Objective:To study the evaluation of left ventricular myocardial function in patients with chronic renal failure by cardiac magnetic resonance feature tracking technique.Methods:Thirty patients with chronic renal failure (chronic renal failure group) who were treated in Jinhua Central Hospital of Zhejiang Province from June 2018 to June 2019 and 30 adult volunteers (healthy control group) who were examined at the same period were enrolled. The cardiac movie sequence was obtained by using Phillips Acheva 3.0 T CMR imaging equipment. The tissue tracking tool in CVI42 software was used to analyze the myocardial strain of the subjects, and the levels of left ventricular ejection fraction (LVEF), end diastolic volume (EDV), end systolic volume (ESV), apoptotic volume (AV), global longitudinal strain (GL), global circumferential strain (GC) and global radial strain (GR) were detected and compared between two groups.Results:The level of EDV in chronic renal failure group was higher than that in healthy control group: (132.3 ± 18.5) ml vs. (111.5 ± 15.1) ml, the level of LVEF in chronic renal failure group was lower than that in healthy control group: (62.41 ± 2.10)% vs. (67.30 ± 3.92)%, and the differences were statistically significant ( P<0.01). The levels of GL, GC and GR in chronic renal failure group were lower than those in healthy control group: (-16.3 ± 3.1)% vs. (-11.1 ± 4.1)%,(-17.5 ± 2.9)% vs. (-13.7 ± 4.7)% and (36.5 ± 9.5)% vs. (46.3 ± 8.4)%, and the differences were statistically significant ( P<0.01). When b = 300, 500 and 800 s/mm 2, the apparent diffusion coefficient (ADC) value of different clinical stages in healthy control group and chronic renal failure group were compared, and the differences were statistically significant ( P<0.01). When the clinical stage of chronic renal failure was higher, its ADC value was lower gradually. Conclusions:Cardiac magnetic resonance feature tracking technology can accurately and effectively evaluate the changes of left ventricular myocardial function in patients with chronic renal failure.

Objective To evaluate effects of dexmedetomidine on onset ,duration of supraclavicular brachial plexus block induced by levobupivacaine and postoperative analgesia with ultrasound guide .Methods Eighty patients undergoing elective surgeries of distal arm and forearm with class Ⅰ ~ Ⅱ ASA were enrolled ,and the patients were randomly divided into two groups ,one was control group (group C) patients with supraclavicular brachial plexus block by 30 ml of 5% levobupivacaine contained 1 ml normal saline ,the other was dexmedetomidine group patients (group D) with supraclavicular brachial plexus block by 30 ml of 5% levobupivacaine contained 100μg dexmedetomidine .The supraclavicular brachial plexus block was guided with ultrasound .Observation indicators include :sensory and motor onset blocks ,duration of sensory and motor blocks ,time to first rescue analgesia and hemodynamic parameters .Results The differences of sensory block onset between group C and D were not significant .Compared to group C ,motor block onset of group D was significantly shorter (P<0 .01) ,sensory block duration and motor block duration were longer (P<0.001) ,time to first rescue analgesia after the surgeries was longer (P<0 .001) .Mean arterial pressure and mean heart rate of group D were significantly lower than those of group C ,respectively (P<0 .02) .Conclusions Dexmedetomidine can significantly prolong the duration of block and postoperative analgesia of supracla-vicular brachial plexus block induced by levobupivacaine .