The advantages and disadvantages of applying high positive end￣expiratory pressure in acute respiratory distress syndrome / 中国小儿急救医学

ABSTRACT

The main pathophysiological features of acute respiratory distress syndrome (ARDS) are alveolitis edema,collapse and V/Q ratio imbalance. Consensus Recommendations from the Pediatric Acute Lung Injury Consensus Conference recommends that the lung protective ventilation strategy be the first choice for mechanical ventilation of PARDS with small tidal volume and high positive end-expiratory pressure (PEEP) used to improve oxygenation. High PEEP is an important technical tool for the " Open Lung Con-cept". It is beneficial to improve oxygenation through the operation of lung recruitment (RM) and the main-tenance of alveolar open. High PEEP reduced the formation of pulmonary edema in animal experimental mod-els. Large-scale adult randomized controlled trials have shown that high PEEP may reduce mortality in patients with severe hypoxemia,but it is currently subject to some challenges. Simultaneously,high PEEP and ventilator-induced lung injury(VILI) caused by excessive lung expansion are closely related,and increase the incidence of barotrauma and pneumothorax. High PEEP may reduce the volume of blood returning to the heart,reduce cardiac output,and also reduce cerebral perfusion pressure and aggravate brain edema. It is still a highly controversial issue to use high PEEP to optimize lung recruitment in patients with ARDS and to choose the best PEEP to maintain the alveolar open. It has been suggested that the purpose of lung recruitment is no longer to restore normal lung ventilation,but to provide reasonable arterial oxygen saturation and reduce oxy-gen toxicity priority. PEEP above 10 cmH2 O is suggested to be used to optimize lung recruitment if lung col-lapse is diffuse. When the lung collapse is locally distributed,it is not suitable to use excessive PEEP for RM and other methods can be used to improve V/Q ratio.