How to Choose an HME Filter for ICU

They directly impact the condition of the airway, infection control and the efficiency of ventilation. Of all the components, the ICU HME filter is key because it is literally sandwiched between the patient and the breathing circuit. When it comes to ICU filters, hospitals, distributors and OEM buyers must think carefully about not just cost and availability, but performance matching clinical requirements over longer periods of ventilation.

What is an ICU HME filter?

An ICU HME filter (Heat and Moisture Exchange Filter) is a disposable breathing filter that is used in ventilator tubes to provide: Passive humidification Bacterial and viral filtration Reduction in airway dryness They salvage heat and moisture from exhaled gases and refund these to the lungs in inhaled gases, while at the same time cleaning them of airborne contaminants. A breathing filter of this type may be used more commonly in the short to medium term during patient transport in ICUs.

Why HME filters are important in ICU use

Unlike a relatively mundane procedure such as a short anesthesia.During this time, an HME filter for ICU patients must:

The dangers of this choice are that the airway:

becomes less humidified
the secretions become viscous and difficult to handle
increases the risk of cross-infection

The last two points are not trivial. A correctly selected HME filter for ICU patients:

maintains the humidity of the airway therapy
lowers the risk of infection
improves the comfort of the recipient of the therapy
enables a stable performance of ventilation as required.

Lesser selection will just lead to increased resistance, blockage – or insufficiency as before.

Key factors in the selection of an HME filter for ICU patients

Filtration efficacy

Part of the function of an HME filter is to block the bacteria and viruses present in the airway.

Look for:

BFE – Bacterial Filtration Efficiency
VFE – Viral Filtration Efficiency

A particular need in ICU units.

Moisture output

Not all HME filters produce the same performance of humidification.

Points to note:

the more moisture produced so the more the defence against drying out of the airway
stabilisation in performance is vital – which comes with longer use
the duration of ventilation is to be considered in the ICU patient – if longer, risk of insufficient humidification and perhaps the use of a more active humidifier and system.

Airflow resistance

This is a paramount parameter for any ICU breathing filter.

Low resistance enables:

lesser work of breathing
stabilisation of ventilatory pressure
improved ease for the patient.

Becomes worse in the “other” way, if resistance is too great – especially with a saturated filter.Patients in the ICU:

Some generalizations can be made about the differed requirements by type of patient. Adult patients in ICU generally tolerate higher dead space in their HME filters. Pediatric HME filter should be low-dead-space. A filter which is either too large, or too small, can impact CO2 retention and/or ventilation efficiency. Type of use: Some HME filters in ICU will be designed for a single use or 24 hours type. Others are designed for longer, depending on specific protocol. General length of time of use in ICU will increase the need for consideration of stable performance characteristics and the control of resistance.

Compatibility with ICU circuits

ICU HME filter should fit seamlessly into ICU system.

Standard 15mm / 22mm connectability.
Secure fit with breathing circuit.
Ventilator/airway device compatibility.

Poor connector compatibility is a recognized problem leading to simply poor performance (air leak, loss of suction to deliver effective therapy).

HME filter vs active humidification in ICU

Unlike surgical theater or non-invasive use, more than one method of humidification is used. HMEs as well as heating humidifier entire system.

HME

Simple, easy to understand use and replacement.
Tuition cost.
Less confusing to use.

Heating humidifier system

Higher & stable level of humidity.
Use is better suited for longer term ventilation.
Complexity of setup is greater.

Typical usage in ICU is generally HME for short term ventilation or for transport and heating humidifier for active long term patients in ICU.

Common problems that arise with use of HME filters in ICU

In practice of life these items have several usual problems to expect.

Filter blockage leading to poor and decreased delivery of important secretions.
Increased airflow resistance from time in use? Why?
Inability to humidify sufficient amount of air with usage over longer time of use. Air leakage due to poor connector fit.

Most are attributable to product design or choice of material and perhaps improper selection or misunderstanding about proper use of a filter and not necessarily the concept itself.

What to look for in a supplier

For distributors/OEM buyers of ICU HME filter, selection of proper supplier is as incumbent as selection of product itself.

Individualized bins for personalized attention in patients.
Stability in amount of patient mukbar delivery and timing delivery, within range.
Reliability of connector.
Full size range of HME bleed (adult and pediatric.
Stable bulk supply of product. No surprises.
Legible and clear identification markings on product. Good tracking system in place to trace history of use.
Firm capable of OEM use.

Firm with experience in use of HME in ICU applications; already know problems involved for their users, then to help reduce the number of complaints to purchaser and finally improve longterm continuing cooperation.

In conclusion

Selecting proper ICU HME filter is balance between filtration and another of humidifing air, controlling resistance of delivery devices and proper and secure fit with patients. Selecting proper fit may not yield best results all the time. One size will not fit all possible ICU applications in hospitals.

For short term and HME really well designed for patient, simple type of use, flat surfacessurface for filtration / humidification deaths. For longer term and much more involved care, may deal more with system as a whole.