HYPEROXIA DURING PORCINE FAECAL PERITONITIS: II. THE HEPATO-SPLANCHIC SYSTEM

Abstract

Introduction: Early goal directed therapy for septic shock aims at optimization of O2 delivery. Despite its ability to improve survival in hypodynamic shock models, pure O2 breathing has insufficiently been studied in this context, since sepsis is associated with oxidative stress from increased production of O2 radicals, which in turn is directly related to the O2 partial pressure. Therefore we studied the effects of pure O2 ventilation during hyperdynamic porcine septic shock. Methods: After induction of fecal peritonitis, pigs were ventilated for 24 h with 100 % O2 or air using protective ventilation according to the ARDS network (tidal volume 8 mL/kg, PEEP 10cmH2O, I/E ratio 1:1.5, peak airway pressure ≥ 40 cm H2O; PEEP 12 cm H2O, I/E 1:1 if PaO2/FiO2 ratio ≤ 300 mmHg, PEEP 15 cm H2O ≤ 200 mmHg, respectively). Lung compliance and resistance (BiCor-system) as well as gas exchange function were measured before as well as at 12, 18 and 24 h of peritonitis. Apoptosis in post mortem lung biopsies was analysed with the TUNEL assay. Results: While lung mechanics did not show any intergroup difference, pure O2 ventilation was associated with improved pulmonary gas exchange and a markedly reduced number of apoptotic cells in the lung. Conclusions: During the first 24 h of peritonitis-induced septic shock ventilation with pure O2 is safe with respect to lung mechanics and gas exchange. The lower rate of apoptosis may be due to the protective ventilatory strategy. Supported by the Deutscher Akademischer Austauschdienst and the Alexander-von-Humboldt-Stiftung.