Umbilical artery catheters in the newborn: effects of heparin

 

Abstract

Background

Umbilical arterial catheters (UACs) are among the most commonly used monitoring methodologies in neonatal intensive care. There seems to be significant variance between neonatal intensive care units in exactly how these catheters are used. This variance involves heparin dosing, catheter materials and catheter design and positioning of the catheter.

Objectives

To determine whether the use of heparin in fluids infused through an umbilical arterial catheter in newborn infants influences the frequency of clinical ischemic events, catheter occlusion, aortic thrombosis, intraventricular hemorrhage, hypertension, death, or the duration of catheter usability.

Search methods

Randomized and quasi-randomized controlled trials of umbilical catheterization use were obtained using the search methods of the Cochrane Neonatal Review Group. The Cochrane Library, MEDLINE (search via PubMed), CINAHL and EMBASE were searched from 1999 to 2009.

Selection criteria

Randomized trials in newborn infants of any birthweight or gestation.
Comparison of heparinised to non heparinised infusion fluids, including comparison of heparin in the infusate to heparin just in the flush solution.
Clinically important end points such as catheter occlusion or aortic thrombosis.

Data collection and analysis

There were five randomized controlled trials retrieved. All gave details of the incidence of catheter occlusion. Two also reported the incidence of aortic thrombosis. The intervention was reasonably consistent: heparin in the infusate at a concentration of 1 unit/mL was investigated in all trials except one which used a concentration of 0.25 units/mL. Studies generally included both term and preterm infants.

Main results

Heparinization of the infusate decreases the incidence of catheter occlusion but does not affect the frequency of aortic thrombosis. Heparinization of the flush solution is not an adequate alternative.
There does not appear to be an effect on frequency of intraventricular hemorrhage, death or clinical ischemic phenomena.

Authors' conclusions

Heparinization of the fluid infused through an umbilical arterial catheter decreases the likelihood of umbilical arterial catheters occluding. The lowest concentration tested so far (0.25 units/mL) has been shown to be effective. Heparinization of flushes without heparinizing the infusate is ineffective. The frequency of aortic thrombosis has not been shown to be affected; however, the confidence intervals for this effect are very wide. The frequency of intraventricular hemorrhage has not been shown to be affected by heparinization of the infusate, but again the confidence intervals are very wide and even a major increase in the incidence of grade 3 and 4 intraventricular hemorrhage would not have been detected.

 

Plain language summary

Umbilical artery catheters in the newborn: effects of heparin

The umbilical artery catheters (tubes) (UACs) commonly used in neonatal intensive care to monitor babies can sometimes cause them problems. They can be placed in high or low positions, and come in different materials and designs. The blood anticoagulant, heparin, theoretically helps prevent blood clots forming (thromboses), but high doses could lead to haemorrhage (bleeding). This review found that low heparin doses are effective in preventing catheters becoming blocked and needing to be re-inserted. There is not enough evidence to rule out the possibility of adverse effects. Heparin does not seem to lower the rate of blood clots in the major artery.

 

摘要

背景

新生兒使用臍動脈導管: 肝素(Heparin)的效果

此部份仍在著手中，在下次討論中會再列入。

目標

討論在新生兒中，將含有肝素(Heparin)的溶液注入臍動脈導管是否會影響臨床上發生缺血性事件、導管阻塞、主動脈血栓形成、腦室出血、高血壓及死亡的頻率,或影響導管使用期限。

搜尋策略

利用Cochrane Neonatal Review Group的搜尋策略找出使用臍動脈導管的隨機及半隨機對照試驗。 搜尋Cochrane Library、MEDLINE (透過PubMed搜尋)、 CINAHL及，時間自1999 – 2009。

選擇標準

隨機試驗中包含所有出生體重或週數之新生兒。我們比較注入混合液中含肝素或是不含肝素液體所產生的差異，其中也包含只是用加入肝素的液體沖洗者。我們主要比較加入肝素對於導管阻塞或主動脈血栓是否有影響。

資料收集與分析

總共搜尋到五個隨機對照試驗。每個試驗都詳細報告了試驗中發生導管阻塞的機率。其中2個試驗還報告了主動脈血栓形成的發生率。在所有的試驗中肝素的濃度幾乎是一致的：為1單位/毫升，除了其中一個試驗使用的濃度為0.25單位/毫升。研究包括了足月兒和早產兒。

主要結論

注入肝素降低了導管阻塞的發生率，但並不影響主動脈血栓的發生率。臨床上發生腦室出血、死亡或臨床缺血現象的機率似乎並沒有受到影響。

作者結論

從臍動脈導管注入含有肝素的液體下降了發生臍動脈導管阻塞的可能性。至今所證實的有效最低濃度為0.25單位/毫升。只是單純使用肝素沖洗導管而沒有注入體內是沒有效果的。因為其信賴區間大，所以沒有觀察到主動脈血栓的頻率有受到影響。腦室出血也沒有被證實會受影響，其信賴區間也同樣的過大，就算3級和4腦室出血有顯著的增加也無法發現。

翻譯人

本摘要由高雄醫學大學附設醫院吳佩玲翻譯。

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

新生兒使用臍動脈導管: 肝素(Heparin)的效果：臍動脈導管合併使用肝素可以避免導管阻塞。新生兒重症照護上，經常使用臍動脈導管來監測嬰兒的病況，然而有時也產生問題。它們可以放置於高位或是低位，也可以由不同的材料製作或設計。血液抗凝劑，也就是肝素，理論上有助於防止血栓形成，但高劑量也可能導致出血。這次審查發現低劑量肝素是可以有效地防止導管阻塞而不需要重新更換。然而沒有足夠的證據排除其可能造成的不利影響。肝素似乎無法降低主要動脈中血栓產生的比率。