title: Influence of body position, PEEP and intra-abdominal pressure on the catheter positioning for neurally adjusted ventilatory assist.
abstract: OBJECTIVE
  Neurally adjusted ventilatory assist (NAVA) relies on the patient's electrical activity of the diaphragm (EAdi) for actuating the ventilator. Thus a reliable positioning of the oesophageal EAdi catheter is mandatory. We aimed to evaluate the effects of body position (BP), positive end-expiratory pressure (PEEP) and intra-abdominal pressure (IAP) on catheter positioning.
  
  
  METHODS
  Twenty-one patients were enrolled in this study. In six different situations [supine or 45° head of bed elevation (HBE) at PEEP 5 and 15 cmH(2)O; left lateral anti-decubitus at PEEP 5 cmH(2)O; supine at PEEP 5 cmH(2)O with abdominal surgical belt (ASB)] the catheter position was evaluated for the stability of the EAdi signal and information provided by a catheter positioning tool (highlighted electrical activity in central leads, absence of p waves in the distal lead).
  
  
  RESULTS
  With an optimal catheter position EAdi signals were stable for all tested situations. During "45° PEEP 15" and "supine PEEP 15" absence of p waves in the distal lead revealed a difference compared with "supine PEEP 5" (p = 0.03), suggesting a caudal shift of the diaphragm relative to the oesophagus. The analysis of the highlighted electrical activity in the central leads supports this finding, revealing an influence of PEEP, BP and IAP on EAdi catheter position (p < 0.01).
  
  
  CONCLUSIONS
  PEEP, BP and IAP may affect the EAdi catheter position, although not compromising a stable signal. Additional information as provided by the catheter positioning tool is needed to ensure an optimal EAdi catheter position.
authors: Department of Anaesthesiology, Emergency and Intensive Care Medicine, Georg-August University of Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.
authors: Jürgen
authors: J
authors: Barwing
authors: Cristina
authors: C
authors: Pedroni
authors: Michael
authors: M
authors: Quintel
authors: Onnen
authors: O
authors: Moerer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002404:Catheterization / Q000379:methods*; D005260:Female; D005858:Germany; D006801:Humans; D007362:Intensive Care Units; D059725:Interactive Ventilatory Support; D059325:Intra-Abdominal Hypertension; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration; D011187:Posture / Q000502:physiology*