title: Effect of flumazenil on diaphragm electrical activation during weaning from mechanical ventilation after acute respiratory distress syndrome.
abstract: BACKGROUND
  Diaphragm electrical activation (EAdi) and the ratio of tidal volume to EAdi (VT/EAdi) may provide clinical information on neuroventilatory efficiency (NVE) in patients being weaned from mechanical ventilation. We tested the hypothesis that residual sedation could interfere with respiratory recovery, by assessing the effects of flumazenil on EAdi and VT/EAdi ratio.
  
  
  METHODS
  This observational study included 13 patients breathing with pressure-support ventilation (PSV) after a long period of controlled mechanical ventilation (i.e. >4 days) plus midazolam-based sedation for acute respiratory distress syndrome. EAdi and respiratory patterns were compared before and after a bolus of flumazenil, which was given because neurological status needed to be evaluated.
  
  
  RESULTS
  Flumazenil induced a significant increase in EAdi [+71 (41-123)%, P=0.0002] and VT [+17 (8-32)%, P=0.0005], resulting in significantly decreased NVE [-34 (15-43)%]. The increased VT was significantly correlated with the increased EAdi (ρ=0.70, P=0.009).
  
  
  CONCLUSIONS
  During weaning from mechanical ventilation, the diaphragmatic contribution to the breathing process may be reduced by residual midazolam-induced ventilatory depression. The increased EAdi with reversal of residual sedation was associated with a proportional increase in VT. These findings should be considered by the attending physician when interpreting daily EAdi and VT changes during weaning from mechanical ventilation.
authors.affiliation: CHU de Bordeaux, Service d'Anesthésie-Réanimation II, Unité de Réanimation polyvalente de la Maison du Haut-Lévêque, Hôpital Haut Lévêque, Avenue Magellan, F-33600 Pessac, France University of Bordeaux, Adaptation cardiovasculaire à l'ischémie, U1034, F-33600 Pessac, France INSERM, Adaptation cardiovasculaire à l'ischémie, U1034, F-33600 Pessac, France hadrien.roze@chu-bordeaux.fr.
authors.forename: H
authors.initials: H
authors.lastname: Rozé
authors.affiliation: CHU de Bordeaux, Service d'Anesthésie-Réanimation II, Unité de Réanimation polyvalente de la Maison du Haut-Lévêque, Hôpital Haut Lévêque, Avenue Magellan, F-33600 Pessac, France.
authors.forename: A
authors.initials: A
authors.lastname: Germain
authors.affiliation: CHU de Bordeaux, Service d'Anesthésie-Réanimation II, Unité de Réanimation polyvalente de la Maison du Haut-Lévêque, Hôpital Haut Lévêque, Avenue Magellan, F-33600 Pessac, France.
authors.forename: V
authors.initials: V
authors.lastname: Perrier
authors.affiliation: CHU de Bordeaux, Service d'Anesthésie-Réanimation II, Unité de Réanimation polyvalente de la Maison du Haut-Lévêque, Hôpital Haut Lévêque, Avenue Magellan, F-33600 Pessac, France University of Bordeaux, Bioingénierie tissulaire, U1026, F-33000 Bordeaux, France.
authors.forename: A
authors.initials: A
authors.lastname: Dewitte
authors.affiliation: CHU de Bordeaux, Service d'Anesthésie-Réanimation II, Unité de Réanimation polyvalente de la Maison du Haut-Lévêque, Hôpital Haut Lévêque, Avenue Magellan, F-33600 Pessac, France.
authors.forename: O
authors.initials: O
authors.lastname: Joannes-Boyau
authors.affiliation: CHU de Bordeaux, Service d'Anesthésie-Réanimation II, Unité de Réanimation polyvalente de la Maison du Haut-Lévêque, Hôpital Haut Lévêque, Avenue Magellan, F-33600 Pessac, France.
authors.forename: C
authors.initials: C
authors.lastname: Fleureau
authors.affiliation: CHU de Bordeaux, Service d'Anesthésie-Réanimation II, Unité de Réanimation polyvalente de la Maison du Haut-Lévêque, Hôpital Haut Lévêque, Avenue Magellan, F-33600 Pessac, France University of Bordeaux, Adaptation cardiovasculaire à l'ischémie, U1034, F-33600 Pessac, France INSERM, Adaptation cardiovasculaire à l'ischémie, U1034, F-33600 Pessac, France.
authors.forename: A
authors.initials: A
authors.lastname: Ouattara
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001784:Blood Gas Analysis; D003964:Diaphragm / Q000187:drug effects*; D055724:Electrophysiological Phenomena / Q000187:drug effects; D005260:Female; D005442:Flumazenil / Q000627:therapeutic use*; D018757:GABA Modulators / Q000627:therapeutic use*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006993:Hypnotics and Sedatives / Q000627:therapeutic use; D008297:Male; D008874:Midazolam / Q000627:therapeutic use; D008875:Middle Aged; D012128:Respiratory Distress Syndrome / Q000188:drug therapy* / Q000503:physiopathology / Q000628:therapy*; D013990:Tidal Volume; D015300:Ventilator Weaning / Q000379:methods*
chemical_list: D018757:GABA Modulators; D006993:Hypnotics and Sedatives; D005442:Flumazenil; D008874:Midazolam
keywords: electrical diaphragm activation; mechanical ventilation; sedation; tidal volume