title: Short-term effects of neuromuscular blockade on global and regional lung mechanics, oxygenation and ventilation in pediatric acute hypoxemic respiratory failure.
abstract: BACKGROUND
  Neuromuscular blockade (NMB) has been shown to improve outcome in acute respiratory distress syndrome (ARDS) in adults, challenging maintaining spontaneous breathing when there is severe lung injury. We tested in a prospective physiological study the hypothesis that continuous administration of NMB agents in mechanically ventilated children with severe acute hypoxemic respiratory failure (AHRF) improves the oxygenation index without a redistribution of tidal volume VTtoward non-dependent lung zones.
  
  
  METHODS
  Oxygenation index, PaO2/FiO2ratio, lung mechanics (plateau pressure, mean airway pressure, respiratory system compliance and resistance), hemodynamics (heart rate, central venous and arterial blood pressures), oxygenation [oxygenation index (OI), PaO2/FiO2and SpO2/FiO2], ventilation (physiological dead space-to-VTratio) and electrical impedance tomography measured changes in end-expiratory lung volume (EELV), and VTdistribution was measured before and 15 min after the start of continuous infusion of rocuronium 1 mg/kg. Patients were ventilated in a time-cycled, pressure-limited mode with pre-set VT. All ventilator settings were not changed during the study.
  
  
  RESULTS
  Twenty-two patients were studied (N = 18 met the criteria for pediatric ARDS). Median age (25-75 interquartile range) was 15 (7.8-77.5) weeks. Pulmonary pathology was present in 77.3%. The median lung injury score was 9 (8-10). The overall median CoV and regional lung filling characteristics were not affected by NMB, indicating no ventilation shift toward the non-dependent lung zones. Regional analysis showed a homogeneous time course of lung inflation during inspiration, indicating no tendency to atelectasis after the introduction of NMB. NMB decreased the mean airway pressure (p = 0.039) and OI (p = 0.039) in all patients. There were no significant changes in lung mechanics, hemodynamics and EELV. Subgroup analysis showed that OI decreased (p = 0.01) and PaO2/FiO2increased (p = 0.02) in patients with moderate or severe PARDS.
  
  
  CONCLUSIONS
  NMB resulted in an improved oxygenation index in pediatric patients with AHRF. Distribution of VTand regional lung filling characteristics were not affected.
authors: Division of Paediatric Intensive Care, Department of Paediatrics, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands.|Department of Paediatrics, Nij Smellinghe Hospital, Drachten, The Netherlands.
authors: Marlon E F
authors: MEF
authors: Wilsterman
authors: Division of Paediatric Intensive Care, Department of Paediatrics, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands.
authors: Pauline
authors: P
authors: de Jager
authors: Division of Paediatric Intensive Care, Department of Paediatrics, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands.
authors: Robert
authors: R
authors: Blokpoel
authors: Department of Anaesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors: Inez
authors: I
authors: Frerichs
authors: Division of Paediatric Intensive Care, Department of Paediatrics, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands.
authors: Sandra K
authors: SK
authors: Dijkstra
authors: Division of Paediatric Intensive Care, Department of Paediatrics, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands.
authors: Marcel J I J
authors: MJIJ
authors: Albers
authors: Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors: Johannes G M
authors: JGM
authors: Burgerhof
authors: Division of Paediatric Intensive Care, Department of Paediatrics, VU University Medical Center, Amsterdam, The Netherlands.
authors: Dick G
authors: DG
authors: Markhorst
authors: Division of Paediatric Intensive Care, Department of Paediatrics, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands. m.c.j.kneyber@umcg.nl.|Critical Care, Anaesthesia, Peri-operative Medicine and Emergency Medicine (CAPE), University of Groningen, Groningen, The Netherlands. m.c.j.kneyber@umcg.nl.
authors: Martin C J
authors: MCJ
authors: Kneyber
keywords: Acute hypoxemic respiratory failure; Children; Electrical impedance tomography; Lung mechanics; Mechanical ventilation; Neuromuscular blockade; Oxygenation; Pediatric acute respiratory distress syndrome