Análise de métodos baseados na tomografia de impedância elétrica na escolha da pressão positiva ao final da expiração em obesos

Abstract

The positive end-expiratory pressure (PEEP) is one adjustable parameter during mechanical ventilation. Maintaining a pressure above the atmospheric in the airways is a consolidate technic to avoid injuries caused by the cyclical closure of the alveoli (cyclic recruitment) caused by low lung volumes. Although if high PEEPs can minimize the cyclicrecruitment, they can also cause other injuries due to the high volumes and pressures involved (overdistension). Therefore, a PEEP must be individually selected to ensure an adequate oxygenation as well as the lungs protection. However, there isnt a consensus about the PEEP selection approach. Electrical impedance tomography is a portable and noninvasive tool for monitoring the regional pulmonary ventilation overtly inhomogeneous. The objective of this study is to evaluate the effect of using two global methods (based on the optimization of the volume-pressure relationship) and three local methods (basedin the lungs homogenization assessed by the electrical impedance tomography information) to determine a PEEP value in a group of obese patients. A local/global comparison showed significant differences in PEEP identified, observing thus, a complementarity of information provided by methods.