摘要目的 探讨不同呼气末二氧化碳分压(PETCO2)水平对慢性阻塞性肺疾病(COPD)患者巾枢驱动和呼吸应答的影响.方法 13例稳定期COPD患者和10例健康志愿者常规测定肺通气功能后,采用二氧化碳(CO2)重复呼吸方法 ,增加PETCO2,从45 mm Hg上升至70 mm Hg.连续记录并计算在不同PETCO2水甲时中枢驱动和呼吸应答的各项生理参数.结果 PETCO2达到70mm Hg的实验时间在COPD组为(8.5±1.6)min,正常组为(16.3±3.2)min,差异有统计学意义(P＜0.05).两组的呼吸频牢(RR)均呈线性增加,正常组稍高于COPD组.COPD组潮气量(VT和分钟通气量(VE)在PETCO2=45～55 mm Hg时,呈显著的线性增加,VT山(0.68±0.25)L 上升到(1.04±0.44)L,VE由(10.59±3.36)L/min上升到(20.13±4.52)L/min.在PETCO2=55～70 mm Hg时VT和VE出现平台.正常组VT和VE呈线性增加,高于COPD组.正常组的吸气时间占呼吸周期比值(T1/Ttot)高于COPD组,差异有统计学意义(P＜0.05).COPD组的呼吸困难评分高于正常组,差异有统计学意义(P＜0.05).两组的平均吸气流量(VT/Ti)和膈肌电电压的均方根(RMS)均呈线性增加,COPD组VT/T1在PETCO2=65～70mm Hg时低于正常组,差异有统计学意义(P＜0.05),而不同PETCO2水平时RMS高于正常组,差异有统计学意义(P＜0.05).COPD组VE/RMS呈抛物线样变化,明显低于正常组,差异有统计学意义(P＜0.05).结论在CO2重复呼吸过程中,COPD患者的呼吸应答和中枢驱动在早期表现为线性递增,后期通气量出现平台,通气-中枢耦联显著异常.正常组的呼吸应答和中枢驱动均表现为线性递增,呼吸应答高于COPD组,而中枢驱动低于COPD组.

abstractsObjective To evaluate the effects of end tidal pressure of carbon dioxide (PETCO2) at different levels on the central drive and respiratory response in patients with chronic obstructive pulmonary disease (COPD). Methods After the completion of a pulmonary function test, 13 moderate COPD patients in stable stage and 10 healthy volunteers were studied with a CO2 rebreathing method by improving PETCO2 from 45 mm Hg to 70 mm Hg. The parameters of the central drive and respiratory response were monitored continuously and calculated at different PETCO2 levels. Results The experiment duration was respectively (8.5±1.6) rain in the COPD group and (16.3±3.2) min in the normal group when PETCO2 reached 70 mm Hg. Both groups experienced a linear increase in respiratory rate(RR), and the RR of normal group was higher than that of the COPD group. When PETCO2 was increased from 45 mm Hg to 55 mm Hg, the COPD group resulted in a linear increase in the tidal volume (VT) and minute ventilation (VE); VT increased from (0.68±0.25) L to (1.04±0.44) L and VE increased from (10.59±3.36) L/min to (20.13±4.52) L/min. But when PETCO2 was 55-70 mm Hg, VT and VE appeared a plat in the COPD group, while VT and VE maintained a linear increase in the normal group and higher than those of the COPD group. The ratio ofinspiratory time to duration of one breath (Ti/Ttot) was higher in the normal group than in the COPD group (P<0.05), while the Borg scale scores were lower in the normal group than in the COPD group (P<0.05). Both groups showed a linear increase in mean inspiratory volume per second (VT/T1) and root mean square (RMS), but when PETCO2 was increased from 65 mm Hg to 70 mm Hg, VT/T1 in the COPD group, it was obviously lower than that in the normal group (P<0.05). While RMS in the COPD group was higher than that in the normal group on different PETCO2 levels (P<0.05). COPD group showed a parabolic change in VE/RMS, which was significantly lower than that in the normal group (P<0.001). Conclusion During the early stage of CO2 rebreathing, the respiratory response and central drive of COPD patients show a linear increase, but during late stage, the ventilation appears a plat and ventilation-central coupling is obviously abnormal. The normal group shows a linear increase in respiratory response and central drive, in which respiratory response is higher and central drive is lower than in COPD group.