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Ballók B, Schranc Á, Tóth I, Somogyi P, Tolnai J, Peták F, Fodor GH. Comparison of the respiratory effects of commonly utilized general anaesthesia regimes in male Sprague-Dawley rats. Front Physiol 2023; 14:1249127. [PMID: 37791348 PMCID: PMC10544940 DOI: 10.3389/fphys.2023.1249127] [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: 06/28/2023] [Accepted: 09/05/2023] [Indexed: 10/05/2023] Open
Abstract
Background: Respiratory parameters in experimental animals are often characterised under general anaesthesia. However, anaesthesia regimes may alter the functional and mechanical properties of the respiratory system. While most anaesthesia regimes have been shown to affect the respiratory system, the effects of general anaesthesia protocols commonly used in animal models on lung function have not been systematically compared. Methods: The present study comprised 40 male Sprague-Dawley rats divided into five groups (N = 8 in each) according to anaesthesia regime applied: intravenous (iv) Na-pentobarbital, intraperitoneal (ip) ketamine-xylazine, iv propofol-fentanyl, inhaled sevoflurane, and ip urethane. All drugs were administered at commonly used doses. End-expiratory lung volume (EELV), airway resistance (Raw) and tissue mechanics were measured in addition to arterial blood gas parameters during mechanical ventilation while maintaining positive end-expiratory pressure (PEEP) values of 0, 3, and 6 cm H2O. Respiratory mechanics were also measured during iv methacholine (MCh) challenges to assess bronchial responsiveness. Results: While PEEP influenced baseline respiratory mechanics, EELV and blood gas parameters (p < 0.001), no between-group differences were observed (p > 0.10). Conversely, significantly lower doses of MCh were required to achieve the same elevation in Raw under ketamine-xylazine anaesthesia compared to the other groups. Conclusion: In the most frequent rodent model of respiratory disorders, no differences in baseline respiratory mechanics or function were observed between commonly used anaesthesia regimes. Bronchial hyperresponsiveness in response to ketamine-xylazine anaesthesia should be considered when designing experiments using this regime. The findings of the present study indicate commonly used anaesthetic regimes allow fair comparison of respiratory mechanics in experimental animals undergoing any of the examined anaesthesia protocols.
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Affiliation(s)
- Bence Ballók
- Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Álmos Schranc
- Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
- Unit for Anaesthesiological Investigations, Department of Anaesthesiology, Pharmacology, Intensive Care, and Emergency Medicine, University of Geneva, Geneva, Switzerland
| | - Ibolya Tóth
- Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Petra Somogyi
- Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
- Department of Cell Biology and Molecular Medicine, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - József Tolnai
- Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Ferenc Peták
- Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Gergely H. Fodor
- Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
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Valerianova A, Mlcek M, Malik J, Grus T, Tejkl L, Kolosova B, Lejsek V, Kittnar O. Comparing the hemodynamic effect of a large arteriovenous fistula during high and low cardiac output states. Front Physiol 2023; 14:1180224. [PMID: 37465699 PMCID: PMC10351416 DOI: 10.3389/fphys.2023.1180224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 06/22/2023] [Indexed: 07/20/2023] Open
Abstract
Background: A large arteriovenous fistula (AVF) is a low-resistant circuit that affects organ perfusion and systemic hemodynamics even in standard conditions. The extent of its' effect in critical states has not been elucidated yet. We used norepinephrine to create systemic vasoconstriction, dobutamine to create high cardiac output, and rapid right ventricle pacing as a model of acute heart failure in a porcine model of high-flow AVF circulation. Methods: The protocol was performed on nine domestic female pigs under general anesthesia. AVF was created by connecting two high-diameter ECMO cannulas inserted in the femoral artery and vein. Continuous hemodynamic monitoring was performed throughout the protocol. Three interventions were performed-moderate dose of norepinephrine (0.25 ug/kg/min), moderate dose of dobutamine (10 ug/kg/min) and rapid right ventricle pacing to simulate low cardiac output state with mean arterial pressure under 60 mmHg. Measurements were taken with opened and closed arteriovenous fistula. Results: Continuous infusion of norepinephrine with opened AVF significantly increased mean arterial pressure (+20%) and total cardiac output (CO) (+36%), but vascular resistance remained virtually unchanged. AVF flow (Qa) rise correlated with mean arterial pressure increase (+20%; R = 0.97, p = 0.0001). Effective cardiac output increased, leading to insignificant improvement in organ perfusion. Dobutamine substantially increased cardiac output with insignificant effect on AVF flow and mean arterial pressure. Carotid artery blood flow increased significantly after dobutamine infusion by approximately 30%, coronary flow velocity increased significantly only in closed AVF state. The effective cardiac output using the heart failure model leading to decrease of carotid artery flow and worsening of brain and peripheral tissue oximetry. AVF blood flow also dropped significantly and proportionally to pressure, but Qa/CO ratio did not change. Therefore, the effective cardiac output decreased. Conclusion: In abovementioned extreme hemodynamic conditions the AVF flow was always directly proportional to systemic perfusion pressure. The ratio of shunt flow to cardiac output depended on systemic vascular resistance. These experiments highlight the detrimental role of a large AVF in these critical conditions' models.
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Affiliation(s)
- A. Valerianova
- 3rd Department of Internal Medicine, General University Hospital in Prague and 1st Faculty of Medicine, Charles University, Prague, Czechia
- Institute of Physiology, 1st Faculty of Medicine, Charles University, Prague, Czechia
| | - M. Mlcek
- Institute of Physiology, 1st Faculty of Medicine, Charles University, Prague, Czechia
| | - J. Malik
- 3rd Department of Internal Medicine, General University Hospital in Prague and 1st Faculty of Medicine, Charles University, Prague, Czechia
| | - T. Grus
- 2nd Surgical Clinic—Cardiovascular Surgery, General University Hospital in Prague and 1st Faculty of Medicine, Charles University, Prague, Czechia
| | - L. Tejkl
- Institute of Physiology, 1st Faculty of Medicine, Charles University, Prague, Czechia
| | - B. Kolosova
- 3rd Department of Internal Medicine, General University Hospital in Prague and 1st Faculty of Medicine, Charles University, Prague, Czechia
| | - V. Lejsek
- 3rd Department of Internal Medicine, General University Hospital in Prague and 1st Faculty of Medicine, Charles University, Prague, Czechia
| | - O. Kittnar
- Institute of Physiology, 1st Faculty of Medicine, Charles University, Prague, Czechia
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Zhao G, Han H, Wang W, Jia K. Propofol rather than Isoflurane Accelerates the Interstitial Fluid Drainage in the Deep Rat Brain. Int J Med Sci 2021; 18:652-659. [PMID: 33437200 PMCID: PMC7797541 DOI: 10.7150/ijms.54320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 11/23/2020] [Indexed: 11/15/2022] Open
Abstract
Objective: Different anesthetics have distinct effects on the interstitial fluid (ISF) drainage in the extracellular space (ECS) of the superficial rat brain, while their effects on ISF drainage in the ECS of the deep rat brain still remain unknown. Herein, we attempt to investigate and compare the effects of propofol and isoflurane on ECS structure and ISF drainage in the caudate-putamen (CPu) and thalamus (Tha) of the deep rat brain. Methods: Adult Sprague-Dawley rats were anesthetized with propofol or isoflurane, respectively. Twenty-four anesthetized rats were randomly divided into the propofol-CPu, isoflurane-CPu, propofol-Tha, and isoflurane-Tha groups. Tracer-based magnetic resonance imaging (MRI) and fluorescent-labeled tracer assay were utilized to quantify ISF drainage in the deep brain. Results: The half-life of ISF in the propofol-CPu and propofol-Tha groups was shorter than that in the isoflurane-CPu and isoflurane-Tha groups, respectively. The ECS volume fraction in the propofol-CPu and propofol-Tha groups was much higher than that in the isoflurane-CPu and isoflurane-Tha groups, respectively. However, the ECS tortuosity in the propofol-CPu and propofol-Tha groups was much smaller than that in isoflurane-CPu and isoflurane-Tha groups, respectively. Conclusions: Our results demonstrate that propofol rather than isoflurane accelerates the ISF drainage in the deep rat brain, which provides novel insights into the selective control of ISF drainage and guides selection of anesthetic agents in different clinical settings, and unravels the mechanism of how general anesthetics function.
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Affiliation(s)
- Guomei Zhao
- Department of Geriatrics, Beijing Shijitan Hospital, Capital Medical University, Beijing 100038, China
| | - Hongbin Han
- Department of Radiology, Peking University Third Hospital, Beijing 100191, China.,Beijing Key Laboratory of Magnetic Resonance Imaging Technology, Beijing 100191, China.,Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Wei Wang
- Research Institute for Translation Medicine on Molecular Function and Artificial Intelligence Imaging, Department of Radiology, The First People's Hospital of FoShan, Foshan 52800, China
| | - Kaiying Jia
- Department of Geriatrics, Beijing Shijitan Hospital, Capital Medical University, Beijing 100038, China
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Carreiro S, Blum J, Jay G, Hack JB. Intravenous lipid emulsion alters the hemodynamic response to epinephrine in a rat model. J Med Toxicol 2014; 9:220-5. [PMID: 23412937 DOI: 10.1007/s13181-013-0291-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Intravenous lipid emulsion (ILE) is an adjunctive antidote used in selected critically ill poisoned patients. These patients may also require administration of advanced cardiac life support (ACLS) drugs. Limited data is available to describe interactions of ILE with standard ACLS drugs, specifically epinephrine. Twenty rats with intra-arterial and intravenous access were sedated with isoflurane and split into ILE or normal saline (NS) pretreatment groups. All received epinephrine 15 μm/kg intravenously (IV). Continuous mean arterial pressure (MAP) and heart rate (HR) were monitored until both indices returned to baseline. Standardized t tests were used to compare peak MAP, time to peak MAP, maximum change in HR, time to maximum change in HR, and time to return to baseline MAP/HR. There was a significant difference (p = 0.023) in time to peak MAP in the ILE group (54 s, 95 % CI 44-64) versus the NS group (40 s, 95 % CI 32-48) and a significant difference (p = 0.004) in time to return to baseline MAP in ILE group (171 s, 95 % CI 148-194) versus NS group (130 s, 95 % CI 113-147). There were no significant differences in the peak change in MAP, peak change in HR, time to minimum HR, or time to return to baseline HR between groups. ILE-pretreated rats had a significant difference in MAP response to epinephrine; ILE delayed the peak effect and prolonged the duration of effect of epinephrine on MAP, but did not alter the peak increase in MAP or the HR response.
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Affiliation(s)
- Stephanie Carreiro
- Department of Emergency Medicine, The Alpert Medical School, Brown University, Providence, RI, USA,
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