The reduction in functional residual capacity (FRC) is a significant pathological factor in the development of postoperative pulmonary complications. Appropriate positive end-expiratory pressure (PEEP) is critical to preserve FRC during mechanical ventilation. Our previous study suggests that using driving pressure-guided PEEP can reduce postoperative pulmonary complications. In this study, we hypothesize that individualized PEEP can increase immediate postoperative FRC and improve lung ventilation.

This single-centered, randomized controlled trial included a total of 91 patients scheduled for laparoscopic surgery for colorectal carcinoma. Patients were randomly assigned to receive individualized PEEP guided by minimum driving pressure or a fixed PEEP of six cmH2O. The primary outcome was postoperative FRC. Secondary outcomes included the incidence of postoperative pulmonary complications, postoperative Oxygenation Index, alveolar-arterial oxygen tension difference (PA-aO2), intrapulmonary shunt (QS/QT), and Respiratory Index, as well as lung ventilation measured by electrical impedance tomography.

The median value of PEEP in the individualized group was 14 cmH2O, with an interquartile range of 12-14 cmH2O. The postoperative FRC was significantly higher in the individualized PEEP group than that in the PEEP six cmH2O group (32.8 [12.8] vs. 25.0 [12.6] mL/kg, P=0.004). Patients receiving driving pressure-guided PEEP also had significantly higher Oxygenation Index, better ventilation distribution, and lower PA-aO2, QS/QT, and Respiratory Index.

Driving pressure-guided PEEP can preserve postoperative FRC and provide better ventilation and oxygenation for patients undergoing laparoscopic colorectal surgery.

Patients with acute exacerbation of lung fibrosis with usual interstitial pneumonia (EUIP) pattern are at increased risk for ventilator-induced lung injury (VILI) and mortality when exposed to mechanical ventilation (MV). Yet, lack of a mechanical model describing UIP-lung deformation during MV represents a research gap. Aim of this study was to develop a constitutive mathematical model for UIP-lung deformation during lung protective MV based on the stress-strain behavior and the specific elastance of patients with EUIP as compared to that of acute respiratory distress syndrome (ARDS) and healthy lung. Partitioned lung and chest wall mechanics were assessed for patients with EUIP and primary ARDS (1:1 matched based on body mass index and PaO2/FiO2 ratio) during a PEEP trial performed within 24 h from intubation. Patient's stress-strain curve and the lung specific elastance were computed and compared with those of healthy lungs, derived from literature. Respiratory mechanics were used to fit a novel mathematical model of the lung describing mechanical-inflation-induced lung parenchyma deformation, differentiating the contributions of elastin and collagen, the main components of lung extracellular matrix. Five patients with EUIP and 5 matched with primary ARDS were included and analyzed. Global strain was not different at low PEEP between the groups. Overall specific elastance was significantly higher in EUIP as compared to ARDS (28.9 [22.8-33.2] cmH2O versus 11.4 [10.3-14.6] cmH2O, respectively). Compared to ARDS and healthy lung, the stress/strain curve of EUIP showed a steeper increase, crossing the VILI threshold stress risk for strain values greater than 0.55. The contribution of elastin was prevalent at lower strains, while the contribution of collagen was prevalent at large strains. The stress/strain curve for collagen showed an upward shift passing from ARDS and healthy lungs to EUIP lungs. During MV, patients with EUIP showed different respiratory mechanics, stress-strain curve and specific elastance as compared to ARDS patients and healthy subjects and may experience VILI even when protective MV is applied. According to our mathematical model of lung deformation during mechanical inflation, the elastic response of UIP-lung is peculiar and different from ARDS. Our data suggest that patients with EUIP experience VILI with ventilatory setting that are lung-protective for patients with ARDS.

Capnodynamic lung function monitoring generates variables that may be useful for pediatric perioperative ventilation.

Establish normal values for end-expiratory lung volume CO2 in healthy children undergoing anesthesia and to compare these values to previously published values obtained with alternative end-expiratory lung volume methods. The secondary aim was to investigate the ability of end-expiratory lung volume CO2 to react to positive end-expiratory pressure-induced changes in end-expiratory lung volume. In addition, normal values for associated volumetric capnography lung function variables were examined.

Fifteen pediatric patients with healthy lungs (median age 8 months, range 1-36 months) undergoing general anesthesia were examined before start of surgery. Tested variables were recorded at baseline positive end-expiratory pressure 3 cmH2 O, 1 and 3 min after positive end-expiratory pressure 10 cmH2 O and 3 min after returning to baseline positive end-expiratory pressure 3 cmH2 O.

Baseline end-expiratory lung volume CO2 was 32 mL kg-1 (95% CI 29-34 mL kg-1 ) which increased to 39 mL kg-1 (95% CI 35-43 mL kg-1 , p < .0001) and 37 mL kg-1 (95% CI 34-41 mL kg-1 , p = .0003) 1 and 3 min after positive end-expiratory pressure 10 cmH2 O, respectively. End-expiratory lung volume CO2 returned to baseline, 33 mL kg-1 (95% CI 29-37 mL kg-1 , p = .72) 3 min after re-establishing positive end-expiratory pressure 3 cmH2 O. Airway dead space increased from 1.1 mL kg-1 (95% CI 0.9-1.4 mL kg-1 ) to 1.4 (95% CI 1.1-1.8 mL kg-1 , p = .003) and 1.5 (95% CI 1.1-1.8 mL kg-1 , p < .0001) 1 and 3 min after positive end-expiratory pressure 10 cmH2 O, respectively, and 1.2 mL kg-1 (95% CI 0.9-1.4 mL kg-1 , p = .08) after 3 min of positive end-expiratory pressure 3 cmH2 O. Additional volumetric capnography and lung function variables showed no major changes in response to positive end-expiratory pressure variations.

Capnodynamic noninvasive and continuous end-expiratory lung volume CO2 values assessed during anesthesia in children were in close agreement with previously reported end-expiratory lung volume values generated by alternative methods. Furthermore, positive end-expiratory pressure changes resulted in physiologically expected end-expiratory lung volume CO2 responses in a timely manner, suggesting that it can be used to trend end-expiratory lung volume changes during anesthesia.

Exaggerated lung strain and stress could damage lungs in anesthetized children. The authors hypothesized that the association of capnoperitoneum and lung collapse in anesthetized children increases lung strain-stress. Their primary aim was to describe the impact of capnoperitoneum on lung strain-stress and the effects of an individualized protective ventilation during laparoscopic surgery in children.

The authors performed an observational cohort study in healthy children aged 3 to 7 yr scheduled for laparoscopic surgery in a community hospital. All received standard protective ventilation with 5 cm H2O of positive end-expiratory pressure (PEEP). Children were evaluated before capnoperitoneum, during capnoperitoneum before and after lung recruitment and optimized PEEP (PEEP adjusted to get end-expiratory transpulmonary pressure of 0), and after capnoperitoneum with optimized PEEP. The presence of lung collapse was evaluated by lung ultrasound, positive Air-Test (oxygen saturation measured by pulse oximetry 96% or less breathing 21% O2 for 5 min), and negative end-expiratory transpulmonary pressure. Lung strain was calculated as tidal volume/end-expiratory lung volume measured by capnodynamics, and lung stress as the end-inspiratory transpulmonary pressure.

The authors studied 20 children. Before capnoperitoneum, mean lung strain was 0.20 ± 0.07 (95% CI, 0.17 to 0.23), and stress was 5.68 ± 2.83 (95% CI, 4.44 to 6.92) cm H2O. During capnoperitoneum, 18 patients presented lung collapse and strain (0.29 ± 0.13; 95% CI, 0.23 to 0.35; P < 0.001) and stress (5.92 ± 3.18; 95% CI, 4.53 to 7.31 cm H2O; P = 0.374) increased compared to before capnoperitoneum. During capnoperitoneum and optimized PEEP, children presenting lung collapse were recruited and optimized PEEP was 8.3 ± 2.2 (95% CI, 7.3 to 9.3) cm H2O. Strain returned to values before capnoperitoneum (0.20 ± 0.07; 95% CI, 0.17 to 0.22; P = 0.318), but lung stress increased (7.29 ± 2.67; 95% CI, 6.12 to 8.46 cm H2O; P = 0.020). After capnoperitoneum, strain decreased (0.18 ± 0.04; 95% CI, 0.16 to 0.20; P = 0.090), but stress remained higher (7.25 ± 3.01; 95% CI, 5.92 to 8.57 cm H2O; P = 0.024) compared to before capnoperitoneum.

Capnoperitoneum increased lung strain in healthy children undergoing laparoscopy. Lung recruitment and optimized PEEP during capnoperitoneum decreased lung strain but slightly increased lung stress. This little rise in pulmonary stress was maintained within safe, lung-protective, and clinically acceptable limits.

Monitoring is essential to assess changes in the lung condition, to identify heart-lung interactions, and to personalize and improve respiratory support and adjuvant therapies in pediatric acute respiratory distress syndrome (PARDS). The objective of this article is to report the rationale of the revised recommendations/statements on monitoring from the Second Pediatric Acute Lung Injury Consensus Conference (PALICC-2).

MEDLINE (Ovid), Embase (Elsevier), and CINAHL Complete (EBSCOhost).

We included studies focused on respiratory or cardiovascular monitoring of children less than 18 years old with a diagnosis of PARDS. We excluded studies focused on neonates.

Title/abstract review, full-text review, and data extraction using a standardized data collection form.

The Grading of Recommendations Assessment, Development and Evaluation approach was used to identify and summarize evidence and develop recommendations. We identified 342 studies for full-text review. Seventeen good practice statements were generated related to respiratory and cardiovascular monitoring. Four research statements were generated related to respiratory mechanics and imaging monitoring, hemodynamics monitoring, and extubation readiness monitoring.

PALICC-2 monitoring good practice and research statements were developed to improve the care of patients with PARDS and were based on new knowledge generated in recent years in patients with PARDS, specifically in topics of general monitoring, respiratory system mechanics, gas exchange, weaning considerations, lung imaging, and hemodynamic monitoring.

Mechanical ventilation can lead to the severe impairment of the metabolic pathway of alveolar surfactants, inactivating alveolar surfactants and significantly reducing lung-chest compliance. The cardiopulmonary function of elderly patients usually reduced to a certain extent, and there are lung complications after surgical anesthesia, just like lung barotrauma caused by mechanical ventilation, atelectasis and postoperative hypoxemia.

To investigate the effects of different positive end expiratory pressures (PEEPs) and tidal volumes (VTs) on respiratory function, the degree of the inflammatory response and hemodynamic indexes in patients undergoing surgery under general anesthesia.

A total of 120 patients undergoing surgery for gastric or colon cancer under general anesthesia in Xinghua People's Hospital from January 2017 to January 2021 were randomly divided into Group A and Group B, with 60 cases in each group. The ventilation mode in Group A was VT (6.0 mL/kg) + PEEP (5.0 cmH2O), while that in Group B was VT (6.0 mL/kg) + PEEP (8.0 cmH2O). Blood gas parameters, respiratory mechanical parameters, inflammatory response indicators, hemodynamic indicators and related complications were compared between the two groups.

There were no significant differences in PaCO2, PaO2, oxygen or the examined indexes at T0 between group A and group B (P > 0.05). The measured PaO2 value of patients in group A at T3 was higher than that in group B, and the difference was significant (P < 0.05). There were no significant differences in peak airway pressure (Ppeak), mean airway pressure or dynamic pulmonary compliance (Cdyn) at T0 between group A and group B (P > 0.05). The measured Ppeak value of patients in group A at T1 was higher than that in group B, and the difference was significant (P < 0.05). The measured Cdyn value at T1 and T2 was greater than that in group B (P < 0.05). Before surgery, there were no significant differences in tumor necrosis factor-α (TNF-α), interleukin (IL)-6 or IL-10 between group A and group B (P > 0.05). After 4 h, the measured values of TNF-α and IL-6 in group A were lower than those in group B, and the differences were significant (P < 0.05). The IL-10 Level in group A was higher than that in group B (P < 0.05). At T0, there were no significant differences in cardiac output, cardiac index (CI), stroke volume index (SVI) or mean arterial pressure between group A and group B (P > 0.05). The measured values of CI and SVI at T2 in patients in group A were higher than those in group B, and the differences were significant (P < 0.05).

For patients undergoing surgery for gastric or colon cancer under general anesthesia, the VT (6.0 mL/kg) + PEEP (5.0 cmH2O) regimen was more effective than the VT (6.0 mL/kg) + PEEP (8.0 cmH2O) regimen in protecting the lung function and ventilatory function of patients, and it had better effects on maintaining hemodynamic stability and reducing inflammatory reactions.