Abstract: Objective To explore the application effect of indwelling arterial catheter 4~5 cm near the cardiac end of radial styloid process under ultrasound guidance in ICU patients. Methods 82 critically ill patients in ICU of a tertiary class A hospital in Hubei Province from August 2020 to July 2021 were selected as the research objects by convenient sampling method. They were divided into two groups with 41 in each group according to the sequence of enrollment. In the experimental group,41 patients were punctured at 4~5 cm near the cardiac end of the styloid process of the radius under the guidance of ultrasound. In the control group,41 patients underwent blind puncture and catheterization at the place with the strongest pulsation of the medial styloid artery of the radius by touch. The success rate of first puncture,the time of indwelling the catheter and the incidence of complications such as bleeding,swelling,catheter bending,catheter blockage and extubation at the puncture point were compared between the two groups. Results The success rate of first puncture in the experimental group was 95.12%,and the average catheter retention time was（151.49± 14.41） h. Compared with the control group,the differences were statistically significant（P< 0.05）. At the same time,the incidence of complications in the indwelling catheter puncture point（4.87%）,catheter bending（4.87%） and catheter blockage（0） were lower than those in the control group（P< 0.05）. Conclusion Ultrasound guided arterial catheterization at 4~5 cm near the cardiac end of radial styloid process can effectively improve the success rate of first puncture,prolong the indwelling time of arterial catheter,and improve the incidence of complications such as bleeding.

Key words: Intensive Care Units, Radial Artery, Catheters,Indwelling, Puncture Positions, Ultrasonic Guidance