Neurally adjusted ventilatory assist and proportional assist ventilation both improve patient-ventilator interaction

Abstract

IntroductionThe objective was to compare the impact of three assistance levels of different modes of mechanical ventilation; neurally adjusted ventilatory assist (NAVA), proportional assist ventilation (PAV), and pressure support ventilation (PSV) on major features of patient-ventilator interaction.MethodsPSV, NAVA, and PAV were set to obtain a tidal volume (VT) of 6 to 8 ml/kg (PSV100, NAVA100, and PAV100) in 16 intubated patients. Assistance was further decreased by 50% (PSV50, NAVA50, and PAV50) and then increased by 50% (PSV150, NAVA150, and PAV150) with all modes. The three modes were randomly applied. Airway flow and pressure, electrical activity of the diaphragm (EAdi), and blood gases were measured. VT, peak EAdi, coefficient of variation of VT and EAdi, and the prevalence of the main patient-ventilator asynchronies were calculated.ResultsPAV and NAVA prevented the increase of VT with high levels of assistance (median 7.4 (interquartile range (IQR) 5.7 to 10.1) ml/kg and 7.4 (IQR, 5.9 to 10.5) ml/kg with PAV150 and NAVA150 versus 10.9 (IQR, 8.9 to 12.0) ml/kg with PSV150, P <0.05). EAdi was higher with PAV than with PSV at level100 and level150. The coefficient of variation of VT was higher with NAVA and PAV (19 (IQR, 14 to 31)% and 21 (IQR 16 to 29)% with NAVA100 and PAV100 versus 13 (IQR 11 to 18)% with PSV100, P <0.05). The prevalence of ineffective triggering was lower with PAV and NAVA than with PSV (P <0.05), but the prevalence of double triggering was higher with NAVA than with PAV and PSV (P <0.05).ConclusionsPAV and NAVA both prevent overdistention, improve neuromechanical coupling, restore the variability of the breathing pattern, and decrease patient-ventilator asynchrony in fairly similar ways compared with PSV. Further studies are needed to evaluate the possible clinical benefits of NAVA and PAV on clinical outcomes.Trial registrationClinicaltrials.gov NCT02056093. Registered 18 December 2013.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-015-0763-6) contains supplementary material, which is available to authorized users.

Patient-ventilator asynchrony

“…However, another study found that NAVA produced more double-triggering than PSV, probably because of the biphasic appearance of electrical activity of diaphragm signals [24 & ,25]. Schmidt et al [26] found that PSV was less able to prevent hyperinflation because of overassistance and produced more asynchrony than NAVA or PAV. NAVA also improved asynchronies during noninvasive ventilation in children admitted to pediatric intensive care [26].…”

“…Schmidt et al [26] found that PSV was less able to prevent hyperinflation because of overassistance and produced more asynchrony than NAVA or PAV. NAVA also improved asynchronies during noninvasive ventilation in children admitted to pediatric intensive care [26].…”

Strategies for weaning from mechanical ventilation: A state of the art review

“…Unlike pressure support ventilation (PSV) that provides the same level of pre-set pressure for every inspiration regardless of the patient's inspiratory effort, effort adapted automated modes such as Proportional Assist Ventilation (PAV) (The University of Manitoba, Canada) and Neurally Adjusted Ventilatory Assist (NAVA) (Maquet, Solna, Sweden) adjust the amount of assistance based on continuous measurement of inspiratory effort (Schmidt et al, 2015). This enables physiologic variation in tidal volume, inspiratory pressure and inspiratory time that is more similar than PSV to breathing without ventilatory support (Akoumianaki et al, 2014).…”

Intubation rate, duration of noninvasive ventilation and mortality after noninvasive neurally adjusted ventilatory assist (NIV‐NAVA)

“…Noninvasive ventilation (NIV) is a commonly used treatment of acute respiratory failure and may prevent intubation and reintubation after extubation in the ICU . The most widely used partial ventilation mode is noninvasive pressure support (NIV‐PS) . The possibility of spontaneous breathing during PS is beneficial to avoid atelectasis, improve oxygenation and maintain diaphragmatic function .…”

“…In patients with mild‐to‐moderate chronic obstructive pulmonary disease (COPD) and acute respiratory failure, the risk of treatment failure is 10%‐20% . Asynchrony between the patient's respiratory demands and level of ventilatory assistance can be one of the reasons why the treatment fails . Vignaux et al identified that severe asynchronies occurred in up to 43% of patients treated with NIV …”