RESUMO
Significance: This year, 2024, marks the 50th anniversary of the invention of pulse oximetry (PO), which was first presented by Takuo Aoyagi, an engineer from the Nihon Kohden Company, at the 13th Conference of the Japanese Society of Medical Electronics and Biological Engineering in Osaka in 1974. His discovery and the development of PO for the non-invasive measurement of peripheral arterial oxygenation represents one of the most significant chapters in the history of medical technology. It resulted from research and development efforts conducted by biochemists, engineers, physicists, physiologists, and physicians since the 1930s. Aim: The objective of this work was to provide a narrative review of the history, current status, and future prospects of PO. Approach: A comprehensive review of the literature on oximetry and PO was conducted. Results and Conclusions: Our historical review examines the development of oximetry in general and PO in particular, tracing the key stages of a long and fascinating story that has unfolded from the first half of the twentieth century to the present day-an exciting journey in which serendipity has intersected with the hard work of key pioneers. This work has been made possible by the contributions of numerous key pioneers, including Kurt Kramer, Karl Matthes, Glenn Millikan, Evgenii M. Kreps, Earl H. Wood, Robert F. Show, Scott A. Wilber, William New, and, above all, Takuo Aoyagi. PO has become an integral part of modern medical care and has proven to be an important tool for physiological monitoring. The COVID-19 pandemic not only highlighted the clinical utility of PO but also revealed some of the problems with the technology. Current research in biomedical optics should address these issues to make the technology even more reliable and accurate. We discuss the necessary innovations in PO and present our thoughts on what the next generation of PO might look like.
Assuntos
Oximetria , Oximetria/história , Oximetria/métodos , História do Século XX , História do Século XXI , Humanos , Oxigênio/sangue , Oxigênio/históriaRESUMO
The initial rise of molecular oxygen (O2) shortly after the Archaean-Proterozoic transition 2.5 billion years ago was more complex than the single step-change once envisioned. Sulfur mass-independent fractionation records suggest that the rise of atmospheric O2 was oscillatory, with multiple returns to an anoxic state until perhaps 2.2 billion years ago1-3. Yet few constraints exist for contemporaneous marine oxygenation dynamics, precluding a holistic understanding of planetary oxygenation. Here we report thallium (Tl) isotope ratio and redox-sensitive element data for marine shales from the Transvaal Supergroup, South Africa. Synchronous with sulfur isotope evidence of atmospheric oxygenation in the same shales3, we found lower authigenic 205Tl/203Tl ratios indicative of widespread manganese oxide burial on an oxygenated seafloor and higher redox-sensitive element abundances consistent with expanded oxygenated waters. Both signatures disappear when the sulfur isotope data indicate a brief return to an anoxic atmospheric state. Our data connect recently identified atmospheric O2 dynamics on early Earth with the marine realm, marking an important turning point in Earth's redox history away from heterogeneous and highly localized 'oasis'-style oxygenation.
Assuntos
Atmosfera , Planeta Terra , Oxigênio , Água do Mar , Atmosfera/química , Sedimentos Geológicos/química , História Antiga , Oceanos e Mares , Oxirredução , Oxigênio/análise , Oxigênio/história , Oxigênio/metabolismo , Água do Mar/química , África do Sul , Isótopos de Enxofre/análise , Tálio/análise , Tálio/químicaRESUMO
The oxygen content of the oceans is susceptible to climate change and has declined in recent decades1, with the largest effect in oxygen-deficient zones (ODZs)2, that is, mid-depth ocean regions with oxygen concentrations <5 µmol kg-1 (ref. 3). Earth-system-model simulations of climate warming predict that ODZs will expand until at least 2100. The response on timescales of hundreds to thousands of years, however, remains uncertain3-5. Here we investigate changes in the response of ocean oxygenation during the warmer-than-present Miocene Climatic Optimum (MCO; 17.0-14.8 million years ago (Ma)). Our planktic foraminifera I/Ca and δ15N data, palaeoceanographic proxies sensitive to ODZ extent and intensity, indicate that dissolved-oxygen concentrations in the eastern tropical Pacific (ETP) exceeded 100 µmol kg-1 during the MCO. Paired Mg/Ca-derived temperature data suggest that an ODZ developed in response to an increased west-to-east temperature gradient and shoaling of the ETP thermocline. Our records align with model simulations of data from recent decades to centuries6,7, suggesting that weaker equatorial Pacific trade winds during warm periods may lead to decreased upwelling in the ETP, causing equatorial productivity and subsurface oxygen demand to be less concentrated in the east. These findings shed light on how warm-climate states such as during the MCO may affect ocean oxygenation. If the MCO is considered as a possible analogue for future warming, our findings seem to support models suggesting that the recent deoxygenation trend and expansion of the ETP ODZ may eventually reverse3,4.
Assuntos
Oxigênio , Água do Mar , Clima Tropical , Mudança Climática/história , Mudança Climática/estatística & dados numéricos , Oxigênio/análise , Oxigênio/história , Oceano Pacífico , Água do Mar/química , História Antiga , História do Século XXI , Modelos Climáticos , Foraminíferos/isolamento & purificação , Mapeamento Geográfico , IncertezaRESUMO
Phosphorus is a limiting nutrient that is thought to control oceanic oxygen levels to a large extent1-3. A possible increase in marine phosphorus concentrations during the Ediacaran Period (about 635-539 million years ago) has been proposed as a driver for increasing oxygen levels4-6. However, little is known about the nature and evolution of phosphorus cycling during this time4. Here we use carbonate-associated phosphate (CAP) from six globally distributed sections to reconstruct oceanic phosphorus concentrations during a large negative carbon-isotope excursion-the Shuram excursion (SE)-which co-occurred with global oceanic oxygenation7-9. Our data suggest pulsed increases in oceanic phosphorus concentrations during the falling and rising limbs of the SE. Using a quantitative biogeochemical model, we propose that this observation could be explained by carbon dioxide and phosphorus release from marine organic-matter oxidation primarily by sulfate, with further phosphorus release from carbon-dioxide-driven weathering on land. Collectively, this may have resulted in elevated organic-pyrite burial and ocean oxygenation. Our CAP data also seem to suggest equivalent oceanic phosphorus concentrations under maximum and minimum extents of ocean anoxia across the SE. This observation may reflect decoupled phosphorus and ocean anoxia cycles, as opposed to their coupled nature in the modern ocean. Our findings point to external stimuli such as sulfate weathering rather than internal oceanic phosphorus-oxygen cycling alone as a possible control on oceanic oxygenation in the Ediacaran. In turn, this may help explain the prolonged rise of atmospheric oxygen levels.
Assuntos
Oceanos e Mares , Fósforo , Água do Mar , Atmosfera/química , Dióxido de Carbono/metabolismo , Isótopos de Carbono , Sedimentos Geológicos/química , História Antiga , Hipóxia/metabolismo , Oxigênio/análise , Oxigênio/história , Oxigênio/metabolismo , Fósforo/análise , Fósforo/história , Fósforo/metabolismo , Água do Mar/química , Sulfatos/metabolismo , Carbonatos/análise , Carbonatos/metabolismo , OxirreduçãoRESUMO
The discovery of oxygen and pulmonary gas exchange was a major advancement in our understanding of breathing. For centuries it was believed that the lungs were primarily necessary to cool the heart or to "refine" the blood. Richard Lower (1631-1691) observed that the blood had a different colour before and after passage through the lung. His assumption was that breathing must have been added a special substance to the blood. Georg Ernst Stahl (1660-1734) formulated a fire substance "phlogiston" (phloxâ=âflame) with his phlogiston theory. He postulated that phlogiston is contained in all combustible substances and escapes when burned. John Mayow (1641-1679) recognised that about one fifth of the breathing gas is important for the breathing process. He called the gas "spiritus nitro aerius". Oxygen was first discovered in the early 1770âs by the Swedish-German pharmacist Carl Wilhelm Scheele (1742-1786) and the English chemist Joseph Priestley (1733-1804) - independently of each other. Antoine-Laurent Lavoisier (1743-1794) recognised oxygen as element and for the first time described the oxidation process accurately.
Assuntos
Oxigênio , Troca Gasosa Pulmonar , Humanos , Oxigênio/história , Respiração , SuéciaRESUMO
The rise of atmospheric oxygen fundamentally changed the chemistry of surficial environments and the nature of Earth's habitability1. Early atmospheric oxygenation occurred over a protracted period of extreme climatic instability marked by multiple global glaciations2,3, with the initial rise of oxygen concentration to above 10-5 of the present atmospheric level constrained to about 2.43 billion years ago4,5. Subsequent fluctuations in atmospheric oxygen levels have, however, been reported to have occurred until about 2.32 billion years ago4, which represents the estimated timing of irreversible oxygenation of the atmosphere6,7. Here we report a high-resolution reconstruction of atmospheric and local oceanic redox conditions across the final two glaciations of the early Palaeoproterozoic era, as documented by marine sediments from the Transvaal Supergroup, South Africa. Using multiple sulfur isotope and iron-sulfur-carbon systematics, we demonstrate continued oscillations in atmospheric oxygen levels after about 2.32 billion years ago that are linked to major perturbations in ocean redox chemistry and climate. Oxygen levels thus fluctuated across the threshold of 10-5 of the present atmospheric level for about 200 million years, with permanent atmospheric oxygenation finally arriving with the Lomagundi carbon isotope excursion at about 2.22 billion years ago, some 100 million years later than currently estimated.
Assuntos
Atmosfera/química , Oxigênio/análise , Oxigênio/história , Isótopos de Carbono/análise , Carbonatos/análise , Clima , Ecossistema , Sedimentos Geológicos/química , História Antiga , Oceanos e Mares , Oxirredução , Água do Mar/química , África do Sul , Isótopos de Enxofre/análise , Fatores de TempoRESUMO
Robert John Porra (7.8.1931-16.5.2019) is probably best known for his substantial practical contributions to plant physiology and photosynthesis by addressing the problems of both the accurate spectroscopic estimation and the extractability of chlorophylls in many organisms. Physiological data and global productivity estimates, in particular of marine primary productivity, are often quoted on a chlorophyll basis. He also made his impact by work on all stages of tetrapyrrole biosynthesis: he proved the C5 pathway to chlorophylls, detected an alternative route to protoporphyrin in anaerobes and the different origin of the oxygen atoms in anaerobes and aerobes. A brief review of his work is supplemented by personal memories of the authors.
Assuntos
Clorofila/metabolismo , Fotossíntese , Fenômenos Fisiológicos Vegetais , Tetrapirróis/biossíntese , Austrália , Clorofila/história , História do Século XX , História do Século XXI , Humanos , Masculino , Oxigênio/história , Oxigênio/metabolismo , Tetrapirróis/históriaRESUMO
In his Tractatus Quinque Medico-Physici of 1674, John Mayow wrote that a fifth of atmospheric air is comprised of nitro-aerial spirit. That so-called spirit participates in both respiration and combustion. The etymology of "nitro-aerial spirit" stems from a mineral long called niter and now specified as potassium nitrate. Niter mixed with sulfur and carbon is gunpowder, developed in the ninth century in China. Mayow appreciated that niter was the oxidant in the energy-yielding reaction of gunpowder. The word "oxygen," eventually prompting the word oxidant, was coined a century later by Antoine Lavoisier.
Assuntos
Nitrogênio/história , Oxigênio/história , Terminologia como Assunto , História do Século XVIIRESUMO
Oxygen is the most commonly used drug in critical care. However, because it is a gas, most clinicians and most patients do not regard it as a drug. For this reason, the use of medical oxygen over the past century has been driven by custom, practice, and "precautionary principles" rather than by scientific principles. Oxygen is a life-saving drug for patients with severe hypoxemia, but, as with all other drugs, too much can be harmful. It has been known for many decades that the administration of supplemental oxygen is hazardous for some patients with COPD and other patients who are vulnerable to retention of carbon dioxide (ie, hypercapnia). It has been recognized more recently that excessive oxygen therapy is associated with significantly increased mortality in critically ill patients, even in the absence of risk factors for hypercapnia. This paper provides a critical overview of past and present oxygen use for critically ill patients and will provide guidance for safer oxygen use in the future.
Assuntos
Estado Terminal/terapia , Oxigenoterapia , Oxigênio/uso terapêutico , Serviços Médicos de Emergência , História do Século XVIII , História do Século XIX , História do Século XX , História do Século XXI , Humanos , Unidades de Terapia Intensiva , Oxigênio/efeitos adversos , Oxigênio/história , Oxigenoterapia/efeitos adversos , Oxigenoterapia/história , Padrões de Prática Médica , Respiração ArtificialRESUMO
Oxygen is a prerequisite for all large and motile animals. It is a puzzling paradox that fossils of benthic animals are often found in black shales with geochemical evidence for deposition in marine environments with anoxic and sulfidic bottom waters. It is debated whether the geochemical proxies are unreliable, affected by diagenesis, or whether the fossils are transported from afar or perhaps were not benthic. Here, we improved the stratigraphic resolution of marine anoxia records 100-1000 fold using core-scanning X-Ray Fluorescence and established a centennial resolution record of oxygen availability at the seafloor in an epicontinental sea that existed ~501-494 million years ago. The study reveals that anoxic bottom-water conditions, often with toxic hydrogen sulfide present, were interrupted by brief oxygenation events of 600-3000 years duration, corresponding to 1-5 mm stratigraphic thickness. Fossil shells occur in some of these oxygenated intervals suggesting that animals invaded when conditions permitted an aerobic life style at the seafloor. Although the fauna evidently comprised opportunistic species adapted to low oxygen environments, these findings reconcile a long-standing debate between paleontologists and geochemists, and shows the potential of ultra-high resolution analyses for reconstructing redox conditions in past oceans.
Assuntos
Fósseis/história , Sedimentos Geológicos/análise , Sulfeto de Hidrogênio/história , Oxigênio/história , Água do Mar/análise , Animais , Sedimentos Geológicos/química , História Antiga , Sulfeto de Hidrogênio/química , Oxirredução , Oxigênio/química , Respiração , Água do Mar/química , Espectrometria por Raios XRESUMO
With this Tribute, we remember and honor Thomas John (Tom) Wydrzynski. Tom was a highly innovative, independent and committed researcher, who had, early in his career, defined his life-long research goal. He was committed to understand how Photosystem II produces molecular oxygen from water, using the energy of sunlight, and to apply this knowledge towards making artificial systems. In this tribute, we summarize his research journey, which involved working on 'soft money' in several laboratories around the world for many years, as well as his research achievements. We also reflect upon his approach to life, science and student supervision, as we perceive it. Tom was not only a thoughtful scientist that inspired many to enter this field of research, but also a wonderful supervisor and friend, who is deeply missed (see footnote*).
Assuntos
Fotossíntese , Complexo de Proteína do Fotossistema II/história , Pesquisa/história , História do Século XX , História do Século XXI , Humanos , Mentores/história , Oxirredução , Oxigênio/história , Pesquisadores/história , ÁguaRESUMO
While significant efforts have been invested in reconstructing the early evolution of the Earth's atmosphere-ocean-biosphere biogeochemical nitrogen cycle, the potential role of an early continental contribution by a terrestrial, microbial phototrophic biosphere has been largely overlooked. By transposing to the Archean nitrogen fluxes of modern topsoil communities known as biological soil crusts (terrestrial analogs of microbial mats), whose ancestors might have existed as far back as 3.2 Ga ago, we show that they could have impacted the evolution of the nitrogen cycle early on. We calculate that the net output of inorganic nitrogen reaching the Precambrian hydrogeological system could have been of the same order of magnitude as that of modern continents for a range of inhabited area as small as a few percent of that of present day continents. This contradicts the assumption that before the Great Oxidation Event, marine and continental biogeochemical nitrogen cycles were disconnected.
Assuntos
Consórcios Microbianos/fisiologia , Ciclo do Nitrogênio/fisiologia , Nitrogênio/química , Processos Fototróficos/fisiologia , Planeta Terra , Ecossistema , História Antiga , Consórcios Microbianos/efeitos da radiação , Nitrogênio/história , Nitrogênio/metabolismo , Isótopos de Nitrogênio , Oceanos e Mares , Origem da Vida , Oxirredução , Oxigênio/química , Oxigênio/história , Oxigênio/metabolismo , Processos Fototróficos/efeitos da radiação , Solo/química , Luz SolarRESUMO
William (Bill) E. Vidaver (February 2, 1921-August 31, 2017), who did his Ph.D. with Laurence (Larry) R. Blinks at Stanford (1964) and a postdoc with C. Stacy French (1965), taught and did research at Simon Fraser University (SFU) for almost 30 years. Here he published over 80 papers in photosynthesis-related areas co-authored by his graduate students, postdocs, visiting professors and SFU colleagues. He developed a unique high-pressure cuvette for the study of oxygen exchange and studied high-pressure effects in photosynthesis. Ulrich (Uli) Schreiber, as a postdoctoral fellow from Germany, introduced measurements on chlorophyll (Chl) a fluorescence to Bill's lab, leading to the discovery of reversible inhibition of excitation energy transfer between photosynthetic pigments and of a pivotal role of O2 in the oxidation of the electron transport chain between Photosystem II (PS II) and PS I. Bill's and Uli's work led to a patent of a portable chlorophyll fluorometer, the first available commercially, which was later modified to measure whole plantlets. The latter was used in pioneering measurement of the health of forest and crop plants undergoing in vitro clonal micropropagation. With several other researchers (including Doug Bruce, the late Radovan Popovic, and Sarah Swenson), he localized the quenching site of O2 and showed a dampening effect on measurements of the four-step process of O2 production by endogenous oxygen uptake. Bill is remembered as a hard-working but fun-loving person with a keen mind and strong sense of social justice.
Assuntos
Oxigênio/história , Fotossíntese , Plantas , Transporte de Elétrons , Transferência de Energia , Alemanha , História do Século XX , História do Século XXI , Pessoal de Laboratório/história , Oxigênio/metabolismoRESUMO
Inspired Oxygenation in Surgical Patients During General Anesthesia With Controlled Ventilation: A Concept of Atelectasis. By Bendixen HH, Hedley-Whyte J, and Laver MB. New Engl J Med 1963; 269:991-996. Reprinted with permission. ABSTRACT: The purpose of this study was to determine if the pattern of ventilation, by itself, influences oxygenation during anesthesia and surgery and examine the hypothesis that progressive pulmonary atelectasis may occur during constant ventilation whenever periodic hyperventilation is lacking, but is reversible by passive hyperinflation of the lungs. Eighteen surgical patients, ranging in age from 24 to 87 yr, without known pulmonary disease, were studied during intraabdominal procedures and one radical mastectomy. Although ventilation remained constant, changes occurred in arterial oxygen tension and in total pulmonary compliance, with an average fall of 22% in oxygen tension and 15% in total pulmonary compliance. This fall in oxygen tension supports the hypothesis that progressive mechanical atelectasis may lead to increased venous admixture to arterial blood. The influence of the ventilator pattern on atelectasis and shunting is further illustrated by the reversibility of the fall in oxygen tension that follows hyperinflation. A relation between the degree of ventilation and the magnitude of fall in arterial oxygen tension was found, where large tidal volumes appear to protect against falls in oxygen tension, while shallow tidal volumes lead to atelectasis and increased shunting with impaired oxygenation.
Assuntos
Abdome/cirurgia , Anestesia/história , Oxigênio/sangue , Atelectasia Pulmonar/sangue , Respiração Artificial/história , Feminino , História do Século XX , Humanos , Masculino , Oxigênio/história , Atelectasia Pulmonar/históriaRESUMO
ISOTT was founded by Drs. Duane F. Bruley and Haim I. Bicher in the state of South Carolina, USA in 1973. The symposium was jointly held at Clemson University (Clemson, SC, USA) and the Medical College of South Carolina (Charleston, SC, USA), which are geographically located 260 miles apart. This venue resulted from Dr. Bruley's (Clemson University) wish to have a meeting on Oxygen Transport to Tissue and with it to honor the research collaboration between the two universities and Dr. Melvin H. Knisely's accomplishments on studies regarding "blood sludging" in the microcirculation. Because of the unexpected large response to the symposium, Drs. Bruley and Bicher decided to found an international society at this meeting (ISOTT). The purpose of this paper is to summarize the formalization of ISOTT and to honor important contributors to the society who have since passed away. The authors did their best to include a brief overview of our past icons who have excelled in leadership as well as science/engineering, and apologize if someone has been mistakenly left out or if data is inaccurate or incomplete.
Assuntos
Pesquisa Biomédica/história , Biologia Celular/história , Oxigênio/história , Pesquisadores/história , Sociedades Científicas/história , Transporte Biológico , Congressos como Assunto/história , História do Século XX , História do Século XXI , Humanos , Liderança , Oxigênio/metabolismoRESUMO
During the last century, historians have discovered that between the 13th and 18th centuries, at least six sages discovered that the air we breathe contains something that we need and use. Ibn al-Nafis (1213-1288) in Cairo and Michael Servetus (1511-1553) in France accurately described the pulmonary circulation and its effect on blood color. Michael Sendivogius (1566-1636) in Poland called a part of air "the food of life" and identified it as the gas made by heating saltpetre. John Mayow (1641-1679) in Oxford found that one-fifth of air was a special gas he called "spiritus nitro aereus." Carl Wilhelm Scheele (1742-1786) in Uppsala generated a gas he named "fire air" by heating several metal calcs. He asked Lavoisier how it fit the phlogiston theory. Lavoisier never answered. In 1744, Joseph Priestley (1733-1804) in England discovered how to make part of air by heating red calc of mercury. He found it brightened a flame and supported life in a mouse in a sealed bottle. He called it "dephlogisticated air." He published and personally told Lavoisier and other chemists about it. Lavoisier never thanked him. After 9 years of generating and studying its chemistry, he couldn't understand whether it was a new element. He still named it "principe oxigene." He was still not able to disprove phlogiston. Henry Cavendish (1731-1810) made an inflammable gas in 1766. He and Priestley noted that its flame made a dew. Cavendish proved the dew was pure water and published this in 1778, but all scientists called it impossible to make water, an element. In 1783, on June 24th, Lavoisier was urged to try it, and, when water appeared, he realized that water was not an element but a compound of two gases, proving that oxygen was an element. He then demolished phlogiston and began the new chemistry revolution.
Assuntos
Oxigênio/história , Fisiologia/história , História do Século XVI , História do Século XVII , História do Século XVIII , História do Século XIX , História Medieval , Humanos , Oxigênio/fisiologia , Circulação Pulmonar/fisiologiaRESUMO
Oxygen has often been called the most important discovery of science. I disagree. Over five centuries, reports by six scientists told of something in air we animals all need. Three reported how to generate it. It acquired many names, finally oxygen. After 8 years of studying it, Lavoisier still couldn't understand its nature. No special date and no scientist should get credit for discovering oxygen. Henry Cavendish discovered how to make inflammable air (H2). When burned, it made water. This was called impossible because water was assumed to be an element. When Lavoisier repeated the Cavendish test on June 24, 1783, he realized it demolished two theories, phlogiston and water as an element, a Kuhnian paradigm shift that finally unlocked his great revolution of chemistry.