What is AVap (Adaptive Ventilation)?
AVap is not a standard medical term or recognized ventilation mode in the current literature. You may be referring to one of several adaptive ventilation technologies that exist in clinical practice.
Possible Interpretations
Adaptive Servo-Ventilation (ASV)
Adaptive servo-ventilation is a form of bilevel positive airway pressure (BiPAP) therapy that dynamically adjusts inspiratory pressure support breath-by-breath and utilizes an auto-backup rate to normalize breathing patterns, primarily used for treating central sleep apnea. 1
Key Mechanisms
- ASV provides expiratory positive airway pressure (EPAP) that can be adjusted to control obstructive events, similar to CPAP and BiPAP. 1
- The technology differs from conventional BiPAP by providing dynamic (breath-by-breath) adjustment of inspiratory pressure support (IPS) and utilizing an auto-backup rate to normalize breathing rate relative to a predetermined target. 1
- ResMed ASV devices use a three-minute moving average to monitor and determine an appropriate target minute ventilation, set to 90% of the patient's most recent minute ventilation, preventing under- and over-ventilation by dynamically increasing or decreasing inspiratory pressure support as needed. 1
Critical Contraindication
In patients with NYHA class II-IV heart failure with reduced ejection fraction and central sleep apnea, adaptive servo-ventilation causes harm and is absolutely contraindicated. 1 This stems from the SERVE-HF trial which demonstrated increased cardiovascular mortality in this specific population, resulting in a manufacturer Field Safety Notice in 2015. 1
Adaptive Support Ventilation (ASV - Different Acronym)
Adaptive support ventilation is a closed-loop positive pressure mode of mechanical ventilation that automatically adjusts respiratory rate and tidal volume based on measured respiratory parameters to deliver target minute ventilation with minimal work of breathing. 2, 3
Clinical Applications
- ASV may shorten the duration of weaning and total mechanical ventilation duration with fewer manual ventilator settings in medical ICU patients. 3
- The mode automatically provides pressure-controlled synchronized intermittent mandatory ventilation (P-SIMV) and weaning as individually required in any clinical situation. 4
Adaptive Ventilation Mode 2 (AVM2)
AVM2 is a newer adaptive ventilation mode that automatically minimizes inspiratory power rather than following Otis' equation, aiming to ensure lung-protective combinations of tidal volume and respiratory rate. 5
Advantages Over Traditional Adaptive Ventilation
- AVM2 significantly reduces tidal volume (7.2 ± 0.9 vs. 8.2 ± 0.6 ml/kg, p < 0.0001), driving pressure (11.5 ± 1.6 vs. 12.6 ± 2.5 cmH₂O, p < 0.0001), and total mechanical power (16.8 ± 3.9 vs. 18.6 ± 4.6 J/min, p = 0.0024) compared to traditional adaptive ventilation based on Otis' equation. 5
- In ARDS patients specifically, AVM2 reduces tidal volume to 6.6 ± 0.8 ml/kg compared to 7.9 ± 0.5 ml/kg with traditional adaptive ventilation (p < 0.0001). 5
Clarification Needed
If you are asking about a specific device or mode called "AVap," please verify the exact terminology with the manufacturer or device documentation, as this abbreviation does not appear in major clinical guidelines or the medical literature. The most likely possibilities are adaptive servo-ventilation for sleep-disordered breathing or adaptive support ventilation for ICU mechanical ventilation, but the specific term "AVap" requires clarification from the source where you encountered it.