Cerebral oxygenation and autoregulation during rewarming on cardiopulmonary bypass

Arthursson, Henrik; Kjellberg, Gunilla; Tovedal, Thomas; Lennmyr, Fredrik

doi:10.1177/02676591211064961

Cited by 2 publications

(2 citation statements)

References 32 publications

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“…Furthermore, in an experimental study, decreased pump flow was found to decrease cerebral perfusion, despite variable changes in MAP, in normothermic porcine CPB 60 . In contrast, in a recent small (n = 25) clinical trial, a pump flow 20% greater than normal was not found to increase cerebral rSO 2 or improve cerebral autoregulation during rewarming on bypass 61 …”

Section: Discussionmentioning

confidence: 82%

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Differential responses of cerebral and renal oxygenation to altered perfusion conditions during experimental cardiopulmonary bypass in sheep

Evans,

Cochrane,

Hood

et al. 2024

Clin Exp Pharma Physio

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We tested whether the brain and kidney respond differently to cardiopulmonary bypass (CPB) and to changes in perfusion conditions during CPB. Therefore, in ovine CPB, we assessed regional cerebral oxygen saturation (rSO2) by near‐infrared spectroscopy and renal cortical and medullary tissue oxygen tension (PO2), and, in some protocols, brain tissue PO2, by phosphorescence lifetime oximetry. During CPB, rSO2 correlated with mixed venous SO2 (r = 0.78) and brain tissue PO2 (r = 0.49) when arterial PO2 was varied. During the first 30 min of CPB, brain tissue PO2, rSO2 and renal cortical tissue PO2 did not fall, but renal medullary tissue PO2 did. Nevertheless, compared with stable anaesthesia, during stable CPB, rSO2 (66.8 decreasing to 61.3%) and both renal cortical (90.8 decreasing to 43.5 mm Hg) and medullary (44.3 decreasing to 19.2 mm Hg) tissue PO2 were lower. Both rSO2 and renal PO2 increased when pump flow was increased from 60 to 100 mL kg−1 min−1 at a target arterial pressure of 70 mm Hg. They also both increased when pump flow and arterial pressure were increased simultaneously. Neither was significantly altered by partially pulsatile flow. The vasopressor, metaraminol, dose‐dependently decreased rSO2, but increased renal cortical and medullary PO2. Increasing blood haemoglobin concentration increased rSO2, but not renal PO2. We conclude that both the brain and kidney are susceptible to hypoxia during CPB, which can be alleviated by increasing pump flow, even without increasing arterial pressure. However, increasing blood haemoglobin concentration increases brain, but not kidney oxygenation, whereas vasopressor support with metaraminol increases kidney, but not brain oxygenation.

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Section: Discussionmentioning

confidence: 82%

“…60 In contrast, in a recent small (n = 25) clinical trial, a pump flow 20% greater than normal was not found to increase cerebral rSO 2 or improve cerebral autoregulation during rewarming on bypass. 61…”

Section: Pump Flowmentioning

confidence: 99%

Differential responses of cerebral and renal oxygenation to altered perfusion conditions during experimental cardiopulmonary bypass in sheep

Evans,

Cochrane,

Hood

et al. 2024

Clin Exp Pharma Physio

View full text Add to dashboard Cite

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Cerebral Oxygen Saturation Associates with Changes in Oxygen Transport Parameters during Cardiopulmonary Bypass

Eisner,

Adam,

Weigand

et al. 2024

JPM

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(1) Background: Adequate organ perfusion during cardiopulmonary bypass (CPB) requires accurate estimation and adjustment of flow rates which conventional methods may not always achieve. Perioperative monitoring of cerebral oxygen saturation (ScO2) may detect changes in oxygen transport. This study aims to compare estimated and measured perfusion flow rates and assess the capacity of ScO2 to detect subtle changes in oxygen transport during CPB. (2) Methods: This observational study included 50 patients scheduled for elective coronary artery bypass grafting (CABG) surgery, all of whom provided written informed consent. Perfusion flow rates were estimated using the DuBois formula and measured using echocardiography and a flow probe in the arterial line of the CPB system. ScO2 was continuously monitored, alongside intermittent measurements of oxygen delivery and extraction ratios. (3) Results: Significant discrepancies were found between estimated flow rates (5.2 [4.8–5.5] L/min) and those measured at the start of the surgery (4.6 [4.0–5.0] L/min). These discrepancies were flow rate-dependent, being more pronounced at lower perfusion rates and diminishing as rates increased. Furthermore, ScO2 showed a consistent correlation with both oxygen delivery (r = 0.48) and oxygen extraction ratio (r = 0.45). (4) Conclusions: This study highlights discrepancies between estimated and actual perfusion flow rates during CPB and underscores the value of ScO2 monitoring as a continuous, noninvasive tool for maintaining adequate organ perfusion, suggesting a need for improved, patient-tailored perfusion strategies.

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Cerebral oxygenation and autoregulation during rewarming on cardiopulmonary bypass

Cited by 2 publications

References 32 publications

Differential responses of cerebral and renal oxygenation to altered perfusion conditions during experimental cardiopulmonary bypass in sheep

Differential responses of cerebral and renal oxygenation to altered perfusion conditions during experimental cardiopulmonary bypass in sheep

Cerebral Oxygen Saturation Associates with Changes in Oxygen Transport Parameters during Cardiopulmonary Bypass

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