Success of ultrasound-guided peripheral intravenous access with skin marking.

OBJECTIVES: The most effective technique for ultrasound-guided peripheral intravenous access (USGPIVA) is unknown. In the traditional short-axis technique (locate, align, puncture [LAP]), the target vessel is aligned in short axis with the center of the transducer. The needle is then directed toward the target under real-time ultrasound (US) guidance. Locate, align, mark, puncture (LAMP) requires the extra step of marking the skin at two points over the path of the vein and proceeding with direct visualization as in LAP. The difference in success between these two techniques was compared among variably experienced emergency physician and emergency nurse operators. METHODS: Subjects in an urban academic emergency department (ED) were randomized to obtain intravenous (IV) access using either LAP or LAMP after two failed blind attempts. Primary outcomes were success of the procedure and time to complete the procedure in variably experienced operators. RESULTS: A total of 101 patients were enrolled. There was no difference in success between LAP and LAMP, even among the least experienced operators. Of successful attempts, LAMP took longer than LAP (median 4 minutes, interquartile range [IQR] 4-10.5 vs. median 2.9 minutes, IQR 1.6-7; p = 0.004). Only the most experienced operators were associated with higher levels of success (first attempt odds ratio [OR] 6.64; 95% confidence interval [CI] = 2 to 22). Overall success with up to two attempts was 73%. Complications included a 2.8% arterial puncture rate and 12% infiltration rate. CONCLUSIONS: LAMP did not improve success of USGPIVA in variably experienced operators. Experience was associated with higher rates of success for USGPIVA.

Comparison of two transducers for ultrasound-guided vascular access in long axis.

The long-axis technique for ultrasound-guided vascular access may benefit users attempting deeper targets. The purpose of this study was to determine if a difference exists in the difficulty experienced by novice ultrasound users in obtaining vascular access in long axis with linear vs. curvilinear transducers. Subjects obtained access on simulated peripheral veins in a gel model. Time to successful cannulation, number of surface breaks, and number of needle redirects was recorded. Statistical methods used include analysis of variance, regression analysis, and negative binomial regression. The study population was a convenience sample of 24 4th-year medical students, Emergency Medicine residents, attendings, and nurses, and off-service residents rotating in the Emergency Department who had performed less than three ultrasound-guided vascular access procedures. The difference between the number of surface breaks and redirects and the perceived difficulty between the linear and curvilinear transducers was statistically significant (p = 0.002, p = 0.049, p = 0.04). The difference in time to cannulation with the linear and curvilinear transducers was not statistically significant. Novice ultrasound users found the curvilinear transducer easier to use for simulated vascular access in the long axis. Studies utilizing live patients and more experienced ultrasonographers could determine whether the preference for the curvilinear transducer amounts to clinically meaningful shorter times to needle entry and more successful first attempts.