The Reign of the Ventilator: Acute Respiratory Distress Syndrome, COVID-19, and Technological Imperatives in Intensive Care.

In the early phase of the COVID-19 pandemic, a dispute arose as to whether the disease caused a typical or atypical version of acute respiratory distress syndrome (ARDS). This essay recounts the emergence of ARDS and places it in the context of the technological transformation of modern hospital care-particularly the emergence of intensive care after the 1952 Copenhagen polio epidemic. The polio epidemic seemed to show the value of manual positive-pressure ventilation, leading to the proliferation of mechanical ventilators and the expansion of intensive care units in the 1960s. This created the conditions of possibility for ARDS to be described and institutionalized within modern intensive care. Yet the centrality of the ventilator to descriptions and definitions of ARDS quickly made it difficult to conceive of the disorder outside the framework of mechanical ventilation and blood gas levels, or to acknowledge the degree to which the ventilator was a source of iatrogenic injury and complications. Moreover, the imperative to understand and treat ARDS with mechanical ventilation set the stage for the early confusion about whether patients with COVID-19 should receive mechanical ventilation. This history offers many crucial lessons about how new technologies can lead to new and valuable therapies but can also subtly shape and constrain medical thinking. Moreover, ventilators not only changed how respiratory disorders were conceived; they also brought new forms of respiratory illness into existence.

Philip Drinker versus John Haven Emerson: Battle of the iron lung machines, 1928-1940.

The "iron lung," originally known as the Drinker respirator, was developed in 1928 by Dr Philip Drinker and Dr Louis Agassiz Shaw to improve the respiration of polio patients. In 1931, John Haven Emerson, an inventor from Cambridge, MA, enhanced the design of the Drinker respirator and introduced a new and highly improved model of the iron lung that was cheaper and significantly lighter. Dr Drinker eventually filed a lawsuit against Emerson for alleged patent infringement. In his defense, Emerson argued that devices that help save human lives should be widely accessible to all patients. He also questioned the novelty of Drinker's design, claiming that Drinker's device comprised of patented technology that existed since the late 1800s, and that he therefore did not have full ownership of the machine's intellectual property. Ultimately, the case backfired on Drinker, as he not only lost the court case but also lost the entire panel of patents that were in his possession.

The Connection of Life with Respiration: Edmund Goodwyn's unexplored treasure of cardiopulmonary physiology.

The advent of artificial ventilation was largely sparked by the popular belief that drowning and other causes of asphyxia could induce death-like states known as suspended animation. While the mystical nature of such states befuddled some physicians into the early 1900s, an English medical student by the name of Edmund Goodwyn (1756-1829) published a thesis in 1786, which demonstrated that suspended animation was simply the physical manifestation of extreme hypoxia. Goodwyn's work advanced one of the earliest arguments in favor of artificial ventilation for the treatment of asphyxia over alternative resuscitation measures like heat and exsanguination. In addition, Goodwyn's remarkable dissertation contains the first account of a reflex known as diving bradycardia, and possibly the first vehement refutation of claims by his contemporaries that pulmonary circulation stopped during exhalation. While miscellaneous aspects of his thesis have occasionally been mentioned by a few medical historians, the overall visionary nature of his work has yet to be recognized. This article attempts to accomplish this goal and to provide a first biographical glimpse of a man whose scientific career appears to have ended prematurely, perhaps because of his profound aversion to controversy.

Birth of Airway Surgery and Evolution over the Past Fifty Years.

Significant developments in airway surgery occurred following the introduction of mechanical ventilators and intubation with cuffed endotracheal tubes during the poliomyelitis epidemic of the 1950s. The resulting plethora of postintubation injuries provided extensive experience with resection and reconstruction of stenotic tracheal lesions. In the early 1960s, it was thought that no more 2 cm of trachea could be removed. By the late 1960s, this was challenged owing to better knowledge of airway anatomy and blood supply, tension-releasing maneuvers, and improved anesthetic techniques. Currently, about half of the tracheal length can be safely removed and continuity restored by primary anastomosis.

Tracheal Injuries Complicating Prolonged Intubation and Tracheostomy.

Respiratory care advances such as the introduction of ventilatory assistance have been associated with postintubation airway stenosis resulting from tracheal injury at the site of the inflatable cuff on endotracheal or tracheostomy tubes. Low-pressure cuffs have significantly reduced this occurrence. Loss of airway stability at the site of a tracheostomy stoma may result in tracheal stenosis. Subglottic stenosis may result from a high tracheostomy site at, or just inferior to, the cricoid arch, or to malposition of an endotracheal tube cuff. Awareness of these complications and their causes is essential to prevent their occurrence.

Fifty Years of Research in ARDS. Is Extracorporeal Circulation the Future of Acute Respiratory Distress Syndrome Management?

Mechanical ventilation (MV) remains the cornerstone of acute respiratory distress syndrome (ARDS) management. It guarantees sufficient alveolar ventilation, high FiO2 concentration, and high positive end-expiratory pressure levels. However, experimental and clinical studies have accumulated, demonstrating that MV also contributes to the high mortality observed in patients with ARDS by creating ventilator-induced lung injury. Under these circumstances, extracorporeal lung support (ECLS) may be beneficial in two distinct clinical settings: to rescue patients from the high risk for death associated with severe hypoxemia, hypercapnia, or both not responding to maximized conventional MV, and to replace MV and minimize/abolish the harmful effects of ventilator-induced lung injury. High extracorporeal blood flow venovenous extracorporeal membrane oxygenation (ECMO) may therefore rescue the sickest patients with ARDS from the high risk for death associated with severe hypoxemia, hypercapnia, or both not responding to maximized conventional MV. Successful venovenous ECMO treatment in patients with extremely severe H1N1-associated ARDS and positive results of the CESAR trial have led to an exponential use of the technology in recent years. Alternatively, lower-flow extracorporeal CO2 removal devices may be used to reduce the intensity of MV (by reducing Vt from 6 to 3-4 ml/kg) and to minimize or even abolish the harmful effects of ventilator-induced lung injury if used as an alternative to conventional MV in nonintubated, nonsedated, and spontaneously breathing patients. Although conceptually very attractive, the use of ECLS in patients with ARDS remains controversial, and high-quality research is needed to further advance our knowledge in the field.

AJRCCM: 100-Year Anniversary. Homeward Bound: A Centenary of Home Mechanical Ventilation.

The evolution of home mechanical ventilation is an intertwined chronicle of negative and positive pressure modes and their role in managing ventilatory failure in neuromuscular diseases and other chronic disorders. The uptake of noninvasive positive pressure ventilation has resulted in widespread growth in home ventilation internationally and fewer patients being ventilated invasively. As with many applications of domiciliary medical technology, home ventilatory support has either led or run in parallel with acute hospital applications and has been influenced by medical and societal shifts in the approach to chronic care, the creation of community support teams, a preference of recipients to be treated at home, and economic imperatives. This review summarizes the trends and growing evidence base for ventilatory support outside the hospital.

Intraabdominal Surgery and Anesthesia Management.

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.

Ventilación mecánica: una breve historia / Mechanical ventilation: a short history

This review is a short history of mechanical ventilation, from its origins to the present day. This changing history provides the basis for speculation on the future innovations in the ventilatory support.

Se revisa la historia de la ventilación mecánica desde sus orígenes hasta el presente, una historia cambiante que permite especular sobre las futuras innovaciones en el soporte ventilatorio.

W. Ritchie Russell, A.B. Baker, and Fred Plum: Pioneers of ventilatory management in poliomyelitis.

Historically, neurologists were not involved in the day-to-day management of critically ill patients with bulbar poliomyelitis, but some were. The major contributions of 3 neurologists-W. Ritchie Russell, A.B. Baker, and Fred Plum-in the respiratory management of poliomyelitis have not been recognized. Russell's work was instrumental in identifying multiple types of poliomyelitis defined by their respiratory needs, and he advised treatment that varied from simple postural drainage to use of respirators. He participated in the development of the Radcliffe respiratory pump. Baker recognized the essential involvement of the vagal nerve in respiratory distress, but also observed that involvement of vital centers without cranial nerve involvement would lead to irregular and shallow respiration in some patients and in others with marked dysautonomic features. A similar finding of central involvement of respiration was noted by Plum, who also stressed the importance of hypercapnia. Plum emphasized measurements of vital capacity and techniques to minimize trauma with suctioning after tracheostomy. These 3 neurologists understood the importance of airway and ventilator management, which is currently one of the many pillars of neurocritical care.

The introduction of expired air resuscitation into Surf Life Saving Australia.

Surf Life Saving Australia, which began in the early 1900s, initially adopted the indirect resuscitation methods used by the Royal Life Saving Society. As new indirect methods became available, both organisations adapted their resuscitation techniques and followed international developments closely. In the 1950s, accumulating evidence suggested that direct methods of resuscitation, such as mouth-to-mouth ventilation, might be more efficacious. Subsequently a number of investigations were carried out in Sydney at the Royal Prince Alfred Hospital on anaesthetised and paralysed patients. These experiments were recorded for an ABC documentary and reported at the International Convention on Life Saving Techniques held in Sydney in March 1960. Following the convention, Queensland Surf Life Saving conducted training sessions in cooperation with anaesthetists Roger Bennett and Tess Brophy (later Cramond), at St Andrew's Hospital in Brisbane. Two volunteers were anaesthetised and paralysed on two separate weekends to allow over one hundred people to gain experience in expired-air and bag-mask ventilation. One of the volunteers in these training exercises kindly provided much of the material that led to this paper, providing a first hand account of the experiments and an invaluable insight into the cooperation between anaesthetists and volunteer rescue associations.

"Treating Lungs": The Scientific Contributions of Dr. Theodor Kolobow.

We are fortunate to live in an age in which biomedical technology has provided us with unprecedented ability to supplant the functions of organs and support the physiologic processes of the human body. Ingenious doctors, physiologists, and engineers helped create these advances with new and innovative ideas. One of these pioneers was Dr. Theodor Kolobow. He is best known for one of his earliest inventions, the spiral coil membrane lung. His contributions to medical innovation, however, are diverse, as he also contributed to advances in hemodialysis, improvements in extracorporeal life support technology/circuit components, and through his laboratory experiments helped shape our current understanding of cardiopulmonary pathophysiology. In retrospect, much of Kolobow's work was unified by the theme of preventing iatrogenic lung injury caused by mechanical ventilation. This tenet became more obvious as his later studies progressed to developing techniques and devices intended to limit ventilator pressures, and prevent bacterial colonization of the lungs. Although he formally retired from his research endeavors in 2009, the impact of his contributions remains prominent in our everyday use of techniques and equipment that he either originated or helped to develop.

An Anesthesiologist's Perspective on the History of Basic Airway Management: The "Preanesthetic" Era-1700 to 1846.

Basic airway management modern history starts in the early 18th century in the context of resuscitation of the apparently dead. History saw the rise and fall of the mouth-to-mouth and then of the instrumental positive-pressure ventilation generated by bellows. Pulmonary ventilation had a secondary role to external and internal organ stimulation in resuscitation of the apparently dead. Airway access for the extraglottic technique was to the victim's nose. The bellows-to-nose technique was the "basic airway management technique" applicable by both medical and nonmedical personnel. Although the techniques had been described at the time, very few physicians practiced glottic (intubation) and subglottic (tracheotomy) techniques. Before the anesthetic era, positive-pressure ventilation was discredited and replaced by manual negative-pressure techniques. In the middle of the 19th century, physicians who would soon administer anesthetic gases were unfamiliar with the positive-pressure ventilation concept.