Effects of body temperature on ventilator-induced lung injury

Purpose: To evaluate the effects of body temperature on ventilator-induced lung injury. Material and Methods: Thirty-four male Sprague-Dawley rats were randomized into 6 groups based on Mechanical ventilation; their body temperature (normothermia, 37 +/- 1 degrees C; hypothermia, 31 +/- 1 degrees C; hyperthermia, 41 +/- 1 degrees C. Ventilator-induced lung injury was achieved by ventilating for I hour with pressure-controlled Ventilator-induced lung ventilation mode set at peak inspiratory pressure (PIP) of 30 cmH(2)O (high pressure, or HP) and positive injury end-expiratory pressure (PEEP) of 0 cmH(2)O. In control subjects, PIP was set at 14 cmH(2)O (low pressure, or LP) and PEEP set at 0 cmH20- Systemic chemokine and cytokine (tumor necrosis factor alpha, interleukin 1 beta, interleukin 6, and monocyte chemoatractant protein 1) levels were measured. The lungs were assessed for histological changes. Results: Serum chemokines and cytokines were significantly elevated in the hyperthermia HP group compared with all 3 groups, LP (control), normothermia HP, and hypothermia HP. Oxygenation was better but not statistically significant in hypothermia HP compared with other HP groups. Cumulative mean histology Conclusions: Concomitant hyperthermia increased systemic inflammatory response during HP ventilation. Although hypothermia decreased local inflammation in the lung, it did not completely attenuate systemic inflammatory response associated with HP ventilation. (c) 2005 Elsevier Inc. All rights reserved.