Effect of unilateral endobronchial valve insertion on pulmonary ventilation and perfusion: a pilot study.

BACKGROUND AND OBJECTIVE: The effects of bronchoscopic lung volume reduction (BLVR) on pulmonary ventilation and perfusion are incompletely understood. In this pilot trial, we investigated serial changes in regional ventilation and perfusion following unilateral endobronchial valve placement in COPD patients with heterogeneous emphysema. METHODS: At baseline and at days 30 and 90 following BLVR, subjects underwent lung function, 6MWD and St George's Respiratory Questionnaire. Ventilation and perfusion scintigraphy were performed to quantitate and serially compare regional differences. RESULTS: Six out of eight subjects completed the study; all had endobronchial valves targeting their left upper lobe. At day 90 post-BLVR, there was a trend towards an increase in FEV(1) and a mean reduction in St George's Respiratory Questionnaire score of nine units. In the targeted left upper zone there was reduced ventilation and perfusion. Ventilation and perfusion to the right lung; and specifically the right lower zone, significantly increased. CONCLUSIONS: There appears to be redistribution of ventilation and perfusion to the contralateral lung following endobronchial valve placement. This may be of importance when assessing patients for unilateral BLVR. Selecting patients with heterogeneous disease is emphasized, taking into consideration not just comparison between upper and lower lobes, but between left and right lungs. A larger trial is currently underway, guided by these findings.

Glossopharyngeal insufflation causes lung injury in trained breath-hold divers.

BACKGROUND AND OBJECTIVE: Glossopharyngeal insufflation (GI) is a technique practised by competitive breath-hold divers to enhance their performance. Using the oropharyngeal musculature, air is pumped into the lungs to increase the lung volume above physiological TLC. Experienced breath-hold divers can increase their lung volumes by up to 3 L. Although the potential for lung injury is evident, there is limited information available. The aim of this study was to examine whether there is any evidence of lung injury following GI, independent of diving. METHODS: Six male, competitive breath-hold divers were studied. CT of the thorax was performed during breath-holding at supramaximal lung volumes following GI (CT(GI)), and subsequently at baseline TLC (CT(TLC)). CT scans were performed a minimum of 3 days apart. Images were analysed for evidence of pneumomediastinum or pneumothorax by investigators who were blinded to the procedure. RESULTS: None of the subjects showed symptoms or signs of pneumomediastinum. However, in five of six subjects a pneumomediastinum was detected during the CT(GI). In three subjects a pneumomediastinum was detected on the CT(GI), but had resolved by the time of the CT(TLC). In two subjects a pneumomediastinum was seen on both the CT(GI) and the CT(TLC), and these were larger on the day that a maximal GI manoeuvre had been performed. The single subject, in whom a pneumomediastinum was not detected, was demonstrated separately to not be proficient at GI. CONCLUSIONS: Barotrauma was observed in breath-hold divers who increased their lung volumes by GI. The long-term effects of this barotrauma are uncertain and longitudinal studies are required to assess cumulative lung damage.