Respiratory physiology & neurobiology
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Respir Physiol Neurobiol · May 2012
Comparative StudyImpact of mechanical ventilation and fluid load on pulmonary glycosaminoglycans.
The combined effect of mechanical ventilation and fluid load on pulmonary glycasaminoglycans (GAGs) was studied in anaesthetized rats ((BW 290±21.8 (SE)g) mechanically ventilated for 4h: (a) at low (∼7.5mlkg(-1)) or high (∼23mlkg(-1)) tidal volume (V(T)) and zero alveolar pressure; (b) at low or high V(T) at 5cmH(2)O positive end-expiratory pressure (PEEP); (c) with or without 7mlkg(-1)h(-1) intravenous infusion of Phosphate Buffer Solution (PBS). Compared to spontaneous breathing, GAGs extractability decreased by 52.1±1.5% and 42.2±7.3% in not-infused lungs mechanically ventilated at low V(T) or at high V(T) and PEEP, respectively. ⋯ In the absence of an inflammatory process, these results suggest that PEEP was protective at low but not at high V(T) when alveolar structures experience exceedingly high stresses. When combined to mechanical ventilation, fluid load might exacerbate edema development and lung injury.