title: A minimally invasive method for clinical trans-diaphragmatic pressure measurement in anaesthetized dogs.
abstract: OBJECTIVE
  To measure trans-diaphragmatic pressures, as an indication of diaphragmatic contractility, in anaesthetized dogs breathing normally, or during inspiratory obstruction (Mueller's manoeuvre) in order to assess if the method is practicable for use in clinical circumstances.
  
  
  METHODS
  Pilot study.
  
  
  METHODS
  Twenty eight client-owned dogs, ASA I or II, 1-10 years old, 5-30 kg bodyweight, which required anaesthesia for surgery, and were to be positioned in lateral recumbency.
  
  
  METHODS
  Following a standardized regimen of premedication and anaesthetic induction, anaesthesia was stabilized and maintained with isoflurane. Two commercially available balloon catheters were introduced orally, and advanced, one into the stomach and one into the mid-third of the oesophagus. Oesophageal and gastric pressures were measured from these catheters, and trans-diaphragmatic pressure (Pdi ) calculated and recorded continuously. At three separate time points during anaesthesia, for one breath, inspiration was obstructed (Mueller's manoeuvre) and Pdi was measured.
  
  
  RESULTS
  Placement of the catheters in the stomach was not easy, and failed in three cases. In five dogs, their size resulted in failure of correct placement of catheters. Good traces of all three pressures reflecting respiratory cycles were obtained from 20 dogs. During normal spontaneous breathing (mean ± SD [range]) Pdi was 5 ± 2.1 (3-10) mmHg. During Mueller's manoeuvre, Pdi was 14.6 ± 4.5 (9-21) mmHg. Abnormal waveforms were seen included cardiac oscillations (five dogs), inadequate intra-gastric pressure tracing (one dog), deflections with a double peak (one dog), and multiple artifacts when there was increased heart rate and tachypnoea (two dogs in response to surgery).
  
  
  CONCLUSIONS
  Measurement of trans-diaphragmatic pressure with balloon catheters was practicable in suitably sized dogs anaesthetized for clinical purposes and might be a useful tool in the assessment of diaphragmatic function. A range of catheters are required if the technique is to work in all dogs.
authors.affiliation: Anaesthesiology and Intensive Care Unit, Companion Animal Clinic, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Kiriaki
authors.initials: K
authors.lastname: Pavlidou
authors.forename: Ioannis
authors.initials: I
authors.lastname: Savvas
authors.forename: Yves
authors.initials: Y
authors.lastname: Moens
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Vasilakos
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Raptopoulos
mesh_terms: D000768:Anesthesia, General / Q000662:veterinary*; D000818:Animals; D003964:Diaphragm / Q000502:physiology*; D004285:Dogs / Q000502:physiology*; D008991:Monitoring, Physiologic / Q000379:methods / Q000662:veterinary*; D010865:Pilot Projects; D011312:Pressure
keywords: Dog; balloon catheters; intra-gastric pressure; intra-oesophageal pressure; trans-diaphragmatic pressure