Objective To investigate the appropriate venous access for obese patients undergoing metabolic and bariatric surgery by comparing the clinical outcomes of different lengths of peripheral intravenous catheters. Methods Inpatients who underwent bariatric surgery in a tertiary hospital in Zhejiang from August 2022 to December 2022 were selected as the study population using a fixed-point continuous convenience sampling method. A stratified block randomisation method was used to divide the group into an experimental group 1（mini-midline catheters），an experimental group 2（midline catheters） and a control group（short peripheral intravenous catheters，Short PIVCs）. The incidence of catheter-related complications，the rate of extubation due to complications，the duration of catheter retention，the time to first catheter-related complication were compared in the 3 groups. Results A total of 186 patients were included，with 62 patients in each group. The overall incidence of catheter-related complications in experimental group 1，experimental group 2，and control group were 25.81%，8.06%，and 58.06%. The extubation rates due to complications were 19.35%，4.84%，and 41.94%，and the duration of catheter retention was 7.00（6.00，7.00） d，7.00（6.00，7.00） d，6.00（3.00，6.25） d. The differences were statistically different（P<0.05） when comparing the 3 groups. Among them，the differences in the overall incidence of catheter-related complications and the rate of extubation due to complications were statistically significant when comparing experimental group 1 with the control group，experimental group 2 with the control group，and experimental group 1 with experimental group 2（P<0.017）；the duration of catheter retention in both experimental group 1 and experimental group 2 were higher than it in the control group，and the differences were statistically different（P<0.017）. Conclusion The complication rate of mini-midline catheters and midline catheters is lower than that of short ones，and the indwelling time is consistent with the perioperative period of metabolic and bariatric surgery，which is suitable for use in patients undergoing metabolic and bariatric surgery.

Objective To compare the clinical effects of midline’s tip at different position. Methods From September 2020 to January 2021,a multi-center randomized controlled study was used to select 384 inpatients as the research subjects from 6 tertiary A general hospitals in Zhejiang province,Fujian province,Jiangsu province,and Liaoning province. They were randomly divided into 3 groups according to random numbers generated by Excel. The midline’s tips were located in the subclavian vein in the experimental group 1,in the axillary vein of the chest in the experimental group 2,and at the distal of the axillary vein in the control group. The incidences of catheter-related complications（including phlebitis,catheter-related thrombosis,catheter-related infections,catheter occlusion,catheter dislodgment,bleeding,oozing） were compared in 3 groups,as well as unplanned removal rate due to complications,catheter indwelling time,and the incidence of abnormal intima after midline removal. Results A total of 384 patients were included. The total incidence of catheter-related complications in experimental group 1,experimental group 2,and control group were 9.93%,14.63%,and 34.17%. Unplanned removal rate due to complications were 2.13%,4.07%,and 13.33% in 3 groups. Catheter indwelling time were 12.00（8.00,19.75） d,12.00（8.00,21.00） d,and 10.00（6.00,17.75） d. After the removal,the incidence of abnormal intima were 0.75%,1.69%,and 6.36%. The differences of 3 groups were statistically significant（P<0.05）. Among them,the differences in the total incidence of catheter-related complications and unplanned removal rate between the experimental group 1 and the control group,the experimental group 2 and the control group were statistically significant（P<0.017）;the difference between the experimental group 1 and the experimental group 2 was not statistically significant（P>0.017）. In terms of the catheter indwelling time,the difference was statistically significant between the experimental group 1 and the control group（P<0.017）. Conclusion When the tip of midline catheter is located in the axillary vein of the chest or subclavian vein,the incidence of catheter-related complications is lower,with longer indwelling time and better clinical outcome.

Objective To explore the influence of PICC catheterization history on the reinsertion process and the indwelling effect. Methods The data of the operation and indwelling process of PICC patients in a tertiary hospital in Hangzhou from January to December 2019 were reviewed and analyzed. A total of 2 877 effective cases were collected to compare the puncture and delivery process,the occurrence of complications and the indwelling time between patients with different catheterization history. Results There were statistical differences in the total success rate of catheterization,vein selection,arm selection,adjustment ratio during catheterization,and the incidence of primary malposition between 2 groups without catheterization history and those with catheterization history. There was a statistically significant difference in the total incidence of complications between 2 groups without a history of catheterization and that with a history of catheterization. There was a statistically significant difference in the total incidence of complications and the incidence of catheter-related thrombosis between the ipsilateral catheterization history and the non-ipsilateral catheterization history. Conclusion Patients with a history of PICC catheterization are limited in the veins available for puncture,while brachial veins are often used for puncture. The difficulty of catheterization was increased. The incidence of primary malposition is higher,and the incidence of complications during indwelling is higher. Particularly,for patients with a history of ipsilateral catheterization,the incidence of catheter-related thrombosis is higher,which affects the safe use and long-term indwelling of PICC.