Mechanical ventilation provides respiratory support for individuals experiencing difficulty breathing independently. This intervention can be delivered invasively, through a tube inserted into the airway, or non-invasively, using a mask. Average Volume Assured Pressure Support (AVAPS) represents an advanced mode of non-invasive ventilation (NIV) designed to provide precise and adaptive support for various respiratory conditions.
What is AVAPS Ventilation?
AVAPS stands for Average Volume Assured Pressure Support, a mode primarily utilized in non-invasive ventilators to provide respiratory assistance. Its core objective is to ensure a patient consistently receives a specific, predetermined amount of air with each breath, known as the target tidal volume. This mode combines features of both volume-controlled and pressure-controlled ventilation, offering a hybrid approach to respiratory support. AVAPS addresses the challenge of delivering a consistent tidal volume, which can be difficult with simpler fixed-pressure modes where delivered volume can fluctuate. AVAPS aims to overcome this by automatically adjusting pressure to achieve the desired average volume over time.
How AVAPS Delivers Support
AVAPS operates through a feedback mechanism that continuously monitors the patient’s exhaled tidal volume on a breath-by-breath basis. If the exhaled volume deviates from the pre-set target tidal volume, the ventilator automatically adjusts the inspiratory positive airway pressure (IPAP) for subsequent breaths. This adjustment occurs within a clinician-defined range of maximum and minimum IPAP settings, ensuring the patient consistently receives the targeted air volume over a period, typically averaged over one minute or a few breaths. The system compensates for variations in a patient’s lung mechanics, such as changes in lung compliance or airway resistance, or fluctuations in their breathing effort. While the inspiratory pressure dynamically changes, the expiratory positive airway pressure (EPAP) usually remains fixed in AVAPS, helping to keep the airways open during exhalation and improve oxygenation.
Conditions Where AVAPS is Used
AVAPS ventilation is commonly prescribed for individuals with chronic respiratory conditions that lead to insufficient breathing or elevated carbon dioxide levels. These conditions include Chronic Obstructive Pulmonary Disease (COPD), particularly when it results in hypercapnic respiratory failure. Patients with Obesity Hypoventilation Syndrome (OHS) also frequently benefit from AVAPS, as it helps manage their impaired breathing and improve gas exchange. Certain neuromuscular disorders, such as Amyotrophic Lateral Sclerosis (ALS) or muscular dystrophy, and restrictive lung diseases that weaken respiratory muscles also represent common indications for AVAPS. This contributes to better overall respiratory function and can reduce the work of breathing for these patients.
Advantages of AVAPS
AVAPS offers several advantages over other non-invasive ventilation modes, particularly in managing chronic respiratory conditions. One benefit is improved gas exchange, leading to more effective removal of carbon dioxide and better oxygenation of the blood. The adaptive nature of AVAPS also leads to enhanced patient comfort and better synchrony with the ventilator. This smooth adjustment of inspiratory pressure helps prevent “fighting the ventilator,” which can improve adherence to therapy. Patients often experience a reduction in their overall work of breathing, making the therapy more tolerable for long-term use. Ultimately, these benefits can lead to a reduction in hospitalizations and an improved quality of life for individuals living with chronic respiratory conditions.
Patient Experience and Considerations
When initiating AVAPS therapy, patients can expect an initial setup process involving fitting a comfortable mask, which may be a nasal mask, full-face mask, or nasal pillows. Healthcare professionals will carefully select the appropriate mask type and size to ensure a proper seal and minimize air leaks. Patients may initially perceive the sensation of pressurized airflow as unusual, but most adapt to it over time.
Regular monitoring by healthcare professionals is an ongoing consideration, as ventilator settings may require adjustments based on the patient’s evolving respiratory needs or changes in their condition. Managing mask fit is an ongoing aspect of therapy, as a poor seal can reduce effectiveness and cause discomfort or skin irritation. Patients might also experience minor side effects, such as dry mouth, which can often be managed with humidification settings on the device. Adhering to consistent daily use is encouraged to maximize the therapeutic benefits.