Positive end-expiratory pressure management in patients with severe ARDS: implications of prone positioning and extracorporeal membrane oxygenation.

The optimal strategy for positive end-expiratory pressure (PEEP) titration in the management of severe acute respiratory distress syndrome (ARDS) patients remains unclear. Current guidelines emphasize the importance of a careful risk-benefit assessment for PEEP titration in terms of cardiopulmonary function in these patients. Over the last few decades, the primary goal of PEEP usage has shifted from merely improving oxygenation to emphasizing lung protection, with a growing focus on the individual pattern of lung injury, lung and chest wall mechanics, and the hemodynamic consequences of PEEP. In moderate-to-severe ARDS patients, prone positioning (PP) is recommended as part of a lung protective ventilation strategy to reduce mortality. However, the physiologic changes in respiratory mechanics and hemodynamics during PP may require careful re-assessment of the ventilation strategy, including PEEP. For the most severe ARDS patients with refractory gas exchange impairment, where lung protective ventilation is not possible, veno-venous extracorporeal membrane oxygenation (V-V ECMO) facilitates gas exchange and allows for a "lung rest" strategy using "ultraprotective" ventilation. Consequently, the importance of lung recruitment to improve oxygenation and homogenize ventilation with adequate PEEP may differ in severe ARDS patients treated with V-V ECMO compared to those managed conservatively. This review discusses PEEP management in severe ARDS patients and the implications of management with PP or V-V ECMO with respect to respiratory mechanics and hemodynamic function.

Positive end-expiratory pressure and postoperative pulmonary complications in laparoscopic bariatric surgery: systematic review and meta-analysis.

BACKGROUND: This study compares the effect of positive end-expiratory pressure (PEEP) on postoperative pulmonary complications (PPCs) in patients with obesity undergoing laparoscopic bariatric surgery (LBS) under general anesthesia with mechanical ventilation. METHODS: A comprehensive search was conducted in PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials, China National Knowledge Internet, Wanfang database, and Google Scholar for studies published up to July 29, 2023, without time or language restrictions. The search terms included "PEEP," "laparoscopic," and "bariatric surgery." Randomized controlled trials comparing different levels of PEEP or PEEP with zero-PEEP (ZEEP) in patients with obesity undergoing LBS were included. The primary outcome was a composite of PPCs, and the secondary outcomes were intraoperative oxygenation, respiratory compliance, and mean arterial pressure (MAP). A fixed-effect or random-effect model was selected for meta-analysis based on the heterogeneity of the included studies. RESULTS: Thirteen randomized controlled trials with a total of 708 participants were included for analysis. No statistically significant difference in PPCs was found between the PEEP and ZEEP groups (risk ratio = 0.27, 95% CI: 0.05-1.60; p = 0.15). However, high PEEP ≥ 10 cm H2O significantly decreased PPCs compared with low PEEP < 10 cm H2O (risk ratio = 0.20, 95% CI: 0.05-0.89; p = 0.03). The included studies showed no significant heterogeneity (I2 = 20% & 0%). Compared with ZEEP, PEEP significantly increased intraoperative oxygenation and respiratory compliance (WMD = 74.97 mm Hg, 95% CI: 41.74-108.21; p < 0.001 & WMD = 9.40 ml cm H2O- 1, 95% CI: 0.65-18.16; p = 0.04). High PEEP significantly improved intraoperative oxygenation and respiratory compliance during pneumoperitoneum compared with low PEEP (WMD = 66.81 mm Hg, 95% CI: 25.85-107.78; p = 0.001 & WMD = 8.03 ml cm H2O- 1, 95% CI: 4.70-11.36; p < 0.001). Importantly, PEEP did not impair hemodynamic status in LBS. CONCLUSIONS: In patients with obesity undergoing LBS, high PEEP ≥ 10 cm H2O could decrease PPCs compared with low PEEP < 10 cm H2O, while there was a similar incidence of PPCs between PEEP (8-10 cm H2O) and the ZEEP group. The application of PEEP in ventilation strategies increased intraoperative oxygenation and respiratory compliance without affecting intraoperative MAP. A PEEP of at least 10 cm H2O is recommended to reduce PPCs in patients with obesity undergoing LBS. REGISTRATION NUMBER: CRD42023391178 in PROSPERO.

Effect of positive airway pressure on obese patients undergoing surgery: a systematic review and meta-analysis.

This systematic review and meta-analysis (SRMA) evaluates the efficacy and safety of Positive Airway Pressure (PAP) therapy in perioperative care for obese surgical patients. We reviewed 24 studies, encompassing data up to March 23, 2023, analyzing the impacts of Continuous Positive Airway Pressure (CPAP) and Bilevel Positive Airway Pressure (BIPAP) on postoperative adverse outcomes, oxygenation, and pulmonary function. Our findings underscore the significant potential of PAP therapy in managing obese patients during the perioperative period, particularly those at substantial risk for postoperative respiratory complications. PAP therapy not only enhances oxygenation levels and lung function but also substantially reduces the incidence of atelectasis and shortens hospital stays, thereby affirming its vital role in improving perioperative outcomes for this patient population.

Comparison between Air-Q Self Pressurized Airway Device with Blocker and Proseal Laryngeal Mask Airway in anesthetized paralyzed adult female patients undergoing elective gynecological operations.

INTRODUCTION: The Air-Q Self Pressurized Airway Device with Blocker (SP Blocker) was compared to the Proseal Laryngeal Mask Airway (PLMA) during positive pressure ventilation regarding the primary outcome (oropharyngeal leak pressure [OLP]), secondary outcomes (peak inspiratory pressure [PIP], inspired tidal volume [ITV], expired tidal volume [ETV], leak volume [LV] and leak fraction [LF]), insertion time, ventilation score, fiber-optic glottis view score, and postoperative laryngopharyngeal parameters (LPM). MATERIAL AND METHODS: Adult healthy female patients scheduled for elective gynecological laparotomies under general anesthesia using controlled mechanical ventilation were recruited to a prospective randomized comparative clinical trial. Exclusion criteria were body mass index (BMI) ≥ 35 kg m -2 , El-Ganzouri score ≥ 5, upper airway problems, hiatus hernia or pregnancy. Patients were classified into an SP Blocker group ( n = 75) and a PLMA group ( n = 75). Primary and secondary outcomes were assessed initially and at fixed time points after successful insertion of devices. RESULTS: Initially after successful device insertion: the SP Blocker group showed statistically significant higher mean OLP (cmH 2 O) (29.46 ± 2.11 vs. 28.06 ± 1.83 respectively; 95% CI: -2.037 to -0.76, P < 0.0001), lower mean PIP (cmH 2 O) (15.49 ± 0.61 vs. 17.78 ± 1.04 respectively; 95% CI: 2.02 to 2.56, P < 0.0001), higher mean ITV (mL) (411 ± 30 vs. 403 ± 15 respectively; 95% CI: -15.65 to -0.347, P = 0.041), higher mean ETV (mL) (389 ± 12 vs. 354 ± 11 respectively; 95% CI: -38.72 to -31.29, P < 0.0001), lower mean LV (mL) (22 ± 18 vs. 49 ± 10 respectively; 95% CI: 22.3 to 31.7, P < 0.0001) and lower mean LF (%) (5 ± 2.04 vs. 12 ± 6.8 respectively; 95% CI: 5.38 to 8.62, P < 0.0001) than the PLMA group. Mean insertion time (seconds) was shorter in the SP Blocker group than the PLMA group (16.39 ± 2.81 vs. 18.63 ± 3.44 respectively; 95% CI: 1.23 to 3.25, P < 0.0001). The SP Blocker group offered a better fiber-optic glottis view score than the PLMA group without differences concerning ventilation score and LPM. CONCLUSIONS: SP Blocker provided as safe anesthesia during controlled mechanical ventilation as PLMA.

[Artificial ventilation in patients with stroke: main results of the Russian multicenter observational clinical trial RETAS]. / Iskusstvennaya ventilyatsiya legkikh u patsientov s ostrym narusheniem mozgovogo krovoobrashcheniya: osnovnye rezul'taty Rossiiskogo mnogotsentrovogo observatsionnogo klinicheskogo issledovaniya RETAS.

OBJECTIVE: To analyze the relationship between the characteristics of respiratory support (RS) for patients with stroke and clinical factors with the number and structure of complications, deaths, and length of stay in the intensive care unit (ICU) and duration of artificial pulmonary ventilation (ALV). MATERIAL AND METHODS: The Russian multicenter observational clinical study «Respiratory Therapy for Acute Stroke¼ (RETAS) that enrolled 1289 patients with stroke requiring RS was conducted under the auspices of the All-Russian public organization «Federation of Anesthesiologists and Resuscitators¼. Indications for ALV, the use of hyperventilation, the maximum level of positive end-expiratory pressure, starting modes of mechanical ventilation, timing of tracheostomy, the incidence of protein-energy malnutrition (PEM) and infectious complications were analyzed. The following scales were used to assess the severity of the condition: the National Institutes of Health Stroke Severity Scale (NIHSS), the Glasgow Coma Scale, the Glasgow Outcome Scale (GOS). RESULTS: For the group of patients with a stroke severity of more than 20 NIHSS points, the mortality increase was associated with initial hypoxia (p=0.004), hyperventilation used to relieve intracranial hypertension (p=0.034), and starting ventilation with volume control (VC) compared with starting pressure-controlled ventilation (PC) (p<0.001). We found that the use of the instrumental monitoring of intracranial pressure was associated with a decrease in mortality (p<0.001). The absence of PEM in patients with stroke is associated with a higher probability of a positive outcome (GOS 4 and 5) for the group with NIHSS less than 14 points (p<0.001). Ventilator-associated tracheobronchitis and ventilator-associated pneumonia were associated with an increase in the duration of ALV, the duration of weaning from the ventilator (for ventilator-associated tracheobronchitis) and the duration of stay in the ICU, and also reduced the chances of favorable outcomes (p<0.05). CONCLUSION: The factors associated with increased mortality in acute stroke are: hypoxemia at the start of ALV, hyperventilation, starting ventilation with VC in comparison with starting ventilation with PC, the use of only clinical methods of monitoring intracranial pressure in comparison with instrumental monitoring. The adverse effect of PEM and infectious complications on the outcome in patients with acute stroke has been proven.

Use of pressure muscle index to guide pressure support ventilation setting: a study protocol and statistical plan for a prospective randomised controlled proof-of-concept trial.

INTRODUCTION: Although pressure support ventilation is one of the most commonly used assisted ventilation modes in intensive care units, there is still a lack of precise strategies for setting pressure support. By performing an end-inspiratory airway occlusion, the difference between the peak and plateau airway pressure, which is defined as pressure muscle index (PMI), can be easily measured on the ventilator screen. Previous studies have shown that PMI is accurate in detecting high and low inspiratory effort. No study has been conducted to investigate the use of PMI as an indicator for setting inspiratory pressure support. METHOD AND ANALYSIS: This is a study protocol for a prospective, single-centre, randomised controlled, pilot trial. Sixty participants undergoing pressure support ventilation will be randomly assigned in a 1:1 ratio to the control group or intervention group, with pressure support adjusted according to standard care or guided by the PMI strategy for 48 hours, respectively. The feasibility of the PMI-guided strategy will be evaluated. The primary endpoint is the proportion of inspiratory effort measurements within a well-accepted 'normal' range, which is predefined as oesophageal pressure-time product per minute between 50 and 200 cmH2O⋅s/min, for each patient during 48 hours of pressure support adjustment. ETHICS AND DISSEMINATION: The study protocol has been approved by Beijing Tiantan Hospital (KY2023-005-02). The data generated in the present study will be available from the corresponding author on reasonable request. The results of the trial will be submitted to international peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT05963737; ClinicalTrials.org.

Effects of individualised lung-protective ventilation with lung dynamic compliance-guided positive end-expiratory pressure titration on postoperative pulmonary complications of paediatric video-assisted thoracoscopic surgery: protocol for a randomised controlled trial.

INTRODUCTION: Lung-protective ventilation strategies (LPVS) for one-lung ventilation (OLV) in paediatric patients pose greater challenges than in adults. Optimising LPVS for paediatric OLV to mitigate postoperative pulmonary complications (PPCs) has emerged as a current research focal point. However, there remains a divergence of opinions concerning the individualised setting and application of positive end-expiratory pressure (PEEP). Lung dynamic compliance (Cdyn) can serve as a reflection of the lung's physiological state in children during OLV and is a readily obtainable parameter. This study protocol is formulated to assess the effectiveness of Cdyn-guided PEEP titration on PPCs during paediatric OLV. METHODS AND ANALYSIS: This study constitutes a single-centre, prospective, double-blind, randomised controlled trial. The trial aims to recruit 60 paediatric patients scheduled for video-assisted thoracoscopic surgery. These eligible patients will be randomly assigned to either the Cdyn-guided PEEP group or the conventional PEEP group during general anaesthesia for OLV. The primary outcome will involve assessing the incidence of PPCs at 7 days after surgery. Secondary outcomes will encompass the evaluation of the modified lung ultrasound score following surgery, as well as monitoring the oxygenation index, driving pressure and Cdyn during mechanical ventilation. Data collection will be performed by investigators who are kept blinded to the interventions. ETHICS AND DISSEMINATION: The Clinical Trial Ethics Committee at Shenzhen Children's Hospital has conferred ethical approvals for this trial (approval number: 2022076). Results from this trial will be disseminated in peer-reviewed journals and presented at professional symposiums. TRAIL REGISTRATION NUMBER: NCT05386901.

Characterising applied forces during positive pressure ventilation: a randomised cross-over simulation study.

OBJECTIVE: To characterise applied force on the face and head during simulated mask ventilation with varying mask, device and expertise level. DESIGN: Randomised cross-over simulation study. SETTING: A quiet, empty room in the children's hospital. PARTICIPANTS: Neonatal healthcare providers, categorised as novices and experts in positive pressure ventilation (PPV). INTERVENTIONS: PPV for 2 min each in a 2×2 within-subjects design with two masks (round and anatomic) and two ventilation devices (T-piece and self-inflating bag (SIB)). MAIN OUTCOME MEASURES: Applied force (Newton (N)) measured under the head and at four locations on the manikin's face (nasal bridge, mentum, left and right zygomatic arches) and symmetry of force applied around the mask rim. RESULTS: For the 51 participants, force applied to the head was greater with the SIB than the T-piece (mean (SD): 16.03 (6.96) N vs 14.31 (5.16) N) and greater with the anatomic mask than the round mask (mean (SD): 16.07 (6.80) N vs 14.26 (5.35) N). Underhead force decreased over the duration of PPV for all conditions. Force measured on the face was greatest at the left zygomatic arch (median (IQR): 0.97 (0.70-1.43) N) and least at the mentum (median (IQR): 0.44 (0.28-0.61) N). Overall, experts applied more equal force around the mask rim compared with novices (median (IQR): 0.46 (0.26-0.79) N vs 0.65 (0.24-1.18) N, p<0.001). CONCLUSION: We characterised an initial dataset of applied forces on the face and head during simulated PPV and described differences in force when considering mask type, device type and expertise.

Effect of lung volume preservation during spontaneous breathing trial on successful extubation in patients receiving mechanical ventilation: protocol for a multicenter clinical trial.

BACKGROUND: In standard weaning from mechanical ventilation, a successful spontaneous breathing test (SBT) consisting of 30 min 8 cmH2O pressure-support ventilation (PSV8) without positive end-expiratory pressure (PEEP) is followed by extubation with continuous suctioning; however, these practices might promote derecruitment. Evidence supports the feasibility and safety of extubation without suctioning. Ultrasound can assess lung aeration and respiratory muscles. We hypothesize that weaning aiming to preserve lung volume can yield higher rates of successful extubation. METHODS: This multicenter superiority trial will randomly assign eligible patients to receive either standard weaning [SBT: 30-min PSV8 without PEEP followed by extubation with continuous suctioning] or lung-volume-preservation weaning [SBT: 30-min PSV8 + 5 cmH2O PEEP followed by extubation with positive pressure without suctioning]. We will compare the rates of successful extubation and reintubation, ICU and hospital stays, and ultrasound measurements of the volume of aerated lung (modified lung ultrasound score), diaphragm and intercostal muscle thickness, and thickening fraction before and after successful or failed SBT. Patients will be followed for 90 days after randomization. DISCUSSION: We aim to recruit a large sample of representative patients (N = 1600). Our study cannot elucidate the specific effects of PEEP during SBT and of positive pressure during extubation; the results will show the joint effects derived from the synergy of these two factors. Although universal ultrasound monitoring of lungs, diaphragm, and intercostal muscles throughout weaning is unfeasible, if derecruitment is a major cause of weaning failure, ultrasound may help clinicians decide about extubation in high-risk and borderline patients. TRIAL REGISTRATION: The Research Ethics Committee (CEIm) of the Fundació Unió Catalana d'Hospitals approved the study (CEI 22/67 and 23/26). Registered at ClinicalTrials.gov in August 2023. Identifier: NCT05526053.

AARC Clinical Practice Guideline: Patient-Ventilator Assessment.

Given the important role of patient-ventilator assessments in ensuring the safety and efficacy of mechanical ventilation, a team of respiratory therapists and a librarian used Grading of Recommendations, Assessment, Development, and Evaluation methodology to make the following recommendations: (1) We recommend assessment of plateau pressure to ensure lung-protective ventilator settings (strong recommendation, high certainty); (2) We recommend an assessment of tidal volume (VT) to ensure lung-protective ventilation (4-8 mL/kg/predicted body weight) (strong recommendation, high certainty); (3) We recommend documenting VT as mL/kg predicted body weight (strong recommendation, high certainty); (4) We recommend an assessment of PEEP and auto-PEEP (strong recommendation, high certainty); (5) We suggest assessing driving pressure to prevent ventilator-induced injury (conditional recommendation, low certainty); (6) We suggest assessing FIO2 to ensure normoxemia (conditional recommendation, very low certainty); (7) We suggest telemonitoring to supplement direct bedside assessment in settings with limited resources (conditional recommendation, low certainty); (8) We suggest direct bedside assessment rather than telemonitoring when resources are adequate (conditional recommendation, low certainty); (9) We suggest assessing adequate humidification for patients receiving noninvasive ventilation (NIV) and invasive mechanical ventilation (conditional recommendation, very low certainty); (10) We suggest assessing the appropriateness of the humidification device during NIV and invasive mechanical ventilation (conditional recommendation, low certainty); (11) We recommend that the skin surrounding artificial airways and NIV interfaces be assessed (strong recommendation, high certainty); (12) We suggest assessing the dressing used for tracheostomy tubes and NIV interfaces (conditional recommendation, low certainty); (13) We recommend assessing the pressure inside the cuff of artificial airways using a manometer (strong recommendation, high certainty); (14) We recommend that continuous cuff pressure assessment should not be implemented to decrease the risk of ventilator-associated pneumonia (strong recommendation, high certainty); and (15) We suggest assessing the proper placement and securement of artificial airways (conditional recommendation, very low certainty).

Lung volume recruitment and airway clearance for children at home in France.

BACKGROUND: Airway clearance (ACT) and lung volume recruitment (LVR) techniques are used to manage bronchial secretions, increase cough efficiency and lung/chest wall recruitment, to prevent and treat respiratory tract infections. The aim of the study was to review the prescription of ACT/LVR techniques for home use in children in France. METHODS: All the centers of the national pediatric noninvasive ventilation (NIV) network were invited to fill in an anonymous questionnaire for every child aged ≤20 years who started a treatment with an ACT/LVR device between 2022 and 2023. The devices comprised mechanical in-exsufflation (MI-E), intermittent positive pressure breathing (IPPB), intrapulmonary percussive ventilation (IPV), and/or invasive mechanical ventilation (IMV)/NIV for ACT/LVR. RESULTS: One hundred and thirty-nine patients were included by 13 centers. IPPB was started in 83 (60 %) patients, MI-E in 43 (31 %) and IPV in 30 (22 %). No patient used IMV/NIV for ACT/LVR. The devices were prescribed mainly by pediatric pulmonologists (103, 74 %). Mean age at initiation was 8.9 ± 5.6 (0.4-18.5) years old. The ACT/LVR devices were prescribed mainly in patients with neuromuscular disorders (n = 66, 47 %) and neurodisability (n = 37, 27 %). The main initiation criteria were cough assistance (81 %) and airway clearance (60 %) for MI-E, thoracic mobilization (63 %) and vital capacity (47 %) for IPPB, and airway clearance (73 %) and repeated respiratory exacerbations (57 %) for IPV. The parents were the main carers performing the treatment at home. CONCLUSIONS: IPPB was the most prescribed technique. Diseases and initiation criteria are heterogeneous, underlining the need for studies validating the indications and settings of these techniques.

Long-term myocardial effects of noninvasive ventilation in patients with obesity hypoventilation syndrome.

INTRODUCTION: Chronic effects of noninvasive ventilation on myocardial function in patients with obesity hypoventilation syndrome (OHS) are scarcely understood. The aim of the present study was to evaluate the long-term effects of volume-targeted bilevel positive airway pressure ventilation (BiPAP) on cardiac parameters and myocardial biomarkers in patients with OHS. METHODS: Clinically stable patients with OHS referred to the tertiary center for the initiation of long-term BiPAP therapy were consecutively enrolled. At baseline, all participants underwent overnight cardiorespiratory polygraphy. BiPAP therapy using volume-targeted spontaneous/timed mode delivered via an oro-nasal mask was initiated. Beat-to-beat noninvasive monitoring by impedance cardiography was used to assess heart function at baseline and after 3 and 12 months of BiPAP use. Serum troponin 1, N-Terminal Pro-B-Type Natriuretic Peptide (NT-ProBNP), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) were monitored. RESULTS: Thirteen patients (10 men; mean age, 55.8 ± 9.8 years; mean body mass index of 47.8 ± 5.9 kg/m2) were recruited. From baseline to 3, and to 12 months of BiPAP use, left ventricular stroke volume (SV), ejection time (LVET), and ejection time index significantly increased (P = 0.030; P < 0.001; P = 0.003, respectively), while heart rate and systolic time ratio significantly decreased (P = 0.004; P = 0.034, respectively). Reductions in serum NT-proBNP, IL-6 and TNF-α were observed (P = 0.045; P = 0.018; P = 0.003, respectively). No significant changes in serum troponin were detected throughout the study. CONCLUSIONS: The present findings of increased SV, in association with lengthening of LVET, reductions of NT-proBNP and reductions in circulatory inflammatory markers in patients with stable OHS and chronic moderate-to-severe daytime hypercapnia treated with BiPAP over 1 year support the role of this therapeutic mode in such patients.

Recruitment-to-inflation ratio for bedside PEEP selection in acute respiratory distress syndrome.

In acute respiratory distress syndrome, the role of positive end-expiratory pressure (PEEP) to prevent ventilator-induced lung injury is controversial. Randomized trials comparing higher versus lower PEEP strategies failed to demonstrate a clinical benefit. This may depend on the inter-individually variable potential for lung recruitment (i.e. recruitability), which would warrant PEEP individualization to balance alveolar recruitment and the unavoidable baby lung overinflation produced by high pressure. Many techniques have been used to assess recruitability, including lung imaging, multiple pressure-volume curves and lung volume measurement. The Recruitment-to-Inflation ratio (R/I) has been recently proposed to bedside assess recruitability without additional equipment. R/I assessment is a simplified technique based on the multiple pressure-volume curve concept: it is measured by monitoring respiratory mechanics and exhaled tidal volume during a 10-cmH2O one-breath derecruitment maneuver after a short high-PEEP test. R/I scales recruited volume to respiratory system compliance, and normalizes recruitment to a proxy of actual lung size. With modest R/I (<0.3-0.4), setting low PEEP (5-8 cmH2O) may be advisable; with R/I>0.6-0.7, high PEEP (≥15 cmH2O) can be considered, provided that airway and/or transpulmonary plateau pressure do not exceed safety limits. In case of intermediate R/I (≈0.5), a more granular assessment of recruitability may be needed. This could be accomplished with advanced monitoring tools, like sequential lung volume measurement with granular R/I assessment or electrical impedance tomography monitoring during a decremental PEEP trial. In this review, we discuss R/I rationale, applications and limits, providing insights on its clinical use for PEEP selection in moderate-to-severe acute respiratory distress syndrome.

High PEEP/low FiO2 ventilation is associated with lower mortality in COVID-19.

RATIONALE: The positive end-expiratory pressure (PEEP) strategy in patients with coronavirus 2019 (COVID-19) acute respiratory distress syndrome (ARDS) remains debated. Most studies originate from the initial waves of the pandemic. Here we aimed to assess the impact of high PEEP/low FiO2 ventilation on outcomes during the second wave in the Netherlands. METHODS: Retrospective observational study of invasively ventilated COVID-19 patients during the second wave. Patients were categorized based on whether they received high PEEP or low PEEP ventilation according to the ARDS Network tables. The primary outcome was ICU mortality, and secondary outcomes included hospital and 90-day mortality, duration of ventilation and length of stay, and the occurrence of kidney injury. Propensity matching was performed to correct for factors with a known relationship to ICU mortality. RESULTS: This analysis included 790 COVID-ARDS patients. At ICU discharge, 32 (22.5%) out of 142 high PEEP patients and 254 (39.2%) out of 848 low PEEP patients had died (HR 0.66 [0.46-0.96]; P = 0.03). High PEEP was linked to improved secondary outcomes. Matched analysis did not change findings. CONCLUSIONS: High PEEP ventilation was associated with improved ICU survival in patients with COVID-ARDS.

Incremental Application of Positive End-Expiratory Pressure for the Evaluation of Atelectasis During RP-EBUS and Bronchoscopy (I-APPEAR).

BACKGROUND: CT-to-body divergence-described as the difference between preprocedural CT scans and intraprocedural lung architecture-is a significant barrier to improving diagnostic yield during navigational bronchoscopy. A major proposed contributor to CT-to-body divergence is the development of atelectasis, which can confound visualization of peripheral lung lesions via radial probe endobronchial ultrasound (RP-EBUS). High positive end-expiratory pressure (PEEP) ventilatory strategies have been used to decrease atelectasis, allowing the lesion to re-APPEAR on intraprocedure imaging. However, standardized PEEP levels may not be appropriate for all patients due to hemodynamic and ventilatory impacts. METHODS: We performed a multicenter, prospective observational study in which patients were imaged with RP-EBUS under general anesthesia to determine if subsegmental atelectasis would resolve as incremental increases in PEEP were applied. Resolution of atelectasis was based on the transition from a non-aerated pattern to an aerated appearance on RP-EBUS. RP-EBUS images were reviewed by 3 experienced operators to determine correlation. RESULTS: Forty-three patients underwent RP-EBUS examination following navigational bronchoscopy. Thirty-seven patients underwent incremental PEEP application and subsequent RP-EBUS imaging. Atelectasis was determined to have resolved in 33 patients (88.2%) following increased PEEP. The intraclass correlation coefficient between reviewers was 0.76. A recruitment maneuver was performed in 7 (16.3%) patients after atelectasis persisted at maximal PEEP. Atelectasis was not identified in the examined subsegments in 6 (10.8%) patients despite zero PEEP. CONCLUSION: RP-EBUS is an effective tool to monitor what pressure atelectasis within a lung segment has resolved with increasing levels of PEEP.

Comparison of the ability of short time low PEEP challenge and mini fluid challenge to predict fluid responsiveness in patients undergoing open pancreaticoduodenectomy: an observational cohort study.

OBJECTIVE: The mini-fluid challenge (MFC), which assesses the change in stroke volume index (SVI) following the administration of 100 mL of crystalloids, and the short-time low positive end-expiratory pressure (PEEP) challenge (SLPC), which evaluates the temporary reduction in SVI due to a PEEP increment, are two functional hemodynamic tests used to predict fluid responsiveness in the operating room. However, SLPC has not been assessed in patients undergoing abdominal surgery, and there is no study comparing these two methods during laparotomy. Therefore, we aimed to compare the SLPC and MFC in patients undergoing open pancreaticoduodenectomy. PATIENTS AND METHODS: All patients received a standard hemodynamic management. The study protocol evaluated the percentage change in SVI following the application of an additional 5 cmH2O PEEP (SVIΔ%-SLPC) and the infusion of 100 mL crystalloid (SVIΔ%-MFC). Challenges that resulted in an increase of more than 15% in SVI after the 500 ml of fluid loading were classified as positive challenges (PC). Areas under the receiver operating characteristics curves (ROC AUCs) were used for the comparison of the methods. RESULTS: Thirty-three patients completed the study with 94 challenges. Fifty-five (58.5%) of them were PCs. The ROC AUC of SVIΔ%-MFC was observed to be significantly higher than that of SVIΔ%-SLPC (0.97 vs. 0.64, p < 0.001). The best cut-off value for SVIΔ%-MFC was 5.6%. If we had stopped the bolus fluid administration when SVIΔ%-MFC ≤ 5% was observed (lower limit of the gray zone), we would have postponed the fluid loading in 35 (89.7%) of 39 negative challenges. The amount of fluid deferred would have corresponded to up to 40% of the total fluid given. CONCLUSIONS: SVIΔ%-MFC predicts fluid responsiveness with high diagnostic performance and is better than SVIΔ%-SLPC in patients undergoing open pancreatoduodenectomy. Additionally, the use of SVIΔ%-MFC has the potential to defer up to 40% of the total fluid given. CLINICALTRIALS: gov: NCT05419570.

Effects of starting one lung ventilation and applying individualized PEEP right after patients are placed in lateral decubitus position on intraoperative oxygenation for patients undergoing thoracoscopic pulmonary lobectomy: study protocol for a randomized controlled trial.

BACKGROUND: For patients receiving one lung ventilation in thoracic surgery, numerous studies have proved the superiority of lung protective ventilation of low tidal volume combined with recruitment maneuvers (RM) and individualized PEEP. However, RM may lead to overinflation which aggravates lung injury and intrapulmonary shunt. According to CT results, atelectasis usually forms in gravity dependent lung regions, regardless of body position. So, during anesthesia induction in supine position, atelectasis usually forms in the dorsal parts of lungs, however, when patients are turned into lateral decubitus position, collapsed lung tissue in the dorsal parts would reexpand, while atelectasis would slowly reappear in the lower flank of the lung. We hypothesize that applying sufficient PEEP without RM before the formation of atelectasis in the lower flank of the lung may beas effective to prevent atelectasis and thus improve oxygenation as applying PEEP with RM. METHODS: A total of 84 patients scheduled for elective pulmonary lobe resection necessitating one lung ventilation will be recruited and randomized totwo parallel groups. For all patients, one lung ventilation is initiated the right after patients are turned into lateral decubitus position. For patients in the study group, individualized PEEP titration is started the moment one lung ventilation is started, while patients in the control group will receive a recruitment maneuver followed by individualized PEEP titration after initiation of one lung ventilation. The primary endpoint will be oxygenation index measured at T4. Secondary endpoints will include intrapulmonary shunt, respiratory mechanics, PPCs, and hemodynamic indicators. DISCUSSION: Numerous previous studies compared the effects of individualized PEEP applied alone with that applied in combination with RM on oxygenation index, PPCs, intrapulmonary shunt and respiratory mechanics after atelectasis was formed in patients receiving one lung ventilation during thoracoscopic surgery. In this study, we will apply individualized PEEP before the formation of atelectasis while not performing RM in patients allocated to the study group, and then we're going to observe its effects on the aspects mentioned above. The results of this trial will provide a ventilation strategy that may be conductive to improving intraoperative oxygenation and avoiding the detrimental effects of RM for patients receiving one lung ventilation. TRIAL REGISTRATION: www.Chictr.org.cn ChiCTR2400080682. Registered on February 5, 2024.

Respiratory Therapist-Driven Mechanical Ventilation Protocol Is Associated With Increased Lung Protective Ventilation.

BACKGROUND: Mechanical ventilation is a common life-saving procedure but can lead to serious complications, including ARDS and oxygen toxicity. Nonadherence to lung-protective ventilation guidelines is common. We hypothesized that a respiratory therapist-driven mechanical ventilation bundle could increase adherence to lung-protective ventilation and decrease the incidence of pulmonary complications in the ICU. METHODS: A respiratory therapist-driven protocol was implemented on August 1, 2018, in all adult ICUs of a Midwestern academic tertiary center. The protocol targeted low tidal volume, adequate PEEP, limiting oxygen, adequate breathing frequency, and head of the bed elevation. Adherence to lung-protective guidelines and clinical outcomes were retrospectively observed in adult subjects admitted to the ICU and on ventilation for ≥ 24 h between January 2011 and December 2019. RESULTS: We included 666 subjects; 68.5% were in the pre-intervention group and 31.5% were in the post-intervention group. After adjusting for body mass index and intubation indication, a significant increase in overall adherence to lung-protective ventilation guidelines was observed in the post-intervention period (adjusted odds ratio 2.48, 95% CI 1.73-3.56). Fewer subjects were diagnosed with ARDS in the post-intervention group (adjusted odds ratio 0.22, 95% CI 0.08-0.65) than in the pre-intervention group. There was no difference in the incidence of ventilator-associated pneumonia, ventilator-free days, ICU mortality, or death within 1 month of ICU discharge. CONCLUSIONS: A respiratory therapist-driven protocol increased adherence to lung-protective mechanical ventilation guidelines in the ICU and was associated with decreased ARDS incidence.

Comparison of the effect of two recruitment manoeuvres to conventional ventilation on lung atelectasis in paediatric laparoscopic surgery- a prospective randomised controlled trial.

BACKGROUND: There is a high incidence of pulmonary atelectasis during paediatric laparoscopic surgeries. The authors hypothesised that utilising a recruitment manoeuvre or using continuous positive airway pressure may prevent atelectasis compared to conventional ventilation. OBJECTIVE: The primary objective was to compare the degree of lung atelectasis diagnosed by lung ultrasound (LUS) using three different ventilation techniques in children undergoing laparoscopic surgeries. DESIGN: Randomised, prospective three-arm trial. SETTING: Single institute, tertiary care, teaching hospital. PATIENTS: Children of ASA PS 1 and 2 up to the age of 10 years undergoing laparoscopic surgery with pneumoperitoneum lasting for more than 30 min. INTERVENTION: Random allocation to one of the three study groups: CG group: Inspiratory pressure adjusted to achieve a TV of 5-8 ml/kg, PEEP of 5 cm H2O, respiratory rate adjusted to maintain end-tidal carbon dioxide (ETCO2) between 30-40 mm Hg with manual ventilation and no PEEP at induction. RM group: A recruitment manoeuvre of providing a constant pressure of 30 cm H2O for ten seconds following intubation was applied. A PEEP of 10 cm H2O was maintained intraoperatively. CPAP group: Intraoperative maintenance with PEEP 10 cm H2O with CPAP of 10 cm H2O at induction using mechanical ventilation was done. OUTCOME MEASURES: Lung atelectasis score at closure assessed by LUS. RESULTS: Post induction, LUS was comparable in all three groups. At the time of closure, the LUS for the RM group (8.6 ± 4.9) and the CPAP group (8.8 ± 6.8) were significantly lower (p < 0.05) than the CG group (13.3 ± 3.8). In CG and CPAP groups, the score at closure was significantly higher than post-induction. The PaO2/FiO2 ratio was significantly higher (p < 0.05) for the RM group (437.1 ± 44.9) and CPAP group (421.6 ± 57.5) than the CG group (361.3 ± 59.4) at the time of pneumoperitoneum. CONCLUSION: Application of a recruitment manoeuvre post-intubation or CPAP during induction and maintenance with a high PEEP leads to less atelectasis than conventional ventilation during laparoscopic surgery in paediatric patients. TRIAL REGISTRY: CTRI/2019/08/02058.