What Matters Most When Considering Noninvasive Ventilation for Patients With Do-Not-Intubate or Comfort-Measures-Only Orders?

Critical Care Medicine www.ccmjournal. org 1367 Utilizing noninvasive ventilation (NIV) for patients with do-not-intubate (DNI) or comfort-measuresonly (CMO) orders remains controversial, despite decades of debate over this issue (1). Some argue that the use of NIV in these patients provides improved chances for survival and achieves important aims, such as improving patient comfort or providing additional time for patients to interact with loved ones or to fulfill meaningful end-of-life tasks (2, 3). Others claim that implementing NIV in this setting is more likely to produce harm than benefit, constitutes an unjust use of limited healthcare resources, and merely prolongs the dying process (4, 5). However, neither proponents nor opponents of NIV in this setting have had sufficient evidence to support their viewpoints, so the controversy has remained largely unresolved. In this issue of Critical Care Medicine, Wilson et al (6) provide the first systematic review and meta-analysis exploring the outcomes of NIV in patients with acute respiratory failure (ARF) who have DNI or CMO orders. Among patients with DNI orders (2,020 patients, 27 studies), they assessed pooled survival rates to hospital discharge (56%) and at 1 year (32%). Hospital survival rates were highest among patients with chronic obstructive pulmonary disease and pulmonary edema (68%) but much lower for patients with active malignancy (37%). Importantly, they found that survival was comparable regardless of whether patients received NIV in the ICU or in a “well-equipped” hospital ward. Patients generally tolerated NIV well, and those who survived returned to their baseline quality of life (QOL) within 3 months following discharge. Among patients with CMO orders (200 patients, three studies), they assessed outcomes of NIV in terms of dyspnea control, opioid requirements, tolerance of NIV, and survival. Notably, just one study assessed the effect of NIV on dyspnea. This study found only a 1 point per day reduction in dyspnea on the Borg scale (generally accepted as the “minimal clinically significant difference” on the Borg scale [7]) as compared with patients receiving oxygen alone (6), so this reduction in dyspnea was mild at best. Interestingly, “reduction of opioid use” was regarded as a positive outcome of NIV in these patients (6), although it appears that this outcome would not matter much to patients or their families, particularly at the end of life, nor is opioid use a reliable surrogate marker for dyspnea, given wide variability of practice in administering opioids, particularly to patients who cannot request them. One study of 29 patients who received NIV solely for symptom relief reported that 59% of these patients stopped NIV because it did not provide significant relief of dyspnea (8). Thus, the limited evidence presented in this meta-analysis suggests that relief of dyspnea is likely better achieved by palliative measures other than employing NIV. Survival to hospital discharge was low in all three studies of CMO patients (0–38.4%) (6). Importantly, no study assessed the quality of death in nonsurvivors, which, arguably, is the most important outcome for CMO patients when considering whether to utilize NIV. Wilson et al (6) acknowledge several limitations to their study, including the heterogeneity of, and high risk of bias within, the included studies, which limit the generalizability and validity of their conclusions. They note that, in six of the 27 DNI studies, physicians made the DNI decision unilaterally without patient/family involvement. Since these DNI determinations were presumably based on poor prognosis and/or QOL judgements, this likely skewed the survival and QOL outcomes among recipients of NIV in these studies; such outcomes may be quite different among patients who participate in their own decision-making. The authors note other limitations as well. However, in my view, the most important limitation is that the outcomes that Wilson et al (6) examine are not those likely to matter most to patients and families when considering whether to use NIV in relation to achieving their goals of care. What are the goals in pursuing NIV among patients with DNI orders? Many patients with DNI orders have both curative and palliative aims that must be balanced against one *See also p. 1209.