| Effect of posture on the distribution of pulmonary ventilation in patients with increased closing volume. |
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Young Tae Kim1, Mee Kyung Kim1, Chae Man Lim1, Youn Suck Koh1, Woo Sung Kim1, Jin Sook Ryu2, Myung Hae Lee2, Won Dong Kim1 |
1Department of Internal Medicine, College of Medicine, University of Ulsan, Asan Medical Center, Seoul, Korea
2Department of Nuclear Medicine, College of Medicine, University of Ulsan, Asan Medical Center, Seoul, Korea |
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| Abstract |
Background
In normal adults. ventilation is uneven and greater in the base than the apex of the lung in tidal volume breathing‘ However infants have fragile chest wall and reduced elastic recoil, resulting in easy closure of peripheral airways e.specially in the dependent portion of the lung. So ventilation in infants is greater in the apex than the base of the lung. We assumed that in adults whose closing volume is increased, dependent portion could be easily collapsed during tidal breathing and ventilation could be greater in the uppear than than the lower portion of the lung.
Methods
We measured spirometry and closing volume (CV) in normal controls and in patients with chronic lung disease. Also we measured fractional distribution of ventilation at supine, left lateral and right lateral decubitus with 133Xe ventilation scan in normal controls, patients with normal closing volume and patients with increased closing volume.
Results
The subjects consisted of 7 normal controls (mean age ± SD, 62.9 ±6.1 years). 6 patients with normal CV (62 .8 ± 8.2 years) and 7 patients with increased CV (63.0 ±15.3 years). 1) Normal controls have mean (± SD) FVC 104 ± ll % of predicted value, FEV1 120 ± 16 % , FEV1 / FVC 112±5% and CV 86.9 ± 1 2.5%. Patients with normal CV have FVC 62 ± ll% , FEV1 54 ± 17% , FEV1 / FVC 84 ± 23% and. CV 92 .6±15.5%. Patients with increased CV, have FVC 53± 9% , FEV1 38±13, FEV1 / FVC 69 ±16 % and CV 176.1 ± 36.6% , CV was significantly different between two patient groups (p < 0.02). 2) ln normal controls mean fractional ventilation to left lung was 48.1 ± 5.3% at supine, 54.1 ± 9.8% at dependent and 40 .9 ± 6.5 % at left uppel;most position. In patients with normal CV mean fractional ventilation to left lung was 44.6 ± 2.1% at supine, 59.7 ± 5.6% at left dependent and 3L7 ±8.3% at left uppermost position. In patients with increased CV mean fractional ventilation to left lung was 48 .7 ± 4.5% at supine, 41.7 ± 6.6% at left dependent and 60 .9 ± 15 . 7% at left UIψermost position, ln normal controls and patients with normal CV , ventilation t o left lung at left 'CIependent position tends to be higher than that at supine position but without statisitical significance and it was signi ficantly [ower at left uppermost than at left lung dependent position. In patie'nts with increased CV, ventilation to left at left dependent position tends to be higher than that at supine position but without significance and it was significantly higher at left uppermost than that at left dependent position.
Conclusion
These data suggest that in patients with increased CV ventilation to one side of lung could be higher at uppermost than at dependent position on lateral decubitus during tidal breathing and this fact should be taken into account in positioning of patients with unilateral lung disease. |
| Key Words:
Closing volume, 133Xe ventilation scan, Position, Chronic lung disease |
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