Acute native lung hyperinflation is not associated with poor outcomes after single lung transplant for emphysema

Background: Single-lung transplantation for emphysema may be complicated by acute native lung hyperinflation (ANLH) with hemodynamic and ventilatory c ompromise. Some groups advocate the routine use of independent lung ventila tion, double-lung transplant, or right-lung transplant with or without cont ralateral lung volume reduction surgery in high-risk patients, The goal of this study was to determine the incidence of ANLH and identify its potentia l predictors. Methods: We reviewed 51 consecutive single-lung transplants for emphysema. Symptomatic ANLH was defined as mediastinal shift and diaphragmatic flatten ing on chest x-ray with hemodynamic or respiratory failure requiring cardio pressor agents or independent lung ventilation. Preoperative and postoperat ive physiologic and hemodynamic data were analyzed from both recipients and donors. Results: Sixteen patients developed radiographic ANLH; 8 were symptomatic, 2 severely so. We could not identify high-risk patients before transplant b y pulmonary function tests, predicted donor total lung capacity (TLC)/actua l recipient TLC ratio, pulmonary artery pressures, or the side transplanted . There was a trend toward an increased incidence of symptomatic ANLH in pa tients with bullous emphysema on chest computed tomography, but this was ac counted for primarily by patients with of antitrypsin deficiency (4/13 vs 4 /38 with chronic obstructive pulmonary disease, P = 0.10). No patient requi red cardiopulmonary bypass or inhaled nitric oxide intraoperatively. Patien ts with acute native lung hyperinflation did not have increased reperfusion edema as measured by chest x-ray score or PaO2/F1O2 ratio. Compared to pat ients without ANLH, symptomatic patients had longer ventilator times (64.9 +/- 14.6 hours vs 40.4 +/- 3.9, P = 0.02, ANOVA) and longer lengths of stay (19.3 +/- 2.1 days vs 13.7 +/- 1.3, P = 0.07), but 30-day survival was 100 %. Two symptomatic patients required independent lung ventilation or inhale d nitric oxide; the others were managed with decreased minute ventilation, early extubation, and cardiopressor agents. No patient required early lung volume reduction surgery or retransplantation. Acute native lung hyperinfla tion had no effect on FEV1 or 6-minute walk results at 1 year; survival at 1, 2, or 3 years; or the rate of acute rejection, infection, or bronchiolit is obliterans syndrome greater than grade 2. Conclusion: Acute native lung hyperinflation is common radiographically but is rarely clinically severe. Although there was a trend toward an increase in symptomatic ANLH in patients with bullous emphysema, a high-risk group could not be identified preoperatively. Our results do not support the rout ine use of bilateral lung transplant, the exclusive use of right single-lun g transplant, simultaneous lung volume reduction surgery, or independent lu ng ventilation for patients with emphysema. Management strategies should be employed that limit overdistension of the native lung and lead to early ex tubation.