Editorial
Extubation Failure Among Patients With Obesity
Amit Kansal, Maurizio Cecconi
Chest 2025; 167: 11-13
https://doi.org/10.1016/j.chest.2024.08.021
Up to 10% of the adult patients who are being mechanically ventilated in ICUs suffer from extubation failure after planned extubation.1 The risk may increase to 20% among the high-risk patients2; those older than 65 years; and those with underlying cardiac disease, chronic respiratory disorders, or hypercapnia at the time of extubation. Extubation failure in ICU setting is associated with poorer outcomes.1,2 This has led to an interest in use of respiratory support (noninvasive ventilation [NIV] as well as high-flow nasal cannula [HFNC]) to prevent extubation failure.2
Patients with obesity are particularly at high risk of extubation failure because of various pathophysiologic characteristics, including reduction in lung volume, early airway closure, expiratory flow limitation, decreased pulmonary and thoracic compliance, and a reduction of functional residual capacity compared with patients without obesity, making them prone to atelectasis and more frequent obstructive apnea syndrome and sleep-disordered breathing, which is often underdiagnosed.3 Clinical studies also show that the patients with obesity are prone to weaning difficulties, increased duration of mechanical ventilation (MV) before extubation, and high risk of extubation failure (6%-21%).4,5 Patients with obesity who develop extubation failure also have poorer outcomes, as compared with extubation success.2,4,6
Similar to other high-risk patients, clinical studies have investigated the role of respiratory support among patients with obesity.4,5 Application of positive pressure may prevent atelectasis and therefore may improve oxygenation and reduce work of breathing, reduce muscle exhaustion, and also help with OSA.3 Additionally, aggressive physiotherapy has been proposed to reduce the risk of extubation failure.7 Despite the increasing body of evidence suggesting improved outcomes with preemptive application of NIV or HFNC after extubation among patients with obesity,4,5 the studies have variable methodology (historical controls, crossover design, only including high-risk patients, different definition of obesity, timing of outcome measurement, duration of MV before extubation, NIV alone vs cycling with HFNC).
With this background, in this issue of CHEST, De Jong et al8 present retrospective analysis of prospectively collected data of 1,341 patients, including 288 patients with BMI > 30, from the large multicenter, pragmatic observational Practices and Risk Factors for Weaning and Extubation Airway Failure in Adult Intensive Care Unit: A Multicenter Trial (FREE-REA) study.9 Study analysis shows that patients with obesity were older and received significantly more careful preparation before extubation and management after extubation, such as the application of a spontaneous breathing trial, reintubation kit readiness, and more preventive NIV and physiotherapy after extubation. Patients with obesity had a longer duration of MV, a higher proportion required postextubation curative NIV, and longer ICU as well as hospital stay; however, extubation failure rates were comparable, and overall mortality remained similar. Pragmatic study design may have captured the excellent clinical practice; preemptive measures put in place before and after extubation in these high-risk patients led to comparable outcomes despite older patients in the obesity cohort. Additionally, these findings reiterate the weaning difficulties likely to be encountered in patients with obesity.
The study results are nicely supported by literature.4,5 Recently, the Noninvasive Ventilation Following Extubation (Prophylactic) to Prevent Extubation Failure in Critically Obese Patients (EXTUB-OBESE) study, a large multicenter, randomized controlled trial (RCT) conducted in 39 ICUs in France including 981 patients with obesity (BMI ≥ 30) demonstrated that for every eight such patients, using NIV would prevent treatment failure in one patient.4 Similarly, post-hoc analysis from a well-conducted RCT of 206 patients with obesity at high risk of extubation failure suggested improved outcomes with NIV alternating with HFNC.5
Current retrospective work by De Jong et al8 has a few points that are noteworthy. The primary outcome was objective, defined as the need for reintubation within 48 hours after extubation. The authors conducted a post hoc analysis using a composite secondary outcome: reintubation within 48 hours or use of curative NIV, similar to the EXTUB-OBESE RCT.4 The composite outcome did not differ between groups. A subgroup analysis was also performed according to the duration of invasive MV before extubation (≤ or > 8 days) and showed a similar outcome. Additionally, the study captures a real-life approach regarding physiotherapy, which was used in only 50% of the cases and, as the authors point out, it may not benefit the remaining ones with short duration of MV. Finally, the authors need to be congratulated for a thorough statistical plan including use of decision tree analysis to study the risk factors.10
There are certainly several limitations to this study. These include lack of information regarding use of protocols for weaning, readiness for extubation, and selection criteria for pre-emptive measures. Six percent of patients with missing BMI data were excluded from the analysis. Analysis of patient groups according to presence or absence of high-risk features like previous studies definitely would have provided better understanding for readers.5
Additionally, future studies should also analyze the role of HFNC in this setting. Previous studies, including patients with obesity and an unselected population of high-risk patients, have shown comparable outcomes between pre-emptive HFNC and NIV use postextubation.11
What can we learn from the results of the study by De Jong et al? The authors present important work that will add to the existing knowledge base regarding weaning practices among patients with obesity. Obesity is easy to identify and quantify, and preemptive measures (respiratory support, chest physiotherapy) before and after extubation, may improve outcomes, matching the patients without obesity. The due diligence in planning and interventions required are relatively simple and safe. They can be implemented easily in current practice for such high-risk patients, while awaiting further trials comparing various modes of respiratory support. It is important to appreciate that this use of NIV is for prevention and not for the treatment of acute respiratory failure after extubation.6 The potential benefits including mortality benefit would outweigh concerns over physiotherapists’ and respiratory therapists’ higher workload, prolonged duration of MV, or prolonged ICU stay with postextubation respiratory support.
Future large RCTs need to be conducted among patients with obesity to confirm whether NIV or HFNC should be used in all patients with obesity or only certain subgroups. This may be explored by using machine learning methods to enhance the ability to understand complex nonlinear interactions and subsequently identify treatment effect heterogeneity at the individual level.10
