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Erschienen in:
01.01.2013 | Original
An optimized set-up for helmet noninvasive ventilation improves pressure support delivery and patient–ventilator interaction
Erschienen in: Intensive Care Medicine | Ausgabe 1/2013
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Objective
To test the effects on mechanical performance of helmet noninvasive ventilation (NIV) of an optimized set-up concerning the ventilator settings, the ventilator circuit and the helmet itself.
Subjects and methods
In a bench study, helmet NIV was applied to a physical model. Pressurization and depressurization rates and minute ventilation (MV) were measured under 24 conditions including pressure support of 10 or 20 cmH2O, positive end expiratory pressure (PEEP) of 5 or 10 cmH2O, ventilator circuit with “high”, “intermediate” or “low” resistance, and cushion deflated or inflated. In a clinical study pressurization and depressurization rates, MV and patient–ventilator interactions were compared in six patients with acute respiratory failure during conventional versus an “optimized” set-up (PEEP increased to 10 cmH2O, low resistance circuit and cushion inflated).
Results
In the bench study, all adjustments simultaneously applied (increased PEEP, inflated cushion and low resistance circuit) increased pressurization rate (46.7 ± 2.8 vs. 28.3 ± 0.6 %, p < 0.05), depressurization rate (82.9 ± 1.9 vs. 59.8 ± 1.1 %, p ≤ 0.05) and patient MV (8.5 ± 3.2 vs. 7.4 ± 2.8 l/min, p < 0.05), and decreased leaks (17.4 ± 6.0 vs. 33.6 ± 6.0 %, p < 0.05) compared to the basal set-up. In the clinical study, the optimized set-up increased pressurization rate (51.0 ± 3.5 vs. 30.8 ± 6.9 %, p < 0.002), depressurization rate (48.2 ± 3.3 vs. 34.2 ± 4.6 %, p < 0.0001) and total MV (27.7 ± 7.0 vs. 24.6 ± 6.9 l/min, p < 0.02), and decreased ineffective efforts (3.5 ± 5.4 vs. 20.3 ± 12.4 %, p < 0.0001) and inspiratory delay (243 ± 109 vs. 461 ± 181 ms, p < 0.005).
Conclusions
An optimized set-up for helmet NIV that limits device compliance and ventilator circuit resistance as much as possible is highly effective in improving pressure support delivery and patient–ventilator interaction.