Point-of-care ultrasound for monitoring catheter tip location during umbilical vein catheterization in neonates: a prospective study.

Background: Point-of-care ultrasound (POCUS) can guide umbilical vein catheter placement in real time and monitor catheter tip position, allowing avoidance of severe complications due to catheter malposition. This study aims to explore the effectiveness of POCUS in guiding venous catheter insertion and monitoring complications. Methods: Sixty-eight neonates with ultrasound-guided venous catheter insertion at the Neonatal Department of Dongguan Children's Hospital between December 2020 and February 2022 were included. POCUS was applied to monitor catheter tip location daily until catheter removal. A displacement range exceeding the intersection of the inferior vena cava and right atrium by ±0.5 cm was considered misalignment. Results: Sixty-four neonates had a displaced catheter tip (94.1%, 64/68), with a median displacement distance of 0.4 cm (minimum -0.2 cm, maximum 1.2 cm). Ten neonates had a misalignment (14.7%, 10/68) caused by displacement. Displacement usually occurs within 2-4 days after placement, with displacement rates of 94.1% (64/68), 90.6% (58/64), and 98.3% (59/60) on days 2, 3, and 4, respectively, and could still occur on day 9 post-placement. In addition, misalignment mainly occurs on the second day after placement. During the monitoring process, 58 neonates had catheter tip displacement ≥2 times, resulting in 252 displacement and 22 misalignment incidents. Among them, the catheter tip migrated outward from the inferior vena cava seven times, all of which were removed in time. Ultrasound was used for positioning 486 times, and x-ray was indirectly avoided 486 times. Conclusion: The catheter tip is prone to displacement and misalignment after umbilical vein catheterization, which most commonly occurs on days 2-4. POCUS is recommended for daily monitoring of the tip location during umbilical vein catheterization until catheter removal.

Prevalence and molecular characterization of structural hemoglobin variants in the Dongguan region of Guangdong province, southern China.

The aim of the present study was to find the most prevalent structural hemoglobin (Hb) variants in southern China and to present hematological and molecular data of abnormal Hbs in the population from southern China. The type and frequency of structural Hb variants and their hematological and molecular characteristics were identified in 131 individuals from 30,848 unrelated partners who were referred to the prenatal clinic of Dongguan Maternal & Children Health Hospital, Dongguan, Guangdong, People's Republic of China (PRC) from 2011 to 2013. α-Globin or ß-globin chain variants were screened using a capillary electrophoresis (CE) system, and α-globin or ß-globin gene mutations were confirmed using sequencing techniques. The gene frequency of Hb variants was 0.4% (131/30,848). The most common α-globin variants were Hb Constant Spring (Hb CS, HBA2: c.427T > C) (0.2%), followed by Hb Q-Thailand (HBA1: c.223G > C) and Hb G-Honolulu (HBA2: c.91G > C). The most common ß-globin variant was Hb E (HBB: c.79G > A) (0.09%), followed by Hb New York (HBB: c.341T > A). Our results provide a detailed prevalence and molecular characterization of abnormal Hbs in the population of the Dongguan region. These findings have important implications for a region with a high frequency of α- and ß-thalassemias.

Detection of Hb anti-Lepore Hong Kong (NG_000007.3: g.63154_70565dup) in Chinese individuals.

We have identified four Chinese individuals from three unrelated families with raised Hb A2 levels. The anti-Lepore hybrid hemoglobin (Hb) variant was amplified using a pair of primers, 5' to the ß-globin gene Cap site and 3' to the δ-globin gene polyadenylation site (polyA) region, respectively. Direct sequencing of the ßδ fusion products confirmed the anti-Lepore Hong Kong (NG_000007.3: g.63154_70565dup) variant. We found that this anti-Lepore variant is positioned in zone 3 on the capillary electrophoresis system. It may help in differential diagnosis of Hb variants and providing better information in clinical counseling.