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IV Flush Syringe Complications

IV flush syringes are common medical devices used to clear intravenous lines. When used correctly, saline flushes are generally safe and well tolerated by patients, but complications can occur. Although rare, IV flush syringes can introduce air embolisms into a vein, which can lead to heart attacks, strokes and respiratory failure. Contaminated syringes have been linked to serious bacterial infections in patients. In rare cases, a serious allergic reaction may occur.

IV flush syringes are used every day on millions of patients to clear intravenous lines. This helps to ensure that medicines are fully delivered, that different medicines don’t mix inside the tubing and that blood inside the tubing does not form a clot.

The plastic syringes contain normal saline (0.9 percent sodium chloride). Saline flushes rarely cause problems for the patient, and when they do, the problems are generally minor.

When a saline flush is used, patients may notice a cold sensation in their skin where the IV is located. While this may feel slightly uncomfortable, it’s completely normal because the fluid is room temperature. It should go away after the flush is complete.

Common Side Effects
It’s not uncommon for patients to notice a temporary cold sensation or an unpleasant taste or smell after their IV catheter is flushed with saline.

Some people also experience an unpleasant taste in their mouth while the saline is injected into their vein. Participants in a study conducted by Vanderbilt University Medical Center in Nashville were 7.3 times more likely to experience a taste and 10.4 times more likely to experience a smell with a prefilled syringe compared to a multi-dose bag.

Although this common reaction is harmless, it can be nauseating, especially if a patient is receiving chemotherapy. Sucking on a piece of hard candy may help to alleviate any bad taste.

While rare, other more serious complications can also occur. These include serious allergic reactions, air embolisms and fluid overload in patients with certain pre-existing medical conditions. Over the past decade or so, contaminated saline syringes have also caused serious bloodstream infections and several deaths.

Contaminated Syringes and Bacterial Infections

Commercially prefilled saline syringes are generally said to decrease the risk of infection. However, there have been reports of infectious outbreaks, according to the Vanderbilt University study.

In 2016, a Texas-based company called Nurse Assist recalled its Normal Saline Flush syringes following a reported outbreak of Burkholderia cepacia bloodstream infections in 164 patients at dozens of long-term care and rehab facilities across the country.

Seven patients died from their infections from the antibiotic-resistant bacteria, which was identified in unopened packages of syringes. People with weak immune systems were more vulnerable to the infections, according to a recall notice issued by the U.S. Food and Drug Administration.

While B. cepacia is commonly found in soil and water, infections are rare and seen most often in patients with cystic fibrosis (CF). CF patients with B. cepacia infections usually develop respiratory problems. The B. cepacia infections seen in the outbreak involving the Nurse Assist IV flush syringes were bloodstream infections.

According to the Centers for Disease Control and Prevention, symptoms associated with bloodstream infections include:
  • Fever
  • Chills or shivering
  • Clammy or sweaty skin
  • Confusion or disorientation
  • Shortness of breath
  • Increased heart rate

Other contamination incidents involving prefilled saline flush syringes have included a 2008 recall of IV saline flush syringes distributed by B. Braun Medical. The syringes in question, which were manufactured by a vendor called AM2PAT, were contaminated with bacteria known as Serratia marcescens. Five people died and hundreds became sick in the outbreak.

Recall Information
Nurse Assist recalled its Normal Saline Flush syringes after an outbreak of B. cepacia bloodstream infections.
Learn More

Air Embolism

An air embolism occurs when one or more air bubbles enter a vein or artery causing a blockage of blood flow. Air can accidentally be injected into a vein via a syringe or IV. That’s why it’s crucial that your nurse expels any extra air from the syringe, or from associated IV tubing, before performing any injections.

Most air embolisms are minor, causing only mild symptoms or no symptoms at all. These usually resolve on their own with no serious consequences. But in rare cases, air embolisms can travel to vital organs, such as the brain, heart or lungs and possibly lead to a heart attack, stroke or respiratory failure.

Signs and symptoms of a potentially dangerous air embolism may include:
  • Anxiety or feelings of doom
  • Shortness of breath
  • Agitation or disorientation
  • Bluish skin
  • An elevated heart rate
  • Rapid breathing
  • Altered level of consciousness
  • Low blood pressure
  • Chest pain

A loud churning heart murmur known as a “cog wheel murmur,” or “mill wheel murmur,” is a late sign of an air embolism. According to a 2009 study in the Journal of the American Association for Laboratory Animal Science, the “splashing” noise is caused by the presence of gas in the chambers of the heart.

It takes just 0.5 to 1 milliliter of air in the pulmonary vein to cause a cardiac arrest, and just 2 to 3 milliliters of air injected into the cerebral (brain) circulation to potentially lead to death by stroke, according to Medical News Today. Therefore, all air bubbles trapped in the body’s blood vessels must be treated as an emergency requiring immediate medical attention.

Fluid Overload and Allergies

Other serious complications associated with a sodium chloride flush include fluid overload and a hypersensitivity reaction. Both are extremely rare but can be life-threatening.

Fluid Volume Overload

Fluid overload is a condition where there is more fluid in the bloodstream than the body can handle. Those most at risk for fluid overload are patients with congestive heart failure, severe kidney impairment, liver problems or high blood sodium levels (hypernatremia).

Signs and symptoms of fluid overload include:
  • Noticeable swelling (edema) in the feet, legs, arms, wrists and face
  • Fluid in the abdomen (ascites)
  • Shortness of breath and trouble breathing

Hypersensitivity and Anaphylaxis

Although rare, it is possible to have an allergic reaction (hypersensitivity) to the saline solution found inside an IV flush syringe. Anaphylaxis — a sudden, serious and potentially life-threatening whole-body allergic reaction — can occur within just minutes of exposure to the preservatives in the saline solution (sodium chloride).

As histamine is released in various parts of the body, the airways can begin to tighten and other severe symptoms can result.

Other possible symptoms of a reaction to saline solution include:
  • Abdominal pain
  • Feeling anxious
  • Chest discomfort or tightness
  • Difficulty breathing, coughing, wheezing or high-pitched breathing sounds
  • Diarrhea
  • Difficulty swallowing
  • Dizziness or lightheadedness
  • Hives (rash), itchiness or redness of the skin

Anaphylaxis is a medical emergency that requires immediate medical attention.

IV Flush Syringes
IV Flush Syringe Complications
  1. Minor Reactions A person may feel a cold rush of fluid in their vein or develop a strange taste in their mouth during a saline flush injection.
  2. Infection Risk Contaminated syringes can introduce dangerous and even deadly bacteria directly into a person’s blood stream.
  3. Air Embolisms In rare cases, saline flushes can introduce air bubbles into a person’s vein that can travel to other parts of the body.

Please seek the advice of a medical professional before making health care decisions.

Related Pages
Nurse Amy Keller
Written By Amy Keller, RN Registered Nurse

Amy Keller is a registered nurse and award-winning journalist with 22 years of experience writing about politics, business, health and other topics. At Drugwatch, she draws on her clinical experience and investigative reporting skills to write about consumers’ health concerns such as the safety of online pharmacies. She also provides informed analysis on complex health issues. Some of her qualifications include:

  • Recipient of USF’s Nurse Alumni Nightingale award for excellence in nursing
  • Guest Faculty Speaker, “Moving Forward with Patient- and Family-Centered Care Intensive Training Seminar”
  • Member of Sigma Theta Tau International Honor Society of Nursing
Edited By
Emily Miller
Emily Miller Managing Editor
Medically Reviewed By
Dr. John A. Daller
Dr. John A. Daller American Board of Surgery

20 Cited Research Articles writers follow rigorous sourcing guidelines and cite only trustworthy sources of information, including peer-reviewed journals, court records, academic organizations, highly regarded nonprofit organizations, government reports and interviews with qualified experts. Review our editorial policy to learn more about our process for producing accurate, current and balanced content.

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  17. U.S. Food and Drug Administration. (2017, October 17). Nurse Assist Inc. Recalls Normal Saline Flush IV Syringes Due to Possible Burkholderia Cepacia Bloodstream Infections. Retrieved from
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