BACKGROUND:Long-term controlled mechanical ventilation in the intensive care unit induces ventilator-induced diaphragm dysfunction (VIDD). The transition from controlled mechanical ventilation to assisted mechanical ventilation is a challenge that requires clinicians to balance overassistance and underassistance. While the effects of overassistance on the diaphragm are well known, the authors aimed to assess the impact of underassistance on diaphragm function and structure in a piglet model with preexisting VIDD (after long-term controlled mechanical ventilation) or without VIDD (short-term controlled mechanical ventilation). METHODS:Twenty-two Large White female piglets were anesthetized, ventilated, and separated into two groups: a VIDD group (n = 10) with long-term 72-h controlled mechanical ventilation, and a no-VIDD group (n = 12) with short-term 2-h controlled mechanical ventilation. After sedation reduction at the end of the controlled mechanical ventilation period, each piglet was switched to underassisted ventilation for 2 h. Diaphragm function (supramaximal diaphragm pressure-generating capacity assessed by negative tracheal pressure after transvenous phrenic nerve stimulation) and diaphragm structure (mini-invasive in vivo biopsies) were assessed before and after underassisted ventilation. RESULTS:In the VIDD group, supramaximal diaphragm pressure-generating capacity decreased by 22% from (mean ± SD) 69.9 ± 12.7 to 54.9 ± 19.7 cm H 2 O ( P = 0.04) after 72 h of controlled mechanical ventilation evidencing VIDD, then dropped by a further 29% from 54.9 ± 19.7 to 38.9 ± 15.5 cm H 2 O ( P < 0.01) after 2 h of underassisted ventilation. Diaphragm pressure-generating capacity remains stable from 55.3 ± 22.7 to 58.2 ± 24 cm H 2 O ( P = 0.24) in the no-VIDD group. Diaphragm structure showed that sarcomeric injuries increase from 13 ± 10% to 24 ± 19% ( P < 0.01) and lipid droplets decrease from 14 ± 8% to 11 ± 6% ( P = 0.03) of the total micrograph area after 2 h of underassisted ventilation in the VIDD group. Sarcomeric injuries and lipid droplets accounted, respectively, for 17 ± 16% and 2 ± 3% of the total micrograph area after underassisted ventilation in the no-VIDD group. CONCLUSIONS:In this porcine model, a short 2-h exposure of underassisted ventilation induces impairment of diaphragm function with damage to the diaphragm structure in intensive care unit condition with preexisting VIDD.

BACKGROUND: To our knowledge, no large observational study has compared the incidence and risk factors for extubation failure within 48 h and during ICU stay in the same cohort of unselected critically ill patients with and without obesity. RESEARCH QUESTION: What are the incidence and risk factors of extubation failure in patients with and without obesity? STUDY DESIGN AND METHODS: In the prospective multicenter observational Practices and Risk Factors for Weaning and Extubation Airway Failure in Adult Intensive Care Unit: A Multicenter Trial (FREEREA) study in 26 ICUs, the primary objective was to compare the incidence of extubation failure within 48 h in patients with and without obesity. Secondary objectives were to describe and to identify the independent specific risk factors for extubation failure using first a logistic regression model and second a decision tree analysis. RESULTS: Of 1,370 extubation procedures analyzed, 288 (21%) were performed in patients with obesity and 1,082 (79%) in patients without obesity. The incidence of extubation failure within 48 h among patients with or without obesity was 23 of 288 (8.0%) vs 118 of 1,082 (11%), respectively (unadjusted OR, 0.71; 95% CI, 0.45-1.13; P = .15); alongside patients with obesity receiving significantly more noninvasive ventilation [87 of 288 (30%) vs 233 of 1,082 (22%); P = .002] and physiotherapy [165 of 288 (57%) vs 527 of 1,082 (49%); P = .02] than patients without obesity. Risk factors for extubation failure also differed according to obesity status: female sex (adjusted OR, 4.88; 95% CI, 1.61-13.9; P = .002) and agitation before extubation (adjusted OR, 6.39; 95% CI, 1.91-19.8; P = .001) in patients with obesity, and absence of strong cough before extubation (adjusted OR, 2.38; 95% CI, 1.53-3.84; P = .0002) and duration of invasive mechanical ventilation before extubation (adjusted OR, 1.03/d; 95% CI, 1.01-1.06; P = .01) in patients without obesity. The decision tree analysis found similar risk factors. INTERPRETATION: Our findings indicate that anticipation and application of preventive measures for patients with obesity before and after extubation led to similar rates of extubation failure among patients with and without obesity.

This review aims to outline effective strategies for managing postoperative pulmonary complications, emphasizing both preventive and curative treatments across the perioperative timeline. In the post-anesthesia care unit (PACU), attention to the complete reversal of neuromuscular blockade has proven essential to mitigate associated respiratory risks. Furthermore, the application of non-invasive respiratory support like continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BiPAP) in the treatment of acute respiratory failure during the postoperative phase significantly enhances patient outcomes. The supportive measures, including early mobilization and screening for laryngeal injuries, might play a role in the comprehensive management of postoperative patients. As for preventive strategies, the application of perioperative protective (POP) ventilation should be considered standard of care in patients at high risk for postoperative pulmonary complications, such as patients with obesity. The management of severe postoperative pulmonary complications requires a proactive and multifaceted approach. This review underscores the importance of early and accurate intervention, including the timely and strategic use of non-invasive respiratory support to improve patient outcomes, especially in high-risk populations such as patients with obesity.

BACKGROUND:Diaphragm dysfunction is common in intensive care unit and associated with weaning failure and mortality. The diagnosis gold standard is the transdiaphragmatic or tracheal pressure induced by magnetic phrenic nerve stimulation. However, the equipment is not commonly available and requires specific technical skills. This study aimed to evaluate ultrasound-guided transcutaneous phrenic nerve stimulation for daily bedside assessment of diaphragm function by targeted electrical phrenic nerve stimulation. METHODS:This randomized crossover study compared a new method of ultrasound-guided transcutaneous electrical phrenic nerve stimulation (SONOTEPS) using a peripheral nerve stimulator, with magnetic phrenic nerve stimulation. Intensive care unit adult patients under mechanical ventilation with a Richmond Agitation-Sedation Scale score of -4 or -5 were included. Each patient received the two methods of stimulation, in a randomized order. The primary outcome was the tracheal pressure induced by stimulation. RESULTS:This study analyzed 232 measures of tracheal pressure from 116 patients, of whom 77 presented diaphragm dysfunction (tracheal pressure less than 11 cm H 2 O) and 50 presented severe diaphragm dysfunction (tracheal pressure less than 8 cm H 2 O). The Passing-Bablok regression showed no significant differences (intercept A of -0.03 [95% CI, -0.83 to 0.52] and slope B of 0.98 [95% CI, 0.90 to 1.05]) between the SONOTEPS method and magnetic stimulation, which were positively correlated ( R ² = 0.639). The mean bias was -1.08 (95% CI, 5.02 to -7.18) cm H 2 O. The receiver operating curves showed an excellent performance for the diagnosis of diaphragm dysfunction and severe diaphragm dysfunction with areas under the curve of 0.90 (95% CI, 0.83 to 0.97) and 0.88 (95% CI, 0.82 to 0.95), respectively. This performance was not significantly affected by the body mass index or the presence of a neck catheter. CONCLUSIONS:The SONOTEPS method is a simple and accurate tool for bedside assessment of diaphragm function with ultrasound-guided transcutaneous phrenic nerve stimulation in sedated patients with no or minimal spontaneous respiratory activity.

Ultra-protective ventilation is the combination of low airway pressures and tidal volume (Vt) combined with extra corporeal carbon dioxide removal (ECCO2R). A recent large study showed no benefit of ultra-protective ventilation compared to standard ventilation in ARDS (Acute Respiratory Distress Syndrome) patients. However, the reduction in Vt failed to achieve the objective of less than or equal to 3 ml/kg predicted body weight (PBW). The main objective of our study was to assess the feasibility of the ultra-low volume ventilation (Vt ≤ 3 ml/kg PBW) facilitated by ECCO2R in acute respiratory failure patients. Retrospective analysis of a prospective cohort of patients with either high or low blood flow veno-venous ECCO2R devices. A session was defined as a treatment of ECCO2R from the start to the removal of the device (one patient could have one more than one session). Primary endpoint was the proportion of sessions during which a Vt less or equal to 3 ml/kg PBW at 24 h after the start of ECCO2R was successfully achieved for at least 12 h. Secondary endpoints were respiratory variables, rate of adverse events and outcomes. Forty-five ECCO2R sessions were recorded among 41 patients. Ultra-low volume ventilation (tidal volume ≤ 3 ml/kg PBW, success group) was successfully achieved at 24 h in 40.0

Spontaneous breathing trials (SBT) evaluate the patient's capacity to maintain inspiratory effort after extubation. SBT practices are heterogeneous and not individualised. The objective of this study was to assess which SBT best reproduces inspiratory effort after extubation in five critical illnesses. In this multicentre randomized cross-over study, adult intensive care unit patients under invasive mechanical ventilation for at least 24-h and ready for extubation, underwent three 15-min SBTs in random order: pressure support ventilation level of 7-cmH2O with positive end-expiratory pressure (PEEP) level of 0-cmH2O (PSV7PEEP0), PSV 0-cmH2O with PEEP 0-cmH2O (PSV0PEEP0) and T-piece trial. Primary outcome was the variation of pressure–time-product per minute (PTPmin) between each SBT and 20-min after extubation. Five categories of critical illnesses were selected: abdominal surgery, brain injury, chest trauma, chronic obstructive pulmonary disease (COPD) and miscellaneous. Five hundred measures of effort from 100 patients were analysed. PTPmin (cmH2O s/min, median and interquartile range, IQR) was 256 (208–321) after extubation, 192 (127–281) at the end of PSV7PEEP0 (p < 0.001 in comparison to after extubation), 291 (235–347) at the end of PSV0PEEP0 and 262 (198–338) at the end of T-piece (both no different from after extubation). One method of SBT in patients with brain injury (PSV0PEEP0), two in abdominal surgery (PSV0PEEP0 and T-piece) and miscellaneous patients (PSV7PEEP0 and T-piece) and all three methods in chest trauma and COPD exacerbation patients replicated reasonably accurately the postextubation effort to breathe. Unassisted SBTs, namely PSV0PEEP0 and T-piece trial, are the most appropriate to replicate the postextubation effort to breathe.

Background:Patients with obesity are at high-risk of extubation failure. Discrepancies were found in the results of recent randomized controlled trials (RCTs) regarding the roles of noninvasive ventilation (NIV), high flow nasal cannula (HFNC) and conventional oxygen therapy (COT) to prevent extubation failure in critically ill patients with obesity. Methods:In this systematic review and network meta-analysis, we searched MEDLINE, Cochrane Center Register of Controlled Trials and Web of Science from 1 January 1998 to 1 July 2024 for RCTs evaluating noninvasive respiratory support therapies (NIV, HFNC, COT, NIV + HFNC) after extubation in critically ill adults with obesity. Primary outcome was reintubation at day 7. Secondary outcome was 28-day mortality. We generated pooled risk ratios (RR) and numbers needed to treat (NNT). We rated risk of bias using the Cochrane risk-of-bias 2.0 tool. The study was registered with PROSPERO (CRD 42022308995). Findings:In seven RCTs including 1933 patients, NIV + HFNC (RR 0.36 [95% confidence interval (CI) 0.16-0.82], NNT = 10 [95% CI 7-33]) and NIV (RR 0.45 [95% CI 0.23-0.88], NNT = 11 [95% CI 8-50]) but not HFNC (RR 0.79 [95% CI 0.40-1.59]) reduced reintubation at day 7, compared to COT. Compared to HFNC, NIV + HFNC (RR 0.46 [95% CI 0.23-0.90], NNT = 14 [95% CI 10-77]) but not NIV (RR 0.57 [95% CI 0.32-1.02]) reduced reintubation at day 7. Compared to HFNC, both NIV (RR 0.31 [95% CI 0.13-0.74], NNT = 15 [95% CI 12-40]) and NIV + HFNC (RR 0.30 [95% CI 0.10-0.89], NNT = 15 [95% CI 11-90]) reduced 28-day mortality. Interpretation:The results suggest that compared to COT and HFNC, NIV alone or with HFNC reduces reintubation in critically ill patients with obesity after extubation. Compared to HFNC, NIV alone or with HFNC reduces mortality. The number needed to treat with NIV or NIV + HFNC to avoid one death was 15. These findings support the application of NIV to mitigate extubation failure in critically ill adults with obesity. Funding:None.

BACKGROUND:The COVID-19 pandemic abruptly increased the inflow of patients requiring intensive care units (ICU). French health institutions responded by a twofold capacity increase with temporary upgraded beds, supplemental beds in pre-existing ICUs, or newly created units (New-ICU). We aimed to compare outcomes according to admission in expert pre-existing ICUs or in New-ICU. METHODS:This multicenter retrospective observational study was conducted in two 20-bed expert ICUs of a University Hospital (Expert-ICU) and in one 16-bed New-ICU in a private clinic managed respectively by 3 and 2 physicians during daytime and by one physician during the night shift. All consecutive adult patients with COVID-19-related acute hypoxemic respiratory failure admitted after centralized regional management by a dedicated crisis cell were included. The primary outcome was 180-day mortality. Propensity score matching and restricted cubic spline for predicted mortality over time were performed. RESULTS:During the study period, 165 and 176 patients were enrolled in Expert-ICU and New-ICU respectively, 162 (98%) and 157 (89%) patients were analyzed. The unadjusted 180-day mortality was 30.8% in Expert-ICU and 28.7% in New-ICU, (log-rank test, p =  0.7). After propensity score matching, 123 pairs (76 and 78%) of patients were matched, with no significant difference in mortality (32% vs. 32%, OR 1.00 [0.89; 1.12], p = 1). Adjusted predicted mortality decreased over time (p < 0.01) in both Expert-ICU and New-ICU. CONCLUSIONS:In COVID-19 patients with acute hypoxemic respiratory failure, hospitalization in a new ICU was not associated with mortality at day 180.

Background In studies prior to lung-protective ventilation, liver cirrhosis in acute respiratory distress syndrome (ARDS) was associated with high mortality rates. Since patients with cirrhosis have been excluded from many trials on ARDS, their outcome when treated with lung-protective ventilation is unclear. The objectives were to assess whether cirrhosis is associated with mortality in ARDS and trends over time in mortality and severity. Methods We conducted a retrospective analysis of a prospective observational cohort conducted in a 20-bed tertiary ICU from October 2003 to December 2021. All consecutive adult critically ill patients with ARDS were included. ARDS was defined by the Berlin criteria. The primary outcome was 90 day mortality, assessed with Kaplan–Meier curves and multivariate Cox analysis. Time trends were assessed on 90 day mortality, Sequential Organ-Function Assessment score (SOFA) and non-hepatic SOFA. Ventilation settings were compared between patients with and without cirrhosis. Results Of the 7155 patients screened, 863 had a diagnosis of ARDS. Among these ARDS patients, 157(18%) had cirrhosis. The overall 90 day mortality was of 43% (378/863), 57% (90/157) in patients with cirrhosis and 41% (288/706) in patients without cirrhosis ( p < 0.001). On survival curves, cirrhosis was associated with 90 day mortality ( p < 0.001). Cirrhosis was independently associated with 90 day mortality in multivariate analysis (hazard ratio = 1.56, 95% confidence interval 1.20–2.02). There was no change in mortality over time in ARDS patients with and without cirrhosis. SOFA ( p = 0.04) and non-hepatic SOFA ( p = 0.02) increased over time in ARDS patients without cirrhosis, and remained stable in ARDS patients with cirrhosis. Tidal volume, positive end-expiratory pressure, plateau pressure and driving pressure were not different between ARDS patients with and without cirrhosis. Conclusions Although ARDS management improved over the last decades, the 90 day mortality remained high and stable over time for both ARDS patients with (57%) and without cirrhosis (41%). Nevertheless, the severity of patients without cirrhosis has increased over time, while the severity of patients with cirrhosis has remained stable. Graphical Abstract

Introduction Readiness to be freed from ventilatory support can be evaluated by spontaneous breathing trial (SBT) assessing the patient’s ability to sustain respiratory effort after extubation. Current SBT practices are heterogenous and there are few physiological studies on the topic. The objective of this study is to assess which SBT best reproduces inspiratory effort to breathe after extubation depending on the patient’s illness. Methods and analysis This will be a multicentre randomised cross-over physiological study, in a large population, in the era of modern intensive care units using last generation modern ventilators. Each included patient will perform three 15-minute SBTs in a random order: pressure support ventilation (PSV) level of 7 cmH 2 O with positive end expiratory pressure (PEEP) level of 0 cmH 2 O, PSV 0 cmH 2 O with PEEP 0 cmH 2 O and T-piece trial. A rest period of baseline state ventilation will be observed between the SBTs (10 min) and before extubation (30 min). Primary outcome will be the inspiratory muscle effort, reflected by pressure time product per minute (PTPmin). This will be calculated from oesophageal pressure measurements at baseline state, before and after each SBT and 20 min after extubation. Secondary outcomes will be PTPmin at 24 hours and 48 hours after extubation, changes in physiological variables and respiratory parameters at each step, postextubation respiratory management and the rate of successful extubation. One hundred patients with at least 24 hours of invasive mechanical ventilation will be analysed, divided into five categories of critical illness: abdominal surgery, brain injury, chest trauma, chronic obstructive pulmonary disease and miscellaneous (pneumonia, sepsis, heart disease). Ethics and dissemination The study project was approved by the appropriate ethics committee (2019-A01063-54, Comité de Protection des Personnes TOURS - Région Centre - Ouest 1, France). Informed consent is required, for all patients or surrogate in case of inability to give consent. Trial registration number NCT04222569 .

BACKGROUND: In critically ill patients, warnings about a risk of death and acute kidney injury (AKI) with hydroxyethyl starch (HES) solutions have been raised. However, HES solutions may yet have a role to play in major abdominal surgery. This meta-analysis and trial sequential analysis (TSA) aimed to investigate the effect of HES intravascular volume replacement on the risk of AKI, intraoperative blood transfusion, and postoperative intra-abdominal complications compared to crystalloid intravascular volume replacement. METHODS: In this meta-analysis and TSA, we searched for randomized controlled trials (RCTs) comparing intraoperative HES intravascular volume replacement to crystalloid intravascular volume replacement in adult patients undergoing major abdominal surgery. Primary outcome was 30-day AKI, defined as a binary outcome according to Kidney Disease Improving Global Outcomes (KDIGO) criteria, combining stages 1, 2, and 3 into an AKI category versus no AKI category (stage 0). Secondary outcomes included rates of intraoperative blood transfusion and postoperative intra-abdominal complications. We used random effects models to calculate summary estimates. We used relative risk (RR) as summary measure for dichotomous outcomes, with corresponding 95% confidence intervals (CIs) for the primary outcome ( P value <.05 was considered statistically significant) and 99% CI after Bonferroni correction for the secondary outcomes ( P value <.01 was considered statistically significant). RESULTS: Seven RCTs including 2398 patients were included. HES intravascular volume replacement was not associated with an increased risk of 30-day AKI (RR = 1.22, 95% CI, 0.94–1.59; P = .13), when compared to crystalloid intravascular volume replacement. According to TSA, this analysis was underpowered. HES intravascular volume replacement was associated with higher rates of blood transfusion (RR = 1.57 99% CI, 1.10–2.25; P = .001), and similar rates of postoperative intra-abdominal complications (RR = 0.76 99% CI, 0.57–1.02; P = .02). CONCLUSIONS: In this meta-analysis to focus on HES intravascular volume replacement in major abdominal surgery, HES intravascular volume replacement was not associated with a higher risk of 30-day AKI when compared to crystalloid intravascular volume replacement. However, CI and TSA do not exclude harmful effects of HES intravascular volume replacement on the renal function.

L’obésité est un facteur de risque important de complications majeures, de morbidité et de mortalité liées à la procédure d’intubation et de ventilation en réanimation. La chute de la capacité résiduelle fonctionnelle entraîne une fermeture des voies aériennes et la formation d’atélectasies. Pour optimiser la prise en charge des voies aériennes ainsi que la ventilation, qu’elle soit non invasive ou invasive, la position semi-assise ou en Trendelenburg inversé est conseillée. La préoxygénation par pression positive avant la procédure d’intubation est la méthode de référence, pouvant s’associer à une oxygénation apnéique pendant la laryngoscopie. Pour l’intubation, la vidéolaryngoscopie peut avoir un intérêt quand elle est réalisée par des opérateurs entraînés, surtout chez les patients qui ont plusieurs facteurs de risque d’intubation difficile. Concernant la ventilation mécanique chez les patients avec et sans syndrome de détresse respiratoire aiguë (SDRA), sont conseillés : un volume courant bas (6mL/kg de poids prédit), une pression expiratoire positive (PEP) modérée à élevée en cas de présence d’un SDRA, si possible titrée de manière décrémentielle après une manœuvre de recrutement. Le décubitus ventral est un traitement de choix chez les patients avec obésité en SDRA sévère.

Obesity is an important risk factor for major complications, morbidity and mortality associated with the intubation and ventilation procedure in intensive care unit (ICU). The drop in functional residual capacity leads to airway closure and the formation of atelectasis. To optimise airway management, as well as ventilation, whether non-invasive or invasive, the semi-seated or reverse Trendelenburg position is recommended. Positive pressure pre-oxygenation before the intubation procedure is the gold standard, which can be combined with apnoeic oxygenation during laryngoscopy. For intubation, video laryngoscopy may be of interest when performed by trained operators, especially in patients who have several risk factors for difficult intubation. Regarding mechanical ventilation in patients with and without acute respiratory distress syndrome (ARDS), the following are recommended: low tidal volume (6 mL/kg of predicted body weight), moderate to high positive expiratory pressure (PEEP) if present of an ARDS, if possible titrated using a decremental method after a recruitment manoeuvre. Prone position is the treatment of choice in patients with obesity and severe ARDS.

Plus de 10 % des patients chirurgicaux vont présenter au moins une complication pulmonaire postopératoire. Plus les patients ont des comorbidités et plus la chirurgie est longue et invasive, plus le risque de complications pulmonaires augmente. L’oxygénothérapie nasale à haut débit (OHD) est un dispositif qui fournit un gaz inspiratoire chauffé et humidifié par une canule nasale à des débits plus élevés que l’oxygénothérapie conventionnelle (jusqu’à 70L/min), avec une fraction inspirée en oxygène (FiO2) pouvant varier de 21 % à 100 %. Au niveau physiologique, l’OHD améliore l’oxygénation, augmente les résistances expiratoires (responsable d’un modeste « effet Pression Expiratoire Positive » (PEP)), présente un effet lavage d’espace mort anatomique, améliore la clairance muco-ciliaire et diminue le coût métabolique de la respiration en fournissant un gaz inspiratoire réchauffé et humidifié. L’OHD a été proposée pour la procédure d’intubation au bloc opératoire. Seule, elle n’est pas aussi efficace que la méthode au masque pour la préoxygénation. Elle permet une oxygénation apnéique après la perte de la ventilation spontanée du patient, sans remplacer la ventilation au ballon en cas de désaturation. L’OHD peut être utilisée pour certaines procédures sans intubation, comme la chirurgie oro-pharyngée, l’endoscopie digestive ou l’électroconvulsivothérapie. L’oxygénation apnéique est efficace dans ces situations pour prévenir la désaturation. En périopératoire, l’OHD peut être utilisée pour la prévention de la détresse respiratoire aiguë postopératoire, notamment chez le patient hypoxémique ne tolérant pas la ventilation non invasive (VNI) ou la pression positive continue (continuous positive airway pressure, CPAP). En cas de survenue d’une détresse respiratoire aiguë postopératoire, une complication chirurgicale devra être éliminée. La VNI reste aujourd’hui la technique de référence, même si l’OHD a montré sa non-infériorité après chirurgie cardiothoracique.

More than 10 % of surgical patients will present at least one postoperative pulmonary complication. The more patients have comorbidities and the longer and more invasive the surgery, the greater the risk of pulmonary complications. High-Flow Nasal Oxygen Therapy (HFNO) is a device that delivers inspiratory gas heated and humidified through a nasal cannula at higher flow rates than conventional oxygen therapy (up to 70 L/min), with an inspired fraction in oxygen (FiO2) which can vary from 21 % to 100 %. At the physiological level, HFNO improves oxygenation, increases expiratory resistance (responsible for a modest "Positive Expiratory Pressure effect'' (PEP)), presents an anatomical dead space washing effect, improves mucociliary clearance and decreases the metabolic cost of respiration by providing warmed and humidified inspiratory gas. HFNO has been proposed for the operating theatre intubation procedure. It is not as effective as the bag valve mask method for pre-oxygenation. However, it can allow apnoeic oxygenation after the patient has lost spontaneous ventilation, without replacing bag valve mask ventilation in the event of desaturation. HFNO can be used for some procedures without intubation, such as oropharyngeal surgery, gastrointestinal endoscopy or electroconvulsive therapy. Apnoeic oxygenation is effective in these situations to prevent desaturation. Perioperatively, HFNO can be used for the prevention of acute postoperative respiratory distress, particularly in hypoxemic patients who cannot tolerate non-invasive ventilation (NIV) or continuous positive airway pressure (CPAP). If acute postoperative respiratory distress occurs, a surgical complication should be eliminated. NIV remains the gold standard nowadays, even though HFNO has shown its non-inferiority after cardiothoracic surgery.