Importance of slow vital capacity in the detection of airway obstruction

This was a quantitative, retrospective cross-sectional study. The sample comprised 1,084 individuals who underwent spirometry and plethysmography in a central hospital in Lisbon, Portugal. The study sample was stratified into six groups, by pulmonary function.

RESULTS:

The analysis of the FEV₁/FVC ratio revealed the presence of airway obstruction in 476 individuals (43.9%), compared with 566 individuals (52.2%) for the analysis of the FEV₁/SVC ratio. In the airway obstruction, airway obstruction plus lung hyperinflation, and mixed pattern groups, the difference between SVC and FVC (SVC − FVC) was statistically superior to that in the normal pulmonary function, reduced FEF, and restrictive lung disease groups. The SVC − FVC parameter showed a significant negative correlation with FEV₁ (in % of the predicted value) only in the airway obstruction plus lung hyperinflation group.

CONCLUSIONS:

The FEV₁/SVC ratio detected the presence of airway obstruction in more individuals than did the FEV₁/FVC ratio; that is, the FEV₁/SVC ratio is more reliable than is the FEV₁/FVC ratio in the detection of obstructive pulmonary disease.

Airway Obstruction; Spirometry; Plethysmography

	Variables	Groups
		Normal pulmonary function	Reduced FEF	Airway obstruction	Airway obstruction with lung hyperinflation	Restrictive lung disease	Mixed obstructive and restrictive lung disease
		(n = 176)	(n = 225)	(n = 316)	(n = 215)	(n = 117)	(n = 35)
Gender
	Male	67 (38.0)	72 (32.0)	173 (54.7)	143 (66.5)	68 (58.1)	24 (68.6)
	Female	109 (62.0)	153 (68.0)	143 (45.3)	72 (33.5)	49 (41.9)	11 (31.4)
Age, years		54.3 ± 14.5	57.9 ± 11.3	61.8 ± 13.1	61.2 ± 12.3	60.1 ± 12.6	64.1 ± 12.3
Height, m		1.61 ± 0.09	1.60 ± 0.09	1.63 ± 0.09	1.64 ± 0.09	1.62 ± 0.10	1.65 ± 0.08
Weight, kg		72.6 ± 15.7	74.8 ± 15.8	75.7 ± 15.4	71.1 ± 15.8	74.7 ± 15.6	76.2 ± 16.2
BMI, kg/m2		28 ± 5	29 ± 6	28 ± 5	26 ± 6	28 ± 6	28 ± 5

Variables	Groups
	Normal pulmonary function	Reduced FEF	Airway obstruction	Airway obstruction with lung hyperinflation	Restrictive lung disease	Mixed obstructive and restrictive lung disease
	(n = 176)	(n = 225)	(n = 316)	(n = 215)	(n = 117)	(n = 35)
FEV₁, L	2.78 ± 0.05	2.30 ± 0.04	1.90 ± 0.04	1.33 ± 0.04	1.90 ± 0.05	1.17 ± 0.07
FEV₁, %	109.5 ± 1.03	95.9 ± 0.74	74.8 ± 0.99	51.0 ± 1.17	75.8 ± 1.61	45.8 ± 2.65
FVC, L	3.43 ± 0.07	3.07 ± 0.05	3.04 ± 0.06	2.68 ± 0.05	2.38 ± 0.07	1.92 ± 1.16
FVC, %	111.3 ± 1.16	105.4 ± 0.91	96.4 ± 1.06	82.3 ± 1.28	76.3 ± 1.45	59.5 ± 3.31
SVC, L	3.51 ± 0.07	3.14 ± 0.06	3.18 ± 0.05	2.81 ± 0.06	2.45 ± 0.07	2.06 ± 0.12
SVC, %	110.0 ± 1.18	103.6 ± 0.87	97.4 ± 1.00	82.5 ± 1.30	75.9 ± 1.46	61.5 ± 3.20
SVC − FVC, mL	79.3 ± 7.61	74.5 ± 14.3	140.9 ± 9.20	127.4 ± 9.83	78.0 ± 9.41	134.3 ± 21.1
FEV₁/FVC, %	81.5 ± 0.29	75.3 ± 0.24	62.6 ± 0.48	49.4 ± 0.73	80.2 ± 0.57	61.3 ± 1.30
FEV₁/SVC, %	79.7 ± 0.34	73.8 ± 0.28	59.4 ± 0.47	47.2 ± 0.73	77.5 ± 0.63	57.0 ± 1.25
RV, L	1.64 ± 0.42	1.83 ± 0.43	2.35 ± 0.59	3.86 ± 0.95	1.39 ± 0.43	1.88 ± 0.50
RV, %	87.8 ± 18.9	96.6 ± 20.7	111.8 ± 20.0	180.3 ± 36.3	67.4 ± 17.8	86.3 ± 29.0
TLC, L	5.16 ± 1.05	4.97 ± 1.01	5.53 ± 1.19	6.67 ± 1.22	3.84 ± 0.93	3.94 ± 0.91
TLC, %	98.7 ± 11.5	97.6 ± 11.2	99.8 ± 10.7	117.0 ± 14.6	70.0 ± 9.16	68.7 ± 16.3
RV/TLC	32.4 ± 7.76	37.4 ± 7.47	43.1 ± 9.36	57.9 ± 9.08	36.9 ± 9.71	48.5 ± 9.75
FRC, L	2.51 ± 0.62	2.59 ± 0.63	3.18 ± 0.75	4.64 ± 1.07	2.04 ± 0.54	2.48 ± 0.59
FRC, %	87.7 ± 16.9	91.6 ± 17.2	104.2 ± 16.4	148.0 ± 25.0	67.1 ± 12.2	78.5 ± 19.6

Groups	Groups
	Normal pulmonary function	Reduced FEF	Airway obstruction	Airway obstruction with lung hyperinflation	Restrictive lung disease	Mixed obstructive and restrictive lung disease
	p	P	p	p	p	p
Normal pulmonary function	N/A	0.103	< 0.001	< 0.001	0.922	0.002
Reduced FEF	0.103	N/A	< 0.001	< 0.001	0.181	< 0.001
Airway obstruction	< 0.001	< 0.001	N/A	0.647	< 0.001	0.336
Airway obstruction with lung hyperinflation	< 0.001	< 0.001	0.647	N/A	0.001	0.245
Restrictive lung disease	0.922	0.181	< 0.001	0.001	N/A	0.002
Mixed obstructive and restrictive lung disease	0.002	< 0.001	0.336	0.245	0.002	N/A

Groups
Normal pulmonary function		Reduced FEF		Airway obstruction		Airway obstruction with lung hyperinflation		Restrictive lung disease		Mixed obstructive and restrictive lung disease
r	p	r	p	r	p	r	p	r	p	r	p
0.027	0.719	−0.719	0.292	−0.049	0.384	−0.156	0.022	−0.025	0.790	0.089	0.615

Sociedade Brasileira de Pneumologia e Tisiologia SCS Quadra 1, Bl. K salas 203/204, 70398-900 - Brasília - DF - Brasil, Fone/Fax: 0800 61 6218 ramal 211, (55 61)3245-1030/6218 ramal 211 - São Paulo - SP - Brazil
E-mail: jbp@sbpt.org.br

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[1] Correspondence to: Raquel Barros Rua Castelo dos Mouros 118A, Bairro 7 Castelos 2785-290, São Domingos de Rana, Lisboa, Portugal Tel. 351 965205783 E-mail: raquel.barros@cardiocvp.net

Brasil

Brasil

Importance of slow vital capacity in the detection of airway obstruction* * Study carried out at the Portuguese Red Cross School of Health and at the Northern Lisbon Hospital Center Pulido Valente Hospital, Lisbon, Portugal.

OBJECTIVE:

METHODS:

RESULTS:

CONCLUSIONS:

Importance of slow vital capacity in the detection of airway obstruction^* * Study carried out at the Portuguese Red Cross School of Health and at the Northern Lisbon Hospital Center Pulido Valente Hospital, Lisbon, Portugal.