title: Advanced positive airway pressure modes: adaptive servo ventilation and volume assured pressure support.
abstract: BACKGROUND
  Volume assured pressure support (VAPS) and adaptive servo ventilation (ASV) are non-invasive positive airway pressure (PAP) modes with sophisticated negative feedback control systems (servomechanism), having the capability to self-adjust in real time its respiratory controlled variables to patient's respiratory fluctuations. However, the widespread use of VAPS and ASV is limited by scant clinical experience, high costs, and the incomplete understanding of propriety algorithmic differences in devices' response to patient's respiratory changes. Hence, we will review and highlight similarities and differences in technical aspects, control algorithms, and settings of each mode, focusing on the literature search published in this area.
  
  
  METHODS
  One hundred twenty relevant articles were identified by Scopus, PubMed, and Embase databases from January 2010 to 2016, using a combination of MeSH terms and keywords. Articles were further supplemented by pearling. Recommendations were based on the literature review and the authors' expertise in this area. Expert commentary: ASV and VAPS differ in their respiratory targets and response to a respiratory fluctuation. The VAPS mode targets a more consistent minute ventilation, being recommended in the treatment of sleep related hypoventilation disorders, while ASV mode attempts to provide a more steady breathing airflow pattern, treating successfully most central sleep apnea syndromes.
authors.affiliation: a Division of Pulmonary and Critical Care Medicine , Mayo Clinic , Rochester , MN , USA.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Selim
authors.affiliation: a Division of Pulmonary and Critical Care Medicine , Mayo Clinic , Rochester , MN , USA.
authors.forename: Kannan
authors.initials: K
authors.lastname: Ramar
mesh_terms: D045422:Continuous Positive Airway Pressure / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007040:Hypoventilation / Q000628:therapy; D012123:Pulmonary Ventilation / Q000502:physiology*
keywords: Non-invasive ventilation; adaptive servo ventilation; bilevel positive airway pressure ventilation; servomechanism; volume assured pressure support