PEEP Setting Guided By Esophageal Pressure In Intra-abdominal Hypertension Patients ——Randomized Controlled Clinical Trial

Intra-abdominal hypertension(IAH) could cause improvement of pleural pressure(Ppl), then some clinical problems such as alveolus collapse, pulmonary compliance reduce and hypoxemia followed it. Adoption of PEEP could prevent such problems. However, PEEP setup recommendation in guidance didn’t take IAH’s effect in consideration. So, routine setup of PPEP couldn’t afford to resistance the effects of IAH, especially increase of Ppl, alveolus collapse, pulmonary atelectasis. Matching PEEP to intra-abdominal pressure to prevent alveolus collapse, increase pulmonary compliance and correct hypoxemia need more attention and trails.Objective:The aim of this study was to investigate the effects of PEEP guided by esophageal pressure on oxygenation and respiratory mechanics in mechanical ventilation patients with intra-abdominal hypertension, as well as the value for clinical application.Methods:All of the IAH patients enrolled in this study were randomly allocated to setting PEEP either guided by esophageal pressure (experimental group) or followed the ARDSnet trial (control group). PEEP settings in experimental group is in accordance with esophageal pressure until next record. PEEP settings in control group follows the guidelines advocated by the ARDSnetwork. The values of intra-abdominal pressure were recorded per 6-hour, while the frequency of esophageal pressure monitoring for 1 time in a day. Both of the two pressure monitoring continued for 2 weeks or until discharged from ICU. Oxygenation, respiratory system compliance, airway pressure, PEEP and intra-abdominal pressure were recorded and analyzed at the time of randomization,12 hours,24 hours and 72 hours after randomization. Layered those patients according to the respiratory system compliance at the point of selecting and compared the experimental group with the other one in oxygenation in different level for respiratory system compliance.Results:Selecting 35 patients met the criteria from October 2011 to October 2012 in surgery intensive care unit (SICU) of Jinling hospital. No significant differences were found between the two groups at baseline.On the main points, statistical significances were not find at 12h,24h,72h on improvement of oxygenation and respiratory system compliance between two groups.On the secondary end points, during the study period, experimental group had set higher PEEP level significantly compared with control group. Significant results on airway pressure, PEEP and intra-abdominal pressure were not appeared at the check points of the study.After layered as higher respiratory system compliance and lower respiratory system compliance subgroup, oxygenation were improved obviously in experimental group at 12h later and 1day after randomization(47.5%vs.52.5%.p=0.01;45%vs.50%. p=0.008). Respiratory system compliance obviously increased in Pes-guided group at 1day after randomization(28.9±8.9;21.4±6.4.P=0.03). On the other hand, there were no different between the two groups on oxygenation and the parameters of respiratory mechanics in the subgroup with higher respiratory system compliance. Pes-guided group had the higher PEEP than the other group at randomization 12h,24h,72h later.Conclusions:①Patients with IAH who received MV had set higher PEEP level according to Pes; ②This method for setting PEEP could not improve oxygenation and respiratory system compliance in patients with IAH;③This method for setting PEEP would improve oxygenation and respiratory system compliance during a short term under the condition with "lower" respiratory system compliance; while in such patients with "higher" respiratory system compliance, PEEP guided by Pes would have no such benefit.