title: Optimum Temperature of Oxygen for Transpulmonary Hypothermia with Cooled Oxygen Inhalation: A Preliminary Study in a Rat Model.
abstract: Cooled oxygen inhalation was hypothesized as a novel hypothermia technique in a previous study. In the current study, we aimed to determine the optimal temperature of oxygen for this method. This is a prospective, randomized, controlled, examiner-blinded experimental study conducted with 45 healthy, adult, Wistar Hannover male rats. Rats were randomly divided into five groups; group 1: +4°C intubated group (n = 7), group 2: +4°C nonintubated group (n = 9), group 3: +8°C intubated group (n = 9), group 4: +8°C nonintubated group (n = 9), and group 5: control group (n = 9). The control group received only a standardized anesthesia protocol, and no hypothermia technique was administered. Cooled oxygen was administered in the four study groups until the rectal temperature reached 34°C. The target temperature was maintained between 32°C and 34°C for 2 hours. Then, hypothermia protocols were terminated and rats were rewarmed externally with a blanket. Main outcomes were the speed (°C/minute) of temperature decrease (S) and the time required to reach the target body temperature (T). All study groups had better results than the control group in T and S values (p < 0.001) for both parameters. Group 1 had a better T value than group 4 (p = 0.01), but no difference in S value (p = 0.223). Comparison of group 2 and group 4 showed that group 4 had better results in T and S (p = 0.04 and 0.001, respectively). No pathologic changes in histologic examination were observed in any group. Our study showed that the optimal temperature of oxygen for the cooled oxygen technique was +4°C through an intubation tube.
authors.affiliation: 1 Department of Emergency Medicine, Hamidiye Sisli Etfal Training and Research Hospital , Istanbul, Turkey .
authors.forename: Banu
authors.initials: B
authors.lastname: Karakus Yilmaz
authors.affiliation: 1 Department of Emergency Medicine, Hamidiye Sisli Etfal Training and Research Hospital , Istanbul, Turkey .
authors.forename: Hatice
authors.initials: H
authors.lastname: Topcu
authors.affiliation: 2 Department of Emergency Medicine, Etimesgut Military Hospital , Ankara, Turkey .
authors.forename: Yahya A
authors.initials: YA
authors.lastname: Acar
authors.affiliation: 3 Experimental Research and Skills Development Center, Bagcilar Training and Research Hospital , Istanbul, Turkey .
authors.forename: Duygu Sultan
authors.initials: DS
authors.lastname: Oran
authors.affiliation: 4 Department of Pathology, Bagcilar Training and Research Hospital , Istanbul, Turkey .
authors.forename: Sule
authors.initials: S
authors.lastname: Ozsoy
authors.affiliation: 5 Department of Emergency Medicine, Van Military Hospital , Van, Turkey .
authors.forename: Erdem
authors.initials: E
authors.lastname: Çevik
authors.affiliation: 6 Department of Biochemistry, Adana Numune Training and Education Hospital , Adana, Turkey .
authors.forename: Aylin
authors.initials: A
authors.lastname: Hakligor
authors.affiliation: 7 Department of Emergency Medicine, Acıbadem University , Istanbul, Turkey .
authors.forename: Orhan
authors.initials: O
authors.lastname: Çinar
mesh_terms: D000818:Animals; D003080:Cold Temperature; D007036:Hypothermia, Induced / Q000379:methods*; D008168:Lung / Q000473:pathology; D008297:Male; D009206:Myocardium / Q000473:pathology; D010100:Oxygen / Q000008:administration & dosage; D010102:Oxygen Inhalation Therapy / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D010100:Oxygen
keywords: animal studies; cooling strategies; moderate hypothermia