Hemodynamic monitoring in critically ill patients is often invasive, using an arterial line. The monitoring accuracy is highly dependent on the patency of the arterial line, which is often compromised by artery blockages. So far, heparin in normal saline is believed to prevent these complications compared to normal saline alone. This study aimed to compare the effectiveness of normal saline flushing with heparin with normal saline use on arterial line patency. The method of the study was a review. Keywords were compiled using words such as critical care unit, heparinized saline, normal saline, and arterial line patency with boolean operators. Searched extensively through PubMed, Science Direct, and Google Scholar, Data were analyzed using the extraction table and presented with qualitative analysis. The initial search identified 370 articles. Seven articles were obtained after being selected through the duplication, title, abstract, and inclusion-exclusion criteria. All articles mentioned that there was no significant difference between the use of normal saline added with heparin with normal saline on arterial line patency. Based on the study, it can be concluded that the use of normal saline alone as an arterial line flush is recommended because it reduces the risk of Heparin-Induced Thrombocytopenia, allergy to heparin, bleeding and is economically more costsaving.