EDITORIALS Postextubation Respiratory Support: One More Piece to the Puzzle Extubation failure is defined as the need for mechanical ventilation A previous study showed that HFNC was superior to low-flow within days after planned extubation, and it occurs in 10–20% oxygen in preventing extubation failure (4). The question was, of critically ill patients (1). Importantly, extubation failure is therefore, once again on the table: is HFNC superior to independently associated with longer ventilation duration, conventional oxygen in preventing reintubation? One main longer ICU and hospital length of stay, and higher mortality. difference between the two studies is that in the present study, As several causes may contribute to extubation failure (indeed some Venturi masks were used in the control group. Compared with of them may even coexist in the same patient), the study of the low-flow oxygen, a Venturi mask allows higher flow delivery while pathophysiology of extubation failure is still challenging. In this achieving higher oxygen concentrations. Moreover, HFNC scenario, different noninvasive supportive therapies could be used treatment was applied for shorter periods of time, and the use of to decrease the rate of extubation failure. rescue NIV was allowed in those patients with worsening High-flow nasal cannula (HFNC) has various effects that could postextubation respiratory failure. Indeed, the results of the present be of interest after extubation (2). Compared with conventional study are consistent with those observed in the PROPER oxygen, it increases dead-space washout, improves secretion (Protocolized Postextubation Respiratory Support to Prevent clearance using heated humidification, and generates a certain Reintubation: A Randomized Clinical Trial) trial (7), which also degree of positive airway pressure, increasing the end-expiratory suggested that postextubation HFNC did not reduce the rate of lung volume and decreasing expiratory diaphragm loading. It is also reintubation under these circumstances. However, if considering associated with better oxygenation and decreased respiratory rate a composite outcome of escalation of treatment that encompasses and inspiratory effort (3). Consistent with these physiological the use of NIV and the need for reintubation, it is possible that the benefits, one previous study showed that HFNC use immediately results of both studies would have been similar, and HFNC may be after extubation decreased reintubation rate within the first 72 considered superior to conventional oxygen in terms of preventing hours after extubation compared with low-flow oxygen delivery escalation of treatment after a scheduled extubation. applied continuously through a nasal cannula or a nonrebreather Recent NIV guidelines suggest the use of NIV to prevent facemask (4). Compared with low-flow oxygen devices, a Venturi postextubation respiratory failure in high-risk patients for mask delivers higher flows of gas admixture. However, in a reintubation (8). However, they do not suggest the use of NIV for previous physiological study comparing the use of HFNC with that overt postextubation respiratory failure (8), and it may even be of a Venturi mask, HFNC was also associated with improved harmful and increase ICU mortality because of delayed intubation oxygenation, lower respiratory rate, and better comfort (5). (9). Moreover, compared with HFNC, the use of NIV is associated Whether these physiological benefits were associated with improved with increased patient discomfort and increased workload for clinical outcomes was uncertain. healthcare personnel. These results may be especially relevant in In this issue of the Journal, Maggiore and colleagues the context of different situations with high medical demand and (pp. 1452–1462) report the results of a randomized trial assessing shortage of ventilators, such as the recent coronavirus disease whether HFNC after extubation decreased the reintubation rate (COVID-19) pandemic. Importantly, the results of the present within 72 hours in critically ill patients among those who succeeded study showed that NIV used by an experienced team may prevent to a spontaneous breathing trial but presented hypoxemia within the need for reintubation in almost the half of these patients. the first 120 minutes after extubation; the results were compared Unfortunately, no data about differences in ICU length of stay or with those obtained with Venturi mask oxygen (6). Interestingly, mortality of those patients who finally needed to be intubated were prespecified criteria for both reintubation and the need for reported. noninvasive ventilation (NIV) were used, and the use of these Another difference is that, in the present study, the Venturi criteria was blindly revised a posteriori by three independent mask was used despite low-flow oxygen. The Venturi mask used with experts. No differences in the need for reintubation at 72 hours and a FIO2 at a treatment initiation of 36% should correspond to total gas at 28 days were observed. However, patients randomized to be outflow exceeding 30 L/min. However, different physiological effects supported with the Venturi mask after extubation more frequently have been observed between high-flow oxygen therapy through needed to be rescued with NIV because of the presence of tracheostomy and HFNC (10), suggesting that the effects of high flow tachypnea and respiratory distress. also depend on the interface that is used. Indeed, the intubation rates in the Venturi mask group were similar to those observed in the low-flow group in the study by Hernandez and colleagues (4) This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives (11% vs. 12%). Therefore, it is unlikely that this could lead to significant License 4.0. For commercial usage and reprints, please e-mail differences in intubation rates. The differences were, in fact, in the Diane Gern (dgern@thoracic.org). HFNC group (14% vs. 5%). Other differences may explain this result. Originally Published in Press as DOI: 10.1164/rccm.202208-1485ED First, HFNC was not used as a preventive strategy immediately after on August 26, 2022 extubation, and patients were randomized if they presented a certain Am J Respir Crit Care Med Vol 206, Iss 12, pp 1437–1451, Dec 15, 2022 Internet address: www:atsjournals:org Editorials 1437 EDITORIALS degree of hypoxemia within the first 120 minutes after extubation. Gonzalo Hernandez, M.D., Ph.D. Second, conservative positive end-expiratory pressure criteria were used Toledo University Hospital Toledo, Spain to attempt a spontaneous breathing test (PaO2/FIO2 . 150 with positive end-expiratory pressure < 5 cm H2O), leading to a low reintubation rate ORCID ID: 0000-0003-3841-4551 (O.R.). secondary to hypoxemia. These differences may limit the potential benefit of using HFNC to prevent extubation failure in some critically ill patients. Finally, it is worth noting that although there was no benefit of any of the supportive therapies compared in the study, it does References not necessary mean that no patients will benefit from the 1. Thille AW, Richard JC, Brochard L. The decision to extubate in the intervention (11). The results presented in randomized controlled intensive care unit. Am J Respir Crit Care Med 2013;187:1294–1302. clinical trials represent the average treatment effect, which is the 2. Goligher EC, Slutsky AS. Not just oxygen? Mechanisms of benefit from mean of all individual treatment effects observed in each patient. high-flow nasal cannula in hypoxemic respiratory failure. Am J Respir Thus, clinical physiological assessments at the bedside could be used Crit Care Med 2017;195:1128–1131. as predictive enrichment tools to design targeted clinical trials to 3. Mauri T, Turrini C, Eronia N, Grasselli G, Volta CA, Bellani G, et al. Physiologic effects of high-flow nasal cannula in acute hypoxemic assess the effectiveness of different noninvasive supportive therapies respiratory failure. Am J Respir Crit Care Med 2017;195:1207–1215. or even their combined use. Indeed, in some patients, the 4. Herna ndez G, Vaquero C, Gonza  lez P, Subira C, Frutos-Vivar F, Rialp G, combination of different therapies may be associated with better et al. Effect of postextubation high-flow nasal cannula vs conventional outcomes (12). oxygen therapy on reintubation in low-risk patients: a randomized clinical trial. JAMA 2016;315:1354–1361. In summary, extubation failure pathophysiology is complex, and 5. Maggiore SM, Idone FA, Vaschetto R, Festa R, Cataldo A, Antonicelli F, different mechanisms could be in play in a single patient at the same et al. Nasal high-flow versus Venturi mask oxygen therapy after time. Identifying potential causes of extubation failure is crucial to extubation: effects on oxygenation, comfort, and clinical outcome. initiate the type of noninvasive supportive therapy that could be most Am J Respir Crit Care Med 2014;190:282–288. beneficial to each patient. Moreover, the use of different noninvasive 6. Maggiore SM, Jaber S, Grieco DL, Mancebo J, Zakynthinos S, Demoule A, et al. RINO Trial Study Group. High-flow versus supportive therapies, or the combination of some of them, according VenturiMask oxygen therapy to prevent re-intubation in hypoxemic to their physiological benefits and different clinical situations, may be patients after extubation: a multicenter, randomized clinical trial. a pragmatic approach to address any clinical situation of potential Am J Respir Crit Care Med 2022;206:1452–1462. extubation failure at the bedside. 䊏 7. Casey JD, Vaughan EM, Lloyd BD, Billas PA, Jackson KE, Hall EJ, et al. Protocolized postextubation respiratory support to prevent reintubation: a randomized clinical trial. Am J Respir Crit Care Med 2021;204:294–302. Author disclosures are available with the text of this article at 8. Rochwerg B, Brochard L, Elliott MW, Hess D, Hill NS, Nava S, et al. www.atsjournals.org. Official ERS/ATS clinical practice guidelines: noninvasive ventilation for acute respiratory failure. Eur Respir J 2017;50:1602426. 9. Esteban A, Frutos-Vivar F, Ferguson ND, Arabi Y, Apezteguıa C, Oriol Roca, M.D., Ph.D. Gonza lez M, et al. Noninvasive positive-pressure ventilation for Parc Taulı Hospital Universitari respiratory failure after extubation. N Engl J Med 2004;350:2452–2460. Sabadell, Spain 10. Stripoli T, Spadaro S, Di Mussi R, Volta CA, Trerotoli P, De Carlo F, et al. Ciber Enfermedades Respiratorias (CIBERES) High-flow oxygen therapy in tracheostomized patients at high risk of Madrid, Spain weaning failure. Ann Intensive Care 2019;9:4. 11. Goligher EC, Pen ~ uelas O. Postextubation respiratory support: of clinical and trials and clinical decisions. Am J Respir Crit Care Med 2021;204: noma de Barcelona Universitat Auto 245–247. Bellaterra, Spain 12. Thille AW, Muller G, Gacouin A, Coudroy R, Decave le M, Sonneville R, et al. HIGH-WEAN Study Group and the REVA Research Network. Lluıs Blanch, M.D., Ph.D. Effect of postextubation high-flow nasal oxygen with noninvasive Parc Taulı Hospital Universitari ventilation vs high-flow nasal oxygen alone on reintubation among Sabadell, Spain patients at high risk of extubation failure: a randomized clinical trial. and JAMA 2019;322:1465–1475. Ciber Enfermedades Respiratorias (CIBERES) Madrid, Spain Copyright © 2022 by the American Thoracic Society 1438 American Journal of Respiratory and Critical Care Medicine Volume 206 Number 12 | December 15 2022