Einfluss der Pufferung einer hyperkapnischen Azidose auf die systemische Inflammationsreaktion und den Grad der Lungenschädigung
LicenseStandard (Fassung vom 03.05.2003)
Permissive hypercapnia has been shown to reduce the degree of lung injury in subjects with surfactant deficiency. Studies in isolated perfused lungs and in animals with ventilator induced lung injury suggest that reduced barotrauma as well as hypercapnic acidosis itself without reduced barotrauma result in less lung injury. Studies in isolated perfused lungs showed an attenuation of this lung protective effect by buffering hypercapnic acidosis. However, there is no information whether or not this is the case in an intact subject. We hypothesized that buffering hypercapnic acidosis worsens wet/dry ratio in surfactant deficient rabbits by aggravating the degree of lung injury. Methods: 28 adult rabbits were randomized into 2 groups: group 1: hypoventilation-hypercapnia (PCO2 75 - 85 mmHg, Vt 5ml/kg, PEEP 6 cm H2O) and buffering with 8,4 % NaHCO3 (pH > 7,35); group 2: hypoventilation-hypercapnia (PCO2 75 - 85mmHg, Vt 5ml/kg, PEEP 6 cm H2O) without buffering the respiratory acidosis. Primary outcome measure: wet/dry weight ratio; secondary outcome measurements: gas exchange (PO2, oxygen transport, lactate), lung histology and macroscopy, interleukin 8, and other markers of lung injury: BAL protein, BAL neutrophil granulocyte count. Results: wet/dry weight ratio was significantly higher in the buffered group. PaO2 was not different. Oxygen transport was significantly higher in the no-buffer group. Serum-lactate, neutrophil granulocytes and protein in BAL were significantly higher in the buffered group. Histology scores were not different, but the buffered lungs showed more evidence for macroscopic hemorrhage and atelectasis. Conclusion: Buffering hypercapnic acidosis may aggravate the degree of lung injury. A significant effect on systemic inflammatory response could not be proven in this study.
Subject HeadingsAllgemeine Entzündungsreaktion [GND]
Respiratorische Azidose [GND]
Respiratory distress syndrome [MeSH]