Time controlled adaptive ventilation™ as conservative treatment of destroyed lung: an alternative to lung transplantation

Abstract

Background: Acute respiratory distress syndrome (ARDS) often requires controlled ventilation, yielding high mechanical power and possibly further injury. Veno-venous extracorporeal membrane oxygenation (VV-ECMO) can be used as a bridge to recovery, however, if this fails the end result is destroyed lung parenchyma. This condition is fatal and the only remaining alternative is lung transplantation. In the case study presented in this paper, lung transplantation was not an option given the critically ill state and the presence of HLA antibodies. Airway pressure release ventilation (APRV) may be valuable in ARDS, but APRV settings recommended in various patient and clinical studies are inconsistent. The Time Controlled Adaptive Ventilation (TCAV™) method is the most studied technique to set and adjust the APRV mode and uses an extended continuous positive airway pressure (CPAP) Phase in combination with a very brief Release Phase. In addition, the TCAV™ method settings are personalized and adaptive based on changes in lung pathophysiology. We used the TCAV™ method in a case of severe ARDS, which enabled us to open, stabilize and slowly heal the severely damaged lung parenchyma.

Case presentation: A 43-year-old woman presented with Staphylococcus Aureus necrotizing pneumonia. Progressive respiratory failure necessitated invasive mechanical ventilation and VV-ECMO. Mechanical ventilation (MV) was ultimately discontinued because lung protective settings resulted in trivial tidal volumes. She was referred to our academic transplant center for bilateral lung transplantation after the remaining infection had been cleared. We initiated the TCAV™ method in order to stabilize the lung parenchyma and to promote tissue recovery. This strategy was challenged by the presence of a large bronchopleural fistula, however, APRV enabled weaning from VV-ECMO and mechanical ventilation. After two months, following nearly complete surgical closure of the remaining bronchopleural fistulas, the patient was readmitted to ICU where she had early postoperative complications. Since other ventilation modes resulted in significant atelectasis and hypercapnia, APRV was restarted. The patient was then again weaned from MV.

Conclusions: The TCAV™ method can be useful to wean challenging patients with severe ARDS and might contribute to lung recovery. In this particular case, a lung transplantation was circumvented.

Keywords: Acute respiratory distress syndrome; Bronchopleural fistula; Destroyed lung; Lung protective ventilation; Time-controlled adaptive ventilation; Veno-venous extracorporeal membrane oxygenation.

Fig. 1

Consecutive CT images showing subsequent phases in the disease course. a CT scan performed in the referring academic hospital. ECMO, chest tube and tracheostomy tube in situ; the patient was not ventilated, since lung protective settings failed to produce significant tidal volumes. The scan shows bilateral atelectasis, a right-sided bronchopleural fistula, consolidations, destroyed lung parenchyma and a right-sided pneumothorax. b CT scan after ICU discharge and first APRV period. VV-ECMO has been removed; chest tube and tracheostomy in situ. The APRV mode was set and adjusted by the TCAV™ method with auto-release mode set at 75%. Tidal volumes increased and FiO2 could be decreased during recovery of lung parenchyma. Although the lungs are opened, there are persisting parenchymatic abnormalities of both lungs and persisting air leakage via the bronchopleural fistula. c CT scan after surgery for right bronchopleural fistula closure. Chest tube and tracheostomy in situ. Pleural effusion is visible after unsuccessful right-sided bronchopleural fistula closure, as well as a persisting pneumothorax. APRV was then restarted. d CT scan after second discharge and APRV period. Chest tube and tracheostomy in situ. Significant improvement of lung parenchyma is seen after reinstitution of APRV