BACKGROUND Critically ill patients often present on admission or develop acute respiratory failure requiring intubation and application of positive pressure ventilation during their hospital stay. AIM To investigate and identify the epidemiological data, parameters associated with respiratory settings or the mechanics, and values related to arterial blood gases (ABGs) that are associated with outcomes in critically ill patients. METHODS A retrospective analysis of 131 patients [mean age, 67.3 years; mean acute physiology and chronic health evaluation (APACHE) score, 21.4] with acute respiratory failure requiring invasive mechanical ventilation was performed. The parameters that were statistically analyzed included demographic data, the presence of comorbidities, the presence of coronavirus disease 19 (COVID-19), the respiratory rate (RR), peak airway pressure (Ppeak), minute ventilation (MV), positive end-expiratory pressure, and the values related to ABGs. In order to facilitate the statistical analysis, patients were evaluated and compared in groups: Survivors (n = 41) vs non-survivors (n = 90) and patients without acute kidney injury (AKI) (n = 60) vs patients with AKI (n = 71). Four endpoints were studied: Mortality, length of stay, duration of mechanical ventilation, and AKI. Group comparisons were performed using the following statistical tests: The χ 2 test with Yates’ correction, Fisher’s exact test, the Mann-Whitney U test, and Spearman’s rank correlation analysis. Binary logistic regression analysis conducted after the univariate statistical tests facilitated the investigation of the independent predictors of mortality and AKI. A two-sided P value of less than 0.05 was considered the threshold of statistical significance. RESULTS Non-survivors presented statistically significant differences in terms of being older in age, the presence of comorbidities, elevated APACHE score, medical (vs surgical) reasons for admission, presence of COVID-19, lower pH at ABGs, lower values of the oxygenation ratio (arterial oxygen partial pressure to the fraction of inspired oxygen) and arterial oxygen partial pressure, and elevated values of Ppeak, positive end-expiratory pressure, RR, arterial carbon dioxide partial pressure, and MV. The factors identified as independent predictors of mortality were the presence of comorbidities, APACHE score, COVID-19 status, arterial carbon dioxide partial pressure, Ppeak, RR, and MV. COVID-19 presence and elevated values of RR and Ppeak were positively correlated with the other three endpoints (length of stay, the duration of mechanical ventilation in survivors, and the occurrence of AKI in the entire study population) that were studied. The other parameters exhibited a variable (either positive/negative, or no) correlation to the four endpoints under investigation. CONCLUSION Among all investigated outcome measures, COVID-19, Ppeak, and RR were strongly associated with all the endpoints studied, suggesting that proper interventions involving the modifiable respiratory parameters Ppeak and RR could improve the overall outcome in these patients. A novel finding of this study was the relationship between RR and AKI, which is worthy of further investigation. Future studies may explore the clinical interpretation of these findings to improve outcomes in critically ill patients with acute respiratory failure.

The effect of individualized high positive end-expiratory pressure (PEEP) and recruitment maneuvers, targeting a low driving pressure, on clinical outcomes in patients undergoing open abdominal surgery is uncertain. To compare driving pressure-guided high PEEP and recruitment maneuvers with standard low PEEP without recruitment maneuvers with respect to postoperative pulmonary complications. Randomized clinical trial of 1435 adults at increased risk for postoperative pulmonary complications who were scheduled for open abdominal surgery. The trial was conducted at 29 sites in 5 countries across Europe from April 2019 to December 2024; final follow-up was in March 2025. Statistical analysis was conducted in May 2025. Patients were randomized to undergo intraoperative ventilation with driving pressure-guided high PEEP and recruitment maneuvers (n = 718) or to intraoperative ventilation with standard low PEEP (n = 717). All patients received low tidal volume ventilation. The primary outcome was a composite of pulmonary complications within the first 5 postoperative days, including severe respiratory failure, bronchospasm, suspected pulmonary infection, pulmonary infiltrates, aspiration pneumonitis, atelectasis, acute respiratory distress syndrome, pleural effusion, cardiopulmonary edema, and pneumothorax. Among the 16 prespecified secondary outcomes, 4 concerned intraoperative complications, including hypotension (decrease in mean arterial pressure of >20% for >3 minutes) and desaturation (Spo2 <92% for >1 minute). Among 1468 adults, 1435 (98%) completed the trial (median [IQR] age, 66 [57-74] years; 52% female). In the primary analysis population, the primary outcome occurred in 142 of 718 patients (19.8%) in the driving pressure-guided high PEEP group compared with 125 of 717 patients (17.4%) in the low PEEP group (absolute difference, 2.5% [95% CI, -1.5% to 6.4%]; P = .23). The incidence of hypotension (382 [54.0%] vs 317 [45.0%]) and use of vasoactive agents (224 [32.0%] vs 130 [18.8%]) was higher in the high PEEP group; the incidence of intraoperative desaturation (6 [0.8%] vs 20 [2.8%]) was higher in the low PEEP group. Among patients at increased risk for postoperative pulmonary complications undergoing open abdominal surgery under general anesthesia, intraoperative ventilation with driving pressure-guided high PEEP and recruitment maneuvers, compared with a strategy with standard low PEEP, did not reduce postoperative pulmonary complications. ClinicalTrials.gov Identifier: NCT03884543.

Pendelluft and expiratory muscle activity during spontaneous breathing should be minimized to reduce potential harmful effects. This study aimed to describe pendelluft and expiratory muscle activity in hypoxemic patients recovering spontaneous breathing after ≥ 72h of lung-protective, fully controlled mechanical ventilation (MV) and assess the effect of pressure support ventilation (PSV) and positive end-expiratory pressure (PEEP). A physiological, randomized crossover study was conducted in hypoxemic patients receiving three levels of PSV: 5, 10, and 15 cmH₂O, and two PEEP levels: based on electrical impedance tomography before spontaneous breathing (PEEPEIT) or according to PEEP-FiO2 tables (PEEPARDS). Pendelluft was defined as the percentage of volume displaced from non-dependent to dependent lung regions during inspiration. Expiratory muscle activity was assessed by the expiratory rise in gastric pressure (ΔPgaEXP), and inspiratory effort was estimated using muscular pressure (Pmus). Statistical analyses included linear mixed-effects models and mediation analyses. Fifteen patients were enrolled (mean PaO2/FiO2 ratio: 262 ± 51mmHg; median duration of MV: 9 [5-13] days; 6 females). PEEPEIT was 11 [10-13] cmH₂O and PEEPARDS 6 [5-7] cmH₂O. Expiratory muscle activity was observed in 13 patients. Compared to PS 5 cmH2O, PS to 10 and 15 cmH2O, adjusted for PEEP, significantly reduced both pendelluft and ΔPgaEXP (p < 0.001). When adjusted for PS, PEEPEIT was associated with a slight reduction in pendelluft (p = 0.039) but a concomitant increase in ΔPgaEXP (p = 0.007) compared to PEEPARDS. The mediation analysis revealed a significant negative mediating effect of ΔPgaEXP on the relationship between PEEPEIT and pendelluft (p < 0.001). Pmus, which was also significantly associated with pendelluft magnitude (p < 0.001), mediated the effect of PS on reducing pendelluft (p = 0.048), but not that of PEEP (p = 0.46). In patients with ARDS transitioning to spontaneous breathing, increasing PS reduces pendelluft and expiratory muscle activity. Higher PEEP can decrease pendelluft, but its effect can be counteracted by increased expiratory activity.

OBJECTIVES:To identify the prevalence of over-assistance from mechanical ventilation (MV) and to assess whether reducing MV support could be done safely in neurosurgical ICU patients in terms of risk of under-assistance and brain’s oxygenation.DESIGN:Prospective observation study.SETTING:Neurosurgical trauma ICU, Toronto, ON, Canada.PATIENTS:Twenty-seven brain-injured patients on MV having indication of a spontaneous breathing trial (SBT).INTERVENTIONS:Level of pressure support ventilation (PSV).MEASUREMENTS AND MAIN RESULTS:In neurosurgical patients, regional ventilation distribution using electrical impedance tomography, patient’s respiratory drive (airway occlusion at 100 ms [P0.1]), respiratory muscle pressure (Pmus), diaphragm and parasternal intercostal (PI) thickening fraction, brain oximetry, and electroencephalogram were assessed at clinical PSV (ClinPS), low PSV (LowPS, pressure support [PS] 5 cm H2O, positive end-expiratory pressure [PEEP] 5 cm H2O), SBT, PS 0 cm H2O, and PEEP 0 cm H2O. Over-assistance was defined by pressure muscle index less than 0 cm H2O; under-assistance was defined as Pmus greater than or equal to 15 cm H2O. Mixed effects models were used for analysis. Imbalanced dorsal/ventral distribution of ventilation improved by reducing assistance while respiratory effort increased. Over-assistance was present in ten cases (37%) during ClinPS and in none at LowPS and SBT; under-assistance was present in two, four, and seven cases at ClinPS, LowPS, and SBT. During SBT, compliance and end-expiratory lung volume decreased (p < 0.0001). Brain activity did not vary. P0.1 greater than or equal to 4 cm H2O was associated with Pmus greater than or equal to 15 cm H2O with 80% sensitivity and 91% specificity during SBT.CONCLUSIONS:Neurosurgical patients seem to frequently be overassisted under PSV. Reducing the ventilatory support is often feasible and Pmus and P0.1 can help with detecting under-assistance.

To review the current knowledge on mechanical ventilation after cardiac arrest, carefully balancing the protection of both the brain and the lungs. Although lung-protective ventilation (LPV) strategies are often considered in the general population and widely studied in acute respiratory distress syndrome (ARDS) patients, current knowledge focused on patients after cardiac arrest is unclear. Mechanical ventilation in this unique population should prevent potential brain injury while also avoiding ventilation-induced lung injury. This includes optimizing ventilation parameters, such as tidal volume ( VT ), positive end-expiratory pressure (PEEP), and gas exchange targets, while also considering the impact on cerebral perfusion and intracranial pressure. The role of LPV in patients without ARDS and after cardiac arrest is still uncertain. In this review, we updated the strategy to optimize mechanical ventilation after cardiac arrest with the primary aim of protecting the lungs and brain, improving the patients' outcomes.

An e-survey study on the practice of recruitment manoeuvres in dogs among board-certified veterinary anaesthesia and analgesia specialists.

Association of intraoperative end-tidal CO2 levels with postoperative outcomes: a patient-level analysis of two randomised clinical trials.

Electrical impedance tomography (EIT)-guided positive end-expiratory pressure (PEEP) titration may optimize ventilation and reduce ventilator-induced lung injury in acute respiratory distress syndrome (ARDS). We compared EIT-guided PEEP with low PEEP/FiO₂ strategy in patients with moderate-to-severe ARDS. In this randomized controlled trial, 108 patients with PaO₂/FiO₂ below 200mmHg were allocated to EIT-guided PEEP after a recruitment maneuver (n = 56) or low PEEP/FiO₂ strategy (n = 52). Patients in the EIT group underwent PEEP titration guided by the intersection point between alveolar overdistension and collapse during a decremental PEEP trial. Primary outcomes were oxygenation (PaO₂/FiO₂) and static compliance. Secondary outcomes included mortality, ventilator-free days, ICU stay, barotrauma, rescue therapies, and sequential organ failure assessment (SOFA) score changes. On day 1, oxygenation was higher with EIT (mean PaO₂/FiO₂ 180 vs. 159mmHg; p = 0.036). Static compliance was greater at both day 1 (26 vs. 23mL/cmH₂O; p = 0.016) and day 2 (27 vs. 24mL/cmH₂O; p = 0.029). Driving pressure was lower with EIT at day 1 (16 vs. 17 cmH₂O; p < 0.001) and day 2 (15 vs. 17 cmH₂O; p = 0.005). SOFA scores improved more in the EIT group (day 1: - 1 vs. 0, p = 0.013; day 2: - 1 vs. - 0.5, p = 0.015). Twenty-eight-day mortality was lower with EIT (29 vs. 44%), although not statistically significant (p = 0.090). ICU stay, ventilation duration, barotrauma, ECMO use, and rescue therapies were similar. Benefits were most pronounced in patients with severe ARDS. EIT-guided PEEP improved oxygenation, lung mechanics, and reduced organ dysfunction in moderate-to-severe ARDS, particularly in severe cases. It showed a trend toward reduced mortality and may serve as a practical bedside tool for lung-protective ventilation. Larger multicenter trials are needed to confirm its clinical benefits.Trial registration: ClinicalTrials, NCT06733168. Registered on 13/12/2024, https://clinicaltrials.gov/study/NCT06733168.

Mechanical ventilation is essential in acute hypoxemic respiratory failure (AHRF), yet excessive respiratory drive and inspiratory effort may aggravate injury, a phenomenon termed patient self-inflicted lung injury (P-SILI). This review summarizes mechanistic insights, preclinical and clinical evidence, and current strategies to prevent P-SILI while preserving diaphragmatic function. Preclinical experimental studies show that vigorous inspiratory efforts amplify pleural pressure swings, regional overdistension, pendelluft, and inflammation, with damage involving both lung and diaphragm. positive end-expiratory pressure (PEEP) and continuous positive airway pressure (CPAP) can homogenize ventilation, reduce strain-rate, and protect diaphragmatic mechanics, whereas uncontrolled effort worsens outcomes. Clinical investigations confirm that high drive and effort increase total lung stress despite protective tidal volumes and are linked to mortality, ventilator dependence, and complications such as pneumomediastinum. Emerging approaches include titrated pressure support and sedation and ventilatory assistance, neuromuscular blockade, phrenic nerve block, pharmacological drive modulation, prone positioning, and extracorporeal CO2 removal. Strategies aimed at preserving diaphragm activity, such as electrical phrenic stimulation or inspiratory muscle training, further broaden protective options. P-SILI arises when excessive inspiratory effort translates into injurious lung and diaphragm stress. Preventive strategies should not abolish but shape effort, integrating ventilatory settings, sedation, and drive-modulating interventions across the continuum from the acute phase to weaning and rehabilitation.

Prolonged ECMO has become more common during the COVID-19 pandemic but is associated with high resource utilization and poor outcomes. This study aimed to identify predictors of prolonged ECMO and explore prognostic indicators in patients who underwent prolonged ECMO. This multicenter retrospective study analyzed patients who underwent venovenous ECMO for severe COVID-19 at three high-volume ECMO centers in Japan from January 2020 to December 2021. Patients requiring ECMO for ≥ 21 days were classified as the prolonged ECMO group. The study was structured in four steps: [1] comparison of baseline characteristics between survivors and non-survivors [2], identification of pre-ECMO predictive factors for prolonged ECMO [3], determination of prognostic factors among prolonged ECMO patients, and [4] comparison with established prognostic scoring systems. Among 121 patients, 32 (26%) required prolonged ECMO. Lower positive end-expiratory pressure (PEEP) before ECMO was identified as an independent predictor of prolonged ECMO (P < 0.001), with an optimal cutoff of 12 cmH₂O (area under the curve [AUC]: 0.70). Among prolonged ECMO patients, the Sequential Organ Failure Assessment (SOFA) score on ECMO day 21 was the only independent predictor of in-hospital survival (P = 0.002), with an optimal cutoff value of 12 (AUC: 0.82). The SOFA score on day 21 outperformed established prognostic scoring systems. Lower PEEP before ECMO is a predictor of prolonged ECMO. In patients undergoing prolonged ECMO, the SOFA score on day 21 is an independent predictor of survival. Continuous assessment of organ dysfunction during ECMO may enhance prognostic evaluation and support clinical decision-making.

Laparoscopic surgery, the application of pneumoperitoneum and surgical positions other than the supine position have been related to hemodynamic changes and respiratory alterations that could modify the pressures of the respiratory system; It is one of the most frequent elective surgical procedures in our environment, so adequate perioperative management of patients is an important strategy to reduce hospital morbidity. A prospective study was carried out in 71 patients undergoing elective laparoscopic cholecystectomy, in which the plateau pressure was determined and the pulmonary distention pressure was calculated at four different moments of the surgical event. Statistical analysis included descriptive analysis and inferential tests (Friedman’s test with Dunn’s post hoc). A p value &lt; 0.5 was considered significant. The study sought to understand the effects of pneumoperitoneum on pulmonary pressures, to improve perioperative care protocols. Statistically significant changes were observed with respect to baseline values at two specific times: after the establishment of pneumoperitoneum and after surgical positioning in inverted Trendelenburg. No statistically significant relationships were identified when comparing body mass index (BMI), age and gender. Pulmonary distension pressure increases significantly with the placement of pneumoperitoneum and with the inverted Trendelenburg surgical position, which results in a change in the relationship between lung compliance, positive end-expiratory pressure and tidal volume.

BackgroundVentilator-associated pneumonia (VAP) is a major contributor to morbidity and mortality in critically ill patients receiving mechanical ventilation. Microaspiration of subglottic secretions has a pivotal role in VAP pathogenesis, yet the optimal positive end-expiratory pressure (PEEP) for preventing microaspiration has not been extablished.MethodsThis prospective, single-center study determined the impact of different PEEP levels on microaspiration in 90 mechanically ventilated patients. Participants were stratified into three groups based on PEEP levels (0–3 cmH₂O, 4–6 cmH₂O, and 7–10 cmH₂O). Primary outcomes included biomarkers, such as pepsin concentration in airway secretions, and the incidence of microaspiration. Secondary outcomes assessed subglottic secretion volume, mechanical ventilation duration, and ICU length of stay.ResultsHigher PEEP levels (4–6 cmH₂O and 7–10 cmH₂O) were associated with significantly lower microaspiration rates and pepsin concentrations in airway secretions compared to the lowest PEEP group (0–3 cmH₂O; P < 0.05). Patients in the higher PEEP groups exhibited reduced total subglottic secretion volumes over 7 d and a shorter duration of mechanical ventilation. Group C (7–10 cmH₂O) demonstrated the most pronounced benefits with respect to microaspiration. No significant differences were observed in the duration of ICU stay among the groups.ConclusionElevated PEEP levels, especially within the 7–10 cmH₂O range, effectively reduce microaspiration, minimize subglottic secretion leakage, and shorten the duration of mechanical ventilation. These findings highlight the clinical importance of higher PEEP settings in reducing VAP risk and improving patient outcomes.

BackgroundMechanical ventilation in bariatric surgery presents unique challenges, requiring strategies that minimize intraoperative atelectasis, maintain adequate oxygenation, and lower the risk of postoperative pulmonary complications. The present study compared driving pressure–guided ventilation with conventional lung-protective ventilation in morbidly obese patients undergoing laparoscopic bariatric surgery.MethodsSixty patients with a body mass index (BMI) of 40–50 kg/m², scheduled for laparoscopic bariatric surgery, were randomized according to intraoperative ventilation strategy into two groups: Group I (n = 30) received the conventional lung-protective strategy, and Group II (n = 30) received the driving pressure–guided ventilation strategy. After induction of pneumoperitoneum, a standardized lung recruitment maneuver was performed, after which ventilation strategies were applied according to group allocation: in Group I, positive end-expiratory pressure (PEEP) was maintained at 5 cmH₂O throughout surgery, whereas in Group II, PEEP was individualized to achieve the lowest driving pressure (DP).ResultsThe PaO₂/FiO₂ ratio showed significant improvement after the recruitment maneuver in both groups compared with baseline values. However, measurements obtained before the end of surgery and after extubation were significantly higher in Group II than in Group I (P < 0.001). Lung mechanics were also significantly better in Group II, with higher compliance, lower driving pressure, and reduced plateau pressure (Pplat). Intraoperative hypoxia requiring rescue therapy occurred in 10 patients (33.3%) in Group I compared with 2 patients (6.7%) in Group II, while postoperative hypoxia requiring supplementary oxygen was observed in 7 patients (23.3%) in Group I and in none of the patients in Group II.ConclusionThe adoption of driving pressure–based ventilation in laparoscopic bariatric surgery for morbidly obese patients was associated with improved oxygenation, optimized lung mechanics, and a lower risk of postoperative hypoxemia.Trial registrationThe trial was registered prior to patient enrolment at ClinicalTrials.gov (NCT04861168, Date of registration: 27/4/2021).

Helmet noninvasive ventilation (NIV) has gained attention for the management of hypoxemic patients, owing to physiological and potential clinical benefits. We summarize the recent advances on the topic. Compared to facemasks, helmets facilitate application of higher positive end-expiratory pressure (PEEP) for prolonged treatments: this improves oxygenation and may mitigate injurious inflation patterns related to lung heterogeneity. The large, highly compliant interface reduces ventilator triggering performance, causing pressure support to be partially out of phase with patient's inspiratory effort; however, it allows patients to breathe from the internal air reservoir, resulting in formally asynchronous breaths that may help attenuate surges in lung stress and tidal volume without causing flow starvation. Through physiological monitoring, ventilator settings can be individualized to modulate inspiratory effort while limiting increases in dynamic transpulmonary driving pressure and tidal volume. Helmet NIV may offer a valuable strategy for noninvasive management of hypoxemic patients, particularly when applied early, for prolonged periods, and with settings aimed at minimizing injurious inflation in moderate-to-severe (PaO2/FiO2 < 200 mmHg) cases. Interface peculiarities affecting patient-ventilator interaction may constitute key differences with facemask NIV for prevention of injurious inflation patterns. Ongoing trials will clarify whether these physiological advantages improve clinical outcomes.

Effect of High Positive End-Expiratory Pressure on Perioperative Atelectasis in Neonates and Small Infants (0-6 months) with Healthy Lungs: A Randomized Controlled Trial.

Mechanical ventilation was frequently conducted in late preterm and term newborn infants because of their severity of neonatal respiratory distress syndrome (NRDS), but the level of positive end expiratory pressure (PEEP) used was not explicit. This study aimed to investigate the efficacy and safety of higher-PEEP in the treatment of NRDS in these infants. Initially, 80 newborn late preterm and term infants diagnosed with NRDS were enrolled, a total of 26 infants were excluded because they were not within the gestational age range of 34+ 0 to 39+ 6 weeks or did not receive mechanical ventilation. Of 54 eligible infants, 6 were excluded: 3 for pre-existing pneumothorax before mechanical ventilation, 1 for hospital transfer, 1 for withdrawal of treatment, and 1 for misdiagnosis with transient tachypnea. Ultimately, 48 infants remained. Following a simple randomization procedure, 23 were assigned to higher-PEEP group and 25 to the control group. The duration of mechanical ventilation was regarded as the primary outcome. We also collected and analyzed data of other clinical factors. We found that higher-PEEP group had significantly shorter durations of mechanical ventilation (P = 0.008) and oxygen inhalation (P = 0.002) compared to the control. Additionally, the fraction of inspired oxygen (FiO2) (P = 0.001) and oxygenation index (OI) (P = 0.048) at 24 h after birth were lower in higher-PEEP group compared to the control. Furthermore, higher-PEEP group had a shorter duration of hospitalization (P = 0.033). However, no significant differences were observed in the comparisons of complications between the two groups. In summary, higher PEEP could reduce the duration of mechanical ventilation by preserving adequate functional residual capacity, without increasing rates of adverse effects.

Small animal experiments are essential in biomedical research, particularly for preclinical investigations. These experiments frequently require mechanical ventilation, but the market offers expensive and functionally limited ventilators. To address this, we developed a cost-effective multi-mode ventilator using commercially available components. Our ventilator utilizes a microcontroller as the primary processing unit, receiving settings from a computer interface. The microcontroller synchronizes five valves to control inspiration and expiration of breathing cycles while managing airflow via piston pumps to generate the required tidal volume. This ensures precise breath regulation in terms of controlling the desired pressure-volume schematic in small animal respiratory systems. Positive end-expiratory pressure is manually adjustable. The system emulates conventional profiles like Volume Control Ventilation and Pressure Control Ventilation, while offering customizable inspiration and expiration patterns (sinusoidal, linear, and exponential). Operating specifications include tidal volumes of 1-15 ml and respiratory rates up to 120 breaths per minute. This versatile system provides customizable ventilation profiles with precise inspiration-expiration cycle synchronization, enabling tailored experimental conditions. Its cost-effectiveness makes it accessible to a broader range of researchers. This system marks a significant advancement in small animal research by offering precise and flexible ventilation strategies that enhance experimental accuracy and contribute to improved research outcomes.

BackgroundNo study has evaluated the inspiratory effort in patients with obesity immediately after extubation according to the noninvasive ventilatory support used. We aimed to determine, in critically ill patients with morbid obesity, whether Non Invasive Ventilation applied with facial mask with Pressure Support above Positive End-Expiratory Pressure (PSV-PEEP) may reduce patient inspiratory efforts to a greater extent than Continuous Positive Airway Pressure (CPAP) after extubation.MethodsWe conducted a post-hoc analysis based on data from a physiological study involving consecutive patients with morbid obesity prior to extubation. Flow, airway, esophageal, and gastric pressure signals were then recorded 20 min after extubation under three distinct conditions: (1) standard oxygen, (2) CPAP and (3) PSV-PEEP. Inspiratory efforts were assessed by calculation of the trans-diaphragmatic pressure (Pdi) and work-of-breathing (WOB).ResultsFifteen patients with mean body mass index of 45 kg/m2 (± 8 kg/m2) were enrolled. WOB and Swing Pdi were lower with PSV-PEEP than with CPAP and standard oxygen respectively 5.3 [3.6–6.0] vs 8.4 [7.4–10.0] and 14.9 [11.1–22.1] J/min (p < 0.001), and 5.9 [4.0–7.8] vs 11.4 [10.1–13.1] and 19.6 [18.5–23.6] cmH2O (p < 0.001). We also observed a significant decrease of respiratory rate (RR) and RR/VT (tidal volume) ratio with the use of PSV-PEEP (24.4 [21.9–27.7] breaths/min and 65.7 [45.1–78.5] min/mL, respectively), and with the use of CPAP (24.6 [24.1–34.5] breaths/min and 75.3 [57.2–108.0] min/mL), compared with standard oxygen (29.0 [24.2–34.9] breaths/min and 81.1 [73.5–108.9] min/mL), p < 0.05.ConclusionIn critically ill post extubation patients with morbid obesity, both PSV-PEEP and CPAP reduced the inspiratory effort indexes including inspiratory work-of-breathing, traducing an unload of inspiratory muscles. This effect was more important when PSV-PEEP was used in comparison to CPAP, suggesting a more pronounced effect of inspiratory muscle unloading.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13613-025-01603-3.

Patients undergoing on-pump cardiac surgery are at high risk for perioperative lung injury and a hyper-inflammatory state associated with postoperative complications. We investigated the hypothesis that Flow-Controlled Ventilation (FCV) reduces the inflammatory stimulus compared to conventional Pressure-Controlled Ventilation (PCV) in this patient cohort. FCV has the unique feature of controlling airway flows during inspiration and expiration and the potential to reduce mechanical power of invasive ventilation. In this single-center randomized controlled trial, 140 adult patients undergoing cardiac surgery with cardiopulmonary bypass were allocated 1:1 to FCV or PCV from Aug 10, 2020, to Nov 16, 2022. Participants received perioperatively either individualized FCV with a compliance-guided positive end-expiratory pressure (PEEP) and a compliance-guided driving pressure (ΔP) or PCV with a compliance-guided PEEP and ΔP for tidal volumes of 6-8 ml/kg predicted body weight. Postoperative plasmatic interleukin 8 (IL-8) levels six hours after cardiopulmonary bypass were defined as the primary endpoint. Explorative secondary outcomes included incidences of postoperative pulmonary and extrapulmonary complications, and hospital length of stay. Median postoperative IL-8 levels did not differ significantly between FCV and PCV (FCV 3.08 vs. PCV 3.60, beta coefficient 0.08 pg/ml, 95% CI -0.17 to 0.33; P = 0.573). ΔP values and tidal volumes were higher in the FCV group, but FCV yielded lower respiratory rates and minute volumes required for normocapnia. As a result, the FCV approach reduced the perioperatively applied mechanical power by 55%. After FCV, incidences of single postoperative pulmonary complications (e.g. confirmed pneumonia, moderate and severe hypoxemia) and any postoperative extrapulmonary complication were lower, and the hospital stay shorter. FCV did not reduce plasmatic IL-8 levels at the predefined timepoint six hours after cardiopulmonary bypass. However, the reduction of mechanical power during individualized FCV application and the findings of the explorative secondary study outcomes justify future trials.

Abstract Background and Aims: Infants are at the highest risk of oxygen desaturation during induction of anesthesia owing to their distinct anatomical and physiological characteristics. Prolongation of non-hypoxic safe apnea time by use of positive end expiratory pressure (PEEP) during induction has been studied extensively in adults. Although few studies have been conducted in infants, they lacked methodological rigor. Hence, we designed a scientifically rigorous study aimed at investigating the effects of application of PEEP during induction of anesthesia on the duration of non-hypoxic apnea time in infants. Material and Methods: Seventy-two infants were induced as per institutional protocol and mechanically ventilated for three minutes with volume-controlled ventilation and set ventilator parameters with PEEP of either 7 cm H 2 O or 0 cm H 2 O according to the group allocated, followed by endotracheal intubation. The duration of non-hypoxic apnea time, i.e., the duration from cessation of mechanical ventilation to the point when SpO 2 reached 95%, was noted. Inferential statistics were done by using the independent ‘t’ test, Mann Whitney test and Chi square test Results: The duration of non-hypoxic apnea time was significantly longer in the PEEP group (n = 33) as compared to the control group (n = 33); 122 s (IQR = 52) vs. 95 s (IQR = 27) ( P = 0.001) The duration of non-hypoxic apnea time increased significantly as the age of the infant increased. Conclusions: Addition of PEEP of 7 cmH 2 O is a useful ventilatory strategy in infants to offset undesired changes in the respiratory physiology during induction of anesthesia.