Complications of umbilical artery catheterization in a model of extreme prematurity

Abstract

Objective: Umbilical artery catheter (UAC) use is common in the management of critically ill neonates; however, little information exists regarding the anatomic and vascular effects of UAC placement in premature newborns.

Study design: Baboons were delivered at 125 days of gestation (term=185 days), treated with surfactant, had UACs placed and were ventilated for either 6 or 14 days. Animals were assigned to short-term (6 days, n=6) and long-term (14 days, n=30) UAC placement. At necropsy, aortas were removed with UACs still in place. Histological examination of upper, middle and lower aorta specimens stained with hematoxylin and eosin and immunolabeled to detect smooth muscle (alpha-actin) was carried out in a blinded manner. Controls were delivered at 125, 140 and 185 days and the aortas acquired immediately after birth. None of the non-catheterized control animals (125 days, n=4; 140 days, n=5; and 185 days, n=5) had aortic vessel thrombi or vascular wall abnormalities.

Result: All 6 animals with short-term (6/6, 100%) and 18 animals with long-term (18/30, 60%) UAC placement displayed aortic thrombi and neointimal proliferation of the vascular wall. The majority (60%) of analyzed animals with UAC placement displaying neointimal hyperplasia were immunopositive for alpha-actin, indicating the presence of smooth muscle in these lesions.

Conclusion: Our findings suggest that both short- and long-term UAC use is associated with aortic wall pathological abnormalities compared with control animals. This study emphasizes the judicious use and early removal of UACs if possible in order to potentially prevent significant hemostatic and aortic wall vascular complications.

Figure 1

Photomicrographs of hematoxylin and eosin-stained aorta sections. Non-catheterized controls (left column) are compared to indwelling UAC animals (right columns). Panels: A) Middle aorta, 125 d gestational control animal; B) Upper aorta, 6 d animal; C) Middle aorta 6 d animal; D) Lower aorta, 140 d gestational control animal; E) Lower aorta, 14 d animal; F) Middle aorta, 14 d animal. All images represent × 4 mag.

Figure 2

Photomicrographs of hematoxylin and eosin-stained aorta sections from 6 d & 14 d UAC animals displaying neointimal hyperplasia and thrombus formations adjacent to the internal elastic lamina (IEL). Panels: A) Lower aorta, 14 d animal (× 4); B) Lower aorta, 14 d animal (× 20); C) Middle aorta, 6 d animal (× 20); D) Middle aorta, 14d animal (× 4).

Figure 3

Photomicrographs of aorta and iliac arteries from 14 d UAC animals. Sections were immunolabelled with an α-actin primary antibody to label smooth muscle (red). Tissues exhibit neointimal hyperplasia and thrombus formations adjacent to the internal elastic lamina (IEL). Panels: A) Lower aorta (× 4); B) Lower aorta (× 20); C) Lower aorta (× 4): D) Right iliac artery (× 4).