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Storlund RL, Rosen DAS, Haulena M, Sanatani S, Vander Zaag J, Trites AW. Ultrasound images of the ascending aorta of anesthetized northern fur seals and Steller sea lions confirm that the aortic bulb maintains continuous blood flow. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2024; 341:458-469. [PMID: 38409932 DOI: 10.1002/jez.2799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 02/02/2024] [Accepted: 02/09/2024] [Indexed: 02/28/2024]
Abstract
The increased size and enhanced compliance of the aortic bulb-the enlargement of the ascending aorta-are believed to maintain blood flow in pinnipeds during extended periods of diastole induced by diving bradycardia. The aortic bulb has been described ex vivo in several species of pinnipeds, but in vivo measurements are needed to investigate the relationship between structure and function. We obtained ultrasound images using electrocardiogram-gated transesophageal echocardiography during anesthesia and after atropine administration to assess the relationship between aortic bulb anatomy and cardiac function (heart rate, stroke volume, cardiac output) in northern fur seals (Callorhinus ursinus) and Steller sea lions (Eumetopias jubatus). We observed that the aortic bulb in northern fur seals and Steller sea lions expands during systole and recoils over the entire diastolic period indicating that blood flow is maintained throughout the entire cardiac cycle as expected. The stroke volumes we measured in the fur seals and sea lions fit the values predicted based on body size in mammals and did not change with increased heart rates, suggesting that greater stroke volumes are not needed for aortic bulb function. Overall, our results suggest that peripheral vasoconstriction during diving is sufficient to modulate the volume of blood in the aortic bulb to ensure that flow lasts over the entire diastolic period. These results indicate that the shift of blood into the aortic bulb of pinnipeds is a fundamental mechanism caused by vasoconstriction while diving, highlighting the importance of this unique anatomical adaptation.
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Affiliation(s)
- Rhea L Storlund
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - David A S Rosen
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia, Canada
- Vancouver Aquarium, Vancouver, British Columbia, Canada
| | | | - Shubhayan Sanatani
- Division of Cardiology, British Columbia Children's Hospital, Vancouver, British Columbia, Canada
- Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jessica Vander Zaag
- Division of Cardiology, British Columbia Children's Hospital, Vancouver, British Columbia, Canada
| | - Andrew W Trites
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
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Le-Bert CR, Bukoski A, Downs J, Hodgson DS, Thombs L, Ridgway SH, Bailey J. Apneustic anesthesia ventilation improves pulmonary function in anesthetized bottlenose dolphins ( Tursiops truncatus). Front Vet Sci 2024; 11:1287478. [PMID: 38645641 PMCID: PMC11027569 DOI: 10.3389/fvets.2024.1287478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 03/12/2024] [Indexed: 04/23/2024] Open
Abstract
Introduction Use of mechanical ventilation during general anesthesia is a necessary practice in the anesthetization of small cetaceans as spontaneous ventilation fails to provide adequate gas exchange. Currently available methods of ventilation do not account for the intermittent breathing strategy of representative species within this infraorder of fully aquatic mammals and may have a significant effect on cardiac and respiratory physiology. Methods To understand the impact of mechanical ventilation on cardiopulmonary function in one small species of cetacean, the bottlenose dolphin (Tursiops truncatus), we compared controlled mechanical ventilation (CMV) to a novel ventilation method known as apneustic anesthesia ventilation (AAV). AAV simulates the normal inspiratory breath-hold pattern of dolphins. Ten anesthetic procedures (dental procedure, n = 9; bronchoscopy, n = 2) were performed on nine dolphins (age range: 10-42 years; mean = 32 years; median = 37 years; female = 3, 40%; male = 6, 60%). In a cross-over study design, dolphins were instrumented and randomly assigned to AAV or CMV as the initial mode of ventilation, then switched to the alternate mode. Baseline cardiopulmonary data were collected and again after 30 min on each mode of ventilation. Cardiac index, stroke volume index, systemic vascular resistance, alveolar dead space, alveolar-arterial oxygen tension gradient, arterial oxygen content, oxygen delivery index, and dynamic respiratory system compliance index were calculated at each of the four time points. Results During AAV, dolphins had higher arterial oxygen tension, higher mean airway pressure, reduced alveolar dead space ventilation and lower alveolar-arterial oxygen difference. Cardiovascular performance was not statistically different between the two modes. Discussion Our study suggests AAV, which more closely resembles the conscious intermittent respiratory pattern phenotype of dolphins, improves ventilation and pulmonary function in the anesthetized dolphin. Future studies should evaluate the cardiopulmonary effects of neutral buoyancy and cardiopulmonary sparing drug protocols to reduce the need for hemodynamic support of current protocols.
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Affiliation(s)
- Carolina R. Le-Bert
- U.S. Navy Marine Mammal Program, Naval Information Warfare Center Pacific, San Diego, CA, United States
| | - Alex Bukoski
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO, United States
| | - John Downs
- Department of Anesthesiology, College of Medicine, University of Florida, Gainesville, FL, United States
- Innovative Veterinary Medicine, Ponte Vedra, FL, United States
| | - David S. Hodgson
- Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - Lori Thombs
- Department of Statistics, College of Arts and Science, University of Missouri, Columbia, MO, United States
| | - Sam H. Ridgway
- U.S. Navy Marine Mammal Program, National Marine Mammal Foundation, San Diego, CA, United States
| | - James Bailey
- Innovative Veterinary Medicine, Ponte Vedra, FL, United States
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John JS, Christen DR, Flammer KL, Kendall TL, Nazario EC, Richter BP, Gill V, Williams TM. Conservation energetics of beluga whales: using resting and swimming metabolism to understand threats to an endangered population. J Exp Biol 2024; 227:jeb246899. [PMID: 38483264 PMCID: PMC11070638 DOI: 10.1242/jeb.246899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 01/24/2024] [Indexed: 05/08/2024]
Abstract
The balance between energetic costs and acquisition in free-ranging species is essential for survival, and provides important insights regarding the physiological impact of anthropogenic disturbances on wild animals. For marine mammals such as beluga whales (Delphinapterus leucas), the first step in modeling this bioenergetic balance requires an examination of resting and active metabolic demands. Here, we used open-flow respirometry to measure oxygen consumption during surface rest and submerged swimming by trained beluga whales, and compared these measurements with those of a commonly studied odontocete, the Atlantic bottlenose dolphin (Tursiops truncatus). Both resting metabolic rate (3012±126.0 kJ h-1) and total cost of transport (1.4±0.1 J kg-1 m-1) of beluga whales were consistent with predicted values for moderately sized marine mammals in temperate to cold-water environments, including dolphins measured in the present study. By coupling the rate of oxygen consumption during submerged swimming with locomotor metrics from animal-borne accelerometer tags, we developed predictive relationships for assessing energetic costs from swim speed, stroke rate and partial dynamic acceleration. Combining these energetic data with calculated aerobic dive limits for beluga whales (8.8 min), we found that high-speed responses to disturbance markedly reduce the whale's capacity for prolonged submergence, pushing the cetaceans to costly anaerobic performances that require prolonged recovery periods. Together, these species-specific energetic measurements for beluga whales provide two important metrics, gait-related locomotor costs and aerobic capacity limits, for identifying relative levels of physiological vulnerability to anthropogenic disturbances that have become increasingly pervasive in their Arctic habitats.
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Affiliation(s)
- Jason S. John
- University of California, Santa Cruz, Department of Ecology and Evolutionary Biology, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | | | | | - Traci L. Kendall
- University of California, Santa Cruz, Department of Ecology and Evolutionary Biology, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Emily C. Nazario
- University of California, Santa Cruz, Department of Ecology and Evolutionary Biology, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Beau P. Richter
- University of California, Santa Cruz, Department of Ecology and Evolutionary Biology, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Verena Gill
- NOAA Fisheries, 222 W. 7th Ave, Anchorage, AK 99501, USA
| | - Terrie M. Williams
- University of California, Santa Cruz, Department of Ecology and Evolutionary Biology, 130 McAllister Way, Santa Cruz, CA 95060, USA
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Doppler echocardiography in a healthy, non-sedated Southern Sea Lion (Otaria flavescens) - a preliminary approach about the feasibility and clinical utility. Vet Res Commun 2022; 47:953-961. [DOI: 10.1007/s11259-022-10019-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 10/09/2022] [Indexed: 11/06/2022]
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Dassis M, De León C, Díaz A, Faiella A, Olguin J, Saubidet A, Rodríguez DH, Castro EF. First description of the Burmeister porpoise (Phocoena spinipinnis) electrocardiogram. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2022; 337:795-801. [PMID: 35833489 DOI: 10.1002/jez.2641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
The aim of this study was to make the first characterization of the electrocardiogram (ECG) of the Burmeister porpoise (Phocoena sipinipinnis). A total of three ECGs were made in one, wild juvenile female (body weight = 32.5 kg, Lt = 1.45 m), temporarily held in captivity for rehabilitation at Mar del Plata Aquarium (Argentina). For ECG recordings, the animal was removed from its pool on a stretcher under constant veterinary supervision. A traditional six-lead system in the frontal plane was used, with the typical four "extremities" electrodes positioned bilaterally. ECGs were readable and all waves were detectable. The QRS complexes were characterized by Q wave absence in all leads. The ECG characteristically displayed distinctly defined STs, with a T wave clearly differentiated from the QRS complex. An STs elevation was detected in leads II and III. The mean electrical axis was -79°, meaning a cranial left axis orientation. The animal showed normal sinus rhythm and heart rate (HR) showed a continuous oscillation between tachycardia and bradycardia. Mean HR from all recordings was 147.02 ± 24.95 bpm (range = 71-176, n = 178). Evidence of the occurrence of respiratory sinus arrhythmia was detected through HR variations and RR interval differences, which suggested an adequate cardiovascular system compensation to handling conditions. This study has reported ECG amplitude and duration measurements of a potentially healthy specimen, which represents the starting point for the determination of normal ECG values for this species. Also, it has confirmed that ECG is a valuable noninvasive tool for rapid cardiac health assessment in small cetaceans.
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Affiliation(s)
- Mariela Dassis
- Grupo de Investigación: Biología, Ecología y Conservación de Mamíferos Marinos, Instituto de Investigaciones Marinas y Costeras (IIMyC), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Facultad de Ciencias Exactas y Naturales (FCEyN), Universidad Nacional de Mar del Plata (UNMdP), Mar del Plata, Argentina
| | - Carolina De León
- Grupo de Investigación: Biología, Ecología y Conservación de Mamíferos Marinos, Instituto de Investigaciones Marinas y Costeras (IIMyC), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Facultad de Ciencias Exactas y Naturales (FCEyN), Universidad Nacional de Mar del Plata (UNMdP), Mar del Plata, Argentina
| | - Alejandro Díaz
- Instituto de Investigación en Ciencias de la Salud, Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Universidad Nacional del Centro de la Provincia de Buenos Aires, Tandil, Argentina
| | - Adrian Faiella
- Centro de Rehabiitación de Fauna Marina y Area técnica veterinaria, Aquarium Mar del Plata, The Dolphin Discovery group, Mar del Plata, Argentina
| | - Javier Olguin
- Centro de Rehabiitación de Fauna Marina y Area técnica veterinaria, Aquarium Mar del Plata, The Dolphin Discovery group, Mar del Plata, Argentina
| | - Alejandro Saubidet
- Centro de Rehabiitación de Fauna Marina y Area técnica veterinaria, Aquarium Mar del Plata, The Dolphin Discovery group, Mar del Plata, Argentina
| | - Diego H Rodríguez
- Grupo de Investigación: Biología, Ecología y Conservación de Mamíferos Marinos, Instituto de Investigaciones Marinas y Costeras (IIMyC), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Facultad de Ciencias Exactas y Naturales (FCEyN), Universidad Nacional de Mar del Plata (UNMdP), Mar del Plata, Argentina
| | - Eduardo F Castro
- Departamento de Fisiopatología, Facultad de Ciencias Veterinarias, Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Universidad Nacional del Centro de la Provincia de Buenos Aires, Tandil, Argentina
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Linnehan BK, Gomez FM, Huston SM, Hsu A, Takeshita R, Colegrove KM, Harms CA, Barratclough A, Deming AC, Rowles TK, Musser WB, Zolman ES, Wells RS, Jensen ED, Schwacke LH, Smith CR. Cardiac assessments of bottlenose dolphins (Tursiops truncatus) in the Northern Gulf of Mexico following exposure to Deepwater Horizon oil. PLoS One 2021; 16:e0261112. [PMID: 34905585 PMCID: PMC8670661 DOI: 10.1371/journal.pone.0261112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 11/24/2021] [Indexed: 11/18/2022] Open
Abstract
The Deepwater Horizon (DWH) oil spill profoundly impacted the health of bottlenose dolphins (Tursiops truncatus) in Barataria Bay, LA (BB). To comprehensively assess the cardiac health of dolphins living within the DWH oil spill footprint, techniques for in-water cardiac evaluation were refined with dolphins cared for by the U.S. Navy Marine Mammal Program in 2018 and applied to free-ranging bottlenose dolphins in BB (n = 34) and Sarasota Bay, Florida (SB) (n = 19), a non-oiled reference population. Cardiac auscultation detected systolic murmurs in the majority of dolphins from both sites (88% BB, 89% SB) and echocardiography showed most of the murmurs were innocent flow murmurs attributed to elevated blood flow velocity [1]. Telemetric six-lead electrocardiography detected arrhythmias in BB dolphins (43%) and SB dolphins (31%), all of which were considered low to moderate risk for adverse cardiac events. Echocardiography showed BB dolphins had thinner left ventricular walls, with significant differences in intraventricular septum thickness at the end of diastole (p = 0.002), and left ventricular posterior wall thickness at the end of diastole (p = 0.033). BB dolphins also had smaller left atrial size (p = 0.004), higher prevalence of tricuspid valve prolapse (p = 0.003), higher prevalence of tricuspid valve thickening (p = 0.033), and higher prevalence of aortic valve thickening (p = 0.008). Two dolphins in BB were diagnosed with pulmonary arterial hypertension based on Doppler echocardiography-derived estimates and supporting echocardiographic findings. Histopathology of dolphins who stranded within the DWH oil spill footprint showed a significantly higher prevalence of myocardial fibrosis (p = 0.003), regardless of age, compared to dolphins outside the oil spill footprint. In conclusion, there were substantial cardiac abnormalities identified in BB dolphins which may be related to DWH oil exposure, however, future work is needed to rule out other hypotheses and further elucidate the connection between oil exposure, pulmonary disease, and the observed cardiac abnormalities.
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Affiliation(s)
- Barbara K. Linnehan
- National Marine Mammal Foundation, San Diego, California, United States of America
- * E-mail:
| | - Forrest M. Gomez
- National Marine Mammal Foundation, San Diego, California, United States of America
| | - Sharon M. Huston
- San Diego Veterinary Cardiology, San Diego, California, United States of America
| | - Adonia Hsu
- San Diego Veterinary Cardiology, San Diego, California, United States of America
| | - Ryan Takeshita
- National Marine Mammal Foundation, San Diego, California, United States of America
| | - Kathleen M. Colegrove
- Zoological Pathology Program, University of Illinois at Urbana-Champaign, Brookfield, Illinois, United States of America
| | - Craig A. Harms
- North Carolina State University, Center for Marine Sciences and Technology, Morehead City, North Carolina, United States of America
| | - Ashley Barratclough
- National Marine Mammal Foundation, San Diego, California, United States of America
| | - Alissa C. Deming
- Dauphin Island Sea Lab, Dauphin Island, Alabama, United States of America
| | - Teri K. Rowles
- National Oceanic and Atmospheric Administration, Office of Protected Resources, Silver Spring, Maryland, United States of America
| | - Whitney B. Musser
- National Marine Mammal Foundation, San Diego, California, United States of America
| | - Eric S. Zolman
- National Marine Mammal Foundation, San Diego, California, United States of America
| | - Randall S. Wells
- Chicago Zoological Society’s Sarasota Dolphin Research Program, c/o Mote Marine Laboratory, Sarasota, Florida, United States of America
| | - Eric D. Jensen
- U.S. Navy Marine Mammal Program, Naval Information Warfare Center Pacific, San Diego, California, United States of America
| | - Lori H. Schwacke
- National Marine Mammal Foundation, San Diego, California, United States of America
| | - Cynthia R. Smith
- National Marine Mammal Foundation, San Diego, California, United States of America
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TRANSTHORACIC ECHOCARDIOGRAPHIC EVALUATION AND SERUM CARDIAC TROPONIN VALUES IN ANESTHETIZED HEALTHY FEMALE SOUTHERN SEA OTTERS ( ENHYDRA LUTRIS NEREIS). J Zoo Wildl Med 2021; 52:490-498. [PMID: 34130391 DOI: 10.1638/2020-0137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2020] [Indexed: 11/21/2022] Open
Abstract
Information about antemortem cardiac evaluation in sea otters (Enhydra lutris) is limited, despite well-established clinical care and rehabilitation procedures and a reported elevated risk of cardiac disease for this species. Serum cardiac troponin I (cTnI) concentration and echocardiographic assessment are two ways of screening for and diagnosing cardiac disease. However, no baseline data or reference intervals for either evaluation are published for sea otters. The objectives of this prospective study were to establish serum cTnI concentrations and echocardiographic technique and quantitative measurements in anesthetized healthy female southern sea otters (Enhydra lutris nereis) (n=15). Serum cTnI values were assessed by a high-sensitivity assay. Serum cTnI concentration ranged from <0.006 to 0.038 ng/ml. A complete echocardiogram, including two-dimensional and M-mode modalities, was performed. Echocardiographic measurements for left atrial size, aorta size, left ventricular structure, and left ventricular function were reported. The median left atrial size to aorta ratio was 1.22 (range 0.80-1.59) in short-axis and 1.70 (range 1.39-2.15) in long-axis. The median left ventricular internal dimension was 3.53 cm (range 2.87-4.92 cm) when assessed in two dimensions and 3.58 cm (range 2.80-4.48 cm) by M-mode. Serum concentrations of cTnI and transthoracic echocardiography may represent valuable tools for the antemortem diagnosis of cardiac disease in sea otters.
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Linnehan BK, Hsu A, Gomez FM, Huston SM, Takeshita R, Colegrove KM, Rowles TK, Barratclough A, Musser WB, Harms CA, Cendejas V, Zolman ES, Balmer BC, Townsend FI, Wells RS, Jensen ED, Schwacke LH, Smith CR. Standardization of Dolphin Cardiac Auscultation and Characterization of Heart Murmurs in Managed and Free-Ranging Bottlenose Dolphins ( Tursiops truncatus). Front Vet Sci 2020; 7:570055. [PMID: 33240948 PMCID: PMC7678442 DOI: 10.3389/fvets.2020.570055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 09/24/2020] [Indexed: 12/21/2022] Open
Abstract
Cardiac auscultation is an important, albeit underutilized tool in aquatic animal medicine due to the many challenges associated with in-water examinations. The aims of this prospective study were to (1) establish an efficient and repeatable in-water cardiac auscultation technique in bottlenose dolphins (Tursiops truncatus), (2) describe the presence and characterization of heart murmurs detected in free-ranging and managed dolphins, and (3) characterize heart murmur etiology through echocardiography in free-ranging dolphins. For technique development, 65 dolphins cared for by the Navy Marine Mammal Program (Navy) were auscultated. The techniques were then applied to two free-ranging dolphin populations during capture-release health assessments: Sarasota Bay, Florida (SB), a reference population, and Barataria Bay, LA (BB), a well-studied population of dolphins impacted by the Deepwater Horizon oil spill. Systolic heart murmurs were detected at a frequent and similar prevalence in all dolphin populations examined (Navy 92%, SB 89%, and BB 88%), and characterized as fixed or dynamic. In all three populations, sternal cranial and left cranial were the most common locations for murmur point of maximal intensity (PMI). An in-water transthoracic echocardiogram technique was refined on a subset of Navy dolphins, and full echocardiographic exams were performed on 17 SB dolphins and 29 BB dolphins, of which, 40 had murmurs. Spectral Doppler was used to measure flow velocities across the outflow tracts, and almost all dolphins with audible murmurs had peak outflow velocities ≥1.6 m/s (95%, 38/40); three dolphins also had medium mitral regurgitation which could be the source of their murmurs. The presence of audible murmurs in most of the free-ranging dolphins (88%) was attributed to high velocity blood flow as seen on echocardiography, similar to a phenomenon described in other athletic species. These innocent murmurs were generally characterized as Grade I-III systolic murmurs with PMI in the left or sternal cranial region. This study is the first to describe an efficient technique for in-water dolphin cardiac auscultation, and to present evidence that heart murmurs are common in bottlenose dolphins.
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Affiliation(s)
| | - Adonia Hsu
- San Diego Veterinary Cardiology, San Diego, CA, United States
| | - Forrest M Gomez
- National Marine Mammal Foundation, San Diego, CA, United States
| | - Sharon M Huston
- San Diego Veterinary Cardiology, San Diego, CA, United States
| | - Ryan Takeshita
- National Marine Mammal Foundation, San Diego, CA, United States
| | - Kathleen M Colegrove
- Zoological Pathology Program, University of Illinois at Urbana-Champaign, Brookfield, IL, United States
| | - Teri K Rowles
- Office of Protected Resources, National Oceanic and Atmospheric Administration, Silver Spring, MD, United States
| | | | | | - Craig A Harms
- Center for Marine Sciences and Technology, North Carolina State University, Morehead City, NC, United States
| | | | - Eric S Zolman
- National Marine Mammal Foundation, San Diego, CA, United States
| | - Brian C Balmer
- National Marine Mammal Foundation, San Diego, CA, United States
| | | | - Randall S Wells
- Chicago Zoological Society's Sarasota Dolphin Research Program, c/o Mote Marine Laboratory, Sarasota, FL, United States
| | - Eric D Jensen
- U.S. Navy Marine Mammal Program, Naval Information Warfare Center Pacific, San Diego, CA, United States
| | - Lori H Schwacke
- National Marine Mammal Foundation, San Diego, CA, United States
| | - Cynthia R Smith
- National Marine Mammal Foundation, San Diego, CA, United States
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Fahlman A, Miedler S, Marti-Bonmati L, Ferrero Fernandez D, Muñoz Caballero P, Arenarez J, Rocho-Levine J, Robeck T, Blawas A. Cardiorespiratory coupling in cetaceans; a physiological strategy to improve gas exchange? J Exp Biol 2020; 223:jeb226365. [PMID: 32680902 DOI: 10.1242/jeb.226365] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 07/15/2020] [Indexed: 11/20/2022]
Abstract
In the current study we used transthoracic echocardiography to measure stroke volume (SV), heart rate (fH) and cardiac output (CO) in adult bottlenose dolphins (Tursiops truncatus), a male beluga whale calf [Delphinapterus leucas, body mass (Mb) range: 151-175 kg] and an adult female false killer whale (Pseudorca crassidens, estimated Mb: 500-550 kg) housed in managed care. We also recorded continuous electrocardiogram (ECG) in the beluga whale, bottlenose dolphin, false killer whale, killer whale (Orcinus orca) and pilot whale (Globicephala macrorhynchus) to evaluate cardiorespiratory coupling while breathing spontaneously under voluntary control. The results show that cetaceans have a strong respiratory sinus arrythmia (RSA), during which both fH and SV vary within the interbreath interval, making average values dependent on the breathing frequency (fR). The RSA-corrected fH was lower for all cetaceans compared with that of similarly sized terrestrial mammals breathing continuously. As compared with terrestrial mammals, the RSA-corrected SV and CO were either lower or the same for the dolphin and false killer whale, while both were elevated in the beluga whale. When plotting fR against fH for an inactive mammal, cetaceans had a greater cardiac response to changes in fR as compared with terrestrial mammals. We propose that these data indicate an important coupling between respiration and cardiac function that enhances gas exchange, and that this RSA is important to maximize gas exchange during surface intervals, similar to that reported in the elephant seal.
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Affiliation(s)
- Andreas Fahlman
- Global Diving Research, Inc., Ottawa, ON, K2J 5E8, Canada
- Research Department, Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain
- Research Group on Biomedical Imaging (GIBI230), Instituto de Investigación Sanitaria la Fe, 46026 Valencia, Spain
| | - Stefan Miedler
- Veterinary Cardiology, Plaza Mayor 7/10, 46120 Alboraya, Valencia, Spain
| | - Luis Marti-Bonmati
- Research Group on Biomedical Imaging (GIBI230), Instituto de Investigación Sanitaria la Fe, 46026 Valencia, Spain
| | - Diana Ferrero Fernandez
- Biology Department, Avanqua-Oceanográfic SL, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain
| | - Paola Muñoz Caballero
- Biology Department, Avanqua-Oceanográfic SL, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain
| | - Julietta Arenarez
- Biology Department, Avanqua-Oceanográfic SL, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain
| | | | | | - Ashley Blawas
- Nicholas School of the Environment, Duke University Marine Laboratory, Beaufort, NC 28516, USA
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Bernaldo de Quirós Y, Fernandez A, Baird RW, Brownell RL, Aguilar de Soto N, Allen D, Arbelo M, Arregui M, Costidis A, Fahlman A, Frantzis A, Gulland FMD, Iñíguez M, Johnson M, Komnenou A, Koopman H, Pabst DA, Roe WD, Sierra E, Tejedor M, Schorr G. Advances in research on the impacts of anti-submarine sonar on beaked whales. Proc Biol Sci 2020; 286:20182533. [PMID: 30963955 DOI: 10.1098/rspb.2018.2533] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mass stranding events (MSEs) of beaked whales (BWs) were extremely rare prior to the 1960s but increased markedly after the development of naval mid-frequency active sonar (MFAS). The temporal and spatial associations between atypical BW MSEs and naval exercises were first observed in the Canary Islands, Spain, in the mid-1980s. Further research on BWs stranded in association with naval exercises demonstrated pathological findings consistent with decompression sickness (DCS). A 2004 ban on MFASs around the Canary Islands successfully prevented additional BW MSEs in the region, but atypical MSEs have continued in other places of the world, especially in the Mediterranean Sea, with examined individuals showing DCS. A workshop held in Fuerteventura, Canary Islands, in September 2017 reviewed current knowledge on BW atypical MSEs associated with MFAS. Our review suggests that the effects of MFAS on BWs vary among individuals or populations, and predisposing factors may contribute to individual outcomes. Spatial management specific to BW habitat, such as the MFAS ban in the Canary Islands, has proven to be an effective mitigation tool and mitigation measures should be established in other areas taking into consideration known population-level information.
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Affiliation(s)
- Y Bernaldo de Quirós
- 1 Institute of Animal Health, University of Las Palmas de Gran Canaria, Veterinary School , C/Transmontaña s/n, 35416, Arucas, Las Palmas , Spain
| | - A Fernandez
- 1 Institute of Animal Health, University of Las Palmas de Gran Canaria, Veterinary School , C/Transmontaña s/n, 35416, Arucas, Las Palmas , Spain
| | - R W Baird
- 2 Cascadia Research Collective , 218½ W. 4th Avenue, Olympia, WA 98501 , USA
| | - R L Brownell
- 3 NOAA Fisheries, Southwest Fisheries Science Center , Monterey, CA 93940 , USA
| | - N Aguilar de Soto
- 4 BIOECOMAC. Dept. Animal Biology, Geology and Edaphology, University of La Laguna , Tenerife , Spain
| | - D Allen
- 5 US Marine Mammal Commission , 4340 East-West Highway, Suite 700, Bethesda, MD 20814 , USA
| | - M Arbelo
- 1 Institute of Animal Health, University of Las Palmas de Gran Canaria, Veterinary School , C/Transmontaña s/n, 35416, Arucas, Las Palmas , Spain
| | - M Arregui
- 1 Institute of Animal Health, University of Las Palmas de Gran Canaria, Veterinary School , C/Transmontaña s/n, 35416, Arucas, Las Palmas , Spain
| | - A Costidis
- 6 Virginia Aquarium & Marine Science Center Stranding Response Program , 717 General Booth Blvd, Virginia Beach, VA 23451 , USA
| | - A Fahlman
- 7 Fundación Oceanogràfic de la Comunitat Valenciana , Gran Vía Marqués del Turia 19, 46005, Valencia , Spain
| | - A Frantzis
- 8 Pelagos Cetacean Research Institute , Terpsichoris 21, 16671 Vouliagmeni , Greece
| | - F M D Gulland
- 5 US Marine Mammal Commission , 4340 East-West Highway, Suite 700, Bethesda, MD 20814 , USA.,9 The Marine Mammal Center , 2000 Bunker Road, Sausalito, CA 94965 , USA
| | - M Iñíguez
- 10 Fundación Cethus and WDC , Cap J. Bermúdez 1598, (1636), Olivos, Prov. Buenos Aires , Argentina
| | - M Johnson
- 11 Sea Mammal Research Unit, University of St Andrews , St Andrews , UK
| | - A Komnenou
- 12 School of Veterinary Medicine, Aristotle University of Thessaloniki , Thessaloniki , Greece
| | - H Koopman
- 13 Department of Biology and Marine Biology, University of North Carolina Wilmington , Wilmington, NC 28403 , USA
| | - D A Pabst
- 13 Department of Biology and Marine Biology, University of North Carolina Wilmington , Wilmington, NC 28403 , USA
| | - W D Roe
- 14 Massey University , Palmerston North, PN4222 , New Zealand
| | - E Sierra
- 1 Institute of Animal Health, University of Las Palmas de Gran Canaria, Veterinary School , C/Transmontaña s/n, 35416, Arucas, Las Palmas , Spain
| | - M Tejedor
- 15 Canary Islands Stranding Network , Irlanda 7, Playa Blanca, 35580, Lanzarote , Spain
| | - G Schorr
- 16 Marine Ecology & Telemetry Research , 2468 Camp McKenzie Tr NW, Seabeck, WA 98380 , USA
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11
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Fahlman A, Miedler S, Rocho-Levine J, Jabois A, Arenarez J, Marti-Bonmati L, García-Párraga D, Cauture F. Re-evaluating the significance of the dive response during voluntary surface apneas in the bottlenose dolphin, Tursiops truncatus. Sci Rep 2019; 9:8613. [PMID: 31197193 PMCID: PMC6565721 DOI: 10.1038/s41598-019-45064-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 05/29/2019] [Indexed: 11/24/2022] Open
Abstract
The dive response is well documented for marine mammals, and includes a significant reduction in heart rate (fH) during submersion as compared while breathing at the surface. In the current study we assessed the influence of the Respiratory Sinus Arrhythmia (RSA) while estimating the resting fH while breathing. Using transthoracic echocardiography we measured fH, and stroke volume (SV) during voluntary surface apneas at rest up to 255 s, and during recovery from apnea in 11 adult bottlenose dolphins (Tursiops truncatus, 9 males and 2 females, body mass range: 140–235 kg). The dolphins exhibited a significant post-respiratory tachycardia and increased SV. Therefore, only data after this RSA had stabilized were used for analysis and comparison. The average (±s.d.) fH, SV, and cardiac output (CO) after spontaneous breaths while resting at the surface were 44 ± 6 beats min−1, 179 ± 31 ml, and 7909 ± 1814 l min−1, respectively. During the apnea the fH, SV, and CO decreased proportionally with the breath-hold duration, and after 255 s they, respectively, had decreased by an average of 18%, 1–21%, and 12–37%. During recovery, the fH, SV, and CO rapidly increased by as much as 117%, 34%, and 190%, respectively. Next, fH, SV and CO rapidly decreased to resting values between 90–110 s following the surface apnea. These data highlight the necessity to define how the resting fH is estimated at the surface, and separating it from the RSA associated with each breath to evaluate the significance of cardiorespiratory matching during diving.
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Affiliation(s)
- A Fahlman
- Research Group on Biomedical Imaging (GIBI230), Instituto de Investigación Sanitaria la Fe, 46026, Valencia, Spain. .,Departamento de Investigación, Fundación Oceanogràfic de la Comunidad Valenciana, Gran Vía Marqués del Turia 19, 46005, Valencia, Spain.
| | - S Miedler
- Departamento de Investigación, Fundación Oceanogràfic de la Comunidad Valenciana, Gran Vía Marqués del Turia 19, 46005, Valencia, Spain.,Veterinary Cardiology, Plaza Mayor 7/10, 46120 Alboraya, Valencia, Spain
| | | | - A Jabois
- Departamento de Biología, Avanqua-Oceanográfic SL, Gran Vía Marqués del Turia 19, 46005, Valencia, Spain
| | - J Arenarez
- Departamento de Biología, Avanqua-Oceanográfic SL, Gran Vía Marqués del Turia 19, 46005, Valencia, Spain
| | - L Marti-Bonmati
- Research Group on Biomedical Imaging (GIBI230), Instituto de Investigación Sanitaria la Fe, 46026, Valencia, Spain
| | - D García-Párraga
- Departamento de Investigación, Fundación Oceanogràfic de la Comunidad Valenciana, Gran Vía Marqués del Turia 19, 46005, Valencia, Spain.,Departamento de Biología, Avanqua-Oceanográfic SL, Gran Vía Marqués del Turia 19, 46005, Valencia, Spain
| | - F Cauture
- Departamento de Investigación, Fundación Oceanogràfic de la Comunidad Valenciana, Gran Vía Marqués del Turia 19, 46005, Valencia, Spain
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12
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Fahlman A, Brodsky M, Miedler S, Dennison S, Ivančić M, Levine G, Rocho-Levine J, Manley M, Rocabert J, Borque-Espinosa A. Ventilation and gas exchange before and after voluntary static surface breath-holds in clinically healthy bottlenose dolphins, Tursiops truncatus. ACTA ACUST UNITED AC 2019; 222:jeb.192211. [PMID: 30760549 DOI: 10.1242/jeb.192211] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 02/05/2019] [Indexed: 01/14/2023]
Abstract
We measured respiratory flow (V̇), breathing frequency (f R), tidal volume (V T), breath duration and end-expired O2 content in bottlenose dolphins (Tursiops truncatus) before and after static surface breath-holds ranging from 34 to 292 s. There was considerable variation in the end-expired O2, V T and f R following a breath-hold. The analysis suggests that the dolphins attempt to minimize recovery following a dive by altering V T and f R to rapidly replenish the O2 stores. For the first breath following a surface breath-hold, the end-expired O2 decreased with dive duration, while V T and f R increased. Throughout the recovery period, end-expired O2 increased while the respiratory effort (V T, f R) decreased. We propose that the dolphins alter respiratory effort following a breath-hold according to the reduction in end-expired O2 levels, allowing almost complete recovery after 1.2 min.
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Affiliation(s)
- Andreas Fahlman
- Departamento de investigación, Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain .,Departamento de Zoología, Grupo de Investigación Biomédica en Imagen GIBI230, Instituto de Investigación Sanitaria La Fe, Av. Fernando Abril Martorell 106, 46026 Valencia, Spain
| | - Micah Brodsky
- Micah Brodsky, V.M.D. Consulting, 1287 NE 96th Street, Miami Shores, FL 33138, USA
| | - Stefan Miedler
- Departamento de investigación, Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain
| | - Sophie Dennison
- TeleVet Imaging Solutions, PLLC, PO BOX 3344, Oakton, VA 22124, USA
| | - Marina Ivančić
- Chicago Zoological Society, 3300 Golf Road, Brookfield, IL 60513, USA
| | - Gregg Levine
- Dolphin Quest, Oahu, 5000 Kahala Ave, Honolulu, HI 96816, USA
| | | | - Mercy Manley
- Siegfried & Roy's Secret Garden and Dolphin Habitat, The Mirage, Las Vegas, NV 89109, USA
| | - Joan Rocabert
- Mellow Design, C/ Bany dels pavesos 3, 46001 Valencia, Spain
| | - Alicia Borque-Espinosa
- Departamento de investigación, Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain.,Departamento de Zoología, Grupo de Investigación Biomédica en Imagen GIBI230, Instituto de Investigación Sanitaria La Fe, Av. Fernando Abril Martorell 106, 46026 Valencia, Spain.,Universidad de Valencia, Av. de Blasco Ibáñez, 13, 46010 Valencia, Spain
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13
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Bonato M, Bagnoli P, Centelleghe C, Maric M, Brocca G, Mazzariol S, Cozzi B. Dynamics of blood circulation during diving in the bottlenose dolphin ( Tursiops truncatus): the role of the retia mirabilia. ACTA ACUST UNITED AC 2019; 222:jeb.198457. [PMID: 30760548 DOI: 10.1242/jeb.198457] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 02/01/2019] [Indexed: 11/20/2022]
Abstract
The retia mirabilia are vascular nets composed of small vessels dispersed among numerous veins, allowing blood storage, regulation of flow and pressure damping effects. Here, we investigated their potential role during the diving phase of the bottlenose dolphin (Tursiops truncatus). To this effect, the whole vertebral retia mirabilia of a series of dolphins were removed during post-mortem analysis and examined to assess vessel diameters, and estimate vascular volume and flow rate. We formulated a new hemodynamic model to help clarify vascular dynamics throughout the diving phase, based on the total blood volume of a bottlenose dolphin, and using data available about the perfusion of the main organs and body systems. We computed the minimum blood perfusion necessary to the internal organs, and the stroke volume and cardiac output during the surface state. We then simulated breath-holding conditions and perfusion of the internal organs under the diving-induced bradycardia and reduction of stroke volume and cardiac output, using 10 beats min-1 as the limit for the heart rate for an extended dive of over 3 min. Within these simulated conditions, the retia mirabilia play a vital role as reservoirs of oxygenated blood that permit functional performances and survival of the heart and brain. Our theoretical model, based on the actual blood capacity of the retia mirabilia and available data on organ perfusion, considers the dynamic trend of vasoconstriction during the diving phase and may represent a baseline for future studies on the diving physiology of dolphins and especially for the blood supply to their brain.
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Affiliation(s)
- Marco Bonato
- Department of Comparative Biomedicine and Food Science, University of Padova, 35020 Legnaro (PD), Italy.,Department of Biology, University of Padova, 35100 Padova (PD), Italy
| | - Paola Bagnoli
- Technology Transfer Office, Politecnico di Milano, 20133 Milan, Italy
| | - Cinzia Centelleghe
- Department of Comparative Biomedicine and Food Science, University of Padova, 35020 Legnaro (PD), Italy
| | - Mike Maric
- Department of Public Health, Experimental and Forensic Medicine, University of Pavia, 27100 Pavia (PV), Italy
| | - Ginevra Brocca
- Department of Comparative Biomedicine and Food Science, University of Padova, 35020 Legnaro (PD), Italy
| | - Sandro Mazzariol
- Department of Comparative Biomedicine and Food Science, University of Padova, 35020 Legnaro (PD), Italy
| | - Bruno Cozzi
- Department of Comparative Biomedicine and Food Science, University of Padova, 35020 Legnaro (PD), Italy
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14
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Cauture F, Sterba-Boatwright B, Rocho-Levine J, Harms C, Miedler S, Fahlman A. Using Respiratory Sinus Arrhythmia to Estimate Inspired Tidal Volume in the Bottlenose Dolphin ( Tursiops truncatus). Front Physiol 2019; 10:128. [PMID: 30837895 PMCID: PMC6390636 DOI: 10.3389/fphys.2019.00128] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 02/01/2019] [Indexed: 11/21/2022] Open
Abstract
Man-made environmental change may have significant impact on apex predators, like marine mammals. Thus, it is important to assess the physiological boundaries for survival in these species, and assess how climate change may affect foraging efficiency and the limits for survival. In the current study, we investigated whether the respiratory sinus arrhythmia (RSA) could estimate tidal volume (V T) in resting bottlenose dolphins (Tursiops truncatus). For this purpose, we measured respiratory flow and electrocardiogram (ECG) in five adult bottlenose dolphins at rest while breathing voluntarily. Initially, an exponential decay function, using three parameters (baseline heart rate, the change in heart rate following a breath, and an exponential decay constant) was used to describe the temporal change in instantaneous heart rate following a breath. The three descriptors, in addition to body mass, were used to develop a Generalized Additive Model (GAM) to predict the inspired tidal volume (V Tinsp). The GAM allowed us to predict V Tinsp with an average ( ± SD) overestimate of 3 ± 2%. A jackknife sensitivity analysis, where 4 of the five dolphins were used to fit the GAM and the 5th dolphin used to make predictions resulted in an average overestimate of 2 ± 10%. Future studies should be used to assess whether similar relationships exist in active animals, allowing V T to be studied in free-ranging animals provided that heart rate can be measured.
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Affiliation(s)
- Fabien Cauture
- Departamento de Investigación, Fundación Oceanogràfic de la Comunidad Valenciana, Valencia, Spain
| | - Blair Sterba-Boatwright
- Department of Mathematics and Statistics, Texas A&M University–Corpus Christi, Corpus Christi, TX, United States
| | | | - Craig Harms
- Center for Marine Sciences and Technology, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Morehead City, NC, United States
| | | | - Andreas Fahlman
- Departamento de Investigación, Fundación Oceanogràfic de la Comunidad Valenciana, Valencia, Spain
- Research Group on Biomedical Imaging (GIBI2), Instituto de Investigación Sanitaria La Fe, Valencia, Spain
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15
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Li NY, Yu H, Li XL, Wang QY, Zhang XW, Ma RX, Zhao Y, Xu H, Liang W, Bai F, Yu J. Astragalus Membranaceus Improving Asymptomatic Left Ventricular Diastolic Dysfunction in Postmenopausal Hypertensive Women with Metabolic Syndrome: A Prospective, Open-Labeled, Randomized Controlled Trial. Chin Med J (Engl) 2018; 131:516-526. [PMID: 29483384 PMCID: PMC5850666 DOI: 10.4103/0366-6999.226077] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Background: Postmenopausal women with metabolic syndrome (MetS) have increased cardiovascular morbidity and left ventricular diastolic dysfunction (LVDD). The various protective effects of astragalus membranaceus (AM) have been described in previous studies. Therefore, this study aimed to evaluate the effects of different doses of AM on diastolic function in postmenopausal hypertensive women with MetS. Methods: This was a prospective, randomized controlled study. The postmenopausal hypertensive patients with MetS were enrolled from Lanzhou University Second Hospital from March 2014 to April 2015. Patients were divided into three groups: control group (received conventional medical treatment), AM Group 1 (received AM capsules at 5 g/d additionally), and AM Group 2 (received AM capsules at 10 g/d additionally). Echocardiographic and clinical characteristics were evaluated before and 12 months after treatment. Quantitative data were analyzed using unpaired t-test, analysis of variance, and multiple linear regression analysis. Results: A total of 154 patients were subjected to final analysis. In the AM Group 2, significant improvements were noted in diastolic function 12 months after treatment than those of the control group, including the early diastolic mitral annular velocity (E’; 0.065 ± 0.007 m/s vs. 0.061 ± 0.008 m/s, P = 0.014), the ratio of the early diastolic mitral peak flow velocity to the late diastolic mitral peak flow velocity (E/A; 0.81 ± 0.05 vs. 0.80 ± 0.06, P = 0.012), the ratio of E’ to the late diastolic mitral annular velocity (E’/A’; 0.56 ± 0.12 vs. 0.51 ± 0.13, P = 0.048), and the ratio of the early diastolic mitral peak flow velocity (E) to E’ (E/E’; 10.70 ± 1.30 vs. 11.37 ± 1.73, P = 0.031). After treatment, E/E’ (10.70 ± 1.30 vs. 11.24 ± 1.56, P = 0.021), deceleration time (DT; 261.49 ± 44.41 ms vs. 268.74 ± 53.87 ms, P = 0.046), and E’/A’ (0.56 ± 0.12 vs. 0.52 ± 0.13, P = 0.019) values improved more significantly than those of AM Group 2 before treatment. Besides, waist circumference was positively correlated with E’ (r = 0.472; P = 0.003) and E’/A’ (r = 0.321; P = 0.047). In addition, the waist-to-hip ratio was a significant predictor of DT (r = 0.276; P = 0.041), E’ (r = −0.590; P < 0.001), E/E’ (r = 0.454; P = 0.004), and E’/A’ (r = −0.377; P = 0.018). Conclusions: Conventional medical plus AM therapy improved diastolic function. Moreover, WC and WHR might be risk factors for LVDD. Chinese Clinical Trial Register: ChiCTR-TRC-11001747. http://www.chictr.org.cn/showprojen.aspx?proj=7798.
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Affiliation(s)
- Ning-Yin Li
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Heng Yu
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Xiu-Li Li
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Qiong-Ying Wang
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Xiao-Wei Zhang
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Rui-Xin Ma
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Yang Zhao
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Han Xu
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Wei Liang
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Feng Bai
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Jing Yu
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, Gansu 730000, China
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16
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Fahlman A, Jensen FH, Tyack PL, Wells RS. Modeling Tissue and Blood Gas Kinetics in Coastal and Offshore Common Bottlenose Dolphins, Tursiops truncatus. Front Physiol 2018; 9:838. [PMID: 30072907 PMCID: PMC6060447 DOI: 10.3389/fphys.2018.00838] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 06/14/2018] [Indexed: 01/07/2023] Open
Abstract
Bottlenose dolphins (Tursiops truncatus) are highly versatile breath-holding predators that have adapted to a wide range of foraging niches from rivers and coastal ecosystems to deep-water oceanic habitats. Considerable research has been done to understand how bottlenose dolphins manage O2 during diving, but little information exists on other gases or how pressure affects gas exchange. Here we used a dynamic multi-compartment gas exchange model to estimate blood and tissue O2, CO2, and N2 from high-resolution dive records of two different common bottlenose dolphin ecotypes inhabiting shallow (Sarasota Bay) and deep (Bermuda) habitats. The objective was to compare potential physiological strategies used by the two populations to manage shallow and deep diving life styles. We informed the model using species-specific parameters for blood hematocrit, resting metabolic rate, and lung compliance. The model suggested that the known O2 stores were sufficient for Sarasota Bay dolphins to remain within the calculated aerobic dive limit (cADL), but insufficient for Bermuda dolphins that regularly exceeded their cADL. By adjusting the model to reflect the body composition of deep diving Bermuda dolphins, with elevated muscle mass, muscle myoglobin concentration and blood volume, the cADL increased beyond the longest dive duration, thus reflecting the necessary physiological and morphological changes to maintain their deep-diving life-style. The results indicate that cardiac output had to remain elevated during surface intervals for both ecotypes, and suggests that cardiac output has to remain elevated during shallow dives in-between deep dives to allow sufficient restoration of O2 stores for Bermuda dolphins. Our integrated modeling approach contradicts predictions from simple models, emphasizing the complex nature of physiological interactions between circulation, lung compression, and gas exchange.
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Affiliation(s)
- Andreas Fahlman
- Global Diving Research, Ottawa, ON, Canada
- Fundación Oceanografic de la Comunidad Valenciana, Valencia, Spain
| | - Frants H. Jensen
- Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark
| | - Peter L. Tyack
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, United Kingdom
| | - Randall S. Wells
- Chicago Zoological Society's Sarasota Dolphin Research Program, Mote Marine Laboratory, Sarasota, FL, United States
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17
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Garcia Párraga D, Moore M, Fahlman A. Pulmonary ventilation-perfusion mismatch: a novel hypothesis for how diving vertebrates may avoid the bends. Proc Biol Sci 2018; 285:20180482. [PMID: 29695441 PMCID: PMC5936736 DOI: 10.1098/rspb.2018.0482] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 03/28/2018] [Indexed: 11/22/2022] Open
Abstract
Hydrostatic lung compression in diving marine mammals, with collapsing alveoli blocking gas exchange at depth, has been the main theoretical basis for limiting N2 uptake and avoiding gas emboli (GE) as they ascend. However, studies of beached and bycaught cetaceans and sea turtles imply that air-breathing marine vertebrates may, under unusual circumstances, develop GE that result in decompression sickness (DCS) symptoms. Theoretical modelling of tissue and blood gas dynamics of breath-hold divers suggests that changes in perfusion and blood flow distribution may also play a significant role. The results from the modelling work suggest that our current understanding of diving physiology in many species is poor, as the models predict blood and tissue N2 levels that would result in severe DCS symptoms (chokes, paralysis and death) in a large fraction of natural dive profiles. In this review, we combine published results from marine mammals and turtles to propose alternative mechanisms for how marine vertebrates control gas exchange in the lung, through management of the pulmonary distribution of alveolar ventilation ([Formula: see text]) and cardiac output/lung perfusion ([Formula: see text]), varying the level of [Formula: see text] in different regions of the lung. Man-made disturbances, causing stress, could alter the [Formula: see text] mismatch level in the lung, resulting in an abnormally elevated uptake of N2, increasing the risk for GE. Our hypothesis provides avenues for new areas of research, offers an explanation for how sonar exposure may alter physiology causing GE and provides a new mechanism for how air-breathing marine vertebrates usually avoid the diving-related problems observed in human divers.
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Affiliation(s)
| | - Michael Moore
- Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Andreas Fahlman
- Fundación Oceanogràfic, Ciudad de las Artes y las Ciencias, 46013 Valencia, Spain
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18
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Fahlman A, Moore MJ, Garcia-Parraga D. Respiratory function and mechanics in pinnipeds and cetaceans. J Exp Biol 2017; 220:1761-1773. [DOI: 10.1242/jeb.126870] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
ABSTRACT
In this Review, we focus on the functional properties of the respiratory system of pinnipeds and cetaceans, and briefly summarize the underlying anatomy; in doing so, we provide an overview of what is currently known about their respiratory physiology and mechanics. While exposure to high pressure is a common challenge among breath-hold divers, there is a large variation in respiratory anatomy, function and capacity between species – how are these traits adapted to allow the animals to withstand the physiological challenges faced during dives? The ultra-deep diving feats of some marine mammals defy our current understanding of respiratory physiology and lung mechanics. These animals cope daily with lung compression, alveolar collapse, transient hyperoxia and extreme hypoxia. By improving our understanding of respiratory physiology under these conditions, we will be better able to define the physiological constraints imposed on these animals, and how these limitations may affect the survival of marine mammals in a changing environment. Many of the respiratory traits to survive exposure to an extreme environment may inspire novel treatments for a variety of respiratory problems in humans.
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Affiliation(s)
- Andreas Fahlman
- Fundación Oceanográfic de la Comunidad Valenciana, Gran Vía Marques del Turia 19, Valencia 46005, Spain
- Department of Life Sciences, Texas A&M University-Corpus Christi, 6300 Ocean Drive, Corpus Christi, TX 78412, USA
| | - Michael J. Moore
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Daniel Garcia-Parraga
- Fundación Oceanográfic de la Comunidad Valenciana, Gran Vía Marques del Turia 19, Valencia 46005, Spain
- Oceanográfic-Avanqua, Ciudad de las Artes y las Ciencias, Valencia 46013, Spain
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Rosen DAS, Hindle AG, Gerlinsky CD, Goundie E, Hastie GD, Volpov BL, Trites AW. Physiological constraints and energetic costs of diving behaviour in marine mammals: a review of studies using trained Steller sea lions diving in the open ocean. J Comp Physiol B 2016; 187:29-50. [PMID: 27686668 DOI: 10.1007/s00360-016-1035-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 08/26/2016] [Accepted: 09/13/2016] [Indexed: 10/20/2022]
Abstract
Marine mammals are characterized as having physiological specializations that maximize the use of oxygen stores to prolong time spent under water. However, it has been difficult to undertake the requisite controlled studies to determine the physiological limitations and trade-offs that marine mammals face while diving in the wild under varying environmental and nutritional conditions. For the past decade, Steller sea lions (Eumetopias jubatus) trained to swim and dive in the open ocean away from the physical confines of pools participated in studies that investigated the interactions between diving behaviour, energetic costs, physiological constraints, and prey availability. Many of these studies measured the cost of diving to understand how it varies with behaviour and environmental and physiological conditions. Collectively, these studies show that the type of diving (dive bouts or single dives), the level of underwater activity, the depth and duration of dives, and the nutritional status and physical condition of the animal affect the cost of diving and foraging. They show that dive depth, dive and surface duration, and the type of dive result in physiological adjustments (heart rate, gas exchange) that may be independent of energy expenditure. They also demonstrate that changes in prey abundance and nutritional status cause sea lions to alter the balance between time spent at the surface acquiring oxygen (and offloading CO2 and other metabolic by-products) and time spent at depth acquiring prey. These new insights into the physiological basis of diving behaviour further our understanding of the potential scope for behavioural responses of marine mammals to environmental changes, the energetic significance of these adjustments, and the consequences of approaching physiological limits.
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Affiliation(s)
- David A S Rosen
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
| | - Allyson G Hindle
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Carling D Gerlinsky
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Elizabeth Goundie
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Gordon D Hastie
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Beth L Volpov
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Andrew W Trites
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada
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Updating a gas dynamics model using estimates for California sea lions (Zalophus californianus). Respir Physiol Neurobiol 2016; 234:1-8. [PMID: 27562522 DOI: 10.1016/j.resp.2016.08.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 07/24/2016] [Accepted: 08/21/2016] [Indexed: 11/22/2022]
Abstract
Theoretical models are used to predict how breath-hold diving vertebrates manage O2, CO2, and N2 while underwater. One recent gas dynamics model used available lung and tracheal compliance data from various species. As variation in respiratory compliance significantly affects alveolar compression and pulmonary shunt, the current study objective was to evaluate changes in model output when using species-specific parameters from California sea lions (Zalophus californianus). We explored the effects of lung and dead space compliance on the uptake of N2, O2, and CO2 in various tissues during a series of hypothetical dives. The updated parameters allowed for increased compliance of the lungs and an increased stiffness in the trachea. When comparing updated model output with a model using previous compliance values, there was a large decrease in N2 uptake but little change in O2 and CO2 levels. Therefore, previous models may overestimate N2 tensions and the risk of gas-related disease, such as decompression sickness (DCS), in marine mammals.
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