'X-rays don't tell lies': the Medical Research Council and the measurement of respiratory disability, 1936-1945

During the first half of the twentieth century, the mining industry in Britain was subject to recurrent disputes about the risk to miners' lungs from coal dust, moderated by governmental, industrial, medical and mining bodies. In this environment, precise measurements offered a way to present uncontested objective knowledge. By accessing primary source material from the National Archives, the South Wales Miners Library and the University of Bristol's Special Collections, I demonstrate the importance that the British Medical Research Council (MRC) attached to standardized instrumental measures as proof of objectivity, and explore the conflict between objective and subjective measures of health. Examination of the MRC's use of spirometry in their investigation of pneumoconiosis (miner's lung) from 1936 to 1945 will shed light on this conflict and illuminate the politics inherent in attempts to quantify disability and categorize standards of health.

Classical experiments in whole-body metabolism: open-circuit respirometry-diluted flow chamber, hood, or facemask systems

For over two centuries, scientists have measured gas exchange in animals and humans and linked this to energy expenditure of the body. The aim of this review is to provide a comprehensive overview of open-circuit diluted flow indirect calorimetry and to help researchers to make the optimal choice for a certain system and its application. A historical perspective shows that 'open circuit diluted flow' is a technique first used in the 19th century and applicable today for room calorimeters, ventilated hood systems, and facemasks. Room calorimeters are a classic example of an open-circuit diluted flow system. The broadly applied ventilated hood calorimeters follow the same principle and can be classified as a derivative of these room calorimeters. The basic principle is that the subject breathes freely in a passing airflow that is fully captured and analyzed. Oxygen and CO2 concentrations are measured in inlet ambient air and captured outlet air. The airflow, which is adapted depending on the application (e.g., rest versus exercise), is measured. For a room indirect calorimeter, the dilution in the large room volume is also taken into account, and this is the most complex application of this type of calorimeter. Validity of the systems can be tested by alcohol burns, gas infusions and by performing repeated measurements on subjects. Using the latter, the smallest CV (%) was found for repeated VO2max tests (1.2%) with an SD of approximately 1 kJ min-1. The smallest SD was found for sleeping metabolic rate (0.11 kJ min-1) with a CV (%) of 2.4%.

Open-circuit respirometry: a historical review of portable gas analysis systems

Scientists such as physiologists, engineers, and nutritionists have often sought to estimate human metabolic strain during daily activities and physical pursuits. The measurement of human metabolism can involve direct calorimetry as well as indirect calorimetry using both closed-circuit respirometry and open-circuit methods that can include diluted flow chambers and laboratory-based gas analysis systems. For field studies, methods involving questionnaires, pedometry, accelerometery, heart rate telemetry, and doubly labelled water exist, yet portable metabolic gas analysis remains the gold standard for most field studies on energy expenditure. This review focuses on research-based portable systems designed to estimate metabolic rate typically under steady-state conditions by critically examining each significant historical innovation. Key developments include Zuntz's 1906 innovative system, then a significant improvement to this purely mechanical system by the widely adopted Kofranyi-Michaelis device in the 1940s. Later, a series of technical improvements: in electronics lead to Wolf's Integrating Motor Pneumotachograph in the 1950s; in polarographic O₂ cells in 1970-1980's allowed on-line oxygen uptake measures; in CO₂ cells in 1990s allowed on-line respiratory exchange ratio determination; and in advanced sensors/computing power at the turn of the century led to the first truly breath-by-breath portable systems. Very recent significant updates to the popular Cosmed and Cortex systems and the potential commercial release of the NASA-developed 'PUMA' system show that technological developments in this niche area are still incrementally advancing.

The history of COPD

The evolution of knowledge concerning COPD and its components--emphysema, chronic bronchitis, and asthmatic bronchitis--covers 200 years. The stethoscope and spirometer became important early tools in diagnosis and assessment. Spirometry remains the most effective means of identification and assessment of the course of COPD and responses to therapy, and is grossly underused for this purpose. Knowledge of the pathogenesis, course and prognosis, and new approaches to therapy have dramatically improved our understanding of this important clinical entity. Smoking cessation improves the early course of disease. Long-term oxygen improves the length and quality of life in selected patients with hypoxemia. Surgery benefits a select few. Today, COPD is a steadily growing global healthcare problem, with increasing morbidity and mortality. Early identification and prevention, and treatment of emerging stages of disease through smoking cessation and a growing number of bronchoactive drugs promises to change the outcome.

Spirometry, measurement, and race in the nineteenth century

Race correction is a common practice in contemporary pulmonary medicine that involves mathematical adjustment of lung capacity measurements in populations designated as "black" using standards derived largely from populations designated as "white." This article traces the history of the racialization and gendering of spirometry through an examination of the ideas and practices related to lung capacity measurements that circulated between Britain and the United States in the nineteenth century. Lung capacity was first conceptualized as a discrete entity of potential use in the diagnosis of pulmonary disease and monitoring of the vitality of the armed forces and other public servants in spirometric studies conducted in mid-nineteenth-century Britain. The spirometer was then imported to the United States and used to measure the capacity of the lungs in a large study of black and white soldiers in the Union Army sponsored by the U.S. Sanitary Commission at the end of the Civil War. Despite contrary findings and contestation by leading black intellectuals, the notion of mean differences between racial groups in the capacity of the lungs became deeply entrenched in the popular and scientific imagination in the nineteenth century, leaving unexamined both the racial categories deployed to organize data and the conditions of life that shape lung function.

John Hutchinson's mysterious machine revisited

John Hutchinson, a surgeon, recognized that the volume of air that can be exhaled from fully inflated lungs is a powerful indicator of longevity. He invented the spirometer to measure what he called the vital capacity, ie, the capacity to live. Much later, the concept of the timed vital capacity, which became known as the FEV(1), was added. Together, these two numbers, vital capacity and FEV(1), are useful in identifying patients at risk of many diseases, including COPD, lung cancer, heart attack, stroke, and all-cause mortality. This article cites some of the rich history of the development of spirometry, and explores some of the barriers to the widespread application of simple spirometry in the offices of primary care physicians.

42 Years Ago ??? Development of the Concepts of Ventilatory and Lactate Threshold

At the Third Pan-American Congress of Sport Physicians in Chicago in 1959 we reported the physiological and clinical significance of the spiroergometric determination of the aerobic-anaerobic turnover point for judging the performance of sick and healthy persons for the first time. In this context a distinction was made between a ventilatory and a lactate-related (arterial blood) method of determination. We called the former method the 'point of optimal ventilatory efficiency (PoW)', and the latter one 'endurance performance limit'. In the 1950s the clinical spiroergometric examination of patients and athletes for the determination of the aerobic performance capacity was consistently based on the measurement of the maximal oxygen uptake. As entering the individual border area of the performance capacity of a patient with, for example, cardiopulmonary disease, can provoke accidents, we started to think about a criterion in connection with submaximal work in 1954. Determination of pyruvate and lactic acid in the venous blood did not prove to be a valid parameter. If the spiroergometric values were entered into a coordinate system the most striking similarities during increasing exercise would become evident between the curve of the minute ventilation and the curve of the arterial lactate. The findings were interpreted as follows: during lower grades of performance the oxygen demand in the working muscle cells was saturated, whereas in the case of increasing exercise intensity an additional anaerobic metabolism was necessary. We termed the maximal work load which was covered nearly completely aerobically as the PoW and designated heart frequency at this point as 'pulse endurance limit'. The determination of the parameter was derived in the coordinate system with a tangent to the curve of the minute ventilation as well as to the curve of the arterial lactate. The results of patients and athletes were first published in 1959.

[The fiftieth anniversary of Miodonski's electro-rhino-spirometry]

On the 50th anniversary of the introduction of the electro-rhino-spirometry by Miodoński the author recalls its theoretical foundations and diagnostic possibilities. Moreover, it has been stressed that Miodoński's method was the first one which does not disturb the nasal function, and the development of electronics supported and widened its diagnostic possibilities leaving the theoretical basis for examination unchanged.

Chronic obstructive pulmonary disease and '150 years of blowing'

Spirometry is now an established and important aspect of investigation of many lung diseases. This article considers the history of spirometry, how we come to use the current indices of dynamic lung function, and the role of spirometry in the management of patients with chronic obstructive pulmonary disease.

[Forced expiration. Various current concepts, 50 years after Robert Tiffeneau]

One hundred and fifty years after the original description of spirometry by Hutchinson and 50 years after the definition of his famous ratio by Tiffeneau, a certain number of physiological advances have enabled a better understanding of the determinants of the forced expired manoeuvre and to mitigate some of its inconveniences. This review focuses on three of these advances. The first is the influence of an inspiratory manoeuvre which precedes a forced expiration, on the expiratory flow. This influence is probably a consequence of viscoelastic phenomena and impose some strains on standardisation in current practice. The second is the possibility of detecting in a reproducible and simple fashion, without the need for co-operation on the part of the subject, a limitation in expiratory flow by the application of a negative expiratory pressure at the opening of the airways (NEP for negative expiratory pressure). The third is the possibility to verify in a simple fashion the quality of the expiratory performance achieved by the patient and thus to detect an insufficient effort in the force of a falling expiratory flow.

Ergospirometry and its history

Ergospirometry is a diagnostic procedure to continuously measure respiration and gas metabolism during ergometer exercise. It enables judgement of function and performance capacity of the cardiopulmonary system and metabolism. Ergospirometry is made up of the 2 components spirometry and ergometry. The first attempts to measure human gas metabolism while performing quantified physical work can be traced back to the year 1790. The development of procedures to measure gas metabolism and respiration as well as the construction of ergometers in the nineteenth and twentieth centuries are described. Ergospirometry and routinely performed clinical performance diagnosis were introduced in 1929, but it was not until the 1950s when the first ergospirometry apparatus which met all scientific requirements was developed. The parameters used and the physiological and pathophysiological findings by ergospirometry are given in an historical frame. Numerous medical fields have profited from the technique of ergospirometry, for example: cardiology, pneumology, sports medicine, exercise physiology, biochemistry, clinical pharmacology, surgery, orthopaedics, paediatrics and gerontology, besides such global disciplines as preventive medicine, exercise therapy and rehabilitative medicine.

[Normal spirometric values in the Chilean population]

Spirometry began to be used by Chilean clinicians after the end of the II World War. Since then and over 50 years foreign standards have been usually used as reference normal values for the Chilean population. According to the current guidelines for spirometry (Chilean Society of Respiratory Diseases, 1988), Knudson et al's values are being used as reference for both children and adults. However, in the last years several studies have shown that Knudson et al's equations underestimate in more than 10% the spirometric values in normal Chilean population. This discrepancy could be explained by ethnical differences. Fortunately, the efforts carried out to obtain reference spirometric values from the Chilean population have yielded linear regression equations for 6 to 70 years old people. The present national reference values should replace the foreign ones. This replacement should have a positive impact in the use of spirometry for evaluating clinical ventilatory limitations as well as for legal disability purposes.

[The history and clinical importance of cardiopulmonary assessment of working fitness with special reference to spiroergometry]

Spiroergometry-a synonym for ergospirometry or ergospirography - is a diagnostic procedure to continuously registrate respiration and gas metabolism during ergometer exercise. It enables to judge function and performance capacity of the cardiopulmonary system and metabolism. Spiroergometry is made up of the two components spirometry and ergometry. The first attempts to measure human gas metabolism while performing a quantified physical work can be traced back to the year 1789. The development of procedures to measure gas metabolism and respiration as well as the construction of ergometers in the 19th and 20th century are described. 1929 saw the introduction of spiroergometry and routinely performed clinical performance diagnosis. But not until the 1950s was the first spiroergometric apparatus which met all scientific requirements developed. In a historical frame, the used parameters and the physiological and pathophysiological findings by spiroergometry are given. Numerous medical fields have profited from the technique of spiroergometry: cardiology, pulmonology, sports medicine, performance physiology, biochemistry, clinical pharmacology, surgery, orthopedics, pediatrics, gerontology, etc. besides such global disciplines as preventive medicine, exercise therapy, and rehabilitative medicine.

[Fifty years of ergospirometry (author's transl)]

With the development of ergospirometry, Knipping and Brauer introduced the diagnosis of performance in 1929. Ergospirometric methods have a certain importance today in research, diagnosis, therapy, rehabilitation, training and sport. Medical special disciplines such as sports medicine, pulmonology, cardiology, occupational medicine, social medicine and physiology of performance and also the fields of biomechanics, clinical pharmacology and biochemistry make use of ergospirometry and owe much new knowledge to it.

The Australian contribution to the history of the pneumoconioses

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