The aim of this study is to investigate whether utilization of acetaminophen and external cooling to control fever in ewe septic shock model is beneficial and influence HSP70.
Twenty-four fasted, anaesthetized, invasively monitored, mechanically ventilated female sheep (27.0±4.6 Kg) received 0.5 g/kg body weight of feces into the abdominal cavity to induce sepsis. Ringer′s lactate (RL) was titrated to maintain pulmonary artery occlusion pressure (PAOP) at baseline level throughout the experimental period without any antibiotics and vasoactive drugs utilization. After surgical operation, randomization was performed as following: if temperature< 36.0°C, the animal was placed in the hypothermia group; the other animals were randomized to three groups: high fever (T>39.0°C); mild fever (37.8°C<T<38.2°C) and normothermia (36.0°C<T<37.0°C) group. Acetaminophen 25 mg/ kg/ 4∼6 hours combined with external cooling (ice pad) was used to control core temperature in the expected range. Hemodynamic, mechanical ventilation parameters, and gas exchange values were obtained every hr. Plasma samples were obtained every four hrs for HSP70 measurement (Hsp70 ELISA Kit, Stressgen, Canada).RESULT: Survival time was longer in the fever group (25.2 ± 3.0 hrs) than in the mild fever group (17.7 ± 3.5 hrs), normothermia group (16.0 ± 1.9 hrs) and hypothermia group (18.5 ± 2.5 hrs) (p < 0.05). There was no significant difference in homodynamic parameters except that DO2 (oxygen delivery) was higher in the two fever groups then the other two groups (p < 0.05). PaO2/FiO2 ratio was highest and blood lactate level was lowest in the high fever group than the other three groups (p < 0.01 and 0.05 respectively). Plasma HSP70 level was higher in the two fever groups than in the other groups (p<0.05).
In this septic shock model, febrile response had beneficial effects on the respiratory function, blood lactate level and survival time. Antipyretic interventions including acetaminophen and external cooling were associated with lower circulating HSP70 levels.
S. Fuhong, None.