Background: Arterial cannulation in elderly patients is difficult because of age-related morphological changes. Applying dynamic needle tip positioning (DNTP) that guides the catheter to position inside the vessel sufficiently may aid in successful cannulation.
Methods: This prospective study enrolled patients aged over 70 years, who were scheduled for elective surgery under general anaesthesia with arterial cannulation. The patients were randomly assigned to the DNTP (group D, n = 76) or the conventional short-axis view(group C, n = 75) group. The arterial depth, diameter, and arterial conditions(calcification, segmental stenosis, and tortuosity) were evaluated using ultrasound, before puncture. We recorded the first attempt success, cannulation time, the number of attempts, and cannulation-related complications.
Results: A total of 151 patients were enrolled in this study. The first attempt success rate in group D was significantly higher than that in group C (89% versus 72%; P = 0.0168). The median cannulation time per last attempt in group D versus group C was 25 versus 30 sec(P = 0.0001), and the overall cannulation time was 25 versus 35 sec(P = 0.0001), respectively. Arterial cannulation per last attempt and overall cannulation time were shorter in group D. The number of attempts was higher in group C (P = 0.0038). The occurrence rate of hematoma was significantly lower in group D (16% versus 47%, relative risk = 3.0, P = 0.0001).
Conclusions: The DNTP method may improve the first attempt success rate of arterial cannulation and reduce complications in elderly patients over 70 years of age.