Sleep desaturation and its relationship to lung function, exercise and quality of life in LAM.
BACKGROUND
Lymphangioleiomyomatosis (LAM) is characterised by progressive airway obstruction and hypoxaemia in young women. Although sleep may trigger hypoxaemia in patients with airway obstruction, it has not been previously investigated in patients with LAM.


METHODS
Consecutive women with lung biopsy proven LAM and absence of hypoxaemia while awake were evaluated with pulmonary function test, echocardiography, 6-min walk test, overnight full polysomnography, and Short Form 36 health-related quality-of-life questionnaire.


RESULTS
Twenty-five patients with (mean±SD) age 45±10 years, SpO(2) awake 95%±2, forced expiratory volume in the first second (median-interquartile) FEV(1)(% predicted) 77 (47-90) and carbonic monoxide diffusion capacity, DL(CO) (%) 55 (34-74) were evaluated. Six-minute walk test distance and minimum SpO(2) (median-interquartile) were, respectively, 447m (411-503) and 90% (82-94). Median-interquartile apnoea-hypopnoea index was in the normal range 2 (1-5). Fourteen patients (56%) had nocturnal hypoxaemia (10% total sleep time with SpO(2) <90%), and the median sleep time spent with SpO(2) <90% was 136 (13-201)min. Sleep time spent with SpO(2) <90% correlated with the residual volume/total lung capacity ratio (r(s)=0.5, p: 0.02), DL(CO) (r(s)=-0.7, p: 0.001), FEV(1) (r(s)=-0.6, p: 0.002). Multivariate linear regression model showed that RV/TLC ratio was the most important functional variable related to sleep hypoxaemia.


CONCLUSIONS
Significant hypoxaemia during sleep is common in LAM patients with normal SpO(2) while awake, especially among those with some degree of hyperinflation in lung function tests.
Interstitial Lung Disease Group, Heart Institute (InCor), University of São Paulo Medical School, São Paulo 05403-900, SP, Brazil.
Pedro
P
Medeiros
Geraldo
G
Lorenzi-Filho
Suzana P
SP
Pimenta
Ronaldo A
RA
Kairalla
Carlos R R
CR
Carvalho
D000328:Adult; D015444:Exercise / Q000502:physiology; D005080:Exercise Test / Q000379:methods; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000209:etiology* / Q000503:physiopathology / Q000534:rehabilitation; D008168:Lung / Q000503:physiopathology*; D008175:Lung Neoplasms / Q000150:complications* / Q000503:physiopathology / Q000534:rehabilitation; D018192:Lymphangioleiomyomatosis / Q000150:complications* / Q000503:physiopathology / Q000534:rehabilitation; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D017286:Polysomnography / Q000379:methods; D011446:Prospective Studies; D011788:Quality of Life; D012129:Respiratory Function Tests / Q000379:methods; D020919:Sleep Disorders, Intrinsic / Q000209:etiology* / Q000503:physiopathology / Q000534:rehabilitation
D010100:Oxygen