Failure of resistive breathing training to improve pulmonary function tests in patients with chronic obstructive pulmonary disease

The effects on pulmonary function tests and exercise tolerance of resistive breathing training (RBT) were assessed in 16 subjects with stable chronic obstructive pulmonary disease (COPD) who had received no benefit from previous programs of breathing retraining (BR) and medical therapy (MT). 16 male patients with mild degree stable COPD underwent detailed evaluation of pulmonary function tests, blood gas analysis and exercise tolerance test before and after a monthly program of RBT. The patients had received no physiological effects from previous monthly programs of BR and MT. No change in pulmonary function tests, blood gas analysis and exercise tolerance test was observed after RBT. Only maximal static expiratory pressure increased significantly after RBT. We conclude that RBT does not improve pulmonary function tests in subjects who received no physiological benefit from BR.     

Normal expiratory flow rate and lung volumes in patients with combined emphysema and interstitial lung disease: a case series and literature review

Pulmonary function tests in patients with idiopathic pulmonary fibrosis characteristically show a restrictive pattern including small lung volumes and increased expiratory flow rates resulting from a reduction in pulmonary compliance due to diffuse fibrosis. Conversely, an obstructive pattern with hyperinflation results in emphysema by loss of elastic recoil, expiratory collapse of the peripheral airways and air trapping. When the diseases coexist, pulmonary volumes are compensated, and a smaller than expected reduction or even normal lung volumes can be found. The present report describes 10 patients with progressive breathlessness, three of whom experienced severe limitation in their quality of life. All patients showed lung interstitial involvement and emphysema on computed tomography scan of the chest. The 10 patients showed normal spirometry and lung volumes with severe compromise of gas exchange. Normal lung volumes do not exclude diagnosis of idiopathic pulmonary fibrosis in patients with concomitant emphysema. The relatively preserved lung volumes may underestimate the severity of idiopathic pulmonary fibrosis and attenuate its effects on lung function parameters.     

慢性阻塞性肺疾病病患的认知功能探讨

目的评估慢性阻塞性肺疾病(慢阻肺)病患的认知功能状态,以及与临床资料的相关性。方法从2014年10月-2018年12月,160例符合标准的受试者入组;认知评估使用蒙特利尔(MoCA)量表,获取临床资料并完成相关性分析。结果约46%的慢阻肺病患存在认知功能障碍。四组受试者的MOCA总分为:健康对照组26.47±1.31、慢阻肺病患轻度组24.77±2.61、中度组22.39±3.64、重度组21.92±2.65;相比对照组,慢阻肺受试者的认知得分降低(p<0.05),表现在注意、定向、抽象思维、延迟记忆、视空间与执行功能。组间比较亦有统计学差异;同时慢阻肺受试者的MoCA总分和肺功能中FEV 1有正相关(r=0.377,P<0.001),与血气分析中PaO 2有正相关性(r=0.295,P<0.05),与PaCO 2无相关性(r=0.059,P>0.05)。结论慢阻肺病患存在特定的认知障碍。低氧血症、肺功能中的FEV 1降低可能是造成慢阻肺认知障碍的病理生理学机制。     

Cardiovascular autonomic neuropathy in chronic obstructive pulmonary disease

BACKGROUND: While autonomic neuropathy has been reported in chronically hypoxaemic patients of chronic obstructive pulmonary disease (COPD), whether it also occurs in patients with milder disease and in those without chronic hypoxaemia has not been explored. METHODOLOGY: Lung function measurements including spirometry and transfer factor for carbon monoxide, mean pulmonary artery pressure estimation by color-doppler echocardiography and arterial blood gas analysis were carried out in 56 patients with COPD and 11 age-matched controls. Autonomic function was assessed by tests of cardiovascular reflexes and expressed as valsalva ratio, 30:15 ratio, IE difference and the blood pressure response to postural change. RESULTS: Among patients, majority of the test responses were in the abnormal or borderline range compared to more than 90% of test responses in the normal or borderline range among normals. Almost 50% of patients had definite neuropathy as compared to none in normals. Although, the autonomic neuropathy tended to be observed more often in patients with moderate and severe COPD, it was also found in a fair proportion of patients with mild COPD. Similarly, while it was more prevalent in patients with hypoxaemia, it was also found to occur in those without hypoxaemia. The responses to tests of autonomic function had weak relationships with FEV1% predicted and PaO2. CONCLUSIONS: Cardiovascular autonomic neuropathy is common in COPD and is found even in early stages of the disease.     

The role of concomitant respiratory diseases on the rate of decline in FEV1 among adult asthmatics.

Several recent reports have presented evidence suggesting that adults with asthma have an accelerated rate of decline in pulmonary function compared with nonasthmatics. However, most of these studies have not taken into account the possible effect of comorbid lung disease in addition to asthma. This study was designed to determine if comorbid respiratory diseases modify or otherwise change the estimates of decline in forced expiratory volume in one second (FEV1). Study subjects were White, non-Mexican, American participants, who were > or = 20 yrs of age at the initial survey and had at least one pulmonary function testing. Respiratory disease status, based on self-reported questionnaires and pulmonary function tests, were assessed during 12 surveys spanning a period of up to 20 yrs. There were 2,926 subjects who met the inclusion criteria, 214 (7.3%) had physician-confirmed asthma, 325 (11.1%) chronic obstructive pulmonary disease (COPD), and 125 (4.3%) both physician-confirmed asthma and COPD. Longitudinal analysis revealed that among those with longstanding asthma, FEV1 values were low but did not decline at a more rapid rate than normal. Likewise, subjects with both asthma and COPD had the lowest levels of FEV1, but also a rate of decline that was not significantly increased. Only those with COPD in the absence of asthma experienced both a low initial FEV1 level and a significantly steeper rate of decline. Based on these findings, the authors conclude that forced expiratory volume in one second does not decline more rapidly in asthmatics or in those with asthma and chronic obstructive pulmonary disease, compared with nonasthmatics.     

百令胶囊对慢性阻塞性肺病患者的影响

目的观察百令胶囊对COPD患者肺功能、血气和C反应蛋白的影响。方法选择101例住院的轻中度COPD患者,分为治疗组与对照组,进行第一秒用力呼气容积(FEV1)、用力肺活量(FVC)、血气、C反应蛋白检测;对照组常规予以抗炎、平喘、祛痰对症治疗,治疗组在此基础上加服百令胶囊,分别在入院时、出院时、12周后重复上述检查。结果治疗组与对照组比较差异显著(P0.05)。结论 COPD患者服用百令胶囊可改善肺功能,缓解病情,提高生活质量。     

Chronic obstructive pulmonary disease, with and without alpha-1-antitrypsin deficiency: management practices in the U.K.

Alpha-1-antitrypsin deficiency is a common genetic defect associated with the development of severe and rapidly progressive lung disease. This study was undertaken to determine whether respiratory physicians manage patients with alpha-1-antitrypsin (AAT) deficiency differently from patients with chronic obstructive pulmonary disease (COPD) without alpha-1-antitrypsin deficiency. In addition we obtained physicians' views on who should be tested for AAT deficiency. A questionnaire was administered to 88 respiratory physicians based throughout the U.K. (44 in teaching hospitals). The main outcome measures were pulmonary function tests, radiological assessment, frequency of repeat testing, follow-up and screening protocol for alpha-1-antitrypsin deficiency. Subjects with homozygous (PiZ) AAT deficiency were more likely to: 1. have baseline and full pulmonary function testing including dynamic flow rates, static lung volumes, and gas transfer; 2. have more comprehensive assessment with high resolution computed tomography (HRCT) thorax and repeated radiological assessment (with annual chest radiography); 3. be followed-up routinely; and 4. have family members tested for alpha-1-antitrypsin deficiency. Testing remains limited for AAT deficiency and is mainly restricted to young patients with COPD. COPD assessment and management is influenced by the presence of AAT deficiency, which may reflect the poorer prognosis of such patients due to more rapid decline. Assessment and monitoring could be simplified to forced expired manoeuvres, although limited HRCT thorax and tests of gas transfer may prove more sensitive to progression of emphysema. Testing for AAT deficiency in the U.K. remains restricted, which will influence the detection rate for AAT deficiency. A wider policy of testing was advocated by the WHO will detect more patients and also influence our understanding of the natural history of the condition.     

Pharmacological treatment of chronic obstructive pulmonary disease

None of the drugs currently available for chronic obstructive pulmonary disease (COPD) are able to reduce the progressive decline in lung function which is the hallmark of this disease. Smoking cessation is the only intervention that has proved effective. The current pharmacological treatment of COPD is symptomatic and is mainly based on bronchodilators, such as selective β₂-adrenergic agonists (short- and long-acting), anticholinergics, theophylline, or a combination of these drugs. Glucocorticoids are not generally recommended for patients with stable mild to moderate COPD due to their lack of efficacy, side effects, and high costs. However, glucocorticoids are recommended for severe COPD and frequent exacerbations of COPD. New pharmacological strategies for COPD need to be developed because the current treatment is inadequate.     

老年慢性阻塞性肺疾病与继发性骨质疏松症的关系探讨

目的 观察老年慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)患者骨密度(BMD)、肺功能和血气分析的变化,探讨老年COPD与继发性骨质疏松症的关系.方法 用双能X线吸收测定仪测定32例老年男性COPD患者腰椎(L_(1-4))、股骨近端[颈部(Neck)、大粗隆(Troch)、合计(Total)]BMD,同时用肺功能仪测定肺功能,血气分析仪测量动脉血气分析,以及生化、血钙等检查.结果 COPD组的BMD值与对照组相比显著降低(P<0.001),COPD患者BMD与第1秒用力呼气容积占预计百分比呈显著正相关(P<0.001).结论 老年COPD组BMD低于对照组.COPD是继发性骨质疏松症的患病因素之一.老年COPD患者BMD检查能及早发现骨质疏松.低氧血症可能是老年COPD患者合并骨质疏松症的主要危险因素.     

轻度二氧化碳潴留慢性阻塞性肺疾病肺功能和CT的特征

目的探讨轻度CO₂潴留慢性阻塞性肺疾病人群的肺功及影像特征,为监测和治疗提供依据。 方法选择147例慢性阻塞性肺疾病急性加重期患者,分为非CO₂潴留组61例PaCO₂＝40～44.9 mmHg;轻度CO₂潴留组48例PaCO₂＝45～50 mmHg;呼吸衰竭组38例PaCO₂>50 mmHg,比较3组在肺功能和容积CT参数的异同。 结果轻度潴留组在肺功能参数如一秒率(FEV₁%pred)等和肺气肿参数如肺气肿平均密度(MED)、肺密度分布直方图中第15百分位点所对应的CT值(PD15)等,与呼吸衰竭组存在明显差异(P<0.05),与非潴留组无统计学差异(P>0.05)。spearman相关分析显示PaCO₂与FEV₁%Pred、FVC%pred呈中度负相关(r分别是-0.536,-0.576,P<0.001),与PD15和MED存在弱负相关(r＝-0.325,P＝0.002)。 结论轻度CO₂潴留COPD肺结构和功能特征与非潴留COPD相似;呼吸衰竭组COPD具有更严重的病理和肺功能损害;CO₂轻度潴留向Ⅱ型呼吸衰竭进展中,FEV₁%pred等肺功能指标联合PD15和MED影像参数从功能和结构上能更好地反应病情。     

慢性阻塞性肺疾病患者血浆醛固酮的表达特征

目的探讨慢性阻塞性肺疾病(COPD)患者血浆醛固酮的表达特征。方法根据肺功能损害程度将90例COPD患者分为轻中度组(36例)及重度极重度组(54例);再根据病情将COPD患者分为单纯COPD组(33例),肺心病组(57例),同时和29例健康者采用放射免疫分析法进行醛固酮水平的检测,并进行肺功能检查及血气分析检测。结果肺心病组患者醛固酮水平显著高于单纯COPD组及对照组(P0.05);重度极重度COPD组的醛固酮较轻中度组升高(P0.05);血浆醛固酮与动脉血氧分压呈负相关(r=-0.460,P=0.00)。结论醛固酮在COPD患者中有异常表达,与肺心病存在一定的相关性。     

The evaluation of dyspnea and quality of life in COPD

Dyspnea defined as an uncomfortable sensation of breathing is the main cause of disability in chronic obstructive pulmonary disease (COPD) patients. There is evidence that the underlying mechanisms of dyspnea are multifactorial. The aim of this study was to investigate these mechanisms causing dyspnea in COPD patients and the relationship between functional parameters, dyspnea scales and quality of life questionnaire. For this purpose 56 patients (11 female, 45 male) were recruited. Pulmonary function tests including airflow rates, lung volumes, maximal respiratory muscle forces, diffusing capacity, breathing pattern, arterial blood gas analyses as well as dyspnea scales MRC, baseline dyspnea index (BDI) and The Saint George Respiratory Questionnaire (SGRQ) were performed. The overall group showed moderate obstructive disease (FEV1%= 59.02 +/- 3.30) and mild hypoxemia with some air trapping (RV/TLC%= 52.00 +/- 2.00). MRC scale did not show any significant correlation with pulmonary function parameters. There was significant positive correlation between BDI and airflow rates, PImax, DLCO and air trapping. Breathing pattern parameters (Ti/Ttot, VT/Ti) also correlated with BDI. There was positive correlation between PaO2 and BDI (p< 0.001). SGRQ scores correlated significantly with FEV1, PImax, RV/TLC and P 0.1. There was also strong correlation between BDI and SGRQ scores. In conclusion, dyspnea is the result of multiple factors such as airflow limitation, decreased respiratory muscle strength, changes breathing pattern, hypoxemia, and air trapping which in turn affects quality of life in patients with COPD.     

Fractalkine与慢性阻塞性肺疾病并肺源性心脏病患者氧化应激相关性及机制探讨

目的探讨Fractalkine(FKN)与慢性阻塞性肺疾病(COPD)并肺源性心脏病(简称肺心病)患者氧化应激状态的相关性及可能机制。方法 64例AECOPD住院患者按是否合并肺心病、是否使用乙酰半胱氨酸(NAC)、COPD严重程度以及心功能分为8组,8例志愿者为正常对照组,测定各组患者住院次日、治疗后第10天血清各项指标,并检查心脏彩超、肺功能、CAT评分。结果血清FKN、NF-κB、OX-LDL及hs CRP水平在AECOPD的各组患者中均较正常对照组升高(P0.05),重症组及失代偿组升高明显(P0.05),肺心病组治疗前及治疗后均高于COPD组(P0.05),在COPD轻症干预组及肺心病代偿干预组治疗后下降明显(P0.05),SOD则相反。FEV1在肺心病代偿干预组及COPD轻症干预组治疗后较治疗前升高(P0.05)。肺动脉压在肺心病代偿干预组治疗前后有显著差异(P0.05),肺心病失代偿组较代偿组明显升高(P0.05),肺心病组与COPD组比较有显著差异(P0.05)。CAT评分除在肺心病失代偿组外其它各组治疗前后均有显著差异(P0.05),肺心病组与COPD组比较有统计学差异(P0.05)。治疗前8组患者血清FKN与CAT评分及NF-κB、OX-LDL、hs CRP、肺动脉压呈正相关(r=0.417,0.521,0.401,0.456,0.395,P0.05),与SOD负相关(r=-0.387,P0.05),与FEV1无明显相关性(r=0.215,P0.05)。结论 COPD并肺源性心脏病存在的氧化应激,与FKN密切相关,其机制可能系COPD持续低氧引起的氧化应激产物增多,激活NF-κB而促进FKN的生成和释放,NAC可能通过NF-κB途径降低FKN的生成,对早期肺心病的预防有一定作用。     

Pulmonary vasculature in COPD: The silent component

Chronic obstructive pulmonary disease (COPD) is characterized by airflow obstruction that results from an inflammatory process affecting the airways and lung parenchyma. Despite major abnormalities taking place in bronchial and alveolar structures, changes in pulmonary vessels also represent an important component of the disease. Alterations in vessel structure are highly prevalent and abnormalities in their function impair gas exchange and may result in pulmonary hypertension (PH), an important complication of the disease associated with reduced survival and worse clinical course. The prevalence of PH is high in COPD, particularly in advanced stages, although it remains of mild to moderate severity in the majority of cases. Endothelial dysfunction, with imbalance between vasodilator/vasoconstrictive mediators, is a key determinant of changes taking place in pulmonary vasculature in COPD. Cigarette smoke products may perturb endothelial cells and play a critical role in initiating vascular changes. The concurrence of inflammation, hypoxia and emphysema further contributes to vascular damage and to the development of PH. The use of drugs that target endothelium‐dependent signalling pathways, currently employed in pulmonary arterial hypertension, is discouraged in COPD due to the lack of efficacy observed in randomized clinical trials and because there is compelling evidence indicating that these drugs may worsen pulmonary gas exchange. The subgroup of patients with severe PH should be ideally managed in centres with expertise in both PH and chronic lung diseases because alterations of pulmonary vasculature might resemble those observed in pulmonary arterial hypertension. Because this condition entails poor prognosis, it warrants specialist treatment.     

What Predicts Change in Pulmonary Function and Quality of Life in Asthma or COPD?

Information about predictors of decline in pulmonary function (forced expiratory volume in 1 second [FEV₁]) or health-related quality of life (HRQoL) in patients with asthma or (chronic obstructive pulmonary disease [COPD]) might help to determine those who need additional care. A 2-year prospective cohort study was conducted among 380 asthma and 120 COPD patients. In both asthma and COPD patients, a 2-year change in FEV₁ was only weakly associated with a 2-year change in HRQoL (r = .0.19 and 0.24, respectively). In both groups, older age, living in an urban environment, and a lower peak expiratory flow rate (PEFR) at baseline were associated with a decline in FEV₁. Additional predictors of FEV₁ decline were greater body weight, less chronic cough or sputum production, and less respiratory symptoms in asthma patients and current smoking in COPD patients. A decline in HRQoL was associated with older age, non-compliance with medication, more dyspnea, and a lower PEFR in asthma patients and with male gender, lower education, lower body weight, more dyspnea, and more respiratory symptoms in COPD patients. Our results show that FEV₁ and HRQoL appear to represent different disease aspects influenced by different predictors.     

Physiological impairment in mild COPD

Chronic obstructive pulmonary disease (COPD) is a common and often progressive inflammatory disease of the airways, alveoli and microvasculature that is both preventable and treatable. It is well established that smokers with mild airway obstruction, as spirometrically defined, represent the vast majority of patients with COPD, yet this population has not been extensively studied. An insidious preclinical course means that mild COPD is both underdiagnosed and undertreated. In this context, recent studies have confirmed that even patients with mild COPD can have extensive physiological impairment, which contributes to poor perceived health status compared with non‐smoking healthy controls. This review describes the heterogeneous pathophysiology that can exist in COPD patients with only mild airway obstruction on spirometry. It exposes the compensatory adaptations that develop in such patients to ensure that the respiratory system fulfils its primary task of maintaining adequate pulmonary gas exchange for the prevailing metabolic demand. It demonstrates that adaptations such as increased inspiratory neural drive to the diaphragm due to combined effects of increased mechanical loading and chemostimulation underscore the increased dyspnoea and exercise intolerance in this population. Finally, based on available evidence, we present what we believe is a sound physiological rationale for earlier diagnosis in this population.     

Effects of pursed-lip breathing and forward trunk lean postures on total and compartmental lung volumes and ventilation in patients with mild to moderate chronic obstructive pulmonary disease: An observational study

This study identified the effects of pursed-lip breathing (PLB), forward trunk lean posture (FTLP), and combined PLB and FTLP on total and compartmental lung volumes, and ventilation in patients with chronic obstructive pulmonary disease (COPD). Sixteen patients with mild to moderate COPD performed 2 breathing patterns of quiet breathing (QB) and PLB during FTLP and upright posture (UP). The total and compartmental lung volumes and ventilation of these 4 tasks (QB-UP, PLB-UP, QB-FTLP, PLB-FTLP) were evaluated using optoelectronic plethysmography. Two-way repeated measures ANOVA was used to identify the effect of PLB, FTLP, and combined strategies on total and compartmental lung volumes and ventilation. End-expiratory lung volume of ribcage compartment was significantly lower in PLB-UP than QB-UP and those with FTLP (P < .05). End-inspiratory lung volume (EILV) and end-inspiratory lung volume of ribcage compartment were significantly greater during PLB-FTLP and PLB-UP than those of QB (P < .05). PLB significantly and positively changed end-expiratory lung volume of abdominal compartment (EELV_AB ) end-expiratory lung volume, EILV_AB, tidal volume of pulmonary ribcage, tidal volume of abdomen, and ventilation than QB (P < .05). UP significantly increased tidal volume of pulmonary ribcage, tidal volume of abdomen, and ventilation and decreased EELV_AB, end-expiratory lung volume, and EILV_AB than FTLP (P < .05). In conclusion, combined PLB with UP or FTLP demonstrates a positive change in total and compartmental lung volumes in patients with mild to moderate COPD.     

烟草烟雾诱导的慢性阻塞性肺疾病模型大鼠消化道的病理特点

目的观察慢性阻塞性肺疾病(COPD)模型大鼠消化道的病理改变,为探究COPD营养不良的机制提供理论依据。方法采用单纯烟草烟雾暴露的方法建立COPD大鼠模型。造模结束后,检查大鼠肺功能、动脉血气、支气管肺泡灌洗液炎症细胞和炎症介质水平以及肺组织、肝、脾、胃、小肠的病理变化。结果与正常对照组大鼠相比,模型组大鼠体质量明显减轻;功能残气量、肺总量上升,静态肺顺应性增加,呼气流速50毫秒用力呼气量/用力肺活量比值下降;肺泡结构大小不一、部分肺泡间隔断裂、融合;支气管肺泡灌洗液中,炎症细胞总数及分类计数(中性粒细胞、巨噬细胞及淋巴细胞)均高于对照组,促炎介质白细胞介素-6(IL-6)和单核细胞趋化蛋白1水平高于对照组,而抗炎介质IL-10低于对照组;肝小叶中央静脉充血伴炎症细胞浸润,肝细胞轻度水肿、脾出现淤血、胃出现轻度糜烂、小肠黏膜萎缩伴炎症细胞浸润。结论在COPD大鼠模型中,肝、脾、胃黏膜、小肠黏膜等消化道组织均出现充血、水肿、淤血、糜烂、炎症细胞浸润等炎症性病理改变,这些病变可能与COPD营养不良有关。     

Pulmonary hypertension in chronic obstructive pulmonary disease.

Pulmonary hypertension is a common complication of chronic obstructive pulmonary disease (COPD). Its presence is associated with shorter survival and worse clinical evolution. In COPD, pulmonary hypertension tends to be of moderate severity and progresses slowly. However, transitory increases of pulmonary artery pressure may occur during exacerbations, exercise and sleep. Right ventricular function is only mildly impaired with preservation of the cardiac output. Structural and functional changes of pulmonary circulation are apparent at the initial stages of COPD. Recent investigations have shown endothelial dysfunction and changes in the expression of endothelium-derived mediators that regulate vascular tone and cell growth in the pulmonary arteries of patients with mild disease. Some of these changes are also present in smokers with normal lung function. Accordingly, it has been postulated that the initial event in the natural history of pulmonary hypertension in COPD could be the lesion of pulmonary endothelium by cigarette-smoke products. Long-term oxygen administration is the only treatment that slows down the progression of pulmonary hypertension in chronic obstructive pulmonary disease. Nevertheless, with this treatment pulmonary artery pressure rarely returns to normal values and the structural abnormalities of pulmonary vessels remain unaltered. Vasodilators are not recommended on the basis of their minimal clinical efficacy and because they impair pulmonary gas exchange. Recognition of the role of endothelial dysfunction in the physiopathology of pulmonary hypertension in chronic obstructive pulmonary disease opens new perspectives for the treatment of this complication.     

Informative value of simple multibreath nitrogen washout measurements for clinical and research purposes

Some simple multibreath nitrogen washout indexes quantifying inspired gas distribution and ventilatory efficiency were obtained in a group of patients with mild to advanced chronic obstructive pulmonary disease (COPD) and studied in their relationships with routine pulmonary function tests. The indexes (lung clearance index (LCI), mixing ratio (MR) and data obtained by graphic analysis of the washout curve) were correlated with spirometric, pulmonary mechanics and arterial blood gas measurements, but only 8-38% of the interindividual variation in these indexes was explained by the above routine tests. An additional 5-13% of the variation was explained by the washout tidal volume (VT); this finding may reflect changes in gas distribution with VT and/or the influence of the dead space on ventilatory efficiency. Our data indicate that, in patients with COPD, nitrogen washout indexes tend to change in parallel with routine pulmonary function tests, reflecting the severity of the disease; these indexes also contain specific information (in addition to that provided by routine physiologic tests), presumably related to the distribution and efficiency of ventilation. Nitrogen washout measurements may thus represent a helpful adjunct to routine pulmonary function testing; LCI and MR appear to be particularly convenient for practical purposes because of their simplicity, and an informative content comparable with that of more complex indexes.