Neurally-Adjusted Ventilatory Assist Versus Pressure Support Ventilation During Noninvasive Ventilation

Abstract

BACKGROUND: Single-step tests have been proposed as simple and inexpensive challenges to diagnose exercise-induced bronchoconstriction (EIB) in the pediatric population. Work performed and the resulting ventilation, however, might be substantially lower in stepping than running. This might decrease the diagnostic yield of step-based challenges. METHODS: In a cross-sectional study, 53 children with asthma with exercise-related symptoms (34 boys, age 6 -18 y) underwent an incremental stepping test, a 6-min constant stepping test, and a treadmill running test on different days. RESULTS: Constant and incremental stepping tests presented with lower metabolic demands (V ˙O2 1.42 ؎ 0.48 and 1.34 ؎ 0.55 L/min, respectively), ventilatory demands (V ˙O2 45 ؎ 14 and 43 ؎ 16 L/min, respectively), and cardiovascular demands (160 ؎ 20 and 161 ؎ 19 beats/min, respectively) than the treadmill running test (1.65 ؎ 0.60 L/min, 54 ؎ 17 L/min, and 172 ؎ 7 beats/min, respectively) (P < .05). Between-test agreement in diagnosing EIB was poor (kappa 0.217-0.361). Although EIB prevalence was higher after the treadmill running test (60%) compared to constant (53%) and incremental (47%) stepping tests, 7 subjects developed EIB only in stepping. Clinical and resting functional characteristics did not differ in discordant subjects (ie, EIB negative in a given test but positive in another) versus concordant subjects (ie, EIB negative or positive in both tests). EIB was not related to individual test ability in eliciting high to very-high ventilation (> 40% or > 60% maximum voluntary ventilation, respectively). Moreover, a negative stepping test but a positive treadmill test (and vice versa) was not associated with greater ventilatory demands. CONCLUSIONS: Lower prevalence of EIB in stepping compared to treadmill running is not related to less ventilation demand in the former modality. Although stepping might be useful as a screening EIB test due its portability and low cost, a negative test should be confirmed with a running-based test in symptomatic children.

Technische Aspekte und Neuerungen in der nicht-invasiven und invasiven Beatmung

“…Derzeit besteht die Datenlage hauptsächlich aus physiologischen Studien, die sich auf die Interaktion zwischen Patient und Beatmungsgerät fokussieren. Eine aktuelle Metaanalyse kommt zu dem Schluss, dass Asynchronitäten mit NAVA weniger häufig vorkommen als unter einer konventionellen BiPAP-Therapie [41]. Der Patientenkomfort scheint dagegen durch das Verfahren nicht verbessert zu werden [41,42].…”

“…Eine aktuelle Metaanalyse kommt zu dem Schluss, dass Asynchronitäten mit NAVA weniger häufig vorkommen als unter einer konventionellen BiPAP-Therapie [41]. Der Patientenkomfort scheint dagegen durch das Verfahren nicht verbessert zu werden [41,42].…”