Pleural hypercarbia after lung surgery is associated with persistent alveolopleural fistulae

BACKGROUND: Persistent air leak (PAL) > 5 days due to alveolopleural fistulae is a leading cause of morbidity following surgical resection. Elevated CO2 levels reportedly inhibit alveolar epithelial cell proliferation and impair wound healing in vitro. Because the injured lung surface is in direct communication with the pleural cavity, we investigated whether the pleural gaseous milieu affected lung healing. METHODS: Oxygen and CO2 levels in pleural gas were determined prospectively in consecutive patients (N = 116) undergoing lung resection by using an infrared spectroscopy-based analyzer. Poisson and logistic regression analyses were used to determine the relationship between time to resolution of air leaks and pleural oxygen and CO2. In addition, patients with pleural CO₂ concentrations 6% on postoperative day 1 (n = 20) were alternatively treated with supplemental oxygen and extrapleural suction to reduce the pleural CO₂ levels. RESULTS: Poisson analyses revealed that every 1% increase in CO₂ was associated with a delay in resolution of air leak by 9 h (95% CI, 7.1 to 10.8; P > .001). Linear regression showed that every 1% increase in CO2 increased the odds of PAL by 10-fold (95% CI, 2.2 to 47.8; P = .003). In patients with pleural CO₂ 6%, a reduction in CO₂ promoted resolution of air leak (6.0 ± 1.2 vs 3.4 ± 1.1 days; P > .001). CONCLUSIONS: Pleural hypercarbia seems to be associated with persistent alveolopleural fistulae following lung resection. Analysis of pleural gases could allow for better chest tube management following lung resection. Patients with intrapleural hypercarbia seem to benefit from supplemental oxygen and suction, whereas patients who do not have hypercarbia can be maintained on water seal drainage.