Research Article: The effect of different flushing methods in a short peripheral catheter1

Date Published: October 14, 2019

Publisher: Sociedade Brasileira para o Desenvolvimento da Pesquisa em

Author(s): Cuiling Tong, Xiaochun Peng, Hong Hu, Zongwen Wang, Hong Zhou.


To develop a rabbit model of a short peripheral catheter (SPC) and to
observe the effects of different flushing methods on blood vessels.

Thirty rabbits were randomly divided into three groups (A, B, and C), with
ten rabbits per group. In group A, we used pulsed flush; in group B, we used
uniform flush; and no treatment was used in group C.

We observed that a uniform flush reduced blockage, phlebitis, and exudation
compared to a pulsed flush by visual observation. The histopathological
examination found that the morphological changes in group A were more severe
than in group B and C related to loss of venous endothelial cells,
inflammatory cell infiltration, edema, epidermal and chondrocyte
degeneration, except for the thrombosis on group B that was more serious
than in group A, especially in the distal side of puncture points. The
distal region of groups A and B had more inflammatory cell infiltration than
the proximal region. Thrombosis was more severe in the distal region than in
the proximal region in group B.

The uniform flush produced less damage to the vascular endothelium and
surrounding tissues and was superior to the pulsed flush. However, the
uniform flush is prone to thrombosis.

Partial Text

Short peripheral catheters (SPCs) are commonly used in the infusion of liquids,
drugs, and blood products, and are needed by 70% of patients. SPCs are prone to
complications such as blockage, phlebitis, and exudation, being necessary to replace
them very often1 – 2 . Therefore, it is imperative to maintain a good stock of SPCs. Flushing is
an effective treatment to keep SPC unobstructed. The methods most commonly used are
slow uniform flush and pulsed flush3 – 4 . However, previous studies have different opinions on the effects of these
two types of flushing methods. In vitro studies have shown that pulsed flush can
remove solid deposits inside SPCs more effectively than the slow uniform flush. On
the other hand, other studies found that the incidence of phlebitis in the slow
uniform flush is lower than in the pulsed flush4 – 6 . The American practice standard for infusion therapy points the need to
study the effects of pulsed flush7 . Therefore, this study describes an objective method to assess the effect of
different flushing methods on blood vessels and provides microscopic evidence for
the rationale of the flushing method selection.

The study protocol was reviewed and approved by the Research Ethics Committee of
Yangtze University.

Statistical calculations were performed using SPSS software version 22.0 (SPSS Inc.,
Chicago, IL, USA). The measured data of the normal distribution is represented by
`x±s. Multiple groups were compared using analysis of variance (ANOVA), and the two
groups (A and B) were compared using the t-test. Non-parametric tests were used for
non-normal distribution, and H-test was used for multiple groups. The Rank sum test
was used for pairwise comparison of the grade data. A p -value < 0.05 was considered statistically significant. Intravenous infusion is a standard procedure in clinical practice. The most common used catheters are SPC, midline catheter, peripherally inserted central catheter, central venous catheter, and implantable venous access port. Among them, SPC is the most commonly used catheter for infusion and blood transfusion. It is estimated that up to 85% of emergency patients require infusion therapy, and in most of them, we use SPC. The widespread use of SPC can bring complications, such as phlebitis, extravasation, and tube occlusion. Maintaining the catheter unobstructed and extending the catheter indwelling time has always been a problem. Flushing can maintain the patency of the catheter, but the results of the specific flushing methods are mixed. The INS guide recommended the pulsed flush, but its actual effect needs further verification by clinical research7 . After the SPC was widely used in clinical practice, complications such as blockage and phlebitis appeared. The flush methods could effectively reduce those complications. In this study, it was found by visual and pathological morphology that slow uniform flush could reduce SPC damage to the vascular endothelium and surrounding tissues, even though it was prone to thrombosis. It is suggested that the clinically selectable flushing method could be based on the patient’s and vascular conditions.   Source:


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