and has been widely associated with poor performance; however, scientific evidence supporting this observation is low. The present retrospective study aims to evaluate objectively whether the presence and grade of EIPH could affect some fitness parameters, measured during an incremental treadmill test, in poorly performing Standardbred racehorses. For this purpose, the association between EIPH and the results of a treadmill metabolic test (including blood lactate analysis and venous blood gas analysis) were evaluated in 81 Standardbred racehorses. No relationship between EIPH and aerobic/anaerobic capacity was observed, suggesting that EIPH may affect performance in a different manner. However, EIPH-affected horses were shown to reach higher hematocrit values during exercise compared to EIPH-negative horses; therefore, it may be hypothesized that hemoconcentration may take part in the pathogenesis of EIPH by increasing the pulmonary capillary pressure. Abstract Exercise-induced pulmonary hemorrhage (EIPH) is a condition affecting up to 95% of racehorses, diagnosed by detecting blood in the trachea after exercise and/or the presence of hemosiderophages in the bronchoalveolar lavage fluid (BALf). Although EIPH is commonly associated with poor performance, scientific evidence is scarce. The athletic capacity of racehorses can be quantified through some parameters obtained during an incremental treadmill test; in particular, the speed at a heart rate of 200 bpm (V200), and the speed (VLa4) and the heart rate (HRLa4) at which the blood lactate concentration reaches 4 mmol/L are considered good fitness indicators. The present retrospective study aims to evaluate whether EIPH could influence fitness parameters in poorly performing Standardbreds. For this purpose, data from 81 patients regarding their V200, VLa4, HRLa4, peak lactate, maximum speed, minimum pH, and maximum hematocrit were reviewed; EIPH scores were assigned based on tracheobronchoscopy and BALf cytology. The association between the fitness parameters and EIPH was evaluated through Spearman’s correlation analysis. No relationship between EIPH and V200, VLa4, and HRLa4 was observed. Interestingly, EIPH-positive horses showed higher hematocrit values (p = 0.0072, r = 0.47), suggesting the possible influence of the hemoconcentration on the increase of pulmonary capillary pressure as a part of the pathogenesis of EIPH.
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Affiliation(s)
- Chiara Maria Lo Feudo
- Equine Sports Medicine Laboratory “Franco Tradati”, Department of Veterinary Medicine and Animal Sciences, Università Degli Studi di Milano, 26900 Lodi, Italy; (C.M.L.F.); (E.A.); (E.Z.)
| | - Luca Stucchi
- Veterinary Teaching Hospital, Department of Veterinary Medicine and Animal Sciences, Università Degli Studi di Milano, 26900 Lodi, Italy; (L.S.); (G.S.); (B.C.)
| | - Giovanni Stancari
- Veterinary Teaching Hospital, Department of Veterinary Medicine and Animal Sciences, Università Degli Studi di Milano, 26900 Lodi, Italy; (L.S.); (G.S.); (B.C.)
| | - Elena Alberti
- Equine Sports Medicine Laboratory “Franco Tradati”, Department of Veterinary Medicine and Animal Sciences, Università Degli Studi di Milano, 26900 Lodi, Italy; (C.M.L.F.); (E.A.); (E.Z.)
| | - Bianca Conturba
- Veterinary Teaching Hospital, Department of Veterinary Medicine and Animal Sciences, Università Degli Studi di Milano, 26900 Lodi, Italy; (L.S.); (G.S.); (B.C.)
| | - Enrica Zucca
- Equine Sports Medicine Laboratory “Franco Tradati”, Department of Veterinary Medicine and Animal Sciences, Università Degli Studi di Milano, 26900 Lodi, Italy; (C.M.L.F.); (E.A.); (E.Z.)
| | - Francesco Ferrucci
- Equine Sports Medicine Laboratory “Franco Tradati”, Department of Veterinary Medicine and Animal Sciences, Università Degli Studi di Milano, 26900 Lodi, Italy; (C.M.L.F.); (E.A.); (E.Z.)
- Correspondence: ; Tel.: +39-0250334146
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3
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Keir DA, Iannetta D, Mattioni Maturana F, Kowalchuk JM, Murias JM. Identification of Non-Invasive Exercise Thresholds: Methods, Strategies, and an Online App. Sports Med 2021; 52:237-255. [PMID: 34694596 DOI: 10.1007/s40279-021-01581-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2021] [Indexed: 10/20/2022]
Abstract
During incremental exercise, two thresholds may be identified from standard gas exchange and ventilatory measurements. The first signifies the onset of blood lactate accumulation (the lactate threshold, LT) and the second the onset of metabolic acidosis (the respiratory compensation point, RCP). The ability to explain why these thresholds occur and how they are identified, non-invasively, from pulmonary gas exchange and ventilatory variables is fundamental to the field of exercise physiology and requisite to the understanding of core concepts including exercise intensity, assessment, prescription, and performance. This review is intended as a unique and comprehensive theoretical and practical resource for instructors, clinicians, researchers, lab technicians, and students at both undergraduate and graduate levels to facilitate the teaching, comprehension, and proper non-invasive identification of exercise thresholds. Specific objectives are to: (1) explain the underlying physiology that produces the LT and RCP; (2) introduce the classic non-invasive measurements by which these thresholds are identified by connecting variable profiles to underlying physiological behaviour; (3) discuss common issues that can obscure threshold detection and strategies to identify and mitigate these challenges; and (4) introduce an online resource to facilitate learning and standard practices. Specific examples of exercise gas exchange and ventilatory data are provided throughout to illustrate these concepts and a novel online application tool designed specifically to identify the estimated LT (θLT) and RCP is introduced. This application is a unique platform for learners to practice skills on real exercise data and for anyone to analyze incremental exercise data for the purpose of identifying θLT and RCP.
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Affiliation(s)
- Daniel A Keir
- School of Kinesiology, The University of Western Ontario, AHB 3G18, 1151 Richmond Street, London, ON, N6A 3K7, Canada. .,Toronto General Research Institute, Toronto General Hospital, Toronto, ON, Canada.
| | - Danilo Iannetta
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | | | - John M Kowalchuk
- School of Kinesiology, The University of Western Ontario, AHB 3G18, 1151 Richmond Street, London, ON, N6A 3K7, Canada.,Department of Physiology and Pharmacology, The University of Western Ontario, London, ON, Canada
| | - Juan M Murias
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
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4
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Lindinger MI. Total Carbon Dioxide in Adult Standardbred and Thoroughbred Horses. J Equine Vet Sci 2021; 106:103730. [PMID: 34670689 DOI: 10.1016/j.jevs.2021.103730] [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: 05/25/2021] [Revised: 08/02/2021] [Accepted: 08/08/2021] [Indexed: 10/20/2022]
Abstract
The TCO2 (total carbon dioxide) test is performed on the blood of racehorses as a means of combatting the practice of administering alkalizing agents for the purpose of enhancing performance. The purposes of this review are to present an overview of the factors contributing to TCO2 and to review the literature regarding TCO2 in adult Standardbred and Thoroughbred horses to demonstrate the range of variability of TCO2 in horses. Most of the research published on the topic of TCO2 or bicarbonate measurement in racehorses was accessed and reviewed. PubMed and Google Scholar were the primary search engines used to source the relevant literature. The main physicochemical factors that contribute to changes in TCO2 in horses at rest are changes in strong ions concentration, followed by changes in weak acid (i.e. plasma albumin) concentrations. There is a wide normal distribution of TCO2 in horses ranging from 23 mmol/L to 38 mmol/L. Independent of administration of alkalizing agents, blood TCO2 is affected mainly by feeding, time of day (diurnal variation), season and exercise. There are few studies that have reported hour-by-hour changes in TCO2. Racehorse population studies suffer from lack of validation regarding whether or not a horse was administered an alkalizing agent. It is concluded that the normal range of TCO2 in non-alkalized Standardbred and Thoroughbred horses is significantly wider than has been appreciated, that periods of elevated TCO2 appear to be normal for many horses at rest, and that a TCO2 test alone is not definitive for the purposes of determining of an alkalizing agent has been administered to a horse.
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Lindinger MI, Cairns SP. Regulation of muscle potassium: exercise performance, fatigue and health implications. Eur J Appl Physiol 2021; 121:721-748. [PMID: 33392745 DOI: 10.1007/s00421-020-04546-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 10/29/2020] [Indexed: 12/30/2022]
Abstract
This review integrates from the single muscle fibre to exercising human the current understanding of the role of skeletal muscle for whole-body potassium (K+) regulation, and specifically the regulation of skeletal muscle [K+]. We describe the K+ transport proteins in skeletal muscle and how they contribute to, or modulate, K+ disturbances during exercise. Muscle and plasma K+ balance are markedly altered during and after high-intensity dynamic exercise (including sports), static contractions and ischaemia, which have implications for skeletal and cardiac muscle contractile performance. Moderate elevations of plasma and interstitial [K+] during exercise have beneficial effects on multiple physiological systems. Severe reductions of the trans-sarcolemmal K+ gradient likely contributes to muscle and whole-body fatigue, i.e. impaired exercise performance. Chronic or acute changes of arterial plasma [K+] (hyperkalaemia or hypokalaemia) have dangerous health implications for cardiac function. The current mechanisms to explain how raised extracellular [K+] impairs cardiac and skeletal muscle function are discussed, along with the latest cell physiology research explaining how calcium, β-adrenergic agonists, insulin or glucose act as clinical treatments for hyperkalaemia to protect the heart and skeletal muscle in vivo. Finally, whether these agents can also modulate K+-induced muscle fatigue are evaluated.
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Affiliation(s)
- Michael I Lindinger
- Research and Development, The Nutraceutical Alliance, Burlington, ON, L7N 2Z9, Canada
| | - Simeon P Cairns
- SPRINZ, School of Sport and Recreation, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, 1020, New Zealand.
- Health and Rehabilitation Research Institute, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, 1020, New Zealand.
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Changes in the SID Actual and SID Effective Values in the Course of Respiratory Acidosis in Horses With Symptomatic Severe Equine Asthma-An Experimental Study. J Equine Vet Sci 2019; 78:107-111. [PMID: 31203972 DOI: 10.1016/j.jevs.2019.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 04/20/2019] [Accepted: 05/01/2019] [Indexed: 11/20/2022]
Abstract
Equine asthma syndrome is an allergic, inflammatory airway disease that usually affects older horses. Respiratory acidosis is an acid-base imbalance caused by alveolar hypoventilation. The acid-base balance may be assessed using the Henderson-Hasselbalch equation as well as the Stewart model. The authors hypothesized that systemic respiratory acidosis changes the ionic concentrations affecting water dissociation. The study group included 16 Warmblood, mixed breed horses of both sexes with a history of severe equine asthma, and 10 healthy horses were used as controls. Arterial and venous blood were collected from all the horses. The pH, pO2, and pCO2 and HCO3- were assessed in the arterial blood. Na, K, Cl, albumin, and Pinorganic (Pi) were assessed in the venous blood. The obtained results were used to calculate the anion gap (AG), modified AG, actual strong ion difference (SIDa), weak non-volatile acids, and effective strong ion difference (SIDe) values for all the horses. A systemic, compensatory respiratory acidosis was diagnosed in the study group. The concentration of Na in the blood serum in the study group was significantly higher, whereas the concentration of Cl was significantly lower than the values in the control group. The SIDa and SIDe values calculated in the horses from the study group were significantly higher than those in the control group. Significantly higher SIDa and SIDe values confirm the presence of ionic changes that affect water dissociation in the course of respiratory acidosis in horses. The SIDa and SIDe values may be useful in the diagnosis and treatment of respiratory acidosis in horses, which warrant further investigation.
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7
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Lee SY, Chien DK, Huang CH, Shih SC, Lee WC, Chang WH. Dyspnea in pregnancy. Taiwan J Obstet Gynecol 2018; 56:432-436. [PMID: 28805596 DOI: 10.1016/j.tjog.2017.04.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/20/2017] [Indexed: 10/19/2022] Open
Abstract
Dyspnea in pregnancy is common. It can result from adaption to body changes in pregnancy and also from complications therein. Understanding the mechanisms of change in the respiratory system during pregnancy helps with the differential diagnosis of dyspnea in normal pregnancy as opposed to pathological dyspnea.
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Affiliation(s)
- Shih-Yi Lee
- Division of Pulmonary and Critical Care Medicine, Mackay Memorial Hospital, Taiwan; Department of Nursing, Mackay Junior College of Medicine, Nursing, and Management, Taipei, Taiwan; Department of Medicine, Mackay Medical College, Taipei, Taiwan; Department of Internal Medicine, Mackay Memorial Hospital, Taiwan
| | - Ding-Kuo Chien
- Department of Emergency Medicine, Mackay Memorial Hospital, Taiwan; Institute of Mechatronic Engineering, National Taipei University of Technology, Taiwan; Department of Nursing, Mackay Junior College of Medicine, Nursing, and Management, Taipei, Taiwan; Graduate Institute of Injury Prevention and Control, Taipei Medical University, Taipei, Taiwan; School of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Medicine, Mackay Medical College, Taipei, Taiwan
| | | | - Shou-Chuan Shih
- Department of Nursing, Mackay Junior College of Medicine, Nursing, and Management, Taipei, Taiwan; Department of Medicine, Mackay Medical College, Taipei, Taiwan; Department of Internal Medicine, Mackay Memorial Hospital, Taiwan
| | - Wei-Cheng Lee
- Department of Nursing, Mackay Junior College of Medicine, Nursing, and Management, Taipei, Taiwan; Department of Medicine, Mackay Medical College, Taipei, Taiwan
| | - Wen-Han Chang
- Department of Emergency Medicine, Mackay Memorial Hospital, Taiwan; Institute of Mechatronic Engineering, National Taipei University of Technology, Taiwan; Department of Nursing, Mackay Junior College of Medicine, Nursing, and Management, Taipei, Taiwan; Graduate Institute of Injury Prevention and Control, Taipei Medical University, Taipei, Taiwan; School of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Medicine, Mackay Medical College, Taipei, Taiwan.
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8
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Lühker O, Berger MM, Pohlmann A, Hotz L, Gruhlke T, Hochreiter M. Changes in acid-base and ion balance during exercise in normoxia and normobaric hypoxia. Eur J Appl Physiol 2017; 117:2251-2261. [PMID: 28914359 PMCID: PMC5640730 DOI: 10.1007/s00421-017-3712-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 09/06/2017] [Indexed: 12/01/2022]
Abstract
Purpose Both exercise and hypoxia cause complex changes in acid–base homeostasis. The aim of the present study was to investigate whether during intense physical exercise in normoxia and hypoxia, the modified physicochemical approach offers a better understanding of the changes in acid–base homeostasis than the traditional Henderson–Hasselbalch approach. Methods In this prospective, randomized, crossover trial, 19 healthy males completed an exercise test until voluntary fatigue on a bicycle ergometer on two different study days, once during normoxia and once during normobaric hypoxia (12% oxygen, equivalent to an altitude of 4500 m). Arterial blood gases were sampled during and after the exercise test and analysed according to the modified physicochemical and Henderson–Hasselbalch approach, respectively. Results Peak power output decreased from 287 ± 9 Watts in normoxia to 213 ± 6 Watts in hypoxia (−26%, P < 0.001). Exercise decreased arterial pH to 7.21 ± 0.01 and 7.27 ± 0.02 (P < 0.001) during normoxia and hypoxia, respectively, and increased plasma lactate to 16.8 ± 0.8 and 17.5 ± 0.9 mmol/l (P < 0.001). While the Henderson–Hasselbalch approach identified lactate as main factor responsible for the non-respiratory acidosis, the modified physicochemical approach additionally identified strong ions (i.e. plasma electrolytes, organic acid ions) and non-volatile weak acids (i.e. albumin, phosphate ion species) as important contributors. Conclusions The Henderson–Hasselbalch approach might serve as basis for screening acid–base disturbances, but the modified physicochemical approach offers more detailed insights into the complex changes in acid–base status during exercise in normoxia and hypoxia, respectively. Electronic supplementary material The online version of this article (doi:10.1007/s00421-017-3712-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Olaf Lühker
- Department of Anesthesiology, University Medical Centre Groningen, Groningen, The Netherlands.,Department of Anesthesiology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany
| | - Marc Moritz Berger
- Department of Anesthesiology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany.,Department of Anesthesiology, Perioperative and General Critical Care Medicine, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Alexander Pohlmann
- Department of Anesthesiology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany
| | - Lorenz Hotz
- Division of Sports Medicine, Department of Internal Medicine VII, University of Heidelberg, Heidelberg, Germany
| | - Tilmann Gruhlke
- Department of Anesthesiology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany
| | - Marcel Hochreiter
- Department of Anesthesiology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany.
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9
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Equine Welfare during Exercise: An Evaluation of Breathing, Breathlessness and Bridles. Animals (Basel) 2017; 7:ani7060041. [PMID: 28587125 PMCID: PMC5483604 DOI: 10.3390/ani7060041] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 05/22/2017] [Accepted: 05/23/2017] [Indexed: 01/05/2023] Open
Abstract
Simple Summary Horses have superior athletic capabilities due largely to their exceptional cardiorespiratory responses during exercise. This has particular relevance to horses’ potential to experience breathlessness, especially when their athletic performance is reduced by impaired respiratory function. Breathlessness, incorporating three types of unpleasant experiences, has been noted as of significant animal welfare concern in other mammals. However, the potential for breathlessness to occur in horses as usually ridden wearing bitted bridles has not yet been evaluated in detail. Accordingly, key physiological responses to exercise and the consequences of impaired respiratory function are outlined. Then the physiological control of breathing and the generation of the aversive experiences of breathlessness are explained. Finally, the potential for horses with unimpaired and impaired respiratory function to experience the different types of breathlessness is evaluated. This information provides a basis for considering the circumstances in which breathlessness may have significant negative welfare impacts on horses as currently ridden wearing bitted bridles. Potential beneficial impacts on respiratory function of using bitless bridles are then discussed with emphasis on the underlying mechanisms and their relevance to breathlessness. It is noted that direct comparisons of cardiorespiratory responses to exercise in horses wearing bitless and bitted bridles are not available and it is recommended that such studies be undertaken. Abstract Horses engaged in strenuous exercise display physiological responses that approach the upper functional limits of key organ systems, in particular their cardiorespiratory systems. Maximum athletic performance is therefore vulnerable to factors that diminish these functional capacities, and such impairment might also lead to horses experiencing unpleasant respiratory sensations, i.e., breathlessness. The aim of this review is to use existing literature on equine cardiorespiratory physiology and athletic performance to evaluate the potential for various types of breathlessness to occur in exercising horses. In addition, we investigate the influence of management factors such as rein and bit use and of respiratory pathology on the likelihood and intensity of equine breathlessness occurring during exercise. In ridden horses, rein use that reduces the jowl angle, sometimes markedly, and conditions that partially obstruct the nasopharynx and/or larynx, impair airflow in the upper respiratory tract and lead to increased flow resistance. The associated upper airway pressure changes, transmitted to the lower airways, may have pathophysiological sequelae in the alveolae, which, in their turn, may increase airflow resistance in the lower airways and impede respiratory gas exchange. Other sequelae include decreases in respiratory minute volume and worsening of the hypoxaemia, hypercapnia and acidaemia commonly observed in healthy horses during strenuous exercise. These and other factors are implicated in the potential for ridden horses to experience three forms of breathlessness—”unpleasant respiratory effort”, “air hunger” and “chest tightness”—which arise when there is a mismatch between a heightened ventilatory drive and the adequacy of the respiratory response. It is not known to what extent, if at all, such mismatches would occur in strenuously exercising horses unhampered by low jowl angles or by pathophysiological changes at any level of the respiratory tract. However, different combinations of the three types of breathlessness seem much more likely to occur when pathophysiological conditions significantly reduce maximal athletic performance. Finally, most horses exhibit clear behavioural evidence of aversion to a bit in their mouths, varying from the bit being a mild irritant to very painful. This in itself is a significant animal welfare issue that should be addressed. A further major point is the potential for bits to disrupt the maintenance of negative pressure in the oropharynx, which apparently acts to prevent the soft palate from rising and obstructing the nasopharynx. The untoward respiratory outcomes and poor athletic performance due to this and other obstructions are well established, and suggest the potential for affected animals to experience significant intensities of breathlessness. Bitless bridle use may reduce or eliminate such effects. However, direct comparisons of the cardiorespiratory dynamics and the extent of any respiratory pathophysiology in horses wearing bitted and bitless bridles have not been conducted. Such studies would be helpful in confirming, or otherwise, the claimed potential benefits of bitless bridle use.
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10
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Pronicka E. Hypocapnic hypothesis of Leigh disease. Med Hypotheses 2017; 101:23-27. [PMID: 28351484 DOI: 10.1016/j.mehy.2017.01.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 01/05/2017] [Accepted: 01/26/2017] [Indexed: 11/15/2022]
Abstract
Leigh syndrome (LS) is a neurogenetic disorder of children caused by mutations in at least 75 genes which impair mitochondrial bioenergetics. The changes have typical localization in basal ganglia and brainstem, and typical histological picture of spongiform appearance, vascular proliferation and gliosis. ATP deprivation, free radicals and lactate accumulation are suspected to be the causes. Hypocapnic hypothesis proposed in the paper questions the energy deprivation as the mechanism of LS. We assume that the primary harmful factor is hypocapnia (decrease in pCO2) and respiratory alkalosis (increase in pH) due to hyperventilation, permanent or in response to stress. Inside mitochondria, the pH signal of high pH/low bicarbonate ion (HCO-3) is transmitted by soluble adenyl cyclase (sAC) through cAMP dependent manner. The process can initiate brain lesions (necrosis, apoptosis, hypervascularity) in OXPHOS deficient cells residing at the LS area of the brain. The major message of the article is that it is not the ATP depletion but intracellular alkalization (and/or hyperoxia?) which seem to be the cause of LS. The paper includes suggestions concerning the methodology for further research on the LS mechanism and for therapeutic strategy.
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Affiliation(s)
- Ewa Pronicka
- The Children's Memorial Health Institute, Department of Pediatrics, Nutrition and Metabolic Diseases, Aleja Dzieci Polskich 20, 04-730 Warsaw, Poland.
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11
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Tielemans MJ, Erler NS, Franco OH, Jaddoe VWV, Steegers EAP, Kiefte-de Jong JC. Dietary acid load and blood pressure development in pregnancy: The Generation R Study. Clin Nutr 2017; 37:597-603. [PMID: 28189385 DOI: 10.1016/j.clnu.2017.01.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 01/17/2017] [Accepted: 01/23/2017] [Indexed: 01/08/2023]
Abstract
BACKGROUND & AIMS Dietary intake could induce a mild maternal metabolic acidosis that might lead to a higher level of blood pressure. Because studies in pregnancy are scarce, we evaluated the association between maternal dietary acid load and changes in blood pressure during pregnancy, pregnancy-induced hypertension and pre-eclampsia. METHODS We included 3411 pregnant women of Dutch ancestry from a prospective population-based cohort (Rotterdam, The Netherlands). Dietary data was self-reported via a food-frequency questionnaire in early pregnancy. Four dietary acid load measurements were calculated: dietary potential renal acid load (dPRAL), net endogenous acid production (NEAP), animal protein/potassium ratio, and vegetable protein/potassium ratio. Diastolic blood pressure (DBP) and systolic blood pressure (SBP) were measured three times during pregnancy. Information on pregnancy-induced hypertension and pre-eclampsia was obtained from medical records. Linear mixed models and logistic regression were used and adjusted for sociodemographic and lifestyle factors. RESULTS The results indicated that dPRAL, NEAP and animal protein/potassium ratio were not associated with DBP or SBP in pregnancy. One standard deviation higher vegetable protein/potassium ratio was associated with lower DBP (-0.30 mmHg [95% CI -0.54; -0.06]) but not with SBP (-0.29 mmHg [95% CI -0.60; 0.01]). Dietary acid load measurement was neither associated with the prevalence of pregnancy-induced hypertension nor with pre-eclampsia. CONCLUSIONS Dietary acid load was not associated with changes in DBP or SBP during pregnancy, although women with a higher vegetable protein/potassium ratio had a slightly lower DBP. Dietary acid load was not associated with pregnancy-induced hypertension or pre-eclampsia.
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Affiliation(s)
- Myrte J Tielemans
- Department of Epidemiology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; The Generation R Study Group, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
| | - Nicole S Erler
- Department of Epidemiology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; Department of Biostatistics, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Oscar H Franco
- Department of Epidemiology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Vincent W V Jaddoe
- Department of Epidemiology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; The Generation R Study Group, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; Department of Pediatrics, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Eric A P Steegers
- Department of Obstetrics and Gynecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Jessica C Kiefte-de Jong
- Department of Epidemiology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; Department of Pediatrics, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; Leiden University College, The Hague, The Netherlands
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12
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Andrianopoulos V, Vanfleteren LEGW, Jarosch I, Gloeckl R, Schneeberger T, Wouters EFM, Spruit MA, Kenn K. Transcutaneous carbon-dioxide partial pressure trends during six-minute walk test in patients with very severe COPD. Respir Physiol Neurobiol 2016; 233:52-59. [PMID: 27524634 DOI: 10.1016/j.resp.2016.08.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Revised: 07/28/2016] [Accepted: 08/11/2016] [Indexed: 01/28/2023]
Abstract
BACKGROUND Transcutaneous carbon-dioxide partial-pressure (TCPCO2) can be reliably measured and may be of clinical relevance in COPD. Changes in TCPCO2 and exercise-induced hypercapnia (EIH) during six-minute walk test (6MWT) need further investigation. We aimed (1) to define patterns of TCPCO2 trends during 6MWT and (2) to study determinants of CO2-retention and EIH. METHODS Sixty-two COPD patients (age: 63±8years, FEV1: 33±10%pred.) were recruited and TCPCO2 was recorded by SenTec digital-monitoring-system during 6MWT. RESULTS Half of patients (50%) exhibited CO2-retention (TCPCO2[Δ]>4mmHg); 26% preserved and 24% reduced TCPCO2. Nineteen (31%) patients presented EIH (TCPCO2>45mmHg). EIH was associated to higher baseline-PCCO2, worse FEV1, lower inspiratory-pressures, underweight/normal BMI, and pre-walk dyspnea. Stronger determinants of CO2-retention were FEV1 and pre-walk dyspnea, whereas baseline-PCCO2 and pre-walk dyspnea better predict EIH. CONCLUSIONS PCO2 response to 6MWT is highly heterogeneous; however, very low FEV1 and elevated baseline-PCCO2 together with pre-walk dyspnea increase the risk for CO2-retention and EIH. Overweight-BMI seems to carry a protective effect against EIH in very severe COPD.
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Affiliation(s)
- Vasileios Andrianopoulos
- Department of Research and Education, CIRO+, Centre of Expertise for Chronic Organ Failure, Horn, The Netherlands; Department of Respiratory Medicine and Pulmonary Rehabilitation, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany.
| | - Lowie E G W Vanfleteren
- Department of Research and Education, CIRO+, Centre of Expertise for Chronic Organ Failure, Horn, The Netherlands; Department of Respiratory Medicine, Maastricht University Medical Centre (MUMC+), Maastricht, The Netherlands.
| | - Inga Jarosch
- Department of Respiratory Medicine and Pulmonary Rehabilitation, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany.
| | - Rainer Gloeckl
- Department of Respiratory Medicine and Pulmonary Rehabilitation, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany; Department for Prevention, Rehabilitation and Sports Medicine, Klinikum Rechts der Isar, Technische Universität München (TUM), Munich, Germany.
| | - Tessa Schneeberger
- Department of Respiratory Medicine and Pulmonary Rehabilitation, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany; Department of Pulmonary Rehabilitation, Philipps University Marburg, Marburg, Germany.
| | - Emiel F M Wouters
- Department of Research and Education, CIRO+, Centre of Expertise for Chronic Organ Failure, Horn, The Netherlands; Department of Respiratory Medicine, Maastricht University Medical Centre (MUMC+), Maastricht, The Netherlands.
| | - Martijn A Spruit
- Department of Research and Education, CIRO+, Centre of Expertise for Chronic Organ Failure, Horn, The Netherlands; REVAL - Rehabilitation Research Center, BIOMED - Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium.
| | - Klaus Kenn
- Department of Respiratory Medicine and Pulmonary Rehabilitation, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany; Department of Pulmonary Rehabilitation, Philipps University Marburg, Marburg, Germany.
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13
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Wasserman K, Kisaka T, Luehrs RE, Bates ML, Kumar VHS, Lopez-Barneo J, Zuo L, Zhou T, Ni L, Brain J, Banzett R, Chamoun N. Commentaries on Viewpoint: Why do some patients stop breathing after taking narcotics? Ventilatory chemosensitivity as a predictor of opioid-induced respiratory depression. J Appl Physiol (1985) 2016; 119:423-5. [PMID: 26276975 DOI: 10.1152/japplphysiol.00434.2015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Karlman Wasserman
- Division of Respiratory and Critical Care Physiology and Medicine Los Angeles Biomedical Research Institute Harbor-UCLA Medical Center David Geffen School of Medicine University of California at Los AngelesLaboratory of Developmental and Integrative Physiology University of IowaDepartment of Pediatrics The Women & Children's Hospital of Buffalo University at BuffaloProfessor of Physiology Instituto de Biomedicina de Sevilla (IBiS) Hospital Universitario Virgen del Rocio/CSIC/Universidad de SevillaAssistant ProfessorSchool of Health and Rehabilitation Sciences The Ohio State University College of MedicineHarvard University
| | - Tomohiko Kisaka
- Division of Respiratory and Critical Care Physiology and Medicine Los Angeles Biomedical Research Institute Harbor-UCLA Medical Center David Geffen School of Medicine University of California at Los AngelesLaboratory of Developmental and Integrative Physiology University of IowaDepartment of Pediatrics The Women & Children's Hospital of Buffalo University at BuffaloProfessor of Physiology Instituto de Biomedicina de Sevilla (IBiS) Hospital Universitario Virgen del Rocio/CSIC/Universidad de SevillaAssistant ProfessorSchool of Health and Rehabilitation Sciences The Ohio State University College of MedicineHarvard University
| | - Rachel E Luehrs
- Division of Respiratory and Critical Care Physiology and Medicine Los Angeles Biomedical Research Institute Harbor-UCLA Medical Center David Geffen School of Medicine University of California at Los AngelesLaboratory of Developmental and Integrative Physiology University of IowaDepartment of Pediatrics The Women & Children's Hospital of Buffalo University at BuffaloProfessor of Physiology Instituto de Biomedicina de Sevilla (IBiS) Hospital Universitario Virgen del Rocio/CSIC/Universidad de SevillaAssistant ProfessorSchool of Health and Rehabilitation Sciences The Ohio State University College of MedicineHarvard University
| | - Melissa L Bates
- Division of Respiratory and Critical Care Physiology and Medicine Los Angeles Biomedical Research Institute Harbor-UCLA Medical Center David Geffen School of Medicine University of California at Los AngelesLaboratory of Developmental and Integrative Physiology University of IowaDepartment of Pediatrics The Women & Children's Hospital of Buffalo University at BuffaloProfessor of Physiology Instituto de Biomedicina de Sevilla (IBiS) Hospital Universitario Virgen del Rocio/CSIC/Universidad de SevillaAssistant ProfessorSchool of Health and Rehabilitation Sciences The Ohio State University College of MedicineHarvard University
| | - Vasanth H S Kumar
- Division of Respiratory and Critical Care Physiology and Medicine Los Angeles Biomedical Research Institute Harbor-UCLA Medical Center David Geffen School of Medicine University of California at Los AngelesLaboratory of Developmental and Integrative Physiology University of IowaDepartment of Pediatrics The Women & Children's Hospital of Buffalo University at BuffaloProfessor of Physiology Instituto de Biomedicina de Sevilla (IBiS) Hospital Universitario Virgen del Rocio/CSIC/Universidad de SevillaAssistant ProfessorSchool of Health and Rehabilitation Sciences The Ohio State University College of MedicineHarvard University
| | - Jose Lopez-Barneo
- Division of Respiratory and Critical Care Physiology and Medicine Los Angeles Biomedical Research Institute Harbor-UCLA Medical Center David Geffen School of Medicine University of California at Los AngelesLaboratory of Developmental and Integrative Physiology University of IowaDepartment of Pediatrics The Women & Children's Hospital of Buffalo University at BuffaloProfessor of Physiology Instituto de Biomedicina de Sevilla (IBiS) Hospital Universitario Virgen del Rocio/CSIC/Universidad de SevillaAssistant ProfessorSchool of Health and Rehabilitation Sciences The Ohio State University College of MedicineHarvard University
| | - Li Zuo
- Division of Respiratory and Critical Care Physiology and Medicine Los Angeles Biomedical Research Institute Harbor-UCLA Medical Center David Geffen School of Medicine University of California at Los AngelesLaboratory of Developmental and Integrative Physiology University of IowaDepartment of Pediatrics The Women & Children's Hospital of Buffalo University at BuffaloProfessor of Physiology Instituto de Biomedicina de Sevilla (IBiS) Hospital Universitario Virgen del Rocio/CSIC/Universidad de SevillaAssistant ProfessorSchool of Health and Rehabilitation Sciences The Ohio State University College of MedicineHarvard University
| | - Tingyang Zhou
- Division of Respiratory and Critical Care Physiology and Medicine Los Angeles Biomedical Research Institute Harbor-UCLA Medical Center David Geffen School of Medicine University of California at Los AngelesLaboratory of Developmental and Integrative Physiology University of IowaDepartment of Pediatrics The Women & Children's Hospital of Buffalo University at BuffaloProfessor of Physiology Instituto de Biomedicina de Sevilla (IBiS) Hospital Universitario Virgen del Rocio/CSIC/Universidad de SevillaAssistant ProfessorSchool of Health and Rehabilitation Sciences The Ohio State University College of MedicineHarvard University
| | - Lei Ni
- Division of Respiratory and Critical Care Physiology and Medicine Los Angeles Biomedical Research Institute Harbor-UCLA Medical Center David Geffen School of Medicine University of California at Los AngelesLaboratory of Developmental and Integrative Physiology University of IowaDepartment of Pediatrics The Women & Children's Hospital of Buffalo University at BuffaloProfessor of Physiology Instituto de Biomedicina de Sevilla (IBiS) Hospital Universitario Virgen del Rocio/CSIC/Universidad de SevillaAssistant ProfessorSchool of Health and Rehabilitation Sciences The Ohio State University College of MedicineHarvard University
| | - Joseph Brain
- Division of Respiratory and Critical Care Physiology and Medicine Los Angeles Biomedical Research Institute Harbor-UCLA Medical Center David Geffen School of Medicine University of California at Los AngelesLaboratory of Developmental and Integrative Physiology University of IowaDepartment of Pediatrics The Women & Children's Hospital of Buffalo University at BuffaloProfessor of Physiology Instituto de Biomedicina de Sevilla (IBiS) Hospital Universitario Virgen del Rocio/CSIC/Universidad de SevillaAssistant ProfessorSchool of Health and Rehabilitation Sciences The Ohio State University College of MedicineHarvard University
| | - Robert Banzett
- Division of Respiratory and Critical Care Physiology and Medicine Los Angeles Biomedical Research Institute Harbor-UCLA Medical Center David Geffen School of Medicine University of California at Los AngelesLaboratory of Developmental and Integrative Physiology University of IowaDepartment of Pediatrics The Women & Children's Hospital of Buffalo University at BuffaloProfessor of Physiology Instituto de Biomedicina de Sevilla (IBiS) Hospital Universitario Virgen del Rocio/CSIC/Universidad de SevillaAssistant ProfessorSchool of Health and Rehabilitation Sciences The Ohio State University College of MedicineHarvard University
| | - Nassib Chamoun
- Division of Respiratory and Critical Care Physiology and Medicine Los Angeles Biomedical Research Institute Harbor-UCLA Medical Center David Geffen School of Medicine University of California at Los AngelesLaboratory of Developmental and Integrative Physiology University of IowaDepartment of Pediatrics The Women & Children's Hospital of Buffalo University at BuffaloProfessor of Physiology Instituto de Biomedicina de Sevilla (IBiS) Hospital Universitario Virgen del Rocio/CSIC/Universidad de SevillaAssistant ProfessorSchool of Health and Rehabilitation Sciences The Ohio State University College of MedicineHarvard University
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14
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Campos I, Chan L, Zhang H, Deziel S, Vaughn C, Meyring-Wösten A, Kotanko P. Intradialytic Hypoxemia in Chronic Hemodialysis Patients. Blood Purif 2016; 41:177-87. [PMID: 26765143 DOI: 10.1159/000441271] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
When kidney failure occurs, patients are at risk for fluid overload states, which can cause pulmonary edema, pleural effusions, and upper airway obstruction. Kidney disease is also associated with impaired respiratory function, as in central sleep apnea or chronic obstructive pulmonary disease. Hence, respiratory and renal diseases are frequently coexisting. Hypoxemia is the terminal pathway of a multitude of respiratory pathologies. The measurement of oxygen saturation (SO2) is a basic and commonly used tool in clinical practice. Both arterial oxygen saturation (SaO2) and central venous oxygen saturation (ScvO2) can be easily obtained in hemodialysis (HD) patients, SaO2 from an arteriovenous access and ScvO2 from a central catheter. Here, we give a brief overview of the anatomy and physiology of the respiratory system, and the different technologies that are currently available to measure oxygen status in dialysis patients. We then focus on literature regarding intradialytic SaO2 and ScvO2. Lastly, we present clinical vignettes of intradialytic drops in SaO2 and ScvO2 in association with different symptoms and clinical scenarios with an emphasis on the pathophysiology of these cases. Given the fact that in the general population hypoxemia is associated with adverse outcomes, including increased mortality, cardiac arrhythmias and cardiovascular events, we posit that intradialytic SO2 may serve as a potential marker to identify HD patients at increased risk for morbidity and mortality.
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15
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Effects of pre-exercise alkalosis on the decrease in VO2 at the end of all-out exercise. Eur J Appl Physiol 2015; 116:85-95. [PMID: 26297325 DOI: 10.1007/s00421-015-3239-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 08/07/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE This study determined the effects of pre-exercise sodium bicarbonate ingestion (ALK) on changes in oxygen uptake (VO2) at the end of a supramaximal exercise test (SXT). METHODS Eleven well-trained cyclists completed a 70-s all-out cycling effort, in double-blind trials, after oral ingestion of either 0.3 g kg(-1) of sodium bicarbonate (NaHCO3) or 0.2 g kg(-1) body mass of calcium carbonate (PLA). Blood samples were taken to assess changes in acid-base balance before the start of the supramaximal exercise, and 0, 5 and 8 min after the exercise; ventilatory parameters were also measured at rest and during the SXT. RESULTS At the end of the PLA trial, which induced mild acidosis (blood pH = 7.20), subjects presented a significant decrease in VO2 (P < 0.05), which was related to the amplitude of the decrease in minute ventilation (VE) during the SXT (r = 0.70, P < 0.01, n = 11). Pre-exercise metabolic alkalosis significantly prevented the exercise-induced decrease in VO2 in eleven well-trained participants (PLA:12.5 ± 2.1 % and ALK: 4.9 ± 0.9 %, P < 0.05) and the decrease in mean power output was significantly less pronounced in ALK (P < 0.05). Changes in the VO2 decrease between PLA and ALK trials were positively related to changes in the VE decrease (r = 0.74, P < 0.001), but not to changes in power output (P > 0.05). CONCLUSIONS Pre-exercise alkalosis counteracted the VO2 decrease related to mild acidosis, potentially as a result of changes in VE and in muscle acid-base status during the all-out supramaximal exercise.
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Tymko MM, Ainslie PN, MacLeod DB, Willie CK, Foster GE. End tidal-to-arterial CO2 and O2 gas gradients at low- and high-altitude during dynamic end-tidal forcing. Am J Physiol Regul Integr Comp Physiol 2015; 308:R895-906. [DOI: 10.1152/ajpregu.00425.2014] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 03/23/2015] [Indexed: 11/22/2022]
Abstract
We sought to characterize and quantify the performance of a portable dynamic end-tidal forcing (DEF) system in controlling the partial pressure of arterial CO2 (PaCO2) and O2 (PaO2) at low (LA; 344 m) and high altitude (HA; 5,050 m) during an isooxic CO2 test and an isocapnic O2 test, which is commonly used to measure ventilatory and vascular reactivity in humans ( n = 9). The isooxic CO2 tests involved step changes in the partial pressure of end-tidal CO2 (PetCO2) of −10, −5, 0, +5, and +10 mmHg from baseline. The isocapnic O2 test consisted of a 10-min hypoxic step (PetO2 = 47 mmHg) from baseline at LA and a 5-min euoxic step (PetO2 = 100 mmHg) from baseline at HA. At both altitudes, PetO2 and PetCO2 were controlled within narrow limits (<1 mmHg from target) during each protocol. During the isooxic CO2 test at LA, PetCO2 consistently overestimated PaCO2 ( P < 0.01) at both baseline (2.1 ± 0.5 mmHg) and hypercapnia (+5 mmHg: 2.1 ± 0.7 mmHg; +10 mmHg: 1.9 ± 0.5 mmHg). This Pa-PetCO2 gradient was approximately twofold greater at HA ( P < 0.05). At baseline at both altitudes, PetO2 overestimated PaO2 by a similar extent (LA: 6.9 ± 2.1 mmHg; HA: 4.5 ± 0.9 mmHg; both P < 0.001). This overestimation persisted during isocapnic hypoxia at LA (6.9 ± 0.6 mmHg) and during isocapnic euoxia at HA (3.8 ± 1.2 mmHg). Step-wise multiple regression analysis, on the basis of the collected data, revealed that it may be possible to predict an individual's arterial blood gases during DEF. Future research is needed to validate these prediction algorithms and determine the implications of end-tidal-to-arterial gradients in the assessment of ventilatory and/or vascular reactivity.
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Affiliation(s)
- Michael M. Tymko
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada; and
| | - Philip N. Ainslie
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada; and
| | - David B. MacLeod
- Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - Chris K. Willie
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada; and
| | - Glen E. Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada; and
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17
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A mathematical model approach quantifying patients' response to changes in mechanical ventilation: Evaluation in pressure support. J Crit Care 2015; 30:1008-15. [PMID: 26067844 DOI: 10.1016/j.jcrc.2015.05.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 04/30/2015] [Accepted: 05/12/2015] [Indexed: 12/19/2022]
Abstract
PURPOSE This article evaluates how mathematical models of gas exchange, blood acid-base status, chemical respiratory drive, and muscle function can describe the respiratory response of spontaneously breathing patients to different levels of pressure support. METHODS The models were evaluated with data from 12 patients ventilated in pressure support ventilation. Models were tuned with clinical data (arterial blood gas measurement, ventilation, and respiratory gas fractions of O2 and CO2) to describe each patient at the clinical level of pressure support. Patients were ventilated up to 5 different pressure support levels, for 15 minutes at each level to achieve steady-state conditions. Model-simulated values of respiratory frequency (fR), arterial pH (pHa), and end-tidal CO2 (FeCO2) were compared to measured values at each pressure support level. RESULTS Model simulations compared well to measured data with Bland-Altman bias and limits of agreement of fR of 0.7 ± 2.2 per minute, pHa of -0.0007 ± 0.019, and FeCO2 of -0.001 ± 0.003. CONCLUSION The models describe patients' fR, pHa, and FeCO2 response to changes in pressure support with low bias and narrow limits of agreement.
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18
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Marano M. Relationship between reduced albumin and inflammation in the critically ill. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2015; 19:177. [PMID: 25928874 PMCID: PMC4403944 DOI: 10.1186/s13054-015-0746-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Marco Marano
- Hemodialysis Unit, Maria Rosaria Clinic, via Colle San Bartolomeo, 50, Pompeii, 80045, Italy.
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Larraza S, Dey N, Karbing DS, Jensen JB, Nygaard M, Winding R, Rees SE. A mathematical model approach quantifying patients' response to changes in mechanical ventilation: evaluation in volume support. Med Eng Phys 2015; 37:341-9. [PMID: 25686673 DOI: 10.1016/j.medengphy.2014.12.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 11/14/2014] [Accepted: 12/28/2014] [Indexed: 11/17/2022]
Abstract
This paper presents a mathematical model-approach to describe and quantify patient-response to changes in ventilator support. The approach accounts for changes in metabolism (V̇O2, V̇CO2) and serial dead space (VD), and integrates six physiological models of: pulmonary gas-exchange; acid-base chemistry of blood, and cerebrospinal fluid; chemoreflex respiratory-drive; ventilation; and degree of patients' respiratory muscle-response. The approach was evaluated with data from 12 patients on volume support ventilation mode. The models were tuned to baseline measurements of respiratory gases, ventilation, arterial acid-base status, and metabolism. Clinical measurements and model simulated values were compared at five ventilator support levels. The models were shown to adequately describe data in all patients (χ(2), p > 0.2) accounting for changes in V̇CO2, VD and inadequate respiratory muscle-response. F-ratio tests showed that this approach provides a significantly better (p < 0.001) description of measured data than: (a) a similar model omitting the degree of respiratory muscle-response; and (b) a model of constant alveolar ventilation. The approach may help predict patients' response to changes in ventilator support at the bedside.
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Affiliation(s)
- S Larraza
- Respiratory and Critical Care Group (RCARE), Center for Model-based Medical Decision Support, Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7, E4-213, DK-9220 Aalborg, Denmark.
| | - N Dey
- Department of Anaesthesia and Intensive Care, Regions Hospital Herning, Herning, Denmark
| | - D S Karbing
- Respiratory and Critical Care Group (RCARE), Center for Model-based Medical Decision Support, Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7, E4-213, DK-9220 Aalborg, Denmark
| | | | - M Nygaard
- Department of Anaesthesia and Intensive Care, Regions Hospital Herning, Herning, Denmark
| | - R Winding
- Department of Anaesthesia and Intensive Care, Regions Hospital Herning, Herning, Denmark
| | - S E Rees
- Respiratory and Critical Care Group (RCARE), Center for Model-based Medical Decision Support, Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7, E4-213, DK-9220 Aalborg, Denmark
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Abstract
Breathlessness is a negative affective experience relating to respiration, the animal welfare significance of which has largely been underestimated in the veterinary and animal welfare sciences. In this review, we draw attention to the negative impact that breathlessness can have on the welfare of individual animals and to the wide range of situations in which mammals may experience breathlessness. At least three qualitatively distinct sensations of breathlessness are recognised in human medicine--respiratory effort, air hunger and chest tightness--and each of these reflects comparison by cerebral cortical processing of some combination of heightened ventilatory drive and/or impaired respiratory function. Each one occurs in a variety of pathological conditions and other situations, and more than one may be experienced simultaneously or in succession. However, the three qualities vary in terms of their unpleasantness, with air hunger reported to be the most unpleasant. We emphasise the important interplay among various primary stimuli to breathlessness and other physiological and pathophysiological conditions, as well as animal management practices. For example, asphyxia/drowning of healthy mammals or killing those with respiratory disease using gases containing high carbon dioxide tensions is likely to lead to severe air hunger, while brachycephalic obstructive airway syndrome in modern dog and cat breeds increases respiratory effort at rest and likely leads to air hunger during exertion. Using this information as a guide, we encourage animal welfare scientists, veterinarians, laboratory scientists, regulatory bodies and others involved in evaluations of animal welfare to consider whether or not breathlessness contributes to any compromise they may observe or wish to avoid or mitigate.
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Affiliation(s)
- N J Beausoleil
- a Animal Welfare Science and Bioethics Centre, Institute of Veterinary, Animal and Biomedical Sciences , Massey University , Private Bag 11222, Palmerston North , 4442 , New Zealand
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“Pull and push back” concepts of longevity and life span extension. Biogerontology 2013; 14:687-91. [DOI: 10.1007/s10522-013-9472-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 09/27/2013] [Indexed: 10/26/2022]
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