Background: The difficulty of venipuncture depends on the visibility and palpability of the vein and is particularly challenging in older adults, patients with abnormal body mass index, and those with chronic diseases. In these populations, vessel fibrosis, scarring, skin atrophy, and subcutaneous fat reduce vein visibility and palpability, making venous access more challenging. Previous studies have shown that visibility and palpability are associated with vein depth and diameter, respectively. The current study therefore aimed to evaluate the validity of vein depth and vein diameter as predictive indicators of vein visibility and palpability during venipuncture. Methods: Three nurses evaluated the visibility and palpability of superficial veins suitable for venipuncture in 96 healthy volunteers who participated in this study. Using ultrasound imaging devices, the depth and diameter of superficial veins were measured, after which receiver operating characteristic (ROC) curves were created to identify the optimal cutoff values for predicting vein visibility and palpability. Results: Both vein depth and diameter were found to be independent predictors of visibility and palpability (p < 0.05). ROC analysis showed that vein depth was a significant predictor of visibility (AUC = 0.901, 95% CI = 0.834–0.967) and palpability (AUC = 0.724, 95% CI = 0.619–0.829). The optimal cutoff values for vein depth were 1.89 mm for visibility discrimination, with 28.1% of veins exceeding this threshold, and 1.44 mm for palpability, with 59.4% of veins exceeding this threshold. On the other hand, vein diameter was less accurate than vein depth in predicting visibility and palpability (AUC < 0.7). Conclusions: Vein depth is an effective predictor of vein visibility and vein palpability. This finding is expected to inform the development of assistive technology for visual and palpatory examinations.

Background: Venous congestion assessment is essential in heart failure management. Inferior vena cava (IVC) ultrasonography has been widely used to determine fluid status but may not always provide satisfactory images. Hence, internal jugular vein (IJV) ultrasonography has been proposed as an alternative; however, the reliability of IJV ultrasound image acquisition by nurses without previous clinical ultrasound experience remains unclear. This study evaluated the intra- and inter-operator reliability of IJV ultrasound image acquisition by nurses without previous clinical ultrasound experience. Methods: Two nurses without prior clinical ultrasound experience acquired right IJV ultrasound images after preparatory training. Short-axis cine loops were obtained during quiet breathing and the Valsalva maneuver in healthy adults. A single investigator measured the major and minor diameters from selected still frames. Intra- and inter-operator reliability were then assessed using intraclass correlation coefficients (ICCs), after which agreement was evaluated by Bland–Altman analysis. Results: Both nurses successfully acquired IJV images suitable for subsequent quantitative analysis from all participants. Intra-operator reliability ranged from good to excellent, with ICC (1, 1) values of 0.765–0.967. Meanwhile, inter-operator reliability ranged from moderate to excellent, with ICC (2, 1) values of 0.629–0.916. Bland–Altman analysis revealed fixed bias in three parameters but no proportional bias. Absolute bias was <1 mm for all measurements. Conclusions: Following preparatory training, nurses without prior clinical ultrasound experience were able to acquire IJV ultrasound images with moderate-to-excellent inter-operator and good-to-excellent intra-operator relative reliability.