Lung volumes are subdivided into static and dynamic lung volumes. Static lung volumes are measured by methods which are based on the completeness of respiratory manoeuvres, so that the velocity of the manoeuvres should be adjusted accordingly. The measurements taken during fast breathing movements are described as dynamic lung volumes and as forced inspiratory and expiratory flows.

### 1.1 Static lung volumes and capacities

The volume of gas in the lung and intrathoracic airways is determined by the properties of lung parenchyma and surrounding organs and tissues, surface tension, the force exerted by respiratory muscles, by lung reflexes and by the properties of airways. The gas volumes of thorax and lung are the same except in the case of a pneumothorax. If two or more subdivisions of the total lung capacity are taken together, the sum of the constituent volumes is described as a lung capacity. Lung volumes and capacities are described in more detail in § 2.

#### 1.1.1 Determinants

Factors which determine the size of the normal lung include stature, age, sex, body mass, posture, habitus, ethnic group, reflex factors and daily activity pattern. The level of maximal inspiration (total lung capacity, TLC) is influenced by the force developed by the inspiratory muscles (disorders include e.g. muscular dystrophy), the elastic recoil of the lung (disorders include e.g. pulmonary fibrosis and emphysema) and the elastic properties of the thorax and adjacent structures (disorders include e.g. ankylosis of joints). The level of maximal expiration (residual volume, RV) is determined by the force exerted by respiratory muscles (disorders include e.g. muscle paralysis), obstruction, occlusion and compression of small airways (disorders include e.g. emphysema) and by the mechanical properties of lung and thorax (disorders include diffuse fibrosis, kyphoscoliosis).

Assessing the total lung capacity is indispensable in establishing a restrictive ventilatory defect or in diagnosing abnormal lung distensibility, as may occur in patients …

Lung volumes and forced ventilatory flows

ATS/ACCP statement on cardiopulmonary exercise testing.

Excess intra-abdominal adipose tissue accumulation, often termed visceral obesity, is part of a phenotype including dysfunctional subcutaneous adipose tissue expansion and ectopic triglyceride storage closely related to clustering cardiometabolic risk factors. Hypertriglyceridemia; increased free fatty acid availability; adipose tissue release of proinflammatory cytokines; liver insulin resistance and inflammation; increased liver VLDL synthesis and secretion; reduced clearance of triglyceride-rich lipoproteins; presence of small, dense LDL particles; and reduced HDL cholesterol levels are among the many metabolic alterations closely related to this condition. Age, gender, genetics, and ethnicity are broad etiological factors contributing to variation in visceral adipose tissue accumulation. Specific mechanisms responsible for proportionally increased visceral fat storage when facing positive energy balance and weight gain may involve sex hormones, local cortisol production in abdominal adipose tissues, endocannabinoids, growth hormone, and dietary fructose. Physiological characteristics of abdominal adipose tissues such as adipocyte size and number, lipolytic responsiveness, lipid storage capacity, and inflammatory cytokine production are significant correlates and even possible determinants of the increased cardiometabolic risk associated with visceral obesity. Thiazolidinediones, estrogen replacement in postmenopausal women, and testosterone replacement in androgen-deficient men have been shown to favorably modulate body fat distribution and cardiometabolic risk to various degrees. However, some of these therapies must now be considered in the context of their serious side effects. Lifestyle interventions leading to weight loss generally induce preferential mobilization of visceral fat. In clinical practice, measuring waist circumference in addition to the body mass index could be helpful for the identification and management of a subgroup of overweight or obese patients at high cardiometabolic risk.

Pathophysiology of Human Visceral Obesity: An Update

结节病易误诊,据王洪武等~([1])收集国内18篇关于此病误诊的文献,误诊率高达63.2%,当然有误诊就会有误治,如孙永昌等~([2])报道26例结节病在影像学检查诊断的第一印象中拟诊结核5例,其中就有2例完成规范的抗结核治疗,为此应引起临床对本病诊治的重视。

Sarcoidosis

Rationale: Although obesity has been implicated as an asthma risk factor, there is heterogeneity in the published literature regarding its role in asthma incidence, particularly in men.Objectives: To quantify the relationship between categories of body mass index (BMI) and incident asthma in adults and to evaluate the impact of sex on this relationship.Methods: Online bibliographic databases were searched for prospective studies evaluating BMI and incident asthma in adults. Independent observers extracted data regarding annualized asthma incidence from studies meeting predetermined criteria, within defined categories of normal weight (BMI < 25), overweight (BMI, 25–29.9), and obesity (BMI ⩾ 30). Data were analyzed by inverse-variance–weighted, random-effects meta-analysis. Stratified analysis between BMI categories and within sex was performed.Results: Seven studies (n = 333,102 subjects) met inclusion criteria. Compared with normal weight, overweight and obesity (BMI ⩾ 25) conferred increased odds of inc...

http://www.luzimarteixeira.com.br/wp-content/uploads/2009/09/art_beuther_overweight-obesity-and-incident-asthma_meta-an-lise.pdf

Overweight, obesity, and incident asthma: a meta-analysis of prospective epidemiologic studies.

The compliance of the total respiratory system and its components was studied in 24 normal and 12 obese spontaneously breathing unanesthetized subjects. The mean compliance of the total respiratory...

/pdf/compliance-of-the-respiratory-system-and-its-components-in-195be1rupl.pdf

Compliance of the respiratory system and its components in health and obesity.

Respiratory effects of obesity.

https://www.amjmed.com/article/S0002-9343(88)80347-4/pdf

Reuben M. Cherniack

Papers

Compliance of the respiratory system and its components in health and obesity.

Respiratory effects of obesity.

Gas exchange at a given degree of volume restriction is different in sarcoidosis and idiopathic pulmonary fibrosis

The effect of a new carbonic anhydrase inhibitor (dichlorphenamide) in respiratory insufficiency.

Ventilatory function in normal children.