Identification of adequate neurally adjusted ventilatory assist (NAVA) during systematic increases in the NAVA level

Ververidis, D; Van Gils, M; Passath, C; Takala, J; Brander, L (2011). Identification of adequate neurally adjusted ventilatory assist (NAVA) during systematic increases in the NAVA level. IEEE transactions on biomedical engineering, 58(9), pp. 2598-606. New York, N.Y.: Institute of Electrical and Electronics Engineers IEEE 10.1109/TBME.2011.2159790

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Neurally adjusted ventilatory assist (NAVA) delivers airway pressure (P(aw)) in proportion to the electrical activity of the diaphragm (EAdi) using an adjustable proportionality constant (NAVA level, cm·H(2)O/μV). During systematic increases in the NAVA level, feedback-controlled down-regulation of the EAdi results in a characteristic two-phased response in P(aw) and tidal volume (Vt). The transition from the 1st to the 2nd response phase allows identification of adequate unloading of the respiratory muscles with NAVA (NAVA(AL)). We aimed to develop and validate a mathematical algorithm to identify NAVA(AL). P(aw), Vt, and EAdi were recorded while systematically increasing the NAVA level in 19 adult patients. In a multistep approach, inspiratory P(aw) peaks were first identified by dividing the EAdi into inspiratory portions using Gaussian mixture modeling. Two polynomials were then fitted onto the curves of both P(aw) peaks and Vt. The beginning of the P(aw) and Vt plateaus, and thus NAVA(AL), was identified at the minimum of squared polynomial derivative and polynomial fitting errors. A graphical user interface was developed in the Matlab computing environment. Median NAVA(AL) visually estimated by 18 independent physicians was 2.7 (range 0.4 to 5.8) cm·H(2)O/μV and identified by our model was 2.6 (range 0.6 to 5.0) cm·H(2)O/μV. NAVA(AL) identified by our model was below the range of visually estimated NAVA(AL) in two instances and was above in one instance. We conclude that our model identifies NAVA(AL) in most instances with acceptable accuracy for application in clinical routine and research.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > Department of Intensive Care, Emergency Medicine and Anaesthesiology (DINA) > Clinic of Intensive Care
UniBE Contributor:	Passath, Christina-Elisabeth, Takala, Jukka, Brander, Lukas
ISSN:	0018-9294
Publisher:	Institute of Electrical and Electronics Engineers IEEE
Language:	English
Submitter:	Factscience Import
Date Deposited:	04 Oct 2013 14:13
Last Modified:	05 Dec 2022 14:02
Publisher DOI:	10.1109/TBME.2011.2159790
PubMed ID:	21690003
Web of Science ID:	000294127700020
URI:	https://boris.unibe.ch/id/eprint/3057 (FactScience: 206334)