title: Does hypercapnic acidosis, induced by adding CO2 to inspired gas, have protective effect in a ventilator-induced lung injury?
abstract: To investigate whether hypercapnic acidosis, induced by adding CO2 to inspired gas, would be protective effect against ventilator-induced lung injury (VILI), we ventilated 55 normal white rabbits for 6 hr or until PaO2/FIO2 <200 mmHg. Control group (n=15) was ventilated with peak inspiratory pressure (PIP) of 15 cm H2O, positive end-expiratory pressure (PEEP) of 3 cm H2O, an inspiration-to-expiration ratio of 1:2, and an inspired oxygen fraction (FIO2) of 0.40. High pressure hypercapnic group (HPHC; n=20) was ventilated with PIP of 30 cm H2O, PEEP of 0 cm H2O, and FIO2 of 0.40. Carbon dioxide was introduced into the inspiratory limb of the ventilator circuit, as necessary to maintain hypercapnia (PaCO2, 65 to 75 mmHg). High pressure normocapnic group (HPNC; n=20) was ventilated with same setting of HPHC, except normocapnia (PaCO2, 35 to 45 mmHg). Bronchoalveolar lavage fluid (BALF) lactate dehydrogenase, aspartate aminotransferase, interleukin-8 were significantly higher in high pressure ventilator group than control group (p<0.05). Wet weight to dry weight (WW/DW) and histologic scores were significantly higher in high pressure ventilator group than control group (p<0.05). However, there were no significant differences in oxygenation, BALF inflammatory markers, WW/DW and histologic scores between HPHC and HPNC groups. These findings suggest that hypercapnic acidosis at least induced by CO2 insufflation would not be protective effect against VILI in this model.
authors.affiliation: Department of Internal Medicine, Chonnam National University Hospital, Gwangju, Korea.
authors.forename: Chang Min
authors.initials: CM
authors.lastname: Park
authors.forename: Sung Chul
authors.initials: SC
authors.lastname: Lim
authors.forename: Yu Il
authors.initials: YI
authors.lastname: Kim
authors.forename: Kyu Sik
authors.initials: KS
authors.lastname: Kim
authors.forename: In Jae
authors.initials: IJ
authors.lastname: Oh
authors.forename: Soo Ock
authors.initials: SO
authors.lastname: Kim
authors.forename: Young Chul
authors.initials: YC
authors.lastname: Kim
mesh_terms: D000142:Acidosis, Respiratory / Q000139:chemically induced* / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D000280:Administration, Inhalation; D000818:Animals; D002245:Carbon Dioxide / Q000008:administration & dosage*; D006935:Hypercapnia / Q000139:chemically induced* / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D001239:Inhalation; D011659:Pulmonary Gas Exchange; D011817:Rabbits; D012121:Respiration, Artificial / Q000009:adverse effects*; D012128:Respiratory Distress Syndrome / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control*; D016896:Treatment Outcome
chemical_list: D002245:Carbon Dioxide