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Mustonen C, Honkanen HP, Lehtonen S, Tuominen H, Mäkelä T, Kaakinen T, Kiviluoma K, Anttila V, Juvonen T. Moderate hypothermia with remote ischaemic preconditioning improves cerebral protection compared to deep hypothermia: a study using a surviving porcine model. Eur J Cardiothorac Surg 2021; 58:269-276. [PMID: 32236538 DOI: 10.1093/ejcts/ezaa065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 01/30/2020] [Accepted: 02/05/2020] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES The optimal temperature management of hypothermic circulatory arrest is still controversial. Moderate hypothermia preserves cerebral autoregulation and shortens cardiopulmonary bypass (CPB) duration. However, moderate hypothermia alone has inferior organ protection to deep hypothermia, so adjuncts that increase the ischaemic tolerance are needed. Thus, we hypothesized that a combination of remote ischaemic preconditioning (RIPC) and moderate hypothermia would be superior to deep hypothermia alone. METHODS Sixteen pigs were randomized to either RIPC or control groups (8 + 8). The RIPC group underwent 4 cycles of transient hind limb ischaemia. The RIPC group underwent cooling with CPB to 24°C, and the control group underwent cooling with CPB to 18°C, followed by a 30-min arrest period and subsequent rewarming to 36°C. Measurements of cerebral metabolism were made from sagittal sinus blood samples and common carotid artery blood flow. The permissible periods of hypothermic circulatory arrest were calculated based on these measurements. Neurological recovery was evaluated daily during a 7-day follow-up, and the brain was harvested for histopathological analysis. RESULTS Six pigs in the RIPC group reached normal neurological function, but none in the control group reached normal neurological function (P = 0.007). The composite neurological score of all postoperative days was higher in the RIPC group than in the control group [55 (52-58) vs 45 (39-51), P = 0.026]. At 24°C, the estimated permissible periods of hypothermic circulatory arrest were 21 (17-25) min in the RIPC group and 11 (9-13) min in the control group (P = 0.007). CONCLUSIONS RIPC combined with moderate hypothermia provides superior cerebral protection.
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Affiliation(s)
- Caius Mustonen
- Research Unit of Surgery, Anaesthesia and Intensive Care, University of Oulu, Medical Research Center, Oulu, Finland
| | - Hannu-Pekka Honkanen
- Research Unit of Surgery, Anaesthesia and Intensive Care, University of Oulu, Medical Research Center, Oulu, Finland
| | - Siri Lehtonen
- Department of Obstetrics and Gynecology, Oulu University Hospital, Oulu, Finland
| | - Hannu Tuominen
- Department of Pathology, Oulu University Hospital, Oulu, Finland
| | - Tuomas Mäkelä
- Research Unit of Surgery, Anaesthesia and Intensive Care, University of Oulu, Medical Research Center, Oulu, Finland
| | - Timo Kaakinen
- Research Unit of Surgery, Anaesthesia and Intensive Care, University of Oulu, Medical Research Center, Oulu, Finland
| | - Kai Kiviluoma
- Research Unit of Surgery, Anaesthesia and Intensive Care, University of Oulu, Medical Research Center, Oulu, Finland
| | - Vesa Anttila
- Research Unit of Surgery, Anaesthesia and Intensive Care, University of Oulu, Medical Research Center, Oulu, Finland.,Heart Center, University of Turku, Turku University Hospital, Turku, Finland
| | - Tatu Juvonen
- Research Unit of Surgery, Anaesthesia and Intensive Care, University of Oulu, Medical Research Center, Oulu, Finland.,Department of Cardiac Surgery, Heart and Lung Center, Helsinki University Central Hospital, Helsinki University Hospital, Helsinki, Finland
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