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Erik Sandblom - One of the best experts on this subject based on the ideXlab platform.
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cardiac Oxygen limitation during an acute thermal challenge in the european perch effects of chronic environmental warming and experimental hyperoxia
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2016Co-Authors: Andreas Ekstrom, Jeroen Brijs, Timothy Clark, Albin Grans, Fredrik Jutfelt, Erik SandblomAbstract:Oxygen supply to the heart has been hypothesized to limit cardiac performance and whole animal acute thermal tolerance (CTmax) in fish. We tested these hypotheses by continuously measuring Venous Oxygen Tension (Pvo2) and cardiovascular variables in vivo during acute warming in European perch (Perca fluviatilis) from a reference area during summer (18°C) and a chronically heated area (Biotest enclosure) that receives warm effluent water from a nuclear power plant and is normally 5–10°C above ambient (24°C at the time of experiments). While CTmax was 2.2°C higher in Biotest compared with reference perch, the peaks in cardiac output and heart rate prior to CTmax occurred at statistically similar Pvo2 values (2.3–4.0 kPa), suggesting that cardiac failure occurred at a common critical Pvo2 threshold. Environmental hyperoxia (200% air saturation) increased Pvo2 across temperatures in reference fish, but heart rate still declined at a similar temperature. CTmax of reference fish increased slightly (by 0.9°C) in...
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cardiac Oxygen limitation during an acute thermal challenge in the european perch effects of chronic environmental warming and experimental hyperoxia
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2016Co-Authors: Andreas Ekstrom, Jeroen Brijs, Timothy Clark, Albin Grans, Fredrik Jutfelt, Erik SandblomAbstract:Oxygen supply to the heart has been hypothesized to limit cardiac performance and whole animal acute thermal tolerance (CTmax) in fish. We tested these hypotheses by continuously measuring Venous Oxygen Tension (Pvo2) and cardiovascular variables in vivo during acute warming in European perch (Perca fluviatilis) from a reference area during summer (18°C) and a chronically heated area (Biotest enclosure) that receives warm effluent water from a nuclear power plant and is normally 5-10°C above ambient (24°C at the time of experiments). While CTmax was 2.2°C higher in Biotest compared with reference perch, the peaks in cardiac output and heart rate prior to CTmax occurred at statistically similar Pvo2 values (2.3-4.0 kPa), suggesting that cardiac failure occurred at a common critical Pvo2 threshold. Environmental hyperoxia (200% air saturation) increased Pvo2 across temperatures in reference fish, but heart rate still declined at a similar temperature. CTmax of reference fish increased slightly (by 0.9°C) in hyperoxia, but remained significantly lower than in Biotest fish despite an improved cardiac output due to an elevated stroke volume. Thus, while cardiac Oxygen supply appears critical to elevate stroke volume at high temperatures, Oxygen limitation may not explain the bradycardia and arrhythmia that occur prior to CTmax Acute thermal tolerance and its thermal plasticity can, therefore, only be partially attributed to cardiac failure from myocardial Oxygen limitations, and likely involves limiting factors on multiple organizational levels.
N. Simon Faithfull - One of the best experts on this subject based on the ideXlab platform.
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a pilot study of the effects of a perflubron emulsion af 0104 on mixed Venous Oxygen Tension in anesthetized surgical patients
Anesthesia & Analgesia, 1996Co-Authors: Joyce A Wahr, Peter E. Keipert, Ad Trouwborst, Kevin K Tremper, R K Spence, C P Henny, Aurel C Cernaianu, G P Graziano, K E Flaim, N. Simon FaithfullAbstract:A pilot study of a perfluorochemical (PFC) emulsion was undertaken to determine whether administration of a perflubron emulsion could result in measurable changes in mixed Venous Oxygen Tension. Seven adult surgical patients received a 0.9-g PFC/kg intraVenous dose of perflubron emulsion after acute normovolemic hemodilution (ANH). Hemodynamic and Oxygen transport data were collected before and after ANH, immediately after PFC infusion, and at approximate 15-min intervals throughout the surgical period. There were no clinically significant hemodynamic changes associated with the administration of the PFC emulsion. There was a significant increase in mixed Venous Oxygen Tension (PVO2) after the PFC infusion, while cardiac output and Oxygen consumption were unchanged. As surgery progressed, the hemoglobin concentration decreased with ongoing blood loss while PVO2 values remained at or above predosing levels. Peak perflubron blood levels were 0.8 g/dL immediately postinfusion, and approximately 0.3 g/dL at 1 h. This pilot study demonstrates that administration of perflubron emulsion results in measurable changes in mixed Venous Oxygen Tension during intraoperative ANH.
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A Program to Calculate Mixed Venous Oxygen Tension - a Guide to Transfusion?
Advances in experimental medicine and biology, 1994Co-Authors: N. Simon Faithfull, Glenn Rhoades, Peter E. Keipert, Andrew S. Ringle, Ad TrouwborstAbstract:Though it is generally accepted that Venous blood Oxygen Tension (PO2) reflects (but does not measure) PO2 of the tissue from which it is issuing, it is generally impractical, except under unusual circumstances, to monitor PO2 in Venous blood draining from individual tissues or organs. Hence, the mixed Venous PO2 (PvO2) is usually taken as an acceptable estimator of the Oxygen delivery/consumption ratio in the whole body and is used as a guide to the Oxygenation status of the whole body. It would be logical therefore to use PvO2 as an indication for the need for blood transfusion during surgical procedures and in the trauma situation.
Ad Trouwborst - One of the best experts on this subject based on the ideXlab platform.
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a pilot study of the effects of a perflubron emulsion af 0104 on mixed Venous Oxygen Tension in anesthetized surgical patients
Anesthesia & Analgesia, 1996Co-Authors: Joyce A Wahr, Peter E. Keipert, Ad Trouwborst, Kevin K Tremper, R K Spence, C P Henny, Aurel C Cernaianu, G P Graziano, K E Flaim, N. Simon FaithfullAbstract:A pilot study of a perfluorochemical (PFC) emulsion was undertaken to determine whether administration of a perflubron emulsion could result in measurable changes in mixed Venous Oxygen Tension. Seven adult surgical patients received a 0.9-g PFC/kg intraVenous dose of perflubron emulsion after acute normovolemic hemodilution (ANH). Hemodynamic and Oxygen transport data were collected before and after ANH, immediately after PFC infusion, and at approximate 15-min intervals throughout the surgical period. There were no clinically significant hemodynamic changes associated with the administration of the PFC emulsion. There was a significant increase in mixed Venous Oxygen Tension (PVO2) after the PFC infusion, while cardiac output and Oxygen consumption were unchanged. As surgery progressed, the hemoglobin concentration decreased with ongoing blood loss while PVO2 values remained at or above predosing levels. Peak perflubron blood levels were 0.8 g/dL immediately postinfusion, and approximately 0.3 g/dL at 1 h. This pilot study demonstrates that administration of perflubron emulsion results in measurable changes in mixed Venous Oxygen Tension during intraoperative ANH.
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A Program to Calculate Mixed Venous Oxygen Tension - a Guide to Transfusion?
Advances in experimental medicine and biology, 1994Co-Authors: N. Simon Faithfull, Glenn Rhoades, Peter E. Keipert, Andrew S. Ringle, Ad TrouwborstAbstract:Though it is generally accepted that Venous blood Oxygen Tension (PO2) reflects (but does not measure) PO2 of the tissue from which it is issuing, it is generally impractical, except under unusual circumstances, to monitor PO2 in Venous blood draining from individual tissues or organs. Hence, the mixed Venous PO2 (PvO2) is usually taken as an acceptable estimator of the Oxygen delivery/consumption ratio in the whole body and is used as a guide to the Oxygenation status of the whole body. It would be logical therefore to use PvO2 as an indication for the need for blood transfusion during surgical procedures and in the trauma situation.
H A F Dudley - One of the best experts on this subject based on the ideXlab platform.
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comparison of pulmonary artery pressures and mixed Venous Oxygen Tension with other indices in acute haemorrhage an experimental study
British Journal of Surgery, 2005Co-Authors: B J Pardy, H A F DudleyAbstract:A pulmonary artery cannula allows the determination of free and wedge pulmonary artery pressures and mixed Venous Oxygen Tension. These indices have been reported to provide useful information in the assessment of the haemodynamic status of the ill patient. The purpose of this study was to compare them with systemic arterial and central Venous pressures as predictors of cardiac output during acute continuous haemorrhage in the dog. Pulmonary artery pressure changed almost linearly with cardiac output, and the percentage changes in each were similar; by contrast, systemic arterial pressure was an inferior predictor of cardiac output. Pulmonary artery wedge pressure fell rapidly in the initial phase of bleeding, but right atrial pressure more gradually. The Oxygen Tension of blood in the pulmonary artery fell steadily during haemorrhage. These findings suggest that data derived from the use of a pulmonary artery cannula may be more useful than systemic arterial and central Venous pressures in the detection of hypovolaemia and reduced cardiac output; more frequent use of a pulmonary artery cannula should be made in patients in whom blood volume may fluctuate rapidly.
Andreas Ekstrom - One of the best experts on this subject based on the ideXlab platform.
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cardiac Oxygen limitation during an acute thermal challenge in the european perch effects of chronic environmental warming and experimental hyperoxia
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2016Co-Authors: Andreas Ekstrom, Jeroen Brijs, Timothy Clark, Albin Grans, Fredrik Jutfelt, Erik SandblomAbstract:Oxygen supply to the heart has been hypothesized to limit cardiac performance and whole animal acute thermal tolerance (CTmax) in fish. We tested these hypotheses by continuously measuring Venous Oxygen Tension (Pvo2) and cardiovascular variables in vivo during acute warming in European perch (Perca fluviatilis) from a reference area during summer (18°C) and a chronically heated area (Biotest enclosure) that receives warm effluent water from a nuclear power plant and is normally 5–10°C above ambient (24°C at the time of experiments). While CTmax was 2.2°C higher in Biotest compared with reference perch, the peaks in cardiac output and heart rate prior to CTmax occurred at statistically similar Pvo2 values (2.3–4.0 kPa), suggesting that cardiac failure occurred at a common critical Pvo2 threshold. Environmental hyperoxia (200% air saturation) increased Pvo2 across temperatures in reference fish, but heart rate still declined at a similar temperature. CTmax of reference fish increased slightly (by 0.9°C) in...
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cardiac Oxygen limitation during an acute thermal challenge in the european perch effects of chronic environmental warming and experimental hyperoxia
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2016Co-Authors: Andreas Ekstrom, Jeroen Brijs, Timothy Clark, Albin Grans, Fredrik Jutfelt, Erik SandblomAbstract:Oxygen supply to the heart has been hypothesized to limit cardiac performance and whole animal acute thermal tolerance (CTmax) in fish. We tested these hypotheses by continuously measuring Venous Oxygen Tension (Pvo2) and cardiovascular variables in vivo during acute warming in European perch (Perca fluviatilis) from a reference area during summer (18°C) and a chronically heated area (Biotest enclosure) that receives warm effluent water from a nuclear power plant and is normally 5-10°C above ambient (24°C at the time of experiments). While CTmax was 2.2°C higher in Biotest compared with reference perch, the peaks in cardiac output and heart rate prior to CTmax occurred at statistically similar Pvo2 values (2.3-4.0 kPa), suggesting that cardiac failure occurred at a common critical Pvo2 threshold. Environmental hyperoxia (200% air saturation) increased Pvo2 across temperatures in reference fish, but heart rate still declined at a similar temperature. CTmax of reference fish increased slightly (by 0.9°C) in hyperoxia, but remained significantly lower than in Biotest fish despite an improved cardiac output due to an elevated stroke volume. Thus, while cardiac Oxygen supply appears critical to elevate stroke volume at high temperatures, Oxygen limitation may not explain the bradycardia and arrhythmia that occur prior to CTmax Acute thermal tolerance and its thermal plasticity can, therefore, only be partially attributed to cardiac failure from myocardial Oxygen limitations, and likely involves limiting factors on multiple organizational levels.
