title: Comparison of the coaxial circle circuit with the conventional circle circuit.
abstract: OBJECTIVE
  The coaxial circle system helps prevent heat loss during surgery, and it also acts as a humidifier. This study aimed to compare the coaxial breathing system and the conventional system in their ability to warm and moisturize inhaled gases, and we also analyzed lung function protection and saccharin clearance time in patients who underwent tympanomastoidectomy (TMT) with the aid of these two systems.
  
  
  METHODS
  Forty adult patients of ASA physical status I-II were scheduled for elective TMT. A standard volume-dependent ventilator setting was used to establish normocapnia. The coaxial circle system was used in the treated group (n=20), whereas the conventional circuit system was used in the control group (n=20). Saccharin clearance, VC (vital capacity), FRC (functional residual capacity), FEV1 (forced expiratory volume in 1 second), airway pressure, relative humidity and temperature of inspired gas, body temperature and adverse and hemodynamic effects were measured at different perioperative periods.
  
  
  RESULTS
  The relative humidity (mg H2O Lt -1) of inspired gas in the treated group was higher than in the control group at 5, 15, 30, 45, 60 and 90 minutes after anesthesia induction. The temperature of inspired gas (Centigrade) in the treated group was higher than in the control group (p<0.05) after 5, 10, 15, 30, 45, and 90 minutes of anesthesia. Postoperative saccharin clearance time was lower than before the operation in the treated group (p<0.05). Postoperative FRC was lower than preoperative FRC in the study and control groups (p<0.05).
  
  
  CONCLUSIONS
  The coaxial circle system decreased postoperative saccharin clearance time and increased postoperative FRC, relative humidity and the temperature of inspired fresh gas, without any adverse perioperative effects in patients who underwent TMT.
authors.affiliation: Department of Anesthesiology and Reanimation, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey.
authors.forename: Ayse
authors.initials: A
authors.lastname: Mizrak
authors.affiliation: Department of Anesthesiology and Reanimation, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey.
authors.forename: Murat
authors.initials: M
authors.lastname: Bilgi
authors.affiliation: Department of Anesthesiology and Reanimation, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey.
authors.forename: Senem
authors.initials: S
authors.lastname: Koruk
authors.affiliation: Department of Anesthesiology and Reanimation, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey.
authors.forename: Suleyman
authors.initials: S
authors.lastname: Ganidagli
authors.affiliation: Department of Ear Nose and Throat (ENT), Faculty of Medicine, Gaziantep University, Gaziantep, Turkey.
authors.forename: Erkan
authors.initials: E
authors.lastname: Karatas
authors.affiliation: Department of Anesthesiology and Reanimation, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey.
authors.forename: Unsal
authors.initials: U
authors.lastname: Oner
authors.affiliation: Department of Anesthesiology and Reanimation, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey.
authors.forename: Rauf
authors.initials: R
authors.lastname: Gul
authors.affiliation: Department of Anesthesiology and Reanimation, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey.
authors.forename: Levent
authors.initials: L
authors.lastname: Sahin
keywords: Coaxial circle system; Pulmonary function tests; Saccharin clearance test; Standard circle system; Tympanomastoidectomy