Combined recombinant human activated protein C and ceftazidime prevent the onset of acute respiratory distress syndrome in severe sepsis

This experimental animal study investigates the effects of combined recombinant human activated protein C (rhAPC) and ceftazidime on cardiopulmonary function in acute lung injury and severe sepsis. Twenty-one sheep (37 ± 2 kg) were operatively prepared and randomly allocated to either the sham, control, or treatment group (n = 7 each). Single treatments of rhAPC or ceftazidime were published previously; therefore, control groups were dispensed in the present study, what may be considered a study limitation. Acute lung injury and sepsis were induced according to an established protocol. The sham group received only the vehicle. The sheep were studied in awake state for 24 h and mechanically ventilated. Recombinant human APC (continuous infusion 24 μg/kg per hour) and ceftazidime (3-g bolus at 1 and 13 h) were intravenously administered. The animals were fluid resuscitated with Ringer's lactate to maintain hematocrit at baseline. Compared with injured controls, the treatment group had a significantly higher PaO2/FIO2 ratio, and the onset of acute respiratory distress syndrome was prevented. The increase in pulmonary microvascular shunt fraction and airway obstruction in bronchi and bronchiole, as well as lung 3-nitrotyrosine, lung myeloperoxidase, cardiac 3-nitrotyrosine, and cardiac malondialdehyde levels, was significantly reduced as compared with controls (P < 0.05 each). Treated sheep had significantly improved hemodynamics as reflected by mean arterial pressure, heart rate, cardiac index, and systemic vascular resistance index (P < 0.05 each). In addition, plasma oncotic pressure and urine output were significantly improved (P < 0.05 each). Combined rhAPC and ceftazidime significantly improved cardiopulmonary function, reduced pulmonary and cardiac tissue injury, and prevented the onset of acute respiratory distress syndrome in ovine severe sepsis without obvious adverse effects.