INTRODUCTION:Independent lung ventilation (ILV) is a technique employed for patients with unilateral or discordant lung injury who have failed conventional mechanical ventilation. This mode of ventilation is initiated using a double lumen endotracheal tube (DLT). Two ventilators are titrated to optimize oxygenation and ventilation, while minimizing ventilator induced lung injury. The longest documented use of ILV in trauma to date is 17 days. The following case describes successful use of ILV for 38 days in a critically injured patient with bronchopleural fistula (BPF), pulmonary contusion and pneumonia.
CASE PRESENTATION:A 24-year-old male soldier in excellent health suffered a gun a shot wound just below the right clavicle. After presenting in shock with hemopneumothorax he underwent a massive resuscitation including placement of three right chest tubes, a right thoracotomy and right upper lobe resection. He was successfully extubated after transfer from Iraq to Germany and then to the Naval Military Hospital in Bethesda. Eight days post operatively an air leak in one chest tube appeared and he was reintubated for hypoxic respiratory failure. A second thoracotomy repaired a bronchus intermedius leak and no other leaks were seen. Shortly after post operative extubation he was emergently reintubated for acute hypoxic failure. Constant air leaks greater than 50% of the tidal volume in all chest tubes indicated development of a massive BPF. The respiratory failure was complicated by pulmonary contusions, acute respiratory distress syndrome (ARDS) from Acinetobater and Klebsiella pneumonia, and septic shock requiring large vasopressor support. Multiple ventilatory modes were employed and nitric oxide was used resulting in a small improvement in oxygenation. Placement of a DLT allowed initiation of ILV as a salvage measure. After attempting multiple modes of ventilation on each lung, he stabilized on pressure control 8, PEEP 5 in right lung and pressure control 35, PEEP 16 in left lung. Bronchoscopy visualized a massive right stump leak. ILV continued for 38 days with a slow reduction in ventilatory support and eventual surgical repair of the BPF. One month later he was discharged to a rehabilitation facility.
DISCUSSIONS:ILV worked in this case by allowing minimal airway pressures on the right and much higher pressures on the left. Inhaled nitric oxide works preferentially in aerated alveoli and may have assisted oxygenation by helping shunt blood to the left lung due to higher tidal volumes. Indications for ILV include BPF, massive hemoptysis, pulmonary alveolar proteinosis, unilateral lung injury, and single lung transplant. Risks of ILV include challenging placement of the DLT, frequent DLT displacement, increased airway trauma, and mucus plugging. A larger left sided tube decreases risk of dislodgement although frequent placement confirmation via bronchoscopy remains necessary. ILV in a patient with a large BPF can lead to worsened V/Q mismatch via incomplete lung expansion or loss of effective tidal volume. Mortality can be as high as 67% and large leaks diagnosed later in the hospital course confer a grave prognosis. Despite this, asynchronous independent lung ventilation may prove to be a simple, flexible and highly effective technique for managing massive air leak and other types of respiratory failure.
CONCLUSION:We describe a case in which ILV was successfully used as a rescue mode of ventilation for 38 days in a complex trauma patient with a massive BPF, pulmonary contusion, and nosocomial pneumonia complicated by ARDS. We believe this is the longest reported use of ILV in trauma and the multi-factorial respiratory failure renders this case even more unusual. ILV should be considered as a potential salvage measure in selected patients.
DISCLOSURE:Erik Osborn, No Financial Disclosure Information; No Product/Research Disclosure Information