Improved Discriminability of Severe Lung Injury and Atelectasis in Thoracic Trauma at Low keV Virtual Monoenergetic Images from Photon-Counting Detector CT.

Objectives: To evaluate the value of virtual monoenergetic images (VMI) from photon-counting detector CT (PCD-CT) for discriminability of severe lung injury and atelectasis in polytraumatized patients. Materials & Methods: Contrast-enhanced PCD-CT examinations of 20 polytraumatized patients with severe thoracic trauma were included in this retrospective study. Spectral PCD-CT data were reconstructed using a noise-optimized virtual monoenergetic imaging (VMI) algorithm with calculated VMIs ranging from 40 to 120 keV at 10 keV increments. Injury-to-atelectasis contrast-to-noise ratio (CNR) was calculated and compared at each energy level based on CT number measurements in severely injured as well as atelectatic lung areas. Three radiologists assessed subjective discriminability, noise perception, and overall image quality. Results: CT values for atelectasis decreased as photon energy increased from 40 keV to 120 keV (mean Hounsfield units (HU): 69 at 40 keV; 342 at 120 keV), whereas CT values for severe lung injury remained near-constant from 40 keV to 120 keV (mean HU: 42 at 40 keV; 44 at 120 keV) with significant differences at each keV level (p < 0.001). The optimal injury-to-atelectasis CNR was observed at 40 keV in comparison with the remaining energy levels (p < 0.001) except for 50 keV (p > 0.05). In line with this, VMIs at 40 keV were rated best regarding subjective discriminability. VMIs at 60-70 keV, however, provided the highest subjective observer parameters regarding subjective image noise as well as image quality. Conclusions: Discriminability between severely injured and atelectatic lung areas after thoracic trauma can be substantially improved by virtual monoenergetic imaging from PCD-CT with superior contrast and visual discriminability at 40-50 keV.

Lung ultrasound assessment of atelectasis following different anesthesia induction techniques in pediatric patients: a propensity score-matched, observational study.

INTRODUCTION: Atelectasis is a well-documented complication in pediatric patients undergoing general anesthesia. Its incidence varies significantly based on surgical procedures and anesthesia techniques. Inhalation induction, commonly used to avoid the discomfort of venipuncture, is suspected to cause higher rates of respiratory complications, including atelectasis, compared to intravenous induction. This study aimed to evaluate the impact of inhalation versus intravenous anesthesia induction on atelectasis formation in pediatric patients, as assessed by lung ultrasound (LUS). METHODS: This propensity score-matched observational study was conducted at a tertiary pediatric hospital in Milan, Italy. Inclusion criteria were children ≤ 18 years undergoing elective surgery with general anesthesia. Patients were divided into inhalation and intravenous induction groups. LUS was performed before and after anesthesia induction to assess lung aeration. The primary endpoint was the global LUS score post-induction, with secondary endpoints including the incidence and distribution of atelectasis. RESULTS: Of the 326 patients included, 65% underwent inhalation induction and 35% intravenous induction. The global LUS score was significantly higher in the inhalation group (12.0 vs. 4.0, p < 0.001). After propensity score matching (for age, presence of upper respiratory tract infection, duration of induction, and PEEP levels at induction), average treatment effect (ATE) of mask induction was 5.89 (95% CI, 3.21-8.58; p < 0.001) point on LUS global score and a coefficient of 0.35 (OR 1.41) for atelectasis. DISCUSSION: Inhalation induction is associated with a higher incidence of atelectasis in pediatric patients also when we adjusted for clinically relevant covariates. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT06069414.

Awake prone positioning in an infant following living donor liver transplantation.

BACKGROUND: Prone position has been proven to improve ventilation and oxygenation in infants. Currently, there are few reports of early prone position ventilation after pediatric liver transplantation. Here, we present our experience with prone position in an infant following living donor liver transplantation, in an attempt to improve oxygenation. CASE PRESENTATION: An 8-month-old boy, 7.5 kg, experienced two failed extubations that presented with Type II respiratory failure due to dyspnea, potentially caused by consolidation and airway secretions. To prevent the third failure of extubation, prone position ventilation was implemented after the third extubation on the 11th postoperative day. Oxygenation increased after each prone position session with no signs of transplant liver ischemia or other adverse outcomes. Following two days of continuous prone position, airway secretions decreased, and the infant was discharged from the ICU. The third extubation procedure was successful. CONCLUSIONS: Prone position ventilation may be effective in this infant without adverse events, indicating that early prone position is not absolutely contraindicated after pediatric liver transplantation. Therefore, more reasonable prone position strategies should be sought in infants undergoing liver transplantation.

Nuts and bolts of lung ultrasound: utility, scanning techniques, protocols, and findings in common pathologies.

Point of Care ultrasound (POCUS) of the lungs, also known as lung ultrasound (LUS), has emerged as a technique that allows for the diagnosis of many respiratory pathologies with greater accuracy and speed compared to conventional techniques such as chest x-ray and auscultation. The goal of this narrative review is to provide a simple and practical approach to LUS for critical care, pulmonary, and anesthesia providers, as well as respiratory therapists and other health care providers to be able to implement this technique into their clinical practice. In this review, we will discuss the basic physics of LUS, provide a hands-on scanning technique, describe LUS findings seen in normal and pathological conditions (such as mainstem intubation, pneumothorax, atelectasis, pneumonia, aspiration, COPD exacerbation, cardiogenic pulmonary edema, ARDS, and pleural effusion) and also review the training necessary to achieve competence in LUS.

Impact of high-flow nasal oxygen therapy on postoperative atelectasis and reintubation rate after paediatric cardiac surgery.

INTRODUCTION: Airway problems emerging after congenital cardiac surgery operations may have an impact on mortality and morbidity. Recently, to improve alveolar gas exchange and reduce respiratory effort, high-flow nasal cannula (HFNC) has started to be used in paediatric cases. This study aimed to evaluate the potential effects of high-flow nasal oxygen therapy on postoperative atelectasis development and reintubation rate in paediatric cardiac surgery patients. METHODS: This study was conducted retrospectively in term newborns and infants younger than six months of age who underwent congenital cardiac surgery operation from 1 November 2022 to 1 November 2023 and were followed in the paediatric cardiac ICU. Patients who were receiving mechanical ventilator support at least 12 hours postoperatively were evaluated for the development of postoperative atelectasis and reintubation in the first 3 days of extubation. The patients were grouped as HFNC and non-HFNC users. Demographic characteristics, surgery type, and ICU clinical follow-up data were obtained from medical records. The results were statistically evaluated. RESULTS: A total of 40 patients who did not use HFNC in the early postoperative period and 40 patients with HFNC in the late period during the study period were included in the study. The median age was 1 month (IQR 15 days-2 months) with equal gender distribution. Among patients, 70% of them were in the neonatal age group. Reintubation rates in the first 72 hours in HFNC users and non-HFNC users were 2.5% and 12.5%, respectively (p < 0.05). The median postoperative atelectasis scores at 24, 48, and 72 hours of extubation were 2 versus 2.5 (p > 0.05), 1.5 versus 3.5 (p < 0.05), and 1 versus 3 (p < 0.05) in HFNC users and non-HFNC users, respectively. CONCLUSION: HFNC therapy may have a positive effect on preventing atelectasis and reducing the reintubation rate in the early postoperative period.

Combining intraprocedural CT guided navigation with ventilatory strategy for atelectasis: A modified electromagnetic navigation bronchoscopy.

CT-body divergence limits the accuracy of electromagnetic navigation bronchoscopy(ENB) in peripheral lung lesions diagnosis. Finding one effective and safe method to eliminating CT-body divergence may improve ENB accuracy. Thus, we developed a modified ENB which combining intraprocedural CT guided Navigation with Ventilatory strategy for Atelectasis to eliminate CT-body divergence. We called it inCTNVA-ENB. We present the case of an 80-year-old female with peripheral pulmonary nodule (without bronchial direct connection). She underwent inCTNVA-ENB, and the navigation probe accurately reached 6mm next to the target lesion without complications. The operation time was 42 minutes, and rapid on-site evaluation showed adenocarcinoma cells. CT data revealed the CT-body divergence caused by atelectasis was reduced.

Lung Ultrasound Assessment of Regional Distribution of Pulmonary Edema and Atelectasis in Infants with Evolving Bronchopulmonary Dysplasia.

Background: Preterm infants are at risk for bronchopulmonary dysplasia (BPD) due to prolonged respiratory support. Studies have described differences in the regional distribution of lung ventilation (non-dependent (NDL) vs. dependent (DL)). The aim of this study was to use LUS to compare regional distribution of pulmonary edema and atelectasis in infants with evolving BPD. Methods: We prospectively performed LUS in premature infants with evolving BPD. On each side, three lung areas (NDL/anterior, lateral, and DL/posterior) were examined for the presence of pulmonary edema and atelectasis. Pulmonary edema scores were assigned based on the number of B-lines, and atelectasis scores were assigned based on the presence/absence of atelectasis. Results: 38 premature infants were enrolled. The NDL showed more pulmonary edema and atelectasis compared to the DL (p = 0.003, p = 0.049, respectively) and compared to the lateral lung (p =< 0.001, p = 0.004, respectively). There was no difference between the lateral and DL (p = 0.188, p = 0.156, respectively). There was no difference between the right and the left lung (p = 0.223, p = 0.656, respectively). Conclusions: In this cohort of preterm infants with evolving BPD, lung disease was unevenly distributed, with more pulmonary edema and atelectasis in the NDL regions compared to the DL or lateral regions.

A comparison of the effects of lung protective ventilation and conventional ventilation on the occurrence of atelectasis during laparoscopic surgery in young infants: a randomized controlled trial.

Objective: This study utilized lung ultrasound to investigate whether lung protective ventilation reduces pulmonary atelectasis and improves intraoperative oxygenation in infants undergoing laparoscopic surgery. Methods: Eighty young infants (aged 1-6 months) who received general anesthesia for more than 2 h during laparoscopic surgery were randomized into the lung protective ventilation group (LPV group) and the conventional ventilation group (control group). The LPV group received mechanical ventilation starting at 6 mL/kg tidal volume, 5 cmH2O PEEP, 60% inspired oxygen fraction, and half-hourly alveolar recruitment maneuvers. Control group ventilation began with 8-10 mL/kg tidal volume, 0 cmH2O PEEP, and 60% inspired oxygen fraction. Lung ultrasound was conducted five times-T1 (5 min post-intubation), T2 (5 min post-pneumoperitoneum), T3 (at the end of surgery), T4 (post-extubation), and T5 (prior to discharge from the PACU)-for each infant. Simultaneous arterial blood gas analysis was performed at T1, T2, T3, and T4. Results: Statistically significant differences were observed in pulmonary atelectasis incidence, lung ultrasound scores, and the PaO2, PaCO2, PaO2/FiO2 ratios at T2, T3, and T4. However, at T5, no statistically significant differences were noted in terms of lung ultrasound scores (4.30 ± 1.87 vs. 5.00 ± 2.43, 95% CI: -1.67 to 0.27, p = 0.153) or the incidence of pulmonary atelectasis (32.5% vs. 47.5%, p = 0.171). Conclusion: In infants aged 1-6 months, lung protective ventilation during laparoscopy under general anesthesia significantly reduced the incidence of pulmonary atelectasis and enhanced intraoperative oxygenation and dynamic lung compliance compared to conventional ventilation. However, these benefits did not persist; no differences were observed in lung ultrasound scores or the incidence of pulmonary atelectasis at PACU discharge. Clinical trial registration: http://www.chictr.org.cn/, identifier: ChiCTR2200058653.

Detection of spontaneous breathing during an apnea test in a patient with suspected brain death using electrical impedance tomography: a case report.

INTRODUCTION: The apnea test (AT) is a crucial procedure in determining brain death (BD), with detection of spontaneous breathing efforts serving as a key criterion. Numerous national statutes mandate complete disconnection of the patient from the ventilator during the procedure to open the airway directly to the atmosphere. These regulations mandate visual observation as an exclusive option for detecting breathing efforts. However, reliance on visual observation alone can pose challenges in identifying subtle respiratory movements. CASE PRESENTATION: This case report presents a 55-year-old morbidly obese male patient with suspected BD due to cerebral hemorrhage undergoing an AT. The AT was performed with continuous electrical impedance tomography (EIT) monitoring. Upon detection of spontaneous breathing movements by both visual observation and EIT, the AT was aborted, and the patient was reconnected to the ventilator. EIT indicated a shift in ventilation distribution from the ventral to the dorsal regions, indicating the presence of spontaneous breathing efforts. EIT results also suggested the patient experienced a slow but transient initial recovery phase, likely due to atelectasis induced by morbid obesity, before returning to a steady state of ventilatory support. CONCLUSION: The findings suggest EIT could enhance the sensitivity and accuracy of detecting spontaneous breathing efforts, providing additional insights into the respiratory status of patients during the AT.

Navigating Middle Lobe Syndrome: Exploring the Impact of Mycobacterium avium.

Middle lobe syndrome (MLS) is characterized by recurrent or chronic collapse (atelectasis) of the middle lobe of the right lung. Despite its clinical significance, MLS often goes unnoticed in medical practice. It manifests with obstructive symptoms, either due to external compression or internal causes, commonly stemming from infectious agents such as Mycobacterium avium complex (MAC) or occasionally from tumors. We present a unique case of MLS induced by MAC in an immunocompetent 74-year-old female patient with a history of bronchiectasis. Imaging revealed typical findings associated with MLS. Additional testing confirmed the diagnosis, and the patient was successfully treated. This case presents the opportunity to recognize and correctly treat cases of MLS with infectious etiology.

Thymoma-Related Chest Pain and Dyspnea in a Middle-Aged Caucasian Female With Myasthenia Gravis and Good's Syndrome: A Case Report.

Thymomas are rare tumors originating from thymic tissue, often associated with various paraneoplastic syndromes that can pose significant clinical management challenges. Myasthenia gravis, one of the most common paraneoplastic syndromes linked to thymomas, is characterized by autoantibodies targeting the neuromuscular junction, leading to muscle weakness exacerbated by repetitive use. Good's syndrome, an adult-onset immunodeficiency associated with thymomas, results in hypogammaglobulinemia and susceptibility to opportunistic infections, which can be life-threatening. We present the case of a 57-year-old Caucasian female with no prior medical history, who presented with a three-month history of progressive chest pain, dyspnea, and muscle weakness. A computed tomography (CT) scan of the chest revealed an anterior mediastinal soft tissue mass. Upon admission, a diagnostic workup, including serum anti-acetylcholine receptor antibodies and electromyography, confirmed the diagnosis of myasthenia gravis. Immune studies revealed hypogammaglobulinemia, consistent with Good's syndrome. The patient underwent complete surgical resection of the thymoma and received intravenous immunoglobulin (IVIG) therapy. This case report highlights the rarity and clinical significance of concurrent myasthenia gravis and Good's syndrome as paraneoplastic manifestations secondary to thymoma. Given the incidence of thymoma-associated paraneoplastic syndromes, early recognition and intervention are crucial for optimal outcomes. Future research may further elucidate the mechanisms underlying these associations, guiding improved management strategies.

Re-expansion pulmonary edema and atelectasis due to mucus plug following chest tube placement for pneumothorax.

Re-expansion pulmonary edema (REPE) and mucus plug-induced atelectasis are potential complications that clinicians should be aware of following chest tube placement for pneumothorax.

Structured respiratory physiotherapy protocol for resolution of atelectasis in pediatric intensive care.

Children are at higher risk of atelectasis due to their anatomical and physiological particularities. Several physiotherapy techniques are used to treat atelectasis, but only four studies cite methods in pediatric patients undergoing Invasive Mechanical Ventilation (IMV). The objective of this study was to evaluate the Structured Respiratory Physiotherapy Protocol (SRPP) for airway clearance and lung reexpansion for infants on IMV with atelectasis. This is a prospective study including 30 infants (mean ± standard deviation age 8.9 ± 8.0 months; weight 7.5 ± 3.0 kg; BMI 15.8 ± 1.6 kg/cm2 and IMV duration 7.7 ± 4.3 days). The sample was randomized into a Control Group (CG), which received routine physiotherapy, and an Intervention Group (IG), submitted to SRPP (postural drainage, mechanical thoracic vibration, manual hyperinflation, stretching of the accessory respiratory muscles, and functional positioning). Both groups were evaluated before and after physiotherapy for respiratory effort using the Wood Downes Score (WD) and pulmonary aeration using lung ultrasonography (Lung Ultrasound Score ‒ LUS). The outcome of the intervention was evaluated by the magnitude of the effect by the Hedges' g test [(small (0.2 < Hedges' g < 0.5), moderate (0.5 < Hedges' g < 0.8) and large (Hedges' g > 0.8) effects]. There were large within-group effects on the reduction of WD in the CG after intervention in both the CG (Hedges' g = -1.53) and IG (Hedges' g = -2.2). There was a moderate effect on LUS reduction in the CG (Hedges' g = -0.64) and a large effect on IG (Hedges' g = -1.88). This study has shown that the SRPP appears to be safe and may be effective in improving airway clearance and lung reexpansion in children on IMV with atelectasis.

Predictive value of gradient boosting decision trees for postoperative atelectasis complications in patients with pulmonary destruction.

OBJECTIVE: To explore the application value of a gradient boosting decision tree (GBDT) in predicting postoperative atelectasis in patients with destroyed lungs. METHODS: A total of 170 patients with damaged lungs who underwent surgical treatment in Chest Hospital of Guangxi Zhuang Autonomous Region from January 2021 to May 2023 were retrospectively selected. The patients were divided into a training set (n = 119) and a validation set (n = 51). Both GBDT algorithm model and Logistic regression model for predicting postoperative atelectasis in patients were constructed. The receiver operating characteristic (ROC) curve, calibration curve and decision curve were used to evaluate the prediction efficiency of the model. RESULTS: The GBDT model indicated that the relative importance scores of the four influencing factors were operation time (51.037), intraoperative blood loss (38.657), presence of lung function (9.126) and sputum obstruction (1.180). Multivariate Logistic regression analysis revealed that operation duration and sputum obstruction were significant predictors of postoperative atelectasis among patients with destroyed lungs within the training set (P = 0.048, P = 0.002). The ROC curve analysis showed that the area under the curve (AUC) for GBDT and Logistic model in the training set was 0.795 and 0.763, and their AUCs in the validation set were 0.776 and 0.811. The GBDT model's predictions closely matched the ideal curve, showing a higher net benefit than the reference line. CONCLUSIONS: GBDT model is suitable for predicting the incidence of complications in small samples.

Odontogenic Sinusitis Presenting With Infraorbital Numbness and Progressive Maxillary Sinus Atelectasis.

Odontogenic sinusitis is the most common cause of isolated maxillary sinusitis. Accurate diagnosis is important to ensure optimal treatment. We discuss the unique presentation of a 55-year-old man with odontogenic sinusitis and associated infraorbital nerve neuropathy. We document his later development of chronic maxillary atelectasis and discuss the possible underlying pathophysiology linking this with his infraorbital neuropathy.

Endoscopic ear surgery in the treatment of chronic otitis media with atelectasis.

PURPOSE: Atelectasis otitis media (AtOM) is a chronic condition where the tympanic membrane (TM) becomes retracted towards the middle ear and the ossicular chain. Surgical treatment for this condition could be indicated based on stage of atelectasis, patient's clinical condition and hearing loss. Over the years, AtOM has been treated with various types of tympanoplasty under microscopic view. The aim of this study is to present the results of endoscopic ear surgery in AtOM. METHODS: Forty-five patients who underwent endoscopic trans-canal tympanoplasty were included in the study. Preoperative features, intraoperative findings and postoperative outcomes were collected. RESULTS: Preoperatively, none of the study's patients were classified with a Sadè Grade I, whereas grades II, III and IV were 3 (6.6%), 23 (32.1%) and 19 (67.8%) respectively. The 3 patients with Sadè grade II showed a conductive hearing loss higher than 20 dB and a continuous ear fullness, therefore they were surgically treated. The postoperative graft success rate was estimated at 95.5%. During follow-up, 2 patients showed a TM perforation (at 6 and 12 months after surgery) whereas 1 patient experienced a recurrence of atelectasis in the TM (16 months after surgery). The overall success rate at the final follow-up was calculated at 88.8%. The average preoperative air-conduction threshold was 51.1 ± 21.5, which reduced to 34.6 ± 22.1 (p = 0.04) at follow-up. The preoperative air-bone gap decreased from 28 ± 7.2 to 11.8 ± 10 (p = 0.002) after surgery. CONCLUSION: Atelectasis otitis media might be suitable for exclusive endoscopic surgical treatment, as it appears to exhibit a low recurrence rate and promising audiological outcomes.

The effects of laryngeal mask versus endotracheal tube on atelectasis after general anesthesia induction assessed by lung ultrasound: A randomized controlled trial.

STUDY OBJECTIVE: This study aims to evaluate the impact of Supreme™ laryngeal masks versus endotracheal tubes on atelectasis during general anesthesia using lung ultrasound (LUS), and provide evidence for respiratory management. DESIGN: A single-center, double-blind, randomized controlled trial was conducted. SETTING: The study was conducted in both the operating room and the post-anesthesia care unit, with follow-up assessments performed in the ward. PATIENTS: Enrollment included 180 cases undergoing non-laparoscopic surgeries in gynecology, urology, and orthopedic limb surgeries. INTERVENTIONS: Patients were randomly assigned 1:1 to the endotracheal intubation or laryngeal mask group. MEASUREMENTS: LUS scores were recorded across 12 lung regions at baseline, 15 min after airway establishment, at the end of surgery, and 30 min following airway removal. Outcome measures encompassed the oxygenation index, dynamic lung compliance, incidence of postoperative pulmonary complications, throat pain, and other postoperative complications assessed at 24 and 48 h postoperatively. The primary outcome focused on the LUS score in all 12 lung regions at 15 min after airway establishment. MAIN RESULTS: Intention-to-treat analysis of 177 subjects revealed endotracheal intubation led to significantly higher LUS scores at 15 min {P < 0.001, mean difference 4.15 ± 0.60, 95% CI [2.97, 5.33]}, end of surgery (P < 0.001, mean difference 3.37 ± 0.68, 95% CI [2.02, 4.72]), and 30 min post-removal (P < 0.001, mean difference 2.63 ± 0.48, 95% CI [1.68, 3.58]). No major complications occurred in the two groups. CONCLUSIONS: Compared to endotracheal intubation, laryngeal masks effectively reduce atelectasis formation and progression in gynecological, urological non-laparoscopic, and orthopedic limb surgeries. However, caution is warranted when generalizing these findings to surgeries with a higher risk of laryngeal mask leakage or obese patients. Additionally, the efficacy of laryngeal masks in reducing postoperative atelectasis remains uncertain when comprehensive monitoring of muscle relaxation and reversal therapy is employed.

Recruitment-to-inflation ratio to assess response to PEEP during laparoscopic surgery: A physiologic study.

STUDY OBJECTIVE: During laparoscopic surgery, the role of PEEP to improve outcome is controversial. Mechanistically, PEEP benefits depend on the extent of alveolar recruitment, which prevents ventilator-induced lung injury by reducing lung dynamic strain. The hypotheses of this study were that pneumoperitoneum-induced aeration loss and PEEP-induced recruitment are inter-individually variable, and that the recruitment-to-inflation ratio (R/I) can identify patients who benefit from PEEP in terms of strain reduction. DESIGN: Sequential study. SETTING: Operating room. PATIENTS: Seventeen ASA I-III patients receiving robot-assisted prostatectomy during Trendelenburg pneumoperitoneum. INTERVENTIONS AND MEASUREMENTS: Patients underwent end-expiratory lung volume (EELV) and respiratory/lung/chest wall mechanics (esophageal manometry and inspiratory/expiratory occlusions) assessment at PEEP = 0 cmH2O before and after pneumoperitoneum, at PEEP = 4 and 12 cmH2O during pneumoperitoneum. Pneumoperitoneum-induced derecruitment and PEEP-induced recruitment were assessed through a simplified method based on multiple pressure-volume curve. Dynamic and static strain changes were evaluated. R/I between 12 and 4 cmH2O was assessed from EELV. Inter-individual variability was rated with the ratio of standard deviation to mean (CoV). MAIN RESULTS: Pneumoperitoneum reduced EELV by (median [IqR]) 410 mL [80-770] (p < 0.001) and increased dynamic strain by 0.04 [0.01-0.07] (p < 0.001), with high inter-individual variability (CoV = 70% and 88%, respectively). Compared to PEEP = 4 cmH2O, PEEP = 12 cmH2O yielded variable amount of recruitment (139 mL [96-366] CoV = 101%), causing different extent of dynamic strain reduction (median decrease 0.02 [0.01-0.04], p = 0.002; CoV = 86%) and static strain increases (median increase 0.05 [0.04-0.07], p = 0.01, CoV = 33%). R/I (1.73 [0.58-3.35]) estimated the decrease in dynamic strain (p ≤0.001, r = -0.90) and the increase in static strain (p = 0.009, r = -0.73) induced by PEEP, while PEEP-induced changes in respiratory and lung mechanics did not. CONCLUSIONS: Trendelenburg pneumoperitoneum yields variable derecruitment: PEEP capability to revert these phenomena varies significantly among individuals. High R/I identifies patients in whom higher PEEP mostly reduces dynamic strain with limited static strain increases, potentially allowing individualized settings.