Intercomparison Effects Of The Lung Recruitment Maneuvers In ARDS And The Mechanism Of Signal Transduction In VILI

Partâ… Hemodynamic effects of three recruitment maneuvers in dog with acute respiratory distress syndromeObjective To assess the hemodynamic consequences of three RM techniques in dogs with acute respiratory distress syndrome (ARDS). Methods Dogs were divided into three types of ARDS: oleic acid injury, saline-lavaged and hydrochloric acid inspired lung injury. All three models were designed to initiate a similar severity (PaO2/FiO2≤200 mmHg). RM methods included sustained inflation, incremental positive end-expiratory pressure (PEEP) and pressure controlled ventilation. Post-RM PEEP levels were 8, 12, and 16 cmH₂O, the same levels without RM as control. Hemodynamics were measured frequently before the RM, during the RM and at 0, 5, 10, 15 min after the RM. Arterial blood gas analysis and pulmonary mechanics were also observed at the same time. Results Cardiac index decreased greater in the hydrochloric acid inspired model(decreased by 37%) than in the oleic acid injury(decreased by 19%) and saline-lavaged lung injury models(decreased by 23%) during the RM (P﹤0.05). Cardiac index immediately recovered to the value of before the RM in oleic acid injury and saline-lavaged lung injury models. However, cardiac index remained decreased 5mins post-RM in the hydrochloric acid inspired model. There were no differences in hemodynamics among RM methods in oleic acid injury and saline-lavaged lung injury models (Pï¹¥0.05). In the hydrochloric acid inspired model, compared with pressure controlled ventilation(decreased by 25%), cardiac index decreased greater during the RM with sustained inflation(decreased by 46%) and incremental PEEP(decreased by 39%) (P﹤0.05). Conclusions RM transiently depress hemodynamics in three models of ARDS, especially in the hydrochloric acid inspired model. Impairment of pressure controlled ventilation on hemodynamics is smaller than that of sustained inflation and incremental PEEP in the hydrochloric acid inspired model.