Jarenbäck Linnea, Tufvesson Ellen, Ankerst Jaro, Bjermer Leif, Jonson Björn
Respiratory Medicine and Allergology, Department of Clinical Sciences, Skåne University Hospital, Lund University, Lund, Sweden,
Clinical Physiology, Department of Clinical Sciences, Skåne University Hospital, Lund University, Lund, Sweden.
Int J Chron Obstruct Pulmon Dis. 2018 Jun 27;13:2033-2039. doi: 10.2147/COPD.S161345. eCollection 2018.
Spirometry, the main tool for diagnosis and follow-up of COPD, incompletely describes the disease. Based on volumetric capnography (VCap), an index was developed for the diagnosis and grading of COPD, aimed as a complement or alternative to spirometry.
Nine non-smokers, 10 smokers/former smokers without COPD and 54 smokers/former smokers with COPD were included in the study. Multiple breath washout of N and VCap were studied with Exhalyzer D during tidal breathing. VCap was based on signals for flow rate and CO and was recorded during one breath preceding N washout. Efficiency Index (EFFi) is the quotient between exhaled CO volume and the hypothetical CO volume exhaled from a completely homogeneous lung over a volume interval equal to 15% of predicted total lung capacity.
EFFi increased with increased Global initiative for chronic Obstructive Lung Disease (GOLD) stage and the majority of subjects in GOLD 2 and all subjects in GOLD 3 and 4 could be diagnosed as having COPD using the lower 95% confidence interval of the healthy group. EFFi also correlated with N washout (r=-0.73; <0.001), forced expiratory volume in 1 second (r=0.70; <0.001) and diffusion capacity for carbon oxide (r=0.69; <0.001).
EFFi measures efficiency of tidal CO elimination that is limited by inhomogeneity of peripheral lung function. EFFi allows diagnosis and grading of COPD and, together with FEV, may explain limitation of physical performance. EFFi offers a simple, effortless and cost-effective complement to spirometry and might serve as an alternative in certain situations.
肺量计是慢性阻塞性肺疾病（COPD）诊断和随访的主要工具，但对该疾病的描述并不完整。基于容积式二氧化碳描记法（VCap），开发了一种用于COPD诊断和分级的指标，旨在作为肺量计的补充或替代方法。
本研究纳入了9名非吸烟者、10名无COPD的吸烟者/既往吸烟者以及54名患有COPD的吸烟者/既往吸烟者。在潮气呼吸期间，使用Exhalyzer D对氮和VCap进行多次呼气末冲洗研究。VCap基于流速和一氧化碳信号，并在氮冲洗前的一次呼吸过程中记录。效率指数（EFFi）是呼出的一氧化碳体积与在等于预测肺总量15%的容积区间内从完全均匀的肺中呼出的假设一氧化碳体积之间的商。
EFFi随着慢性阻塞性肺疾病全球倡议（GOLD）分期的增加而增加，使用健康组的95%置信区间下限，GOLD 2期的大多数受试者以及GOLD 3期和4期的所有受试者均可诊断为患有COPD。EFFi还与氮冲洗（r=-0.73；<0.001）、第1秒用力呼气量（r=0.70；<0.001）和一氧化碳弥散量（r=0.69；<0.001）相关。
EFFi测量了受外周肺功能不均匀性限制的潮气二氧化碳清除效率。EFFi可用于COPD的诊断和分级，并且与第一秒用力呼气容积（FEV）一起，可能解释身体活动受限的原因。EFFi为肺量计提供了一种简单、便捷且经济高效的补充方法，在某些情况下可能作为替代方法。
