OBJECTIVE: To evaluate the effects of controlled voluntary hyperinflation and increased respiratory rate on the mechanics of the respiratory system, simulating what happens during exercise, in bronchiectasis and healthy subjects.
METHODS: Bronchiectasis (n=30) and healthy (n=16) subjects were evaluated by impulse oscillometry (IOS) during a baseline condition, and in controlled conditions with baseline (b) tidal volume (V) and hyperinflation (H), with respiratory rates at 30(R30) and 40(R40) bpm, in a random order. The mixed effects and a significance level at 0.05 were used for comparisons.
RESULTS: Resistance at 5Hz (R5), and at minus 20Hz (R5-R20), in kPa/L/s, were higher in subjects with bronchiectasis in all experimental conditions (p<0.05). For the bronchiectasis group, R5 and R5-20 increased with R increase at V (VRb versus VR30 and VR40; VR30 versus VR40; R5, R20 and R5-20 increased with R increase at H (HRb versus HR40; HR30 versus HR40). For the same R, there was a decrease with H compared to V (HRb versus VR30 and VR40; and HR30 versus VR30 and VR40). For the healthy group, only R20 showed differences (HR30 versus HR40; HR40 versus VR40).
CONCLUSIONS: The tachypnea increases the resistance and reactance of the respiratory system in bronchiectasis patients, and the voluntary hyperinflation caused attenuates this increase. These results can guide the development of strategies to reduce the limitation of physical activity in patients with bronchiectasis.
目的:为了评估受控的自愿性过度充气和呼吸频率增加对呼吸系统力学的影响,模拟运动过程中发生的事情,在支气管扩张和健康受试者中。
方法:在基线条件下,通过脉冲振荡法(IOS)评估支气管扩张(n=30)和健康(n=16)受试者,在基线(B)潮气量(V)和过度充气(H)的受控条件下,呼吸频率为30(R30)和40(R40)bpm,以随机顺序。混合效应和0.05的显著性水平用于比较。
结果:5Hz(R5)时的电阻,并且在负20Hz(R5-R20)时,kPa/L/s,在所有实验条件下,支气管扩张的受试者均较高(p<0.05)。对于支气管扩张组,R5和R5-20在V时随R增加而增加(VRb对VR30和VR40;VR30对VR40;R5、R20和R5-20在H时随R增加而增加(HRb对HR40;HR30对HR40)。对于相同的R,与V相比,H降低(HRb对VR30和VR40;HR30对VR30和VR40)。对于健康的群体来说,只有R20显示差异(HR30对HR40;HR40对VR40)。
结论:呼吸急促会增加支气管扩张患者呼吸系统的电阻和电抗,自愿性恶性通货膨胀减弱了这种增长。这些结果可以指导制定减少支气管扩张患者体力活动限制的策略。