Article Ventilatory modes. What's in a name? RABEC, Claudio, et al. Reference RABEC, Claudio, et al. Ventilatory modes. What's in a name? Respiratory Care, 2012, vol. 57, no. 12, p. 2138-2150 DOI : 10.4187/respcare.02122 PMID : 23233501 Available at: http://archive-ouverte.unige.ch/unige:77169 Disclaimer: layout of this document may differ from the published version. 1 / 1 Letters addressing topics of current interest or material in RESPIRATORY CARE will be considered for publication. The Editors may accept or decline a letter or edit without changing the author’s views. The content of letters reflects the author’s opinion or interpretation of information; their publication should not be interpreted as an endorsement by the Journal. Authors of criticized material will have the opportunity to reply in print. No anonymous letters can be published. Letters should be submitted electronically via Manuscript Central. Log onto RESPIRATORY Letters CARE’s web site at http://www.RCJournal.com. Ventilatory Modes. What’s technologies led to the more than 30 models • What is the ventilatory mode (pressure or in a Name? presently available, offering numerous op- volume)? tions for settings.2 • How is the inspiration triggered (assisted, We have read with great interest the pa- Moreover, there are no marketing regu- assisted/controlled, or controlled)? per published by Chatburn et al in RESPIRA- lations for ventilators. This leaves manufac- TORY CARE.1 reporting on how familiar turers free to give different names to iden- • How is switching from inspiration to ex- healthcare leaders coming from different tical or very similar ventilators modes and piration (cycling) managed (flow or timed professions are with some general technical settings and even “create” new modes that cycling)? and physiological aspects related to mechan- correspond frequently only to minor modi- These 3 categories may facilitate a stan- ical ventilation. Even if the survey shows a fications of a previously known mode. This dardizing of NIV taxonomy and clarify this reasonable level of knowledge and agree- explains why the wide variety of existing confusion. Based on these principles, Cho- ment between both individuals and profes- terminology describing NIV modes is some- pin et al proposed a “physiological” but sions regarding most of the questions sub- what confusing; it also explains the lack of a mitted, it must be underlined that the target somewhat complex categorization of venti- common nomenclature. Clinicians can to- latory modes applied to ICU ventilators.9 population consisted mainly of profession- day be confronted with a given acronym that als who had prior skills in the field of me- Our group proposes a more pragmatic and corresponds to different modes in different ergonomic approach of this classification, chanical ventilation. More than 50% of re- devices, and conversely to identical modes sponders were respiratory therapists, who applicable to fewer and more simple modes that are called differently in different venti- commonly used to provide NIV by using often have a substantial level of expertise lators. Bi-level ventilators, for example, were regarding these issues. Moreover, it is not portable devices (Table 1). initially referred to as BiPAPs (a commer- Even if there is probably no perfect no- sure that the same rate of agreement would cial name of the first machine of this type on have been found, even in this specific skilled menclature, such an attempt at standardiza- the market), but use of this term has caused population, if more detailed questions (ie, tion could provide the basis for a large con- conflict as the manufacturer claimed for as to nomenclature and technical details of sensus aiming to achieve a more copyright. Other terms and acronyms were ventilator modes proposed by modern ven- comprehensive approach to NIV. This may used such as pressure support ventilation tilators) had been raised.2 In fact, as men- encourage manufacturers to privilege sim- (PSV), IPAP, and EPAP, S/T devices, bi- tioned by the authors, while mechanical ven- plicity in their nomenclature instead of orig- level pressure assist, CPAP ϩ inspiratory tilation has hugely evolved these last inality and confusion. The goal? To make support, and PV with PEEP. This can be a decades, what lags behind is a standard clas- NIV management easier in clinical practice. problem in clinical practice, when a nonspe- sification or taxonomy able to describe this cialized physician is confronted with this in- Claudio Rabec MD increasing complexity. comprehensible plethora of names and de- Service de Pneumologie et This issue is still more worrying regard- Re´animation Respiratoire vices. ing noninvasive ventilation (NIV). Due to Centre Hospitalier et Universitaire In this context, proposing a standardized growing evidence of NIV’s effectiveness in de Dijon classification for a better understanding of a broad range of indications and increasing Dijon, France availability of user-friendly portable de- ventilation and ventilators seems rather log- vices, the number of patients receiving NIV ical. But, even if it were possible, this issue Bruno Langevin MD at home is continuously increasing, For ex- involves a high level of complexity regard- Service de Re´animation Me´dicale ample, NIV is increasingly applied in dif- ing critical care ventilators, because of the Centre Hospitalier Ale`s ferent settings, such as critical care units, overabundance and complexity of new Ale`s, France pulmonary, cardiology3 or neurological4 de- (supposed) “intelligent modes” that include Daniel Rodenstein MD PhD partments, pediatrics facilities, weaning cen- complex closed loops and several different Service de Pneumologie ters, sleep labs, in the emergency room,5,6 targeting algorithms. Furthermore, the clas- Cliniques Universitaires Saint Luc in pre-hospital care,7 and in general wards.8 sification and terminology applied to inten- Universite´ Catholique de Louvain As a “victim of its own success” NIV has sive care respirators does not necessarily ap- Bruxelles, Belgium become a generalized practice, and it is not ply to the smaller yet very versatile Christophe Perrin MD unusual that it may be carried out by non- respirators intended for home use: for these Service de Pneumologie specialized healthcare professionals. When devices it seems easier to provide a stan- Centre Hospitalier Cannes NIV was introduced, there were a very lim- dardized classification Cannes, France ited number of modes and types of ventila- As ventilators can be categorized by how tors, with very few possible settings. But as they deliver gas flow and how they trigger Patrick Leger MD NIV devices were submitted to the same inspiration and expiration, answers to 3 ba- Service de Pneumologie market evolution as conventional mechani- sic questions may serve as a guide to sim- Centre Hospitalier Universitaire Lyon Sud cal ventilation, developments in design and plify terminology: Lyon, France 2138 RESPIRATORY CARE • DECEMBER 2012 VOL 57 NO 12 LETTERS TO THE EDITOR Table 1. “Physiological” Proposed Classification of Noninvasive Ventilation Current Modes erbations of chronic obstructive pulmonary disease on general respiratory wards: a mul- Usual Appellations* “Physiological” Nomenclature ticentre randomised controlled trial. Lancet 2000;355(9219):1931-1935. Volume-controlled ventilation (VCV) V-C-T 9. Chopin C, Chambrin M. An attempt to clas- Volume assisted/controlled ventilation V-A/C-T sify the current positive airway pressure Pressure-controlled ventilation, PCV, T mode P-C-T modes of mechanical ventilation. Re´anima- (in bi-level devices) tion Urgences 1998;7:87-99. Article in Pressure assisted ventilation (PSV, pressure support P-A-V French. ventilation (PSV), spontaneous (S) mode (in bi-level devices) ϩ Pressure assisted ventilation positive end expiratory P-A-V (EPAP) The authors respond: pressure (PEEP) PSV ϩ PEEP, pressure support ϩ PEEP, CPAP ϩ inspiratory support, S mode Rabec et al have supported the concerns (in bi-level devices) mentioned in our paper,1 noting that, “while Pressure assisted /controlled ventilation (PAC) P-A/C-T mechanical ventilation has hugely evolved Pressure assisted/controlled ventilation (PAC) ϩ PEEP P-A/C-T (EPAP) these last decades, what lags behind is a Spontaneous/timed mode (ST), IPAP/EPAP P-A-V˙ (EPAP/f) standard classification or taxonomy able to (in bi-level devices), describe this increasing complexity.” In ad- PACV with volume targeting P-A/C-T (VT) dition, they have pointed out the further con- ˙ ST mode with volume targeting, AVAPS, IVAPS, P-A-V(EPAP/f/ VT) cern that confusion about modes may be an volume assured, PS ϩ PEEP ϩ V T even greater problem regarding home care * Usual appellations correspond to the names devised by the manufacturers for each modality. In the proposed “physiological” ventilation, and particularly noninvasive nomenclature the first character indicates ventilatory modality (P or V), the second how the inspiration is triggered (A ϭ assisted, ventilation “when a non-specialized physi- A/C ϭ assisted/controlled, C ϭ controlled), and third the mode of switching from inspiration to expiration (V˙ ϭ flow, T ϭ timed cian is confronted with this incomprehensi- cycling). IPAP ϭ inspiratory positive airway pressure ble plethora of names and devices.” Indeed, EPAP ϭ expiratory positive airway pressure they reference a paper that lists no less than AVAPS ϭ average volume assured pressure support 24 unique mode names on 11 different home IVAPS ϭ intelligent volume assured pressure support VT ϭ tidal volume care ventilators. Having studied and written about this sub- ject for over 20 years, and having served as a consultant to committees from the Inter- Jean-Louis Pepin MD PhD 2. Gonzalez-Bermejo J, Laplanche V, Hus- national Standards Organization and the IHE Pole Re´e´ducation et Physiologie et seini FE, Duguet A, Derenne JP, Similowski (Integrating the Healthcare Enterprise, T. Evaluation of the user-friendliness of 11 Laboratoire Hoˆpitaux Publique www.ihe.net), I have come to appreciate the Institut National de la Sante´etdela home mechanical ventilators.