What exactly is AVAPS Mode?
Share: As a sleep physician, sleep technologist, or respiratory therapist, you must be well-versed in the AVAPS non-invasive ventilation mode in order to hone your skills in using advanced PAP titration technology.
AVAPS – Non-Invasive Ventilation (NIV): What Is It?
Noninvasive ventilation (NIV) has become an essential tool for managing both chronic and acute respiratory failure in both the critical care unit and the home setting over the last few decades. NIV refers to the administration of ventilator support without the use of an invasive artificial airway.
Because of its flexibility, sleep physicians consider NIV to be an essential supplement in the treatment of sleep disordered breathing patients.
Rather than an invasive interface, such as a tracheostomy or an endotracheal tube, NIV provides positive pressure ventilation via a noninvasive interface, such as:
- Mask for the face
- Mask for the nose
- Nasal cushions
What Is the Process of Non-Invasive Ventilation?
Rather than a tracheostomy or other invasive approach, NIV provides breathing support via a noninvasive technique such as a nasal mask. The NIV machine can help you with:
- Inflate the lungs completely.
- Lower carbon dioxide levels
- Boost blood oxygen levels
- NIV can also improve your patients’ sleep quality and alleviate symptoms such as
- Daytime exhaustion
- Headaches in the morning
- Shortness of breath caused by accumulated carbon dioxide, low oxygen levels, and/or sleep fragmentation.
What Are the Advantages of Non-Invasive Ventilation?
NIV therapy reduces the amount of effort required for patients with chronic respiratory failure to breathe.
Noninvasive ventilation has the following advantages over invasive ventilation:
- more practical
- Saved money
- The ability to interrupt therapy for breaks, allowing for a more gradual transition away from mechanical support.
- Greater accessibility outside of the ICU (i.e. home)
- It is not necessary to have airway skills to begin therapy.
- Better tolerated (no sedation required)
What Exactly Is AVAPS?
The acronym AVAPS stands for average volume-assured pressure support. It is a noninvasive technology that ensures the delivery of a fixed tidal volume; how much air moves in or out of the lungs with each respiratory cycle, as well as the benefits and convenience of pressure support ventilation.
AVAPS is specifically designed to take over control of and automatically adapt to each patient’s changing therapy needs. It is a noninvasive home ventilator that delivers the precise pressure volume required to maintain adequate treatment to your patient.
What Does the AVAPS Rate Indicate?
With the AVAPS rate setting, you can change the pressure support maximum rate at which the device changes to achieve the desired tidal volume. To meet the target tidal volume, the AVAPS algorithm changes pressure support at a faster rate. This can be set in 1 cm H2O per minute increments from 1 to 5 cm H2O per minute.
What are the AVAPS Indications?
AVAPS has several indications, including:
- It provides noninvasive ventilation to patients with chronic respiratory insufficiency, and EPAP is used to treat Obstructive Sleep Apnea (OSA) in the AE mode. It also benefits many patients with chronic respiratory failure who require ventilator support.
- It is typically used in patients suffering from chronic hypoventilation, such as those suffering from neuromuscular diseases, Obesity Hypoventilation Syndrome (OHS), restrictive thoracic disorders, and Chronic Obstructive Pulmonary Disease (COPD).
- It transforms how patients with breathing complications receive Bi-Level therapy. The AVAPS device provides patients with a constant tidal volume of pressure and employs a proprietary algorithm that automatically calculates the pressure changes required to maintain an optimal tidal volume.
What Are the Advantages of AVAPS?
AVAPS have several advantages, including:
- It can aid in the maintenance of tidal volume in many patients.
- It can help patients who have respiratory insufficiency due to restrictive or neuromuscular disorders and whose respiratory effort varies while sleeping.
- It can benefit COPD patients who are at risk of hypoventilation.
- It may be beneficial for patients who require non-invasive positive pressure ventilation (NiPPV) throughout the day.
- It can assist patients with obesity hypoventilation syndrome (OHS) who may require compensation based on sleep stage and/or position changes. Because patients can have far worse hypoventilation during the rapid eye movement (REM) cycle of sleep, BiPAP with fixed pressure support (PS) may provide too much pressure in NREM sleep, leading to complex sleep apnea or intolerance, and may not provide adequate ventilation.
When Should AVAPS Be Avoided?
Patients should not use AVAPS if they need to adjust their rapid inspiratory pressure (IPAP) to achieve the desired tidal volume. This means that no more than 2.5 cmH2O should change in a minute. As a result, you should not use it on all patients.
What are the AVAPS Configuration Options?
Depending on the patient’s pathology, the target tidal volume can be set at 8ml/kg of ideal weight.
The maximum IPAP ranges from 25 to 50 cmH2O, depending on the patient’s condition and the machine’s available pressure.
Depending on the patient’s condition, the minimum IPAP equals EPAP + 4 cmH20.
How does the IPAP know which initial IPAP or pressure to set to start the first breath?
AVAPS includes a startup algorithm that chooses a higher value automatically. Because higher pressures are not well tolerated, the maximum pressure (max P) is typically set in the 20 to 25 cm water range. The minimum pressure (min P) is typically higher than 8 cm water. Additional parameters in the AVAPS settings include:
- The rate of respiration
- Tidal volume goal
- Time to be inspired
- EPAP AVAPS maintains a tidal volume that’s higher or equal to the targeted tidal volume through pressure support changes made with each breath that are between the minimum and maximum IPAP settings.
Pressure support can be adjusted by your patient’s efforts too breathe, as it averages tidal volume over a window of a few minutes. AVAPS will increase tidal volume if your patient’s effort is reduced. If your patient exerts more effort, the device will reduce the pressure delivered. If the desired tidal volume is not reached in AVAPS, the ventilator function will take over to provide the necessary pressure support.
What Research Has Been Done on AVAPS?
AVAPS has been the subject of numerous studies.
- A study was conducted to compare the benefits of ST/AVAPS mode in delivering NIV to patients with AHRF to standard ST/BiPAP mode. The patients in the study were randomly assigned to one of two groups: those who received NIV and those who did not.
- Group 1 consists of 30 patients who use BiPAP-ST mode.
- Group 2 consists of 30 patients who use BiPAP ST/AVAPS.
Both groups showed significant improvement in PaO2 after one hour. At 12 hours, group 2 showed significant improvement in RR, GCS, and PH, as well as sustained improvement in SaO2 and PaO2.
PaCO2 showed significant improvement after 48 hours, while the other parameters remained stable. However, group 1 only showed significant improvement in RR after 12 hours, with further significant improvement in other clinical parameters after 48 hours. Furthermore, the time spent on NIV was significantly shorter in group 2 than in group 1.
- AVAPS and BiPAP were compared in another study. The study included 33 patients over the age of 18 who had acute respiratory failure due to either surgical or internal causes. The Philips V 60 ventilator with AVAPS and BiPAP mode was used in the study.
When researchers evaluated patients based on their BMI (body mass index), patients with BMI 30 had pCO2 and pH values that improved more with AVAPS than with BiPAP in all three measurements. When the researchers looked at the patients’ compliance, they found that 66.7% (20 patients) were comfortable with BiPAP and 83.3% (25 patients) were comfortable with AVAPS.
The study’s findings indicated that AVAPS had a positive impact on pH, patient comfort, and gas variation, indicating that it could be used confidently in clinical practise.
Conclusion:
AAST, the community for sleep-care professionals, is pleased to announce the launch of our brand new online Advanced Sleep Titration e-Learning Course, which is dedicated to cutting-edge titration techniques and technology. This course is made up of five modules that build on each other to give you a thorough understanding of cardiorespiratory anatomy and physiology while also improving your skills in Positive Airway Pressure (PAP) titration at the basic and advanced levels.
Topics covered in the course include:
- Titration Guidelines for CPAP and BPAP
- Positive Pressure Ventilation Without Invasiveness (NPPV and AVAPS)
- Average Volume Assured Pressure Support Physiology and Anatomy EPAP on autopilot (AVAPS-AE)
- Ventilation with Adaptive Servos (ASV)
