Effects of acute hypervolemic hemodilution with hydroxyethyl starch 130/0.4 on the lung in a rabbit model of sepsis

Abstract

To investigate the effects of acute hypervolemic hemodilution (AHH) with hydroxyethyl starch (HES) 130/0.4 on the lung in a rabbit model of sepsis and their possible mechanism. Thirty healthy New Zealand rabbits were randomly divided into three groups (n=10 each): group sham operation (C), group sepsis model (E) and group AHH. Sepsis model was reproduced with modified colon ascendens stent peritonitis (CASP). In group C laparotomy was done but without puncturing the colon. At 4 hours after CASP, AHH was carried out intravenous infusion of 6% HES 130/0.4 20 ml/kg at 20 ml/min. Lactated Ringer solution was infused at 10 ml kg (-1) h (-1) in all three groups during the experiment. The animals breathed spontaneously during the experiment. A catheter was introduced into the right carotid artery for blood sampling, and it was connected to a pressure transducer for continuous mean arterial pressure (MAP) and heart rate (HR) monitoring. At 4 hours and 8 hours after CASP, a median abdominal incision was made and photographic documentation of abdominal situs was made. At the same time arterial blood samples were drawn at 4 hours and 8 hours after CASP for blood gas analysis and determination of hemoglobin (Hb) and hematocrit (Hct). The plasma component was separated and tumor necrosis factor-alpha (TNF-alpha) was measured. Respiratory rate and urinary output were record. The rabbits were sacrificed at 8 hours after CASP. The right lungs were immediately removed for determination of total protein concentration in broncho-alveolar lavage fluid (BALF). The wet/dry (W/D) lung weight rate were calculated. The sections of lung were stained with hematoxylin and eosin for light microscopic examination and the injury score was recorded. (1)MAP declined gradually and HR tended to accelerate during the course of the experiment in group E, but no significant differences were found in both group C and group AHH. (2)After AHH, the Hb and Hct decreased by 20% in group AHH. In group E, arterial oxygen saturation (SaO(2)), arterial partial pressure of oxygen (PaO(2)), arterial partial pressure of carbon dioxide (PaCO(2)) and pH decreased significantly at 8 hours after CASP compared with group C (all P<0.05). (3)TNF-alpha concentration in plasma was higher in group E and group AHH than in group C at 4 hours after CASP (both P<0.05). At 8 hours TNF-alpha concentration was increased in group E compared with group C (P<0.05), but there was no significant difference between group C and group AHH. (4)In group E, score of morphological changes in lung was significantly increased compared with group AHH (6.9+/-1.4 vs. 11.2+/-1.7, P<0.05). AHH with HES 130/0.4 can protect the lungs from sepsis. Inhibition of proinflammatory cytokines may be involved in the mechanism.