Projects per year
Abstract
Cardiac surgery requiring cardiopulmonary bypass is associated with postoperative acute kidney injury and neurocognitive disorders, including delirium. Intra-operative inflammation and/or impaired tissue perfusion/oxygenation are thought to be contributors to these outcomes. It has been hypothesised that these problems may be ameliorated by the highly selective α2-agonist, dexmedetomidine. We tested the effects of dexmedetomidine on renal and cerebral microcirculatory tissue perfusion, oxygenation and histology in a clinically relevant ovine model. Sixteen sheep were studied while conscious, after induction of anaesthesia and during 2 h of cardiopulmonary bypass. Eight sheep were allocated randomly to receive an intravenous infusion of dexmedetomidine (0.4–0.8 μg.kg-1.h-1) from induction of anaesthesia to the end of cardiopulmonary bypass, and eight to receive an equivalent volume of matched placebo (0.9% sodium chloride). Commencement of cardiopulmonary bypass decreased renal medullary tissue oxygenation in the placebo group (mean (95%CI) 5.96 (4.24–7.23) to 1.56 (0.84–2.09) kPa, p = 0.001), with similar hypoxic levels observed in the dexmedetomidine group (6.33 (5.33–7.07) to 1.51 (0.33–2.39) kPa, p = 0.002). While no differences in kidney function (i.e. reduced creatinine clearance) were evident, a greater incidence of histological renal tubular injury was observed in sheep receiving dexmedetomidine (7/8 sheep) compared with placebo (2/8 sheep), p = 0.041. Graded on a semi-quantitative scale (0–3), median (IQR [range]) severity of histological renal tubular injury was higher in the dexmedetomidine group compared with placebo (1.5 (1–2 [0–3]) vs. 0 (0–0.3 [0–1]) respectively, p = 0.013). There was no difference in cerebral tissue microglial activation (neuroinflammation) between the groups. Dexmedetomidine did not reduce renal medullary hypoxia or cerebral neuroinflammation in sheep undergoing cardiopulmonary bypass.
Original language | English |
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Pages (from-to) | 1481-1492 |
Number of pages | 12 |
Journal | Anaesthesia |
Volume | 78 |
Issue number | 12 |
DOIs | |
Publication status | Published - Dec 2023 |
Keywords
- acute kidney injury
- cardiopulmonary bypass
- dexmedetomidine
- neuroinflammation
- postoperative cognitive dysfunction
Projects
- 2 Finished
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Targeting renal hypoxia to avoid cardiac surgery associated acute kidney injury
Lankadeva, Y. R., May, C. N., Evans, R. & Cochrane, A.
1/10/20 → 31/12/22
Project: Research
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Towards Prevention of Acute Kidney Injury after Cardiac Surgery
Evans, R., May, C., Smith, J., Smith, D., Thrift, A., Gardiner, B. & Cochrane, A.
National Health and Medical Research Council (NHMRC) (Australia)
1/01/17 → 31/12/19
Project: Research