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May CN, Ow CP, Pustovit RV, Lane DJ, Jufar AH, Trask-Marino A, Peiris RM, Gunn A, Booth LC, Plummer MP, Bellomo R, Lankadeva YR. Reversal of cerebral ischaemia and hypoxia and of sickness behaviour by megadose sodium ascorbate in ovine Gram-negative sepsis. Br J Anaesth 2024; 133:316-325. [PMID: 38960833 DOI: 10.1016/j.bja.2024.04.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/08/2024] [Accepted: 04/25/2024] [Indexed: 07/05/2024] Open
Abstract
BACKGROUND The mechanisms by which megadose sodium ascorbate improves clinical status in experimental sepsis is unclear. We determined its effects on cerebral perfusion, oxygenation, and temperature, and plasma levels of inflammatory biomarkers, nitrates, nitrites, and ascorbate in ovine Gram-negative sepsis. METHODS Sepsis was induced by i.v. infusion of live Escherichia coli for 31 h in unanaesthetised Merino ewes instrumented with a combination sensor in the frontal cerebral cortex to measure tissue perfusion, oxygenation, and temperature. Fluid resuscitation at 23 h was followed by i.v. megadose sodium ascorbate (0.5 g kg-1 over 30 min+0.5 g kg-1 h-1 for 6.5 h) or vehicle (n=6 per group). Norepinephrine was titrated to restore mean arterial pressure (MAP) to 70-80 mm Hg. RESULTS At 23 h of sepsis, MAP (mean [sem]: 85 [2] to 64 [2] mm Hg) and plasma ascorbate (27 [2] to 15 [1] μM) decreased (both P<0.001). Cerebral ischaemia (901 [58] to 396 [40] units), hypoxia (34 [1] to 19 [3] mm Hg), and hyperthermia (39.5 [0.1]°C to 40.8 [0.1]°C) (all P<0.001) developed, accompanied by malaise and lethargy. Sodium ascorbate restored cerebral perfusion (703 [121] units], oxygenation (30 [2] mm Hg), temperature (39.2 [0.1]°C) (all PTreatment<0.05), and the behavioural state to normal. Sodium ascorbate slightly reduced the sepsis-induced increase in interleukin-6, returned VEGF-A to normal (both PGroupxTime<0.01), and increased plasma ascorbate (20 000 [300] μM; PGroup<0.001). The effects of sodium ascorbate were not reproduced by equimolar sodium bicarbonate. CONCLUSIONS Megadose sodium ascorbate rapidly reversed sepsis-induced cerebral ischaemia, hypoxia, hyperthermia, and sickness behaviour. These effects were not reproduced by an equimolar sodium load.
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Affiliation(s)
- Clive N May
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia; Department of Critical Care, Melbourne Medical School, University of Melbourne, Melbourne, VIC, Australia.
| | - Connie P Ow
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Ruslan V Pustovit
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Darius J Lane
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia; Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Alemayehu H Jufar
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Anton Trask-Marino
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Rachel M Peiris
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Adam Gunn
- Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Lindsea C Booth
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Mark P Plummer
- Department of Intensive Care, Royal Melbourne Hospital, Melbourne, VIC, Australia; Department of Intensive Care, Royal Adelaide Hospital, Adelaide, VIC, Australia
| | - Rinaldo Bellomo
- Department of Critical Care, Melbourne Medical School, University of Melbourne, Melbourne, VIC, Australia; Department of Intensive Care, Royal Melbourne Hospital, Melbourne, VIC, Australia; Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, VIC, Australia; Department of Intensive Care, Austin Hospital, Melbourne, VIC, Australia
| | - Yugeesh R Lankadeva
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia; Department of Critical Care, Melbourne Medical School, University of Melbourne, Melbourne, VIC, Australia
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De Backer D. Novelties in the evaluation of microcirculation in septic shock. JOURNAL OF INTENSIVE MEDICINE 2023; 3:124-130. [PMID: 37188120 PMCID: PMC10175708 DOI: 10.1016/j.jointm.2022.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 08/25/2022] [Accepted: 09/01/2022] [Indexed: 05/17/2023]
Abstract
Microvascular alterations were first described in critically ill patients about 20 years ago. These alterations are characterized by a decrease in vascular density and presence of non-perfused capillaries close to well-perfused vessels. In addition, heterogeneity in microvascular perfusion is a key finding in sepsis. In this narrative review, we report our actual understanding of microvascular alterations, their role in the development of organ dysfunction, and the implications for outcome. Herein, we discuss the state of the potential therapeutic interventions and the potential impact of novel therapies. We also discuss how recent technologic development may affect the evaluation of microvascular perfusion.
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