Finding a solution: Heparinised saline versus normal saline in the maintenance of invasive arterial lines in intensive care

Abstract

Background:We assessed the impact of heparinised saline versus 0.9% normal saline on arterial line patency. Maintaining the patency of arterial lines is essential for obtaining accurate physiological measurements, enabling blood sampling and minimising line replacement. Use of heparinised saline is associated with risks such as thrombocytopenia, haemorrhage and mis-selection. Historical studies draw variable conclusions but suggest that normal saline is at least as effective at maintaining line patency, although recent evidence has questioned this. Methods: We conducted a prospective analysis of the use of heparinised saline versus normal saline on unselected patients in the intensive care of our hospital. Data concerning duration of 471 lines insertion and reason for removal was collected. Results: We found a higher risk of blockage for lines flushed with normal saline compared with heparinised saline (RR ¼ 2.15, 95% CI 1.392-3.32, p 4 0.001). Of the 56 lines which blocked initially (19 heparinised saline and 37 normal saline lines), 16 were replaced with new lines; 5 heparinised saline lines and 11 normal saline lines were reinserted; 5 of these lines subsequently blocked again, 3 of which were flushed with normal saline. Conclusions: Our study demonstrates a clinically important reduction in arterial line longevity due to blockages when flushed with normal saline compared to heparinised saline. We have determined that these excess blockages have a significant clinical impact with further lines being inserted after blockage, resulting in increased risks to patients, wasted time and cost of resources. Our findings suggest that the current UK guidance favouring normal saline flushes should be reviewed.

A low dose heparinized saline protocol is associated with improved duration of arterial line patency in critically ill COVID-19 patients

“…Prior to the COVID-19 outbreak, a number of studies have examined the use of LDHS protocols in ICU patients to improve a-line patency, with mixed results [ [6] , [7] , [8] , [9] , [10] , [11] , [12] , 25 , 26 ]. The proposed mechanism of the LDHS protocol is infusing the anticoagulant directly to the site of potential clot formation proximal to the catheter tip.…”

“…We used proxies of thrombosis including a-line dampening and inability to draw back, as ultrasound evidence was inconsistently documented. Severe a-line dampening and inability to withdraw blood have both been described as appropriate proxies of thrombosis in previous randomized-controlled trials of a-line patency, even in the absence of ultrasound confirmation [ 8 ]. In one study, 84% of patients with either an overdampened wave form, sluggish backflow, inability to withdraw blood or inability to flush were found on bedside ultrasound to have intravascular thrombus adjacent to the catheter tip [ 17 ].…”

“…Outcomes are mixed on the success of similar LDHS protocols implemented to improve a-line duration in non-COVID-19 patients. While some randomized-controlled trials report improved a-line patency in medical ICU and pediatric patients [ [6] , [7] , [8] ], several studies found no clinical effect [ [9] , [10] , [11] , [12] ], and these protocols have not been widely implemented. Study populations and dosages varied between studies, and thus it was unclear whether an LDHS protocol would benefit critically ill patients with COVID-19.…”

Heparinized Saline Solution vs. Saline Solution (0.9% Sodium Chloride) for the Maintenance of Dorsal Pedal Arterial Catheter Patency in Dogs Undergoing General Anesthesia: A Pilot Study

“…The veterinary technician who was not involved in the trial adjusted the study solution. The HS and SS were continuously infused at a rate of 3 mL/h using a pressure bag maintained at 300 mm Hg (6,16). At the end of the procedure, in all dogs, the arterial catheterization was discontinued before tracheal extubation.…”

“…Several studies (2-4) and a Cochrane review (5) showed that HS did not have a significant advantage over a saline (0.9% sodium chloride) solution (SS) for maintaining arterial catheter patency during direct arterial blood pressure measurements. In contrast, Everson et al reported that HS is more effective at preventing occlusion compared to SS (6). Furthermore, heparin exposure can result in complications such as bleeding, alternation of activated partial thromboplastin time (aPTT), and drug hypersensitivity in human patients (7,8).…”