Study On Change Of Inspiratory Respiratory Function Before And After Sleep In Obstructive Sleep Apnea-Hypopnea Syndrome

Objectives: Obstructive sleep apnea hypopnea syndrome(OSAHS)patients have frequent and transient hypopnea or breath-off, accompanied with hypoxemia and hypercarbia at night on account for narrowness or obstruct of upper airway for multi-reasons.It has not been clear for its certain pathogenesis.The impedient function of upper airway dilator maybe is one of the important pathogenies.Our research assume that it is the same state between at midnight and waking instantly in the morning.The study explored the comparison of inspiratory respiratory function (forexample:FIV1,FEV1,FIV1/FVC,FEV1/FVC Pemax,Pimax)inboth OSAHS patients and normal control in order to evaluate the state of upper airway dilator muscle and speculate the relation between upper airway dilator muscles and inspiratory respiratory function,also the effect of respiratory central drive on upper airway dilator muscles,then to explore the effect of upper airway dilator muscles on OSAHS and the initial mechanism of OSAHS.Methods:Based on disease history and polysomnography(PSG),we admitted 48 OSAHS and 40 normal control.There are 17 to be performed CPAP one night among OSAHS.Before sleep and waking instantly in the next morning or the next morning after CPAP, inspiratory respiratory function were checked,such as FIV1,FEV1,FIV1/FVC,FEV1/FVC,Pemax,Pimax.Compare these between OSAHS and normal control.Results:①Patients in both OSAHS and normal control had increase in IVC,and significantly increasein OSAHS (p＜0.05).There was no channge in FIV1 in normal after sleep,but decrease in OSAHS. FIV1/FVC, FEV1/FVC decreased after sleep in both OSAHS and normal, and significantly decrease in OSAHS (p＜0.05). Compare to normal, there were no change in FIV1/FVC and decrease in FIV1,IVC and FEV1/FVC at usual time; significantly increase in IVC in OSAHS after sleep than that at usual time and decrease in FIV1,FEV1/FVC and FIV1/FVC than normal. @There was decrease in MEP and increase in MIP in both OSAHS and normal after sleep, and significantly increase in MIP in OSAHS(p＜0.05). Compare to normal, MEP and MIP increased in OSAHS than that in normal.③There were increased P0.1 and decreased P0.1max in both OSAHS and normal after sleep. Compare to normal, P0.1 and P0.1max decreased in OSAHS both at usual time and after sleep,and P0.1 significantly increased(p＜0.05).④After one night CPAP, the index of disordered-respiration had been improved obviously.Among these CPAP patients,the tendency of inspiratory respiratory function were fit with those in non-CPAP.After CPAP, the change of inspiratory respiratory function were not different in statistics.Conclusions:①There were significantly decreased in FIV1, FIV1/FVC and FEV1/FVC and significantly increased in MIP in OSAHS patients after sleep.It maybe infered that upper airway dilator muscles had worked more,fatigue and weak.②There were significantly increased in P0.1 in OSAHS patients before and after sleep,which infer there is compensatory increase in OSAHS③The inspiratory respiratory function in OSAHS were partly resumed after one night CPAP, which infer that CPAP might have partly reduced the fatigue of upper airway dilator muscles.④There were a little increased in P0.1 and a litter decreased in P0.1max in OSAHS patients after CPAP, which may infer it can be lightened in high central drive in OSAHS after a long time for CPAP.It is not in the same state of upper airway dilator muscles between sleeping and waking.So the change of inspiratory respiratory function only partly explained the state of upper airway dilator muscles at night.The reduce of inspiratory respiratory function after sleep may infer the fatigue of upper airway dilator muscles,the reduce of contracting strength,which result in the occlusion of upper airway and apnea. According to these,we presume that the reduce of upper airway dilator musclesmay play a part in the pathogenesis of OSAHS.