The effect of different methods of intravenous injection on glass particle contamination from ampules.

There have been many studies on glass particle contamination from glass ampules during the injection of glass ampules, but only the contamination from direct IV bolus injection has been measured. This research aimed to study the difference in glass particle contamination from ampules with different intravenous administration methods commonly used in clinical practice. Four methods were studied: IV bolus injection directly after immediate aspiration, IV bolus injection directly after 2 min' delayed aspiration, IV bolus injection directly after aspiration with a filter needle, and side shooting to an infusion set with an in-line filter. 45 ampules per method for a total of 180 ampules were used. The number and length of glass particles were measured using a slide scanner. Aspiration was performed without specifically using a slow aspiration method. The longest glass particle was observed in the immediate aspiration group. The side shooting group showed the lowest maximum number of glass particles per ampule. The side shooting group also showed the smallest number of glass particles, but it was statistically insignificant. Using a filter needle syringe and 2 min' delayed aspiration, which are frequently recommended to minimize contamination, may not be as effective as commonly believed, unless combined with a slow and low pressure aspiration method. Using a side shooting to an infusion set with an in-line filter may minimize glass particle contamination from ampules even without a slow and low pressure aspiration method, but more evidence from a larger study is needed.

Effect of beam-flow angle on velocity measurements in modern Doppler ultrasound systems.

OBJECTIVE: The purpose of this article is to examine the effect of different beam-flow angles on the accuracy of Doppler ultrasound velocity measurements in modern ultrasound systems. MATERIALS AND METHODS: A flow phantom was used to create a steady flow of water in a 4.3-mm-diameter tube. Using three different modern university-grade ultrasound systems, flow was measured at 30°, 40°, 50°, 60°, 70°, 80°, and 88° beam-flow angles twice by two radiologists in consensus using a convex and linear probe. Measured flow ratio, defined as measured velocity divided by estimated actual velocity, was calculated. Intraprobe, interprobe, and intermachine mean variation of measured flow ratio were calculated. RESULTS: Measured flow ratio increased as beam-flow angles increased. Measured flow ratios for the angles 30°, 40°, 50°, 60°, 70°, 80°, and 88° were 0.90, 0.97, 1.10, 1.22, 1.62, 2.34, and 10.29, respectively. Intraprobe, interprobe, and intermachine variation did not show marked differences. For angles grouped as 30-40°, 50-60°, 70°, and 80-88°, intraprobe variation was 12%, 15%, 15%, and 26%; interprobe variation was 20%, 16%, 13%, and 26%; and intermachine variation was 16%, 16%, 17%, and 54%, respectively. As beam-flow angle increased, an increase in spectral broadening was also noted. CONCLUSION: There is no simple cutoff beam-flow value, such as the well-quoted less than 60°, at which velocity measurements can be considered accurate. For follow-up imaging, beam-flow angle differences should be considered, and the same beam-flow angles should be used when possible. Follow-up imaging by different sonography machines is feasible.