High-flow oxygen therapy in cancer patients with acute respiratory failure

Dear Editor,

Acute respiratory failure is a dramatic event and remains a major cause of ICU admission in cancer patients [1]. It has been recently shown that high-flow oxygen therapy through a nasal cannula in association with noninvasive ventilation (HFNC–NIV) during acute respiratory failure is associated with high mortality in unselected patients with hypoxemic acute respiratory failure (FLORALI study) [2]. We retrospectively analyzed 178 cancer patients admitted to the ICU for severe acute respiratory failure (O₂ delivery >9 L/min). We computed a propensity score to predict HFNC–NIV treatment based on specific characteristics at ICU admission. The primary outcome was all-causes mortality at day 28; secondary outcomes included the number of ventilator-free days at day 28 and long-term mortality. The study was approved by our institutional review board. For the initial population (n = 178), pulmonary infection (any pathogen) was present in 116 patients (65 %). At ICU admission the median SAPS II was 47 (IQR 38–57), SOFA score 6 (4–9), and PaO₂/FiO₂ ratio 123 (87–158). A total of 150 patients (84 %) were treated with NIV, 84 (47 %) with HFNC, and 94 (53 %) with standard oxygen. Among these patients, 76 (43 %) were treated with HFNC–NIV, 74 (42 %) with standard O₂–NIV, 8 (5 %) with standard O₂ alone, and 20 (11 %) with HFNC alone. As compared to the others patients, HFNC–NIV patients presented a lower day-28 mortality rate, 37 % (n = 28) vs 52 % (n = 53), p = 0.045; a longer time from ICU admission to intubation 34 h (18–72) vs 16 h (7–45), p = 0.01; and a higher but not significant number of ventilator-free days, 24 (2–28) vs 8 (1–28), p = 0.06. A total of 138 patients were included in the propensity analysis [Table 1, supplementary material (SM) 1]. Day-28 mortality was 36 % in HFNC–NIV patients and 54 % in other patients (Table 1, p = 0.027). After adjustment for the propensity score, HFNC–NIV was independently associated with improved survival (SM 2). Ventilator-free days and day-90 mortality were significantly in favor of HFNC–NIV patients (Table 1, SM 3). Intubation rates at day 28 were similar in the two group of patients: 48 % (HFNC–NIV patients vs 52 % (other patients), p = 0.277 (Table 1).

Table 1 Characteristics of the matched patients

In contrast to recent data [2], we describe significant improvement of day-28 mortality in cancer patients with acute respiratory failure treated with HFNC–NIV as compared with other patients. Although our patients presented with severe acute respiratory failure, mortality rate was particularly encouraging in the HFNC–NIV group, whereas intubation rate and delay of intubation were comparable to those of the FLORALI study [2]. However from our results, the risk of delayed intubation in the HFNC–NIV group has not been clearly evaluated. In our ICU, NIV protocol is strictly standardized; however, at the bedside, controlling for expiratory tidal volume is not easily feasible continuously. In contrast, our NIV presets were always 0.5 h/session (up to 1 h) and four sessions/24 h (up to 6) [3]. NIV treatment in cancer patients is under investigation and needs to be evaluated in the context of the recent survival improvement of these patients [4]. Acute respiratory failure in cancer patients is frequently associated with severe mucositis, tracheal bleeding, and/or alveolar hemorrhage, and under these conditions pulmonary sepsis may be exacerbated by bloody thick secretions. HFNC may prevent from secretions retention, atelectasis [5], and need for invasive mechanical ventilation [2]. Accordingly, in our study HFNC–NIV was associated with more ventilator-free days and less septic shock occurrence. Interestingly, the day-28 mortality rate of patients never treated with NIV was 7/15 (47 %) vs 55/123 (45 %) for others patients, p = 0.89. Regarding patients never treated with HFNC, the day-28 mortality rate was 36/63 (57 %) vs 26/75 (35 %) for HFNC patients, p = 0.008. These findings strongly suggest that the use of NIV was not associated with adverse effects, whereas the use of HFNC was associated with survival. These preliminary results suggest that a trial of HFNC in cancer patients with acute respiratory failure is warranted.