Haemodynamic and metabolic data.

<p>Haemodynamic and metabolic data.</p

Argon does not affect cerebral circulation or metabolism in male humans

<div><p>Objective</p><p>Accumulating data have recently underlined argon´s neuroprotective potential. However, to the best of our knowledge, no data are available on the cerebrovascular effects of argon (Ar) in humans. We hypothesized that argon inhalation does not affect mean blood flow velocity of the middle cerebral artery (Vmca), cerebral flow index (FI), zero flow pressure (ZFP), effective cerebral perfusion pressure (CPPe), resistance area product (RAP) and the arterio-jugular venous content differences of oxygen (AJVDO₂), glucose (AJVDG), and lactate (AJVDL) in anesthetized patients.</p><p>Materials and methods</p><p>In a secondary analysis of an earlier controlled cross-over trial we compared parameters of the cerebral circulation under 15 minutes exposure to 70%Ar/30%O₂ versus 70%N₂/30%O₂ in 29 male patients under fentanyl-midazolam anaesthesia before coronary surgery. Vmca was measured by transcranial Doppler sonography. ZFP and RAP were estimated by linear regression analysis of pressure-flow velocity relationships of the middle cerebral artery. CPPe was calculated as the difference between mean arterial pressure and ZFP. AJVDO₂, AJVDG and AJVDL were calculated as the differences in contents between arterial and jugular-venous blood of oxygen, glucose, and lactate. Statistical analysis was done by t-tests and ANOVA.</p><p>Results</p><p>Mechanical ventilation with 70% Ar did not cause any significant changes in mean arterial pressure, Vmca, FI, ZFP, CPPe, RAP, AJVDO₂, AJVDG, and AJVDL.</p><p>Discussion</p><p>Short-term inhalation of 70% Ar does not affect global cerebral circulation or metabolism in male humans under general anaesthesia.</p></div

Effect of argon inhalation on cerebral circulation and metabolism.

<p>Values of mean blood flow velocity of the middle cerebral artery (Vmca), effective cerebral perfusion pressure (CPPe), resistance area product (RAP), arterio-jugular venous differences in oxygen (AJVDO₂) glucose (AJVDG), and lactate (AJVDL) during baseline (70%N₂/30%O₂) compared with argon inhalation (70%Ar/30%O₂). <i>Straight lines</i> link individual values for each subject. Data are mean (SD) for each measurement. The P values, which refer to the difference between two measurement points, were calculated using two-sided t-test for paired data. Due to artefacts during TCD recording, data of patient 1 and 5 have been excluded from respective analysis § n = 28, * n = 27.</p