Mais um parâmetro para identificar o distúrbio ventilatório obstrutivo: VEF1/VEF6 na berlinda

Abstract

The article entitled "Determination of the efficacy of FEV 6 as a surrogate for FVC in the diagnostic screening for chronic obstructive pulmonary disease through the comparison of FEV 1 /FVC and FEV 1 /FEV 6 ratios", by Lundgren et al.,(1) addresses a number of topics that are highly relevant in pulmonology. Among those, it is important to highlight the role of anti-smoking campaigns and campaigns of diagnostic screening for chronic obstructive pulmonary disease (COPD), from their screening phase to the orientation and appropriate referral of patients. Taking this opportunity, and praising the authors for their vision and qualities, I would like to address some topics that can be listed as follows: 1 The use of a fixed value of 70% for the ratio between forced expiratory volume in one second and forced vital capacity (FEV 1 /FVC) in the diagnosis of obstructive ventilatory defect, as a complement in the diagnosis of COPD -Since this value is partly dependent on age, the use of a fixed value results in underestimation of the critical diagnostic value in younger individuals, in whom early diagnosis and early measurements are highly relevant, as well as its overestimation in elderly individuals, in whom an FEV 1 /FVC ratio of 70% might be normal. False-negative results are as undesirable as false-positive results. However, this is a long-standing debate; 2 The use of the FEV 1 /FVC ratio or the FEV 1 /FEV 6 ratio as a parameter -In fact, I would add the FEV 1 /VC ratio as a better parameter for the comparison, since the greater the denominator, the more sensitive the ratio. In order for the parameter to be sensitive and specific, from a pathophysiological point of view, the numerator and the denominator should not be similarly compromised, that is, if the disease tends to decrease both, the ratio will decrease less and this will delay the diagnosis. Unlike other screening tests, which have high sensitivity, the test proposed, FEV 1 /FEV 6 , will have attributes of higher specificity, that is, it will be useful in ruling out the presence of the disease and not in identifying it, which seems to be what is being inquired into; 3 Can the training of personnel to use a simpler device or conduct field research be facilitated? -In this case, the difference in the tests will only be the duration of expiratory time. The training of personnel to perform the up-to-6-second spirographic test and the up-to-15-second spirographic test is the same. Furthermore, the expertise of the technician will be proven through conducting innumerable tests. In addition to instructing the individual that will perform the test, it is essential that special attention be given to undesirable events, as well as to the analysis of the graphic records, especially at the beginning of the maneuver. Therefore, the weight of the duration of expiratory time in relation to the total time of the test is not the same as its simple time reduction; 4 Cost of the equipment -It seems that the measurement of FEV allows the use of sensors incapable of identifying...

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“…Isto parece estar relacionado a fatores sociológicos e culturais [28]. Manzano et al [16] e Dias [29] defendem que, embora valores de VEF1 e CVF menor que 70% do predito sejam vistos como marcadores de distúrbio obstrutivo, um valor único não deve ser utilizado como limite inferior. Para casos assim, devese considerar a confirmação do diagnóstico por meio de exames complementares.…”