Analysis of the influence of airway resistance on expiratory flow limitation in COPD patients with stable GOLD stages Ⅱ-Ⅲ

doi:10.16150/j.1671-2870.2019.04.007

Abstract

Abstract:

Objective: To study the correlation between airway resistance (R_aw) and expiratory flow limitation (EFL) in patients with chronic obstructive pulmonary disease (COPD). Methods: One hundred and two stable Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages Ⅱ-Ⅲ COPD patients, of them 53 were stage Ⅱ and 49 were stage Ⅲ, were enrolled. Patients were not taking bronchodilator eight hours before examination, then lung function testing and respiratory airway resistance were measured after salbutamol (400 μg) inhalation. Twenty eight healthy subjects were served as controls. Results: The peak expiratory flow (PEF), peak expiratory flow (PEF) and forced expiratory flow at 50% forced vital capacity (FEF₅₀) in stage Ⅲ COPD patients were significantly lower than those in stage Ⅱ COPD patients. Seven (14.3%) patients with stage Ⅲ COPD and only 1 (1.9%) patients with stage Ⅱ COPD revealed inspiratory fraction [ratio of inspiratory capacity and total lung capacity (IC/TLC)] ≤25%. The total airway resistance (R_tot), effective airway resistance (R_eff), inspiratory airway resistance/expiratory airway resistance (R_insp/R_exp) of the two COPD groups were significantly higher than those of the control group. The R_exp of COPD patients had the best correlation with FEV₁, PEF and FEF₅₀ (all r>0.80, P<0.01). Conclusions: R_aw especially R_exp is already obviously increased in stable moderate to severe COPD patients on account of the severe expiratory flow limitation. Peripheral component of air way resistance might be the main factor of the increment. The symptom of dyspnea would be prone to appear with the deterioration of lung function.

Key words: Chronic obstructive pulmonary disease, Flow limitation, Airway resistance, Inspiratory fraction

CLC Number:

R562

CHEN Yuqing, WANG Mingjie, ZHU Dong, LV Chengjian, CHEN Ping. Analysis of the influence of airway resistance on expiratory flow limitation in COPD patients with stable GOLD stages Ⅱ-Ⅲ[J]. Journal of Diagnostics Concepts & Practice, 2019, 18(04): 418-422.

Figures/Tables 3

References 18

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组别	例数（n）	男/女	年龄(岁)	体质量指数 (kg/m²)	mMRC
健康对照组 GOLD Ⅱ级 GOLD Ⅲ级	28 53 49	15/13 39/14 38/11	62.57±7.74 64.30±10.00 65.96±7.46	22.89±4.07 23.72±3.54 22.86±2.64	0.39±0.50 1.30±0.61 1.73±0.73
F值/X²值 P值		5.296 0.070 8	1.406 0.249	1.002 0.372	48.777 <0.01

组别	FEV₁/FVC (%)	FEV₁ (%pred)	FEF₅₀ (%pred)	PEF (%pred)	IC (%pred)	RV/TLC (%)	IC/TLC (%)	R_tot [cmH₂O/ (L·s)]	R_eff [cmH₂O/ (L·s)]	R_insp [cmH₂O/ (L·s)]	R_exp [cmH₂O/ (L·s)]
健康对照组 (n=28) GOLD Ⅱ级 (n=53) GOLD Ⅲ级 (n=49)	86.73±4.38 65.69±5.87 57.12±6.52^* (F=5.508)	111.50±13.59 62.83±8.85 42.58±4.67 (F=0.032)	110.85±27.30 30.01±7.27 16.37±4.27 (F=1.807)	105.24±10.20 55.09±14.54 34.66±7.42^* (F=6.525)	121.76±23.56 98.86±18.01 77.99±16.16 (F=0.329)	38.15±6.23 48.05±7.08 53.67±7.17^* (F=13.234)	52.10±8.66 41.61±8.63 32.87±7.26^* (F=0.066)	3.11±0.80 6.49±2.55 11.02±4.90^* (F=11.491)	2.77±0.70 5.39±1.79 8.12±2.70^* (F=5.275)	2.46±0.61 3.49±1.09 4.45±1.22^* (t=1.180)	3.05±0.89 7.75±3.27 13.90±7.11^* (t=12.046)
F值 P值	230.569 <0.001	536.409 <0.001	461.379 <0.001	346.185 <0.001	50.006 <0.001	44.533 <0.001	50.405 <0.001	50.627 <0.001	61.800 <0.001	32.215 <0.001	47.574 <0.001

参数	r值
参数	FEV₁%	FEV₁/FVC	PEF%	FEF₅₀%	RV/TLC	IC%	IC/TLC
R_tot R_eff R_insp R_exp	-0.743 (P<0.001) -0.738 (P<0.001) -0.797 (P<0.001) -0.853 (P<0.001)	-0.630 (P<0.001) -0.615 (P<0.001) -0.675 (P<0.001) -0.738 (P<0.001)	-0.760 (P<0.001) -0.774 (P<0.001) -0.795 (P<0.001) -0.813 (P<0.001)	-0.730 (P<0.001) -0.720 (P<0.001) -0.773 (P<0.001) -0.838 (P<0.001)	0.572 (P<0.001) 0.582 (P<0.001) 0.664 (P<0.001) 0.620 (P<0.001)	-0.598 (P<0.001) -0.590 (P<0.001) -0.651 (P<0.001) -0.644 (P<0.001)	-0.580 (P<0.001) -0.577 (P<0.001) -0.653 (P<0.001) -0.630 (P<0.001)