Effect of two different techniques of arteriovenous fistula puncture on wound infection in haemodialysis patients

Abstract

Safe and effective arteriovenous fistula (AVF) puncture is very important to reduce the wound complications of haemodialysis (HD). For AVF puncture in dialysis patients, there is a lack of clarity and consistency regarding the relative advantage of buttonhole (BH) over rope-ladder (RL) cannulae in terms of wound complications. The study was published in several scientific databases including Cochrane Library, PubMed and Embase by October 2023. Data from all controlled trials looking at the effect of BH and RL on wound complications in haemodialysis patients were included. The articles were written in English, and they were about adult who had AVF while on dialysis. Studies with or without BH or RL treatment were excluded from the analysis. The data was analysed with RevMan5.3 software. Out of 215 trials, 9 were chosen for the final analysis. The study publication dates were between 2000 and 2023. Of these, 17 326 patients received AVF therapy. Among them, there were 3070 BH and 14 256 RL. In 9 studies, RL had a lower risk of postoperative wound infection compared to BH (OR, 3.38; 95% CI, 3.06, 3.73 p < 0.0001); In all 3 studies, there were no statistically significant differences in the risk of post operative bleeding in RL versus BH(OR, 0.76; 95% CI, 0.25, 2.33 p = 0.63). Our studies have demonstrated that RL trocars are superior to BH trocars in the prevention of wound infection.

Aerodynamic noise characteristics of a centrifugal fan in high-altitude environments

by Xue Liu, Jian Liu

In high-altitude areas, the air is thin and the atmospheric pressure is low, which can affect the performance of centrifugal fans and aerodynamic noise. In this paper, steady and unsteady simulations of a centrifugal fan flow field are performed at altitudes of 0, 1000, 2000, 3000, 4000, and 5000 m, and the Ffowcs Williams-Hawkings equation is used to predict the aerodynamic noise of the fan. The results indicate that the tonal and broadband noise generated by the fan decrease with increasing altitude, and the A-weighted sound pressure level of each frequency band of the fan decreases when the air volume is held fixed. The maximum sound power level L_wmax, sound pressure pulsation interval, and total noise sound pressure level L_p decrease linearly with increasing altitude. For every 1000 m increase in altitude, L_wmax and L_p decrease by 0.45 dB and 1.05 dB respectively. The fan noise characteristics, performance parameters, and human auditory perception are the main factors that affect the establishment of fan noise standards in high-altitude areas.