title: Influence of two different ventilation modes on the function of an anaesthetic conserving device in sevoflurane anaesthetized piglets.
abstract: OBJECTIVE
  To investigate the influence of two ventilation modes on the performance of an anaesthetic conserving device (AnaConDa) in piglets.
  
  
  METHODS
  Prospective randomized experimental trial.
  
  
  METHODS
  Eight female piglets weighing 24.7 +/- 2.2 kg.
  
  
  METHODS
  Anaesthesia was maintained with sevoflurane (in 60% oxygen) delivered from the AnaConDa placed between endotracheal tube (ETT) and Y-piece. Anaesthetic depth was guided using standard clinical parameters. Ventilation mode was volume controlled (VC) during the first and pressure support (PS) during the second period of anaesthesia in four piglets (group 1); the order was reversed in group 2. Anaesthetic gases were sampled before (at the proximal end of the ETT) and after the AnaConDa (Y-piece). Data were analysed using a model I anova, with treatment and group as fixed categorical effects. Using a paired t-test, partial pressures of carbon dioxide (Pe'CO(2)) on both sides of the device were compared.
  
  
  RESULTS
  Although the mean administration rate of sevoflurane was comparable in both groups (3.8 +/- 1.8 mL hour(-1)), E'Sevo was higher in group 1, more specifically during the first period (p = 0.035). Less sevoflurane escaped during VC (14.0 +/- 3.4%) compared with PS ventilation (17.2 +/- 5.7%) (p = 0.001). Pe'CO(2) was lower at the Y-piece (6.4 +/- 0.8 kPa, 48 +/- 6 mmHg) compared with the ETT (9.3 +/- 1.4 kPa, 70 +/- 11 mmHg) in both groups and ventilation modes. On average, inspiratory CO(2) tension was 2.0 +/-1.0 kPa (15 +/- 8 mmHg). Respiration rate was comparable in all piglets while tidal volume () and peak inspiratory pressure were lower during VC compared with PS (p < 0.001, p = 0.015 respectively).
  
  
  CONCLUSIONS
  The observed differences in E'Sevo concentration and sevoflurane breakthrough were probably related to differences in . The observed high FiCO(2) indicated an excessive dead space with the AnaConDa for these piglets.
authors.affiliation: Department of Surgery and Anaesthesia of Domestic Animals, University of Ghent, Merelbeke, Belgium. stijn.schauvliege@ugent.be
authors.forename: Stijn
authors.initials: S
authors.lastname: Schauvliege
authors.forename: Stefaan
authors.initials: S
authors.lastname: Bouchez
authors.forename: Lindsey
authors.initials: L
authors.lastname: Devisscher
authors.forename: Tim
authors.initials: T
authors.lastname: Reyns
authors.forename: Sandra
authors.initials: S
authors.lastname: De Boever
authors.forename: Frank
authors.initials: F
authors.lastname: Gasthuys
mesh_terms: D000769:Anesthesia, Inhalation / Q000295:instrumentation / Q000662:veterinary*; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D005260:Female; D008738:Methyl Ethers / Q000494:pharmacology*; D012121:Respiration, Artificial / Q000295:instrumentation / Q000662:veterinary*; D015656:Respiratory Mechanics; D000077149:Sevoflurane; D013552:Swine / Q000502:physiology*
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane