A Comparative Study between EAR and Coaxial Circle Breathing System

Theerapongpakdee S.,M.D.,Sermdamrongsak U.,M.D.

Department of Anesthesiology, Faculty of Medicine, Srinagarind Hospital, Khon Kaen University, Khon Kaen 40002

  Arterial blood gases were compared in 20 patients of ASA class I-II between breathing system and enclosed afferent reservoir (EAR) breathing system under general anesthesia with controlled ventilation at 70 and 100 ml/kg/min FGF's.
  The results indicated that at FGF of 100 ml/kg/min,there were no statistically significant differences on pH,PaCO² and PaO²,but at FGF of 70 ml/kg/min there were statistically significant differences on pH and PaCO². From this study we concluded that EAR breathing system was as efficient as coaxial circle breathing system at FGF 100 ml/kg/min,but less efficient at FGF 70 ml/kg/min. However,EAR circuit can be used safely at FGF 70 ml/kg/min because the results of the study are within normal clinical range.