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Master Thesis

Évaluation de l’effort respiratoire sous NAVA dans le cadre d’un protocole de titration basé sur l’activité électrique diaphragmatique lors du sevrage respiratoire

Abstract : Introduction: with NAVA assist is proportional and synchronized to diaphragmatic electrical activity (EAdi). EAdi represent the diaphragmatic neural drive. We titrate NAVA according the EAdi max recorded during a failed spontaneous breathing trial (SBT). After a failed SBT NAVA is started and we increase NAVA level in order to reduce the respiratory load until EAdi = 40% EAdi max.(1) Recently, the Pressure Electricy index: Pmus/Eadi index (PEI) has been described. (2) The purpose of this study was to assess muscular pressure (Pmus) using PEI with our NAVA protocol. Material and methods: observational study, patients recovering from pneumonitis and acute respiratory failure. SBT was Pressure Support Ventilation with 7cmH20 of assist and no PEP. PEI was calculated under NAVA and during SBT from airway pressure drop during end-expiratory occlusions, muscular pressure (Pmus) was estimated from PEI (2). Another index, patient ventilator contribution index (PVBC) was also measured using the inspiratory peak of the diaphragmatic electrical activity (ΔEAdi) and Vt (insp) during assisted and non-assisted breaths. We calculated PVBC2 because it is more correlated to Pmus/Ptot. Results: results are summarized in the table. No patient had respiratory distress under NAVA. NAVA VT was higher than SBT VT: 6,2 [4,7-6,7] vs 5,4 [4,8-6,7] ml.kg-1 PBW, p=0,02. After the failed SBT the reduction of 40% of EAdi with NAVA reduced Pmus by 53%. Pmus, EAdi and Paw-PEP were not correlated and PEI during SBT was 22% higher than under NAVA, p=0,013. The ratio Pmus/(Pmus +Paw- PEP) under NAVA was 33% and PVBC2 was 31%. Conclusion: the reduction of 40% of the diaphragmatic neural drive according to our protocol reduced significantly the respiratory load within acceptable range of Pmus. Moreover PEI can increase when the load is too high, probably by accessory muscles recrutement.
Keywords : PEI Pmus NAVA
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Master Thesis
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Maxime Denis. Évaluation de l’effort respiratoire sous NAVA dans le cadre d’un protocole de titration basé sur l’activité électrique diaphragmatique lors du sevrage respiratoire. Médecine humaine et pathologie. 2017. ⟨dumas-01685891⟩

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