Short-term manual compression of hemodialysis fistula leads to a rise in cerebral oxygenation

Abstract

Background: Decreased cerebral perfusion and oxygenation are common in hemodialysis patients. Magnitude of the arteriovenous fistula involvement in this phenomenon is not known. The aim of this study was to investigate the effect that a short-term arteriovenous fistula flow interruption has on cerebral oxygenation and to review and suggest possible explanations. Methods: In 19 patients, basic laboratory and clinical data were obtained and arteriovenous fistula flow volume was measured by ultrasonography. Baseline regional cerebral oxygen saturation (rSO2) was measured by near-infrared spectroscopy. Manual pressure was then applied on the fistula, resulting in total blood flow interruption. After 1 min of manual compression, rSO2 and blood pressure values were noted again. The compression-related change in rSO2 was assessed, as well as its association with arteriovenous fistula flow volume, blood pressure, and other parameters. Results: Mean cerebral rSO2 increased after arteriovenous fistula compression (from 53.6% ± 11.4% to 55.6% ± 10.8%; p = 0.000001; 95% confidence interval = 1.39–2.56). The rSO2 increase was higher in patients with lower rSO2 at baseline (r = −0.46; p = 0.045). Conclusion: A significant rise in cerebral oxygenation was observed following the manual compression of arteriovenous fistula. Therefore, the arteriovenous fistula could have a role in impaired cerebral oxygenation in hemodialysis patients.

New Porcine Model of Arteriovenous Fistula Documents Increased Coronary Blood Flow at the Cost of Brain Perfusion

“…Their return to baseline values allows us to say that propofol did not play any role in the observed changes. Although human and pig brains differ considerably, these observations are in accord with our human data: hemodialysis patients showed lower cerebral rSO 2 than in healthy controls ( Malik et al, 2017 ) with a significant increase after short-term AVF compression ( Kovarova et al, 2021 ). Flow reduction surgery in high-flow arteriovenous fistulas led to increased cerebral rSO 2 in humans in our recently published study ( Malik et al, 2021 ).…”

“…Since AVF is also a low-resistant circuit, its competition with other low-resistant beds is feared. Indeed, first human data suggested negative effect of an AVF on transplanted kidney perfusion ( Laranjinha et al, 2019 ) and on brain oximetry ( Kovarova et al, 2021 ), improving during manual AVF compression. In patients after left mammary artery-left anterior descending artery bypass, ipsilateral upper extremity AVF can cause worsening of angina pectoris ( Feldman et al, 2014 ).…”

The effect of high‐flow arteriovenous fistulas on systemic haemodynamics and brain oxygenation

“…The same values of the left ventricular outflow tract diameter were used in all examinations. AVF flow volume (Qa) was measured by ultrasonography in the brachial artery, as reported elsewhere 13 . Effective CO was calculated as the difference between the measured CO and AVF flow volume.…”

“…AVF flow volume (Qa) was measured by ultrasonography in the brachial artery, as reported elsewhere. 13 Effective CO was calculated as the difference between the measured CO and AVF flow volume. Furthermore, the percentage of the CO running through the AVF was also calculated.…”

“…Moreover, our recent study documented an increase of brain oxygenation during a short-term manual compression of AVF. 13 We hypothesized that AVF flow reduction would result in improved brain oxygenation due to the improved haemodynamics and higher effective CO. This study was aimed at describing haemodynamic changes after AVF high-flow reduction and at investigating the effects of AVF flow reduction on brain oxygenation.…”