Air Eliminating IV Filtration

Air embolism is a preventable hospital-acquired condition (HAC) that can result in serious harm, including death.^2,3 HAC is a medical diagnose that a patient can develop during a hospital stay that was not present on admission.³ In 2008, a provision of the Deficit Reduction Act of 2005 known as Medicare “Nonpayment” went into effect, eliminating reimbursement for the marginal costs of preventable HACs, including air embolism.⁴

Therefore, preventing the entrance of air into the patient’s circulatory system can result in tangible budget savings for healthcare providers. Incidences of vascular air embolism (VAE), when one or more air bubbles enter a vein and block it, costs the healthcare system, on average, $66,007 per incident.^5-7

Within the hospital environment there are multiple ways air may enter the venous circulation, such as surgical procedures, pain management procedures, diagnostic procedures, hemoperfusion and air from intravenous infusion therapy.⁸ Regarding VAE, central venous catheters (CVC) warrants special attention. Approximately eight percent of hospitalized patients require central venous access, e.g. more than five million CVCs are inserted in the United States each year.⁹

Estimates of the frequency of VAE related to CVCs vary from study to study and are reported to range from 1 in 47 to 1 in 3000 catherization events or from 0.1% to 2% per patient.^10-14 According to a Pennsylvania Patient Safety Authority report, 41% of VAEs are associated with central venous access devices.²

While the frequency of this complication may be low, mortality rates attributed to venous air embolisms associated with CVCs range from 23% to 50%.^15-17

Technical measures, such as the use of an air-eliminating filter, play a crucial role for healthcare providers to prevent VAE. In this respect, the Infusion Nurses Society and the American Society for Parenteral and Enteral Nutrition are recommending in-line filtration as a preventive strategy to mitigate the risk of air embolism.^18,19

In 2021 the INS states the following regarding the use of intravenous (IV) in-line filters:

• “Consider filtration of solutions and medications to reduce microbubbles (<1 mm in diameter) of air entrained in infusion solutions and medications.”
• “Use air-eliminating filters for infusion in all patients with a medical diagnosis involving right-to-left cardiac or pulmonary shunting to prevent air and particulate matter from reaching the arterial circulation, also known as paradoxical embolization.”¹⁸

Hydrophobic vent membranes on our IV in-line filters allow effective air elimination that may be entrained in infusions (i.e.: due to degassing, disconnection, etc) and protect against air emboli in patients. Results from internal studies demonstrate that our filters can eliminate entrained air in both a vertical and horizontal position.²¹ Learn more about air emboli and the use of in-line filters in the following chapters.

Air embolism, also called a gas embolism, is a preventable hospital-acquired condition that can result in serious harm, including death.^1,2

An air embolism occurs when one or more air bubbles enter a vein or artery and block it.

• It’s called a venous air embolism (VAE) when an air bubble enters a vein,
• It’s called an arterial air embolism when an air bubble enters an artery.³

Basically, venous air embolism occurs when two conditions are met:

• there is direct connection between a source of air and the vascular system and
• the pressure gradient favors the entry of this air into the bloodstream1

It took almost 350 years from the first description of the fatal potential of vascular air embolism (1667) to the recommendation of the use of IV in-line filter as a technical measure to prevent vascular air embolism (2016). 

Basically, there are two crucial factors that determine the morbidity and mortality of vascular air embolism (VAE):

• the volume of air entrainment and
• the rate of accumulation¹

How much air is lethal?

• Animal studies have demonstrated that approximately 0.5– 0.75 ml/kg of air in rabbits and 7.5–15.0 ml/kg of air in dogs is lethal^.2-4
• Case reports of accidental intravascular delivery of air in humans have described the lethal volume as between 200 and 300 ml, or 3–5 ml/kg^.5,6
• Other case reports have demonstrated that 20 mL or less of rapid air intake may result in fatal embolism.⁷
• In general, air volume greater than 50 mL is considered potentially lethal.⁸

Clinical presentation of air embolism

VAE may have cardiovascular, pulmonary, and neurologic effects, dependent on the rate and entrained volume of air.¹ Rapid bolus injection may result in precipitous cardiovascular collapse, whereas gradual accumulations (Figure 1: microbubbles) may go unnoticed.⁸ The Figure below illustrates the relation between acute embolism volume and clinical symptoms and signs.

Central venous access is invaluable in the treatment of hospitalized patients and a commonly performed procedure. 

• Approximately eight percent of hospitalized patients require central venous access, i.e. more than five million central venous catheters are inserted in the United States each year.^1,2
• Often patients in the intensive care unit (ICU) require central venous access. Roughly 60% of ICU patients have CVCs and 24% of non-ICU patients have CVCs.³
• Over 15 million catheter-days / year (i.e., the total number of days of exposure to CVCs among all patients in a selected population during a selected time period) are recorded in the ICU in the Unites States alone.⁴
• Despite the lower rate of CVCs on non-ICU wards, the overall number of CVCs outside the ICUs exceeds that of the ICUs.³

Central lines are not without risk and are associated with immediate, vascular, cardiac and pulmonary complications.^5,6 Complications occur during catheter insertion, throughout the catheter dwell period, and at the time of removal.⁷ Incidence rates of catheter-related complications vary widely depending on the terminology and definition of complications, patient population, units of measurement, duration of catheterization and follow-up, catheter location, placement and care procedures, and diagnostic methods.⁸ The most common type of complication is catheter-related bloodstream infection (CRBSI). CRBSIs are reported with 4.3% to 26% of placed catheters.⁷ In comparison to CRBSIs the incidence rate of vascular air emboli (VAE) associated with CVCs are lower.

• Estimates of the frequency of VAE associated with CVCs vary widely and range from 1 in 47 to 1 in 3000 catherization events.⁹
• The reported frequency of air embolism associated with use of a central catheter ranges from 0.1% to 2%.^10,11,12,13

According to a Pennsylvania Patient Safety Authority report about air embolism events,

• 41% of VAEs are associated with central venous access devices,
• 30% of VAEs are associated with surgical procedures,
• 24% of VAEs are associated with intravascular procedures and
• 5% of VAEs are associated with peripheral venous access devices.¹⁴

However, either because small amounts of air can go undetected as they often do not cause clinically significant consequences or because the diagnosis is easily missed, the true incidence of VAE is thought to be higher.¹³  While the frequency of this complication may be low, mortality rates attributed to venous air embolisms associated with CVCs range from 23% to 50%.^14,15,16

Even the most conservative estimates (5 million CVCs per year in US, air embolus 0.1% of CVCs, and 23% mortality) indicate 1,150 deaths per year from this complication in the US alone.¹⁷

Specifically, the presence of a PFO is related to arterial air embolization following intravenous air.¹⁰ Patent Foramen Ovale (PFO) is a common abnormality affecting between 20% and 34% of the adult population.¹¹ Heckmann reported a PFO in 40% of cases with cerebral air embolism in association with central venous cannulation.¹²

US guidelines recommend IV filtration to mitigate the risk of Paradoxical Embolism

In 2021 the Infusion Nursing Society (INS) states:

“Use air-eliminating filters for infusion in all patients with a medical diagnosis involving right-to-left cardiac or pulmonary shunting to prevent air and particulate matter from reaching the arterial circulation, also known as paradoxical embolization. Hypercoagulable states and increased right heart pressure are associated with increased risk of paradoxical embolization.”¹³

The Infusion Nurses Society (INS) and the American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.) are recommending in-line filtration as a preventive strategy to mitigate the risk of air embolism.^1,2

INS recommends the use of IV in-line filters¹

• for solutions and medications to reduce microbubbles (<1 mm in diameter) of air and
• for all patients with a medical diagnosis involving right-to-left cardiac or pulmonary shunting to prevent air and particulate matter from reaching the arterial circulation, also known as paradoxical embolization.

A.S.P.E.N. recommends the use of IV in-line filters²

• for Parenteral Nutrition (PN) administration to reduce the potential for patient harm due to particulates, microprecipitates, microorganisms, and air emboli.