1155

Abstract

Introduction: The use of airway pressure release ventilation (APRV) has been well characterized in patients with Acute Lung Injury, Acute Respiratory Distress Syndrome, and atelectasis after major surgeries. APRV allows for the minimization of pulmonary barotrauma and facilitates lung-protective inverse-ratio ventilatory strategies in patients with significant injury who may not tolerate inverted ratios in other ventilation modes. We report the successful use of APRV for surgical site protection in a case of membranous tracheal injury requiring surgical repair and postoperative non-ventilatory extracorporeal membrane oxygenation (ECMO) support. A 57 year-old male with a past history significant for esophageal adenocarcinoma s/p robotically assisted esophogectomy presented as a transfer from outside hospital on post operative day 8 after bronchoscopy demonstrated a 7mm perforation in the left main-stem bronchus and multiple punctate perforations of the carina extending into the proximal right main-stem bronchus. A 37-French left double lumen tube was placed to maintain ventilation distal to these defects, and the patient was taken to the operating room for emergent surgical repair and veno-venous ECMO cannulation. Surgical repair was acheived using a combination of autologous pericardial patch and serratus muscle flap, and the patient was admitted to the ICU for management of non-ventilatory ECMO. His lungs were initially managed for 48 hours with a closed 5cm H2O CPAP circuit, with initiation of APRV ventilation on postoperative day 3. Initial CXR demonstrated complete opacification of bilateral lung fields, and initial tidal volumes were 35-50 cc using a P-high of 15 cm H20 and P-low of 5cm H2O. Inverse-ratio ventilation was achieved at 7:1 using a T-high of 5 seconds, and T-low of 0.7 seconds. Peak airway pressures were maintained below 20cm H2O for 48 hours after resumption of ventilation and below 25cm H2O for an additional 48 hours. Mean airway pressures were consistently 10-11cm H2O during the first 48 hours after resumption of ventilation, and peaked at 16cm H2O on postoperative day 6. Respiratory parameters normalized by 96 hours after resumption of ventilation with the patient spontaneously ventilating in excess of 8cc/kg, and ECMO was de-cannulated. Chest radiography on postoperative day 6 demonstrated clear bilateral lung fields, and bronchoscopy demonstrated patent and intact surgical repairs to the membranous trachea. The patient tolerated this ventilatory strategy well, never developed any signs of acute lung injury, and sedation was weaned sufficiently by postoperative day 4 for him to meaningfully interact with his family. The use of inverse-ratio ventilation with APRV in this case provided an ideal management strategy to minimize barotrauma on surgical airway repairs while recruiting previously non-ventilated lungs after ECMO.