The diffusing capacity in adult cystic fibrosis

The value of adjusting the diffusing capacity for the lung volume has been demonstrated in a large number of patients with other lung diseases but has not been validated in patients with cystic fibrosis (CF). Pulmonary function test results on a cohort of 52 adult CF patients were analyzed to determine whether the diffusing capacity of carbon monoxide by single breath method (DLCO(SB)) when adjusted for alveolar volume (V(A)%), correlated with the severity of pulmonary dysfunction. The DLCO(SB) remained within the reference range except in those with severe lung impairment (61.88 +/- 15.48%). DLCO(SB) has a significant (P < 0.05) positive correlation (0.70, 0.67, 048, 0.69 and 0.31, respectively) with measures of airflow limitation (FVC%, FEV1%, FEV1/FVC%, MVV%, and sGaw) and negative correlation (-0.36 and -0.21, respectively) with measures of air trapping (RV% and RV/TLC%). DLCO(SB)/V(A) remained above 100% of predicted despite worsening lung disease and did not correlate with other measures of lung function. On the other hand, the DLCO(SB) and DLCO(SB)/V(A), when adjusted for V(A)%, decreased and were significantly correlated with worsening airflow limitation and, to a lesser extent, air trapping. The relatively preserved adjusted DLCO(SB) and DLCO(SB)/V(A) values in CF patients up until late in its course may be explained the predominant airway involvement, minimal loss of alveolar-capillary units, and enhanced V/Q relationship due to claustration in CF.

Pneumomediastinum and subcutaneous emphysema from pacemaker placement

Percutaneous insertion of permanent pacemaker leads through the subclavian vein is an alternative to the cephalic vein approach. A rare occurrence and successful conservative management of extensive pneumomediastinum and subcutaneous emphysema without concomitant pneumothorax resulting from permanent transvenous pacemaker insertion in an 80-year-old man with syncope and arrhythmia is reported.

Paradoxical embolization in an adult patient with cystic fibrosis

To our knowledge, we describe the first reported case of paradoxical embolization via a patent foramen ovale (PFO) in an adult with moderately severe cystic fibrosis (CF) and advanced lung disease. Fluctuating neurologic symptoms and signs suggestive of cerebrovascular disease in an adult patient with advanced CF may be due to paradoxical embolization via a PFO. The possibility of a PFO should be considered before placement of a totally implantable venous access device to avert unnecessary risk of stroke in CF patients. Further study is needed to determine whether the use of a totally implantable venous access device increases the risk of paradoxical embolization in adult CF patients with a PFO.