Proportional modes of ventilation: technology to assist physiology

• Published in: Intensive care medicine Vol. 46; no. 12; pp. 2301 - 2313
• Main Authors: Jonkman, Annemijn H., Rauseo, Michela, Carteaux, Guillaume, Telias, Irene, Sklar, Michael C., Heunks, Leo, Brochard, Laurent J.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2020; Springer; Springer Nature B.V
• Subjects: Anesthesiology; Artificial respiration; Care and treatment; Critical Care Medicine; Diaphragm; Emergency Medicine; Female; Humans; Intensive; Intensive care; Interactive Ventilatory Support; Lung; Male; Mechanical ventilation; Medicine; Medicine & Public Health; Methods; Narrative Review; Pain Medicine; Patient outcomes; Patients; Pediatrics; Physiological aspects; Pneumology/Respiratory System; Positive-Pressure Respiration; Respiration; Respiration, Artificial; Technology; Tidal Volume; Ventilation; Ventilators; Canada; Respiratory effort; Inspiratory assist; Mechanical ventilation; Proportional modes
• ISSN: 0342-4642; 1432-1238
• DOI: 10.1007/s00134-020-06206-z

Proportional modes of ventilation assist the patient by adapting to his/her effort, which contrasts with all other modes. The two proportional modes are referred to as neurally adjusted ventilatory assist (NAVA) and proportional assist ventilation with load-adjustable gain factors (PAV+): they deliver inspiratory assist in proportion to the patient’s effort, and hence directly respond to changes in ventilatory needs. Due to their working principles, NAVA and PAV+ have the ability to provide self-adjusted lung and diaphragm-protective ventilation. As these proportional modes differ from ‘classical’ modes such as pressure support ventilation (PSV), setting the inspiratory assist level is often puzzling for clinicians at the bedside as it is not based on usual parameters such as tidal volumes and PaCO 2 targets. This paper provides an in-depth overview of the working principles of NAVA and PAV+ and the physiological differences with PSV. Understanding these differences is fundamental for applying any assisted mode at the bedside. We review different methods for setting inspiratory assist during NAVA and PAV+ , and (future) indices for monitoring of patient effort. Last, differences with automated modes are mentioned.