(1052) Chest Wall-Restrictive Tool for Lung Protection in Ventilation: A Prospective Self-Controlled Study

Introduction: In mechanical ventilation of ARDS patients, proper transpulmonary pressure (PL) is essential to maintain oxygenation meanwhile minimizing repeated alveolar collapse and overdistention. The use of neuromuscular blocking agents (NMBA) can reduce PL partially by stiffening the chest wall. But only short duration is considered and is not suitable for patients without invasive ventilation. Chest wall-restrictive methods have been explored but results remain controversial with limited data on respiratory mechanics. The purpose of this study is to evaluate the effects of chest binder on esophageal pressure (Pes), PL, Pplat and lung compliance in sedated ventilated patients without ARDS.

Methods: This is a prospective self-controlled study. All the enrolled patients were ventilated in VC mode with Vt of 6 mL/kg/IPBW using Mindray SV800 ventilator. PEEP was properly set. Sedatives and remifentanil was continuously infused to inhibit spontaneous breathing. The esophageal pressure was monitored. When patients were stable after ICU admission, a specific chest binder was applied to the tightest for 30 minutes. The respiratory mechanical parameters were recorded before and during the procedure, respectively.

Results: 46 patients were included in analysis (mean age:75 years; BMI: 22 kg/m2; APACHE II score: 12). With chest binder applied, patients had similar arterial pH, PaCO2, PaO2, P/F ratio and MAP. PiP was increased from 25.1±7.1 cmH2O to 26.7±6.3 cmH2O (P < 0.001), while there was no significant change in Pplat. ΔPes was elevated from 2.9±1.8 to 4.2±2.2 cmH2O (P < 0.001). ΔPL was decreased from 10.2±5.3 cmH2O to 9.1±4.8 cmH2O (P=0.001). The compliance of chest wall (Ccw) significantly decreased from 231.6±140.7 to 156.7±103.3 ml/cmH2O (P < 0.001). Lung compliance (CL) was increased from 58.0±39.3 to 65.3±41.8 ml/cmH2O (P=0.002). The global compliance of the integrated respiratory system (Crs) did not change.

Conclusions: The chest binder is an accessible, convenient and noninvasive strategy for lung protection. It may lead to significant decrease in chest wall compliance while increasing lung compliance in non-ARDS patients with mechanical ventilation. These findings might open the avenues for further research to investigate the possible therapeutic implications for all forms and stages of ARDS.