By J. Brady Scott, PhD, RRT, RRT-ACCS, AE-C, FAARC, FCCP

Associate Professor, Department of Cardiopulmonary Sciences, Division of Respiratory Care, College of Health Sciences, Rush University, Chicago

SYNOPSIS: Critical care clinicians, such as nurses, respiratory therapists, and physicians, have varying opinions regarding oxygen therapy and hyperoxia. Interdisciplinary education addressing current evidence of oxygen therapy and the potentially harmful effects of oxygen is warranted.

SOURCE: Curtis BR, Rak KJ, Richardson A, et al. Perceptions of hyperoxemia and conservative oxygen therapy in the management of acute respiratory failure. Ann Am Thorac Soc 2021;18:1369-1379.

Oxygen therapy is an essential component of the management of patients with acute respiratory failure. Although the use of supplemental oxygen is necessary, it is not without complications in some patient populations. Curtis et al sought to understand the perceptions of critical care providers (nurses, respiratory therapists, and physicians) regarding oxygen therapy for patients who require mechanical ventilation in the intensive care unit (ICU). Specifically, they assessed beliefs about hyperoxemia and barriers to implementing clinical practices that promote conservative oxygen therapy strategies.

Using a qualitative study design, the study team conducted semi-structured interviews of individual providers (n = 29) working in a general medical ICU of a community-based hospital and a trauma surgical ICU of an urban, academic hospital. Nurses (n = 10), respiratory therapists (n = 10), and physicians (n = 9, consisting of four critical care medicine fellows and five attendings) were enrolled in the study, since they are actively involved in the management of supplemental oxygen in patients requiring mechanical ventilation.

Three major domains were noted from the interviews: 1) perceptions of hyperoxemia, 2) attitudes toward conservative oxygen therapy, and 3) perceived barriers to and facilitators of the implementation of conservative oxygen therapy. Regarding hyperoxemia, physicians were more familiar with the term and concept, particularly the potential for lung injury due to long-term exposure of high amounts of oxygen and oxygen free radicals. All providers seemed to be familiar with conservative oxygen strategies for patients with chronic obstructive pulmonary disease. Interestingly, some clinicians were clear that they would be more receptive to conservative oxygen strategies if clinical trials showed a clear benefit. Finally, there were concerns, primarily by nurses and respiratory therapists, about lower oxygen saturations and the added work burden associated with a conservative oxygen strategy that may increase the risk of hypoxia but have negligible patient benefit otherwise. All providers cited poor interprofessional communication as a barrier to implementing a conservative oxygen therapy strategy.

The authors noted that hyperoxemia is not a well-understood concept among critical care providers. Perhaps more concerning, this study indicates that the potential dangers of hyperoxemia are not universally understood among providers responsible for the management of supplemental oxygen. That said, they acknowledge conflicting evidence that complicates the matter and admit that the acceptance and implementation of a conservative oxygen strategy likely is dependent on clear and consistent evidence supporting its use.1,2

COMMENTARY

This study highlights the reality that some providers are unsure of the potential dangers of hyperoxemia. Perhaps the most salient point of these findings is that providers will remain uncertain of how to manage supplemental oxygen (hyperoxemia vs. normoxemia) until large, well-designed studies provide clear answers. In a review by Martin et al, the authors assessed the clinical effects of hyperoxia on patients who were critically ill. Evaluating the impact of hyperoxia on cardiovascular conditions, neurological conditions, respiratory failure, sepsis, and mixed ICU conditions, the authors note that hyperoxia has known harmful effects.3 That said, they also admit that questions remain in terms of how hyperoxia affects the clinical outcomes of critically ill patients. 

This study has significant limitations, starting with the acknowledgment that the literature to support conservative oxygen strategies still is developing. There also are some concerns about the generalizability of the study, since providers interviewed were from a single healthcare system, and it may not reflect institutions where respiratory therapists are nonexistent (e.g., some European countries). Importantly, this study recognizes interdisciplinary education as a way to improve awareness, address deep-seated beliefs, and support practice changes regarding practices such as oxygen management. For practice patterns to change (if the literature supports the change), all providers need to understand the intent of the practice change and the expectations of each team member. 

REFERENCES

  1. Barrot L, Asfar P, Mauny F, et al. Liberal or conservative oxygen therapy for acute respiratory distress syndrome. N Engl J Med 2020;382:999-1008.
  2. ICU-ROX Investigators and the Australian and New Zealand Intensive Care Society Clinical Trials Group; Mackle D, Bellomo R, Bailey R, et al. Conservative oxygen therapy during mechanical ventilation in the ICU. N Engl J Med 2020;382:989-998.
  3. Martin J, Mazer-Amirshahi M, Pourmand A. The impact of hyperoxia in the critically ill patient: A review of the literature. Respir Care 2020;65:1202-1210.