Effect of different needle sizes and aspiration techniques on sample quantity / 中华消化内镜杂志

ABSTRACT

Objective To investigate the effect of needle sizes and aspiration techniques on sample quantity. Methods Aspiration was performed on porcine liver in vitro for 10 times with three different sizes of needles(19 G, 22 G and 25 G) and four different aspiration techniques[non?negative pressure(NP), 10 ml NP,20 ml NP and slow?pull], 20 mm in depth. A total of six aspirations were performed with each needle by the same aspiration technique. All the obtained specimens were fixed in formalin with the cell block method. The samples were evacuated according to our grading criteria. Results The mean±standard deviation(SD) score for 19 G,22 G, 25 G were 5?71±0?69,4?63±1?24, 3?79±1?84 respectively. The mean±SD score for methods non?NP,10 ml NP,20 ml NP and slow?pull were 4?72±1?53,4?56±1?46,4?72±1?50,4?83±1?76 respectively. The multi?analysis of variance results showed that there were statistical differences between different needles size( F=12?00,P<0?001) with 19 G being the best,followed by 22 G and the least specimen obtained by 25 G needle. There were no statistical differences among aspiration techniques ( F=0?128, P=0?943).The analysis showed that the thicker the needle was,the better sample quality was 19 G yielded to the highest quantity of specimens. The most specimens could be obtained with 19 G needle and non?NP, 22 G needle and 20 ml NP and 25 G needle and slow?pull. Conclusion In clinic, aspiration technique should be selected according to different aspiration needles. 19 G is superior to others, with non?NP method. For 22 G needle, 20 ml NP is preferred and for 25 G needle,slow?pull is preferred.