Clinical Research Of Sleep-related Breathing Disorders In Idiopathic Pulmonary Fibrosis

Objective:Idiopathic pulmonary fibrosis(IPF)is a kind of interstitial lung disease of unknown cause.The progress of the disease is irreversible and could eventually cause diffuse pulmonary fibrosis.Sleep-related breathing disease not only induces the disorder of sleep structure,but also causes the obstruction of the airway,inducing frequent hypoxemia and hypercapnia,sleep fragmentation,lower sleep efficiency and lower quality of life.IPF patients clinically often appear daytime sleepiness,fatigue or even tired.Sleep-related breathing disorder may be one of the main reasons.The goal purpurse of our research is to contrast the general condition,accessory examination,polysomnography(PSG)results and daytime life of IPF patients,to analysize sleep structure and blood oxygen saturation,and to study morbility and clinical characteristics of sleep-related breathing disorder,and to discusses the influence of sleep-related breathing disorder in patients with IPF.Method:Forty-five IPF patients who have been measured by PSG were collected in the Department of Respiration of Tianjin General Hospital,all of which were divided into pure IPF group(apnea hypoventilation index,AHI<5 events/h)and IPF combined with obstructive sleep apnea hypopnea syndrome(IPF-OSAHS)group(AHI≥5events/h)according to the sleep AHI.Compare the general condition,accessory examination and sleep stucture,blood oxygen,apnea through PSG results between two groups.Evaluate daytime sleepiness and quality of life in use of Epworth sleep scale and SF-36 scale.Conduct the correlation analysis between AHI and pulmonary function and oxygen saturation in sleep and at wake.Result:(1)Of forty-five IPF patients,thirty-nine patients snored at night,twenty-nine patients showed sleep apnea,sixteen patients had the history of waking up at night,ten patients had the history of insomnia.(2)The lung function showed restrictive ventilatory dysfunction and diffusing dyfunction in all patients,demonstrating decreased TLC%pred,FVC%pred and DLCO%pred.The lood gas analysis showed decreased oxygen pressue,increased alveolar-artery pressure difference.The ultrasonic cardiogram showed increased pulmonary artery pressure.All of results above had no statistical differences between two groups.(3)All patients showed increased proportion of stage Ⅰ and Ⅱ,decreased proportion of stage Ⅲand REM and increased arousal index.The arousal index as well as propotion of stage and of IPFⅠ Ⅱ-OSAHS group were higher than pure IPF group(P<0.01),while proportion of stage Ⅲwas lower than pure IPF group(P<0.01).There was no significant difference in stage of rapid eye movement(REM)between two groups.(4)Thirty-five patients(77.7 percent)combined with OSAHS,among which seven subjects(15.6 percent)were mild with 5 events/h ≤ AHI < 15 events/h and twenty-eight subjects(62.2 percent)were moderate-severe with AHI≥15 events/h.Three patients(6.7 percent)was considered as upper airway resistance syndrome.The main type of sleep-disordered breathing was hypoventilation which mainly happened in stage REM.(5)Forty-five IPF patients all showed sleep hypoxemia and the oxygen desaturation index(ODI)of IPF-OSAHS group is higher than pure IPF group(P<0.01).(6)Of forty-five patients,twenty-nine patients had daytime somnolence with ESS>ten scores.There are five patients in pure IPF groups and twenty-four patients in IPF+OSAHS groups.The SF-36 score of IPF patients was not high.The score of IPF+OSAHS group was lower than pure IPF group(P<0.05).(7)The AHI was positively correlated with body mass index(r=0.655,P<0.05)and was negatively correlated with total lung volume(TLC)(r=-0.604,P<0.05)and forced vital capacity(FVC)(r=-0.464 P<0.05).The lowest oxygen saturation(LSO2),mean oxygen saturation(MSO2)in sleep was positively related with oxygen saturation at wake(r=0.412,P<0.05 and r=0.450,P<0.05,respectively).Conclusion:(1)Most of IPF patients could presented as some typical symptoms due to sleep-related disease.(2)IPF patients mainly demonstrated restrictive ventilatory dysfunction and diffusing dysfunction,and also combine with hypoxemia and pulmonary arterial hypertension,which was not influenced by combination of OSAHS.(3)Most of IPF patients could combine with sleep structure disorder,presented as increased persentage of light sleep and decreased persentage of deep sleep,and also combine with sleep breathing disorder and sleep hypoxemia,which could be influenced by combination of OSAHS.(4)Most IPF patients had daytime somnolence with ESS>ten scores and decreased life quality.OSAHS could aggrevate sleepiness and reduce life quality to some extent.(5)The corelation analysis showed AHI was positively correlated with body mass index and was negatively correlated with forced vitalcapacity,suggesting obesity may be a risk factor in IPF combined with OSAHS.The redution of lung volume could reduce stability of upper airway,increase upper resisitance,which may induce upper collapse and respiratory disorder,especially in REM period with much more relax muscle.Furthermore,The level of daytime oxygen may determined level of night oxygen to some extent.