***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: A total of seven studies (606 participants) met the inclusion criteria and measured the primary outcome of interest. All studies were at unclear to high risk of bias. Given the high degree of clinical and statistical heterogeneity of the included studies, no meta-analysis was completed. The results from individual studies that compared heparin at a dose of 1 to 2 IU/mL under continuous pressure were imprecise and do not provide definitive evidence of a difference. The observed difference with a dose of heparin increased to 4 IU/mL came from only one study of 30 participants, and the quality of the reported data was poor. Similarly. consistency in assessment and reporting of adverse events such as haematoma, insertion site infection and limb ischaemia was poor. Further research with well-defined primary and secondary outcome measures using a stratified sampling process that accommodates for the different heparin doses commonly used in clinical practice is needed to confirm the trends seen in research results now reported in the literature. The available evidence is of poor quality because of risk of bias and does not provide sufficient information to support the effects of adding heparin (1 to 2 IU/mL) to a maintenance solution (pressurized to deliver 3 mL of flush solution per hour) of 0.9% normal saline in maintaining the patency and functionality of arterial catheters.
Output:

A total of seven randomized controlled studies met the inclusion criteria and enrolled a total of 606 participants. Because of differences in the way that the studies were designed, we were unable to combine their reported results. The results from individual studies that compared heparin at a dose of 1 to 2 IU/mL under continuous pressure were imprecise and do not provide definitive evidence of a difference. The effective dose of heparin has not yet been determined. This evidence needs to be confirmed in future trials. All studies had a moderate to high risk of methodological bias. The review of trials therefore revealed that more research is needed to determine exactly how long an arterial catheter maintained with a normal saline flush solution can be in place and remain functional (to accurately measure blood pressure and pulse and to provide blood samples that can be used to monitor oxygenation and other variables).