High-Flow Nasal Cannula Oxygen in Patients with Acute Respiratory Failure and Do-Not-Intubate or Do-Not-Resuscitate Orders: A Systematic Review
BACKGROUND AND OBJECTIVES: High-flow nasal cannula (HFNC) oxygen may provide tailored benefits in patients with preset treatment limitations. The objective of this study was to assess the effectiveness of HFNC oxygen in patients with do-not-intubate (DNI) and/or do-not-resuscitate (DNR) orders.
METHODS: We conducted a systematic review of interventional and observational studies. A search was performed using MEDLINE, EMBASE, CINAHL, Scopus, and Web of Science, from inception to October 15, 2018.
RESULTS: We included six studies evaluating 293 patients. All studies had a high risk of bias. The hospital mortality rates of patients with DNI and/or DNR orders receiving HFNC oxygen were variable and ranged from 40% to 87%. In two before and after studies, the initiation of HFNC oxygen was associated with improved oxygenation and reduced respiratory rates. One comparative study found no difference in dyspnea reduction or morphine doses between patients using HFNC oxygen versus conventional oxygen. No studies evaluated quality of life in survivors or quality of death in nonsurvivors. HFNC was generally well tolerated with few adverse events identified.
CONCLUSIONS: While HFNC oxygen remains a viable treatment option for hospitalized patients who have acute respiratory failure and a DNI and/or DNR order, there is a paucity of high-quality, comparative, effectiveness data to guide the usage of HFNC oxygen compared with other treatments, such as noninvasive ventilation, conventional oxygen, and palliative opioids.
© 2019 Society of Hospital Medicine
High-flow nasal cannula (HFNC) oxygen therapy is effective in treating adults with acute hypoxemic respiratory failure, and to a lesser extent acute hypercapnic respiratory failure.1-3 HFNC oxygen is capable of delivering oxygen with flows of 30-60 liters/minute, and can provide a high fraction of inspired oxygen, flush anatomic dead space, augment respiratory efforts, and provide mild continuous positive airway pressure effects. Several systematic reviews and meta-analyses have evaluated the effectiveness of HFNC oxygen and have shown modestly lower rates of intubation compared with conventional oxygen4,5 and similar intubation rates compared with noninvasive positive pressure ventilation.4-9 Although one randomized trial showed a lower risk of 90-day mortality for HFNC oxygen compared with either conventional oxygen or noninvasive positive pressure ventilation, several meta-analyses have shown no difference in intensive care unit (ICU) mortality.4,6,8,10 The majority of studies have shown improvements in oxygenation, comfort, dyspnea scores, and breathing pattern with the initiation of HFNC oxygen.6
While the evidence to support the use of HFNC oxygen in patients with nonhypercapnic acute hypoxemic respiratory failure is growing, this evidence is based on patients enrolled in clinical trials who have no treatment limitations and consent to intubation if necessary. Indeed, several, if not all, randomized trials evaluating HFNC oxygen excluded patients who had do-not-intubate (DNI) or do-not-resuscitate (DNR) orders.1,2,11 For patients with acute respiratory failure whose primary goal is not to extend life or utilize life support interventions such as invasive mechanical ventilation, HFNC oxygen may offer several benefits compared with other treatment options such as noninvasive positive pressure ventilation, conventional oxygen therapy, or palliative opioid therapy (Appendix Table 1). Determining which treatment options to use depends on the goals of care of the individual patient and the reasonable ability of a particular treatment to help the patient achieve those goals.
While a recent systematic review evaluated the existing evidence regarding the utility and outcomes of noninvasive positive pressure ventilation in adult patients with DNI orders,12 a systematic review evaluating the evidence and rationale for HFNC oxygen in patients with DNI and/or DNR orders is lacking. Assessing such evidence is necessary to help clinicians and patients determine appropriate treatment choices and establish research priorities. Therefore, our primary objective was to determine what were the following outcomes: mortality, dyspnea, work of breathing, opioid doses, and quality of life in patients who received HFNC oxygen for acute respiratory failure and had a DNI and/or DNR order.
