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Aim: To explore the optimal vascular diameter and blood flow measured by ultrasound to predict fistula maturity in Chinese patients.Materials and Methods: One hundred and thirty-two patients were enrolled in the study. The blood flow and the diameters of the brachial artery, radial artery, and cephalic vein were analysed according to clinical outcomes. The performances of blood flow, cephalic vein diameter, and the two factors combined in predicting fistula maturity were evaluated and the optimal cut-off values for Chinese patients were determined.Results: During a 6 month follow-up, 113 fistulas were classified as mature and 19 fistulas were classified as failure. In both groups, the diameters of the brachial and radial arteries increased gradually within 2 weeks post-surgery (p<0.05), and cephalic vein diameter and blood flow increased within 4 weeks post-surgery (p<0.05). The blood flow of the failure group was significantly lower than that of the mature group from the first day after creation. The area under the receiver operating characteristic (ROC) curve was 0.95 (529 ml/min, the optimal cut-off value) for blood flow, 0.83 (5.2 mm) for cephalic vein diameter, and 0.96 for the two factors combined in predicting fistula maturity.Conclusions: For Chinese patients, blood flow >529 ml/min could be used to predict fistula maturity and cephalic vein diameter >5.2 mm could be a supplement when necessary. [ABSTRACT FROM AUTHOR]

We report the first direct observations of deranged microcirculatory blood flow at high altitude, using sidestream dark-field imaging. Images of the sublingual microcirculation were obtained from a group of 12 volunteers during a climbing expedition to Cho Oyu (8,201 m) in the Himalayas. Microcirculatory flow index (MFI) was calculated from the moving images of microcirculatory red blood cell flow, and comparison was made between the baseline and high altitude measurements. Peripheral oxygen saturation (SpO(2)) and Lake Louise scores (LLS) were recorded along with MFI. Our data demonstrate that there was a significant reduction in MFI from baseline to 4,900 m in small (less than 25 microm) and medium (26-50 microm) sized blood vessels (P = 0.025 and P = 0.046, respectively). There was no significant correlation between MFI and SpO(2) or MFI and LLS. Disruption of blood flow within microcirculatory may explain persistent abnormal oxygen flux to tissues following the normalisation of systemic oxygen delivery that accompanies acclimatisation to high altitude. [ABSTRACT FROM AUTHOR]