Discussion Guide for the Amorim Article

Oxygen, a mainstay treatment for hypoxemia, is one of the most frequently used therapies for hospitalized patients. Overuse of oxygen may contribute to hyperoxemia, which clinicians may commonly disregard. However, hyperoxemia can cause pulmonary toxicity, disrupt antioxidant function, and strain the cardiovascular system. Similarly, excessive administration of oxygen (EAO) can impair mucociliary transport if not adequately humidified and heated, and high fractions of inspired oxygen contribute to absorption atelectasis, tracheobronchitis, and immunosuppression. Although hyperoxemia is linked to poor clinical outcomes in specific clinical situations (eg, septic shock and acute myocardial infarction), the evidence is conflicting among critically ill patients. Some studies and systematic reviews report an association between hyperoxemia and mortality, whereas others, including randomized clinical trials, show no significant differences in outcomes, leading to uncertainty about the overall impact of EAO on patient survival. Therefore, the authors of the present study sought to determine the prevalence of oxygen therapy–induced hyperoxemia and its association with hospital mortality in nonsurgical critically ill patients. In addition, the authors examined the factors related to oxygen therapy–induced hyperoxemia upon admission, and its association with the need for mechanical ventilation, vasopressors, and renal replacement therapy during the patient's stay in the intensive care unit (ICU).This prospective cohort study included all consecutive admissions of nonsurgical, critically ill adults who received oxygen therapy upon admission to the ICU (N = 3088). Within the first hour of ICU admission, 38% (n = 1174) of patients were hyperoxemic (Pao2 > 120 mm Hg). In multivariate analyses, higher rates of hyperoxemia were associated with increasing age and the presence of chronic kidney disease, while organ dysfunction, late-night admissions, and specific admission diagnoses (ie, renal/metabolic, digestive, and soft tissue/skin/orthopedic) were associated with lower hyperoxemia rates. Compared with normoxemic (Pao2 60–120 mm Hg) and hypoxemic (Pao2 <60 mm Hg) patients, hyperoxemic patients required a longer stay in the hospital. Furthermore, the odds of the patient dying during the hospital stay increased by 32% if the patient was hyperoxemic during the first hour of the ICU stay. However, hyperoxemia was not associated with the need for mechanical ventilation, vasopressors, and renal replacement therapy. Given potential risks associated with hyperoxemia, the authors conclude that ICU clinicians should remain vigilant in monitoring a patient's oxygen levels during critical illness.Dr Fábio Ferreira Amorim, the corresponding author for this article, has observed a concerning trend toward excessive use of oxygen therapy. As he highlights, "oxygen therapy stands as a cornerstone in the management of acute respiratory failure, given its pivotal role in addressing hypoxemia, the primary contributor to mortality in this critical condition." Despite its significance, Dr Amorim notes that oxygen is often overused owing to its ready availability and the fear of the effects of hypoxemia. Furthermore, inadequate monitoring of peripheral oxygen saturation by many ICU monitors compounds the risk, with insufficient alarms for detecting hyperoxemia. Recognizing the potential risks associated with hyperoxemia, Dr Amorim articulates the motivation for the study: "We designed this study to evaluate the prevalence of hyperoxemia induced by oxygen therapy at ICU admission among nonsurgical critically ill patients and its correlation with hospital mortality."According to Dr Amorim, the main difficulty encountered during the study was its execution amid the COVID-19 pandemic. The pandemic, as described by the authors, brought overwhelming demands on Brazil's health care system, including overloaded ICUs, insufficient specialized staff, and shortages of essential equipment and resources. These challenges created a unique scenario where immediate attention and resources were demanded for patient care, while the team was simultaneously dedicated to advancing research that could shed light on the rational use of oxygen.Despite the challenges, Dr Amorim says that the study was successful largely because "the research group has a history of teamwork on previous projects related to the care of critically ill patients." The diverse team of professionals, professors, and students from 4 universities, brings varied expertise to enrich the research process. The gradual formation of this research group highlights the importance of sustained collaboration and the evolution of a collective understanding. Dr Amorin emphasizes, "This collaborative spirit will yield further insights and advancements in critically ill patient care as they continue their research projects."Dr Amorim envisions future clinical trials to evaluate different Pao2 cutoffs, providing a more precise understanding of the relationship between hyperoxe-mia and clinical outcomes. The exploration of diverse targets for oxygen therapy is a pivotal step toward refining the approach and enhancing patient care in the ICU. He concludes, "We expect to forge a path toward personalized and evidence-based approaches that optimize patient outcomes and foster a culture of continuous improvement in critical care medicine."For now, Dr Amorim emphasizes the need for a balanced approach when using oxygen therapy at the bedside: "The primary risk associated with oxygen therapy lies in the narrow safety margin separating effective and toxic oxygen doses." The authors stress the importance of shedding light on hyperoxemia as a prevalent phenomenon at the time of ICU admission, independently linked to an increased risk of hospital mortality. Their research aims to challenge the perception that oxygen is entirely risk-free and to contribute to a more informed and tempered approach to oxygen therapy, ultimately enhancing patient safety and optimizing resource use in the ICU.This feature briefly describes the personal journey and background story of the EBR article's lead investigators, discussing the circumstances that led them to undertake the line of inquiry represented in the research article featured in this issue.Dr Fábio Ferreira Amorim's 29-year career, from the Medical School of the University of Brasília (UnB) to a professorship at the School of Health Sciences (ESCS) in Brasília, has been marked by a commitment to intensive care and research. His passion for acute critical patient care was ignited during a medical residency at the Federal University of Sao Paulo, focusing on respiratory physiology and mechanical ventilation. His academic trajectory, including master's and doctoral studies at the Federal University of São Paulo, was shaped by an evidence-based orientation and curiosity about oxygen therapy's potential adverse effects. Balancing roles as a research manager, coordinator of the graduate program in health sciences of ESCS, and a collaborative professor in the graduate program of health sciences at UnB, Dr Amorim bridges academia and clinical practice, enriching both his personal understanding and that of students.