Changes of respiratory mechanics and central drive in sleeping patients with chronic obstructive pulmonary disease / 中华老年医学杂志

ABSTRACT

Objective To evaluate the changes of respiratory mechanics and central drive in sleeping patients with chronic obstructive pulmonary disease (COPD).Methods A total of 14 patients with moderate to severe COPD (age 63.7± 6.4 years) and 10 healthy volunteers,admitted to our hospital from October 2010 to October 2011,were chosen in our study.After performing routine pulmonary function test,all subjects were monitored by respiratory mechanics,diaphragm electromyogram (EMGdi) and polysomnography (PSG) in waking and sleeping state.The different physiological parameters were recorded and calculated on a continuous basis in time sequence for 30 minutes.Results In sleeping state as compared with waking state,there were no differences(P＞0.05) in respiratory rate(RR) and the ratio of inspiratory time to duration of one breath (Ti/Ttot),but there were reductions (P ＜ 0.05) in the tidal volume (VT),minute ventilation (VE),mean inspiratory volume per second(VT/Ti),dynamic lung compliance(CLdyn),root mean square (RMS)and pulse oxygen saturation(SpO2).Meanwhile there were significant increases (P＜0.05) in airway resistance(Raw) and pressure-time product(PTP) in COPD group.In normal group,there were no differences (P＞0.05) in all above physiological parameters in sleeping state compared with waking state.Conclusions There are abnormal changes in respiratory mechanics characterized by increased airway resistance and work of breathing,meanwhile in reduced central drive and requirement of ventilation,which may be the main reasons for hypopnea and hypoxemia in sleeping COPD patients.