Dry-Pull Method Allows Oncology Nurses to Check IVADs for Abnormalities Prior to Flushing


Aspirating prior to flushing allows nurses to check implanted vascular access devices for abnormalities.

The use of aspiration prior to flushing may allow nurses to safely extend implanted vascular access device (IVAD) flush times, according to findings published in the Clinical Journal of Oncology Nursing.1 Nurses should help patients understand the risk/benefit of retaining IVADS after therapy completion and assess the IVADS for immediate and latent complications, including patency and functionality.1

In an analysis of patients with IVADs (n = 59), visible clots and alterations in color and appearance were observed in 25% of patients between 8 and 17 or more weeks of maintenance when the IVAD was aspirated prior to flushing.

The percentage of abnormal appearing substances tripled between weeks 13 through 16 compared with weeks 0 through 12 and remained high at week 17 and onward. According to investigators, these results suggest that stagnated substances in the reservoir change over time.

“The risk of flushing abnormal-appearing contents into the bloodstream was feasible,” Monica McManus, MHA, BSN, RN, OCN, a medical oncology and surgical nurse manager at Providence Regional Medical Center, and co-investigators, wrote in the study. “Aspirating prior to flushing may be an initial step to ensure reservoir contents are discarded if noticeable abnormal appearance is observed.”

According to the study authors, although 2 billion IVADs are inserted annually, evidence-based guidelines on best flushing practices are limited. Current guidelines recognize that there is insufficient evidence.1 IVAD manufacturers advise flushing every 4 weeks, although other guidelines have suggested that flushing every 8 weeks is feasible and safe.

Nurse investigators performed a review of current IVAD flush maintenance standard of care. Finding the guidelines were inconsistent, they designed a project which would allow them to visually assess blood clots and alterations in patients who went 4 weeks or longer without flushing.

An outpatient oncology clinic collected data surrounding IVAD flush frequency throughout the pandemic. The clinic had a designated injection room, where 10 RNs worked. The study period lasted from June 1, 2021, to August 31, 2021. The researchers also developed a dry-pull method, referred to as aspirating. This method, when performed prior to flushing the IVAD, allows the nurse to observe the reservoir contents for physiologic changes. This allows to them have a greater understanding of potential changes in patients who had gone 4 weeks or longer without a flush.

In this institution, the IVAD maintenance protocol required a flush every 8 weeks with saline, followed by heparin. Nurses followed standard procedure with 2 prespecified deviations. The first deviations was prepriming the extension set, leaving 0.2 ml of normal saline (NS) in the syringe instead of the standard 10 ml. Secondly, after the Huber needle was inserted, nurses attempted to aspirate in order to look for a brisk blood return. If normal appearing blood was aspirated, 6 ml was drawn into the syringe and wasted, and the IVAD was flushed per protocol.

If the nurse was unable to aspirate, then the remaining 0.2 ml in the NS syringe was instilled. If normal-appearing blood was aspirated, 6 ml was drawn into the syringe and wasted, and the IVAD was used and flushed per protocol. If the patency was confirmed, then the volume equal to the reservoir and catheter was removed for discard. If the color or consistency of the blood did not fit normal criteria, the nurse followed with one of the following actions:

If the blood had an abnormal appearance, 10 mL was discarded to remove potentially harmful substances. In the case of a partial occlusion, a 10 ml NS syringe was attached and flushed.

Of note, all abnormal blood was discarded and was not analyzed.

Between each flush, the blood return was assessed. If by 2 ml flushed, a blood return was still not present, the nurse either reassessed or administered a first dose of tissue plasminogen activator (tPA) with a 30- to 120-minute dwell time. If patency was not restored, a second dose was advised, and patients were reassessed the following day.

Among the 59 patients, none were observed between weeks 0 to 4. Three patients were observed between weeks 5 to 8, during which time no abnormal IVAD events were recorded. Between weeks 9 through 12, nine patients were observed, one of whom demonstrated abnormal IVAD characteristics. Twenty-three patients were captured between weeks 13 through 16, eight of whom had abnormal IVAD characters. For weeks 17 or later, 24 patients were included, 6 of whom had abnormal characteristics.

Study authors noted that extending flush intervals has become common place. Some reasons for this include the reduces costs, the improved patient satisfaction, and patient adherence rates.2-5 Moreover, some patients with cancer choose to keep their IVADS out of a fear of recurrence and because it allows for easy venous laboratory draws. However, once active treatment ends, promoting appointment adherence often becomes difficult.1

Because IVADs are not visible, the perceived risk of maintaining the devices is often minimized, study authors wrote. Routine dressings, flushing, and locking are required as IVADs represent an entry point for pathogens to enter the system.

They concluded by noting that IVADs are an integral component of delivering lifesaving treatments to patients with cancer. The manufacturer recommended 4-week extended flush interval has been found to be safe and effective; however, further research is warranted to best strategies in promoting patient care with IVADs.

“The no-flush, dry-pull method provides a workflow that decreases the probability of flushing unknown contents into the patient,” they wrote. “Based on the results of this study, further research is warranted to determine optimal flush frequency.”


  1. McManus M, Sarver MJ, Ser E, Gross KG. Safety of extending implanted vascular access device maintenance flush frequency. Clin J Oncol Nurs. 2023;27(2):165-171. doi:10.1188/23.CJON.165-171
  2. Girda E, Phaeton R, Goldberg GL, Kuo DYS. Extending the interval for port-a-cath maintenance. Modern Chemotherapy. 2013;2(2):15-18. doi:10.4236/mc.2013.22003
  3. Ignatov A, Ignatov T, Taran A, Smith B, Costa SD, Bischoff J. Interval between port catheter flushing can be extended to four months. Gynecol Obstet Invest. 2010;70(2):91-94. doi:10.1159/000294919
  4. Klein J, Jepsen A, Patterson A, Reich RR, Mason TM. Heparin versus normal saline: flushing effectiveness in managing central venous catheters in patients undergoing blood and marrow transplantation. Clin J Oncol Nurs 2018; 22(2):199-202. doi:10.1188/18.CJON.199-202
  5. Kuo YS, Schwartz B, Santiago J, Anderson PS, Fields AL, Goldberg GL. How often should a port-a-cath be flushed? Cancer Invest. 2005;23(7):582-585. doi:10.1080/07357900500276923
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