iVAPS algorithms | ResMed
iVAPs algorithms

iVAPS algorithms

At ResMed, we’re focused on improving patient compliance and providing comfortable, effective therapy. That’s why we continue to develop ventilators around iVAPS algorithms, an innovative technology that adapts to patients, especially those with Chronic Obstructive Pulmonary Disease (COPD). Learn more about COPD. 

By targeting alveolar ventilation, iVAPS continually maintains ventilation according to the patient’s metabolic needs, decreasing the risk of over and under-ventilation with changing respiratory rate. Data from extensive bench testing against VAPS ventilators and clinical trials have shown that iVAPS effectively meets patients’ ventilatory needs. It also responds faster to respiratory changes without compromising patient comfort or sleep quality.

Volume assured pressure support (iVAPS) ventilators combine the advantages of pressure-support ventilation, such as patient comfort and patient-ventilator synchrony, with the assurance of a tidal volume target. However, while this enables VAPS modes to meet ventilatory needs, response to respiratory changes is slow. Another limitation of VAPS modes is the enforcement of a mandatory target tidal volume on every breath. Changes in breath rate will still trigger the same tidal volume to be delivered with each breath, which can lead to patient discomfort and sleep disruption.

Several clinical trials have been conducted to evaluate the iVAPS algorithm compared with the standard pressure-support ventilation (PSV) in different patient populations. Numerous studies have shown iVAPS to be as effective as PSV for the long-term management of ventilatory failure in stable COPD patients.1,2,3,4


  1. Oscroft NS, Ali M, Gulati A, Davies MG, Quinnell TG, Shneerson JM, Smith IE. A randomised crossover trial comparing volume assured and pressure preset noninvasive ventilation in stable hypercapnic COPD. COPD 2010; 7:398-403.
  2. Jaye J, Chatwin M, Dayer M, Morrell MJ, Simonds AK. Autotitrating versus standard noninvasive ventilation: a randomised crossover trial. Eur Respir J 2009; 33:566-573.
  3. Battisti A, Tassaux D, Bassin D, Jolliet P. Automatic adjustment of noninvasive pressure support with a bilevel home ventilator in patients with acute respiratory failure: a feasibility study. Intens Care Med 2007; 33(4):632-638.
  4. Kelly JL, Jaye J, Pickersgill RE, Chatwin M, Morrell MJ, Simonds AK. Randomized trial of 'intelligent' autotitrating ventilation versus standard pressure support non-invasive ventilation: Impact on adherence and physiological outcomes. Respirology (Carlton, Vic) 2014.