Compliance Of The Respiratory System Research Articles

Tidal volume selection in volume-controlled ventilation guided by driving pressure versus actual body weight in healthy anesthetized and mechanically ventilated dogs: A randomized crossover trial

ObjectiveTo compare static compliance of the respiratory system (CstRS) and the ratio of partial pressure of end-tidal to arterial carbon dioxide (Pe′CO2/PaCO2), in healthy dogs using two approaches for tidal volume (VT) selection during volume-controlled ventilation: body mass based and driving pressure (ΔPaw) guided. Study designRandomized, nonblinded, crossover, clinical trial. AnimalsA total of 19 client-owned dogs anesthetized for castration and ovariohysterectomy. MethodsAfter a stable 10 minute baseline, each dog was mechanically ventilated with a VT selection strategy, randomized to a constant VT of 15 mL kg–1 of actual body mass (VTBW) or ΔPaw-guided VT (VTΔP) of 7–8 cmH2O. Both strategies used an inspiratory time of 1 second, 20% end-inspiratory pause, 4 cmH2O positive end-expiratory pressure and fraction of inspired oxygen of 0.4. Respiratory frequency was adjusted to maintain Pe′CO2 between 35 and 40 mmHg. Respiratory mechanics, arterial blood gases and Pe′CO2/PaCO2 were assessed. Continuous variables are presented as mean ± SD or median (interquartile range; quartiles 1–3), depending on distribution, and compared with Wilcoxon signed-rank tests. ResultsThe VT was significantly higher in dogs ventilated with VTΔP than with VTBW strategy (17.20 ± 4.04 versus 15.03 ± 0.60 mL kg–1, p = 0.036). CstRS was significantly higher with VTΔP than with VTBW strategy [2.47 (1.86–2.86) versus 2.25 (1.79–2.58) mL cmH2O−1 kg–1, p = 0.011]. There were no differences in Pe′CO2/PaCO2 between VTΔP and VTBW strategies (0.94 ± 0.06 versus 0.92 ± 0.06, p = 0.094). No discernible difference in ΔPaw was noted between the strategies. Conclusions and clinical relevanceWhile no apparent difference was observed in the Pe′CO2/PaCO2 between the VT selection strategies employed, CstRS significantly increased during the VTΔP approach. A future trial should explore if VTΔP improves perioperative gas exchange and prevents lung damage.

Intraoperative effects of an alveolar recruitment manoeuvre in patients undergoing laparoscopic colon surgery

IntroductionPulmonary atelectasis is common in patients undergoing laparoscopic abdominal surgery under general anaesthesia, which increases the risk of perioperative respiratory complications. Alveolar recruitment manoeuvres (ARM) are used to open up the lung parenchyma with atelectasis, although the duration of their benefit has not been clearly established. The aim of this study was to determine the effectiveness of an ARM in laparoscopic colon surgery, the duration of response over time, and its haemodynamic impact. MethodsTwenty-five patients undergoing laparoscopic colon surgery were included. After anaesthetic induction and initiation of surgery with pneumoperitoneum, an ARM was performed, and then optimal PEEP determined. Respiratory mechanics and gas exchange variables, and haemodynamic parameters, were analysed before the manoeuvre and periodically over the following 90 min. ResultsThree patients were excluded for surgical reasons. The alveolar arterial oxygen gradient went from 94.3 (62.3−117.8) mmHg before to 60.7 (29.6−91.0) mmHg after the manoeuvre (P < .05). This difference was maintained during the 90 min of the study. Dynamic compliance of the respiratory system went from 31.3 ml/cmH2O (26.1–39.2) before the manoeuvre to 46.1 ml/cmH2O (37.5−53.5) after the manoeuvre (P < .05). This difference was maintained for 60 min. No significant changes were identified in any of the haemodynamic variables studied. ConclusionIn patients undergoing laparoscopic colon surgery, performing an intraoperative ARM improves the mechanics of the respiratory system and oxygenation, without associated haemodynamic compromise. The benefit of these manoeuvres lasts for at least one hour.

Respiratory function testing for guiding ventilator mode conversion in congenital diaphragmatic hernia.

For patients with a congenital diaphragmatic hernia, conventional mechanical ventilation (CMV) and high-frequency oscillatory ventilation (HFOV) are used in initial ventilatory management. HFOV has recently been recommended as a rescue therapy; however, we use HFOV for initial ventilation management, with a preoperative challenge test for CMV conversion and respiratory function testing at the time of CMV conversion. We aimed to compare patient characteristics between CMV conversion- and HFOV-preferred treatment groups. Ventilator settings and blood gases were retrospectively evaluated pre- and post-CMV conversion, and respiratory function tests for compliance of the respiratory system (Crs) and for resistance of the respiratory system (Rrs) were performed during the trial to CMV conversion. No differences were observed between the CMV conversion- and HFOV-preferred groups regarding gestational age, birth weight, and observed/expected lung area-to-head circumference ratios. The median Crs (ml/cmH2 O/kg) and Rrs (cmH2 O･kg/L/s) in the CMV conversion- and HFOV-preferred groups was 0.42 versus 0.53 (p = .44) and 467 versus 327 (p = .045), respectively. The pre and posttrial amount of change in blood gas levels and ventilator parameters in the CMV conversion- and HFOV-preferred groups were as follows: mean airway pressure, -2.0 versus 0 cmH2 O; partial pressure of carbon dioxide, 6.1 versus 2.9 Torr; alveolar-arterial oxygen difference, -39.5 versus -50 Torr; and oxygenation index, -1.0 versus -0.6; respectively. Respiratory function tests were useful in tailoring ventilator settings. Patients with high Rrs values responded better to CMV conversion.

Particulate matter-mediated oxidative stress induces airway inflammation and pulmonary dysfunction through TXNIP/NF-κB and modulation of the SIRT1-mediated p53 and TGF-β/Smad3 pathways in mice

Exposure to particulate matter is currently recognized as a serious aggravating factor of respiratory diseases. In this study, we investigated the effects of particulate matter (PM) on the respiratory system in BALB/c mice and NCI-H292 cells. PM (0, 2.5, 5 and 20 mg/kg) was administered to mice by intra-tracheal instillation for 7 days. After a 7 day-repeated treatment of PM, we evaluated inflammatory cytokines/cell counts in bronchoalveolar lavage fluid (BALF) and conducted pulmonary histology and functional test. We also investigated the role of TXNIP/NF-κB and SIRT1-mediated p53 and TGF-β/Smad3 pathways in PM-induced airway inflammation and pulmonary dysfunction. PM caused a significant increase in pro-inflammatory cytokines, inflammatory cell counts in bronchoalveolar lavage fluid. PM-mediated oxidative stress down-regulated thioredoxin-1 and up-regulated thioredoxin-interacting protein and activation of nuclear factor-kappa B in the lung tissue and PM-treated NCI-H292 cells. PM suppressed sirtuin1 protein levels and increased p53 acetylation in PM-exposed mice and PM-treated NCI-H292 cells. In addition, PM caused inflammatory cell infiltration and the thickening of alveolar walls by exacerbating the inflammatory response in the lung tissue. PM increased levels of transforming growth factor-β, phosphorylation of Smad3 and activation of α-smooth muscle actin, and collagen type1A2 in PM-exposed mice and PM-treated NCI-H292 cells. In pulmonary function tests, PM exposure impaired pulmonary function resembling pulmonary fibrosis, characterized by increased resistance and elastance of the respiratory system, and resistance, elastance, and damping of lung tissues, whereas decreased compliance of the respiratory system, forced expired volume and forced vital capacity. Overall, PM-mediated oxidative stress caused airway inflammation and pulmonary dysfunction with pulmonary fibrosis via TXNIP pathway/NF-κB activation and modulation of the SIRT1-mediated TGF-β/Smad3 pathways. The results of this study can provide fundamental data on the potential adverse effects and underlying mechanism of pulmonary fibrosis caused by PM exposure as a public health concern. Due to the potential toxicity of PM, people with respiratory disease must be careful with PM exposure.

Relationship of End Expiratory Lung Volume, Compliance, and Plateau Pressure in Acute Respiratory Distress Syndrome.

COVID-19 ARDS (acute respiratory distress syndrome), caused by SARS-CoV-2,involves a decrease in the end expiratory lung volume (EELV), compliance, and hypoxemia. The authors retrospectively analysed the relationship between the EELV, Plateau pressure (Pplat), and compliance of the respiratory system in a group of 21 mechanically ventilated COVID ARDS patients with moderate to severe hypoxia who were subjected to a recruitment manoeuvre. Further, these parameters were studied after dividing them into two groups as Group 1 of clinically non-recruitable and Group 2 of clinically recruitable patients.There was relationship between EELV, compliance, and Pplat among those patients who were clinically recruited versus those who were not in a homogeneous group of COVID ARDS patients. In Group 1, the statistical value of EELV and compliance were r = 0.395, p>0.05, EELV and Pplat were r = 0.021, p>0.05, and compliance and Pplat were r = -0.848, p<0.001. In Group 2, the statistical values of EELV and compliance were (r = 0.605, p<0.001), EELV and Pplat were r = -0.391, p<0.05, compliance and Pplat were r = -0.848, p<0.001. The additional information gained after understanding this relationship can help to optimise ventilator settings. Key Words: COVID, ARDS, End expiratory lung volume, Plateau pressure, Compliance, Recruitment, Ventilation.

Effects of different positive end-expiratory pressure titration strategies on mechanical power during ultraprotective ventilation in ARDS patients treated with veno-venous extracorporeal membrane oxygenation: A prospective interventional study

PurposeUltraprotective ventilation in acute respiratory distress syndrome (ARDS) patients with veno-venous extracorporeal membrane oxygenation (VV ECMO) reduces mechanical power (MP) through changes in positive end-expiratory pressure (PEEP); however, the optimal approach to titrate PEEP is unknown. This study assesses the effects of three PEEP titration strategies on MP, hemodynamic parameters, and oxygen delivery in twenty ARDS patients with VV ECMO. Material and methodsPEEP was titrated according to: (A) a PEEP of 10 cmH2O representing the lowest recommendation by the Extracorporeal Life Support Organization (PEEPELSO), (B) the highest static compliance of the respiratory system (PEEPCstat,RS), and (C) a target end-expiratory transpulmonary pressure of 0 cmH2O (PEEPPtpexp). ResultsPEEPELSO was lower compared to PEEPCstat,RS and PEEPPtpexp (10.0 ± 0.0 vs. 16.2 ± 4.7 cmH2O and 17.3 ± 4.0 cmH2O, p < 0.001 each, respectively). PEEPELSO reduced MP compared to PEEPCstat,RS and PEEPPtpexp (5.3 ± 1.3 vs. 6.8 ± 2.0 and 6.9 ± 2.3 J/min, p < 0.001 each, respectively). PEEPELSO resulted in less lung stress compared to PEEPCstat,RS (p = 0.011) and PEEPPtpexp (p < 0.001) and increased cardiac output and oxygen delivery (p < 0.001 each). ConclusionsAn empirical PEEP of 10 cmH2O minimized MP, provided favorable hemodynamics, and increased oxygen delivery in ARDS patients treated with VV ECMO. Trial registrationGerman Clinical Trials Register (DRKS00013967). Registered 02/09/2018https://drks.de/search/en/trial/DRKS00013967

Intact cord resuscitation in newborns with congenital diaphragmatic hernia: insights from a lamb model.

Congenital diaphragmatic hernia (CDH) is a rare condition characterized by pulmonary hypoplasia, vascular dystrophy, and pulmonary hypertension at birth. Validation of the lamb model as an accurate representation of human CDH is essential to translating research findings into clinical practice and understanding disease mechanisms. This article emphasizes the importance of validating the lamb model to study CDH pathogenesis and develop innovative therapeutics. At 78 days of gestation, the fetal lamb's left forelimb was exposed through a midline laparotomy and hysterotomy, and a supra diaphragmatic thoracotomy was performed to allow the digestive organs to ascend into the thoracic cavity. At 138 ± 3 days of gestation, lambs were delivered via a cesarean section; then, with umbilical cord intact during 1 hour, the lambs were mechanically ventilated with gentle ventilation in a pressure-controlled mode for 2 h. CDH lambs exhibited a lower left lung-to-body weight ratio of 5.3 (2.03), p < 0.05, and right lung-to-body weight ratio of 8.2 (3.1), p < 0.05. They reached lower Vt/kg (tidal volume per kg) during the course of the resuscitation period with 1.2 (0.7) ml/kg at 10 min and 3 (1.65) ml/kg at 60 min (p < 0.05). Compliance of the respiratory system was lower in CDH lambs with 0.5 (0.3) ml/cmH2O at 60 min (p < 0.05) and 0.9 (0.26) ml/cmH2O at 120 min (p < 0.05). Differences between pre- and postductal SpO2 were higher with 15.1% (21.4%) at 20 min and 6.7% (14.5%) at 80 min (p < 0.05). CDH lambs had lower differences between inspired and expired oxygen fractions with 4.55% (6.84%) at 20 min and 6.72% (8.57%) at 60 min (p < 0.05). CDH lamb had lower left ventricle [2.73 (0.5) g/kg, p < 0.05] and lower right ventricle [0.69 (0.8), p < 0.05] to left ventricle ratio. CDH lambs had significantly lower tidal volume than control lambs due to lower compliance of the respiratory system and higher airway resistance. These respiratory changes are characteristic of CDH infants and are associated with higher mortality rates. CDH lambs also exhibited pulmonary hypertension, pulmonary hypoplasia, and left ventricle hypoplasia, consistent with observations in human newborns. To conclude, our lamb model successfully provides a reliable representation of CDH and can be used to study its pathophysiology and potential interventions.

A Comparison of Proximal and Tracheal Airway Pressures During Pressure Controlled Ventilation.

Airway pressure is usually measured by sensors placed in the ventilator or on the ventilator side of the endotracheal tube (ETT), at the Y-piece. These remote measurements serve as a surrogate for the tracheal or alveolar pressure. Tracheal pressure can only be predicted correctly by using a model that incorporates the pressure at the remote location, the flow through the ETT, and the resistance of the ETT if the latter is a predictable function of Y-piece flow. However, this is not consistently appropriate, and accuracy of prediction is hampered. This in vitro study systematically examined the ventilator pressure in dependence of compliance of the respiratory system (CRS), inspiratory time, and expiratory time during pressure-controlled ventilation by using a small intratracheal pressure sensor and a mechanical lung simulator. Pressures were measured simultaneously at the ventilator outlet, at the Y-piece, and in the trachea during pressure-controlled ventilation with a peak inspiratory pressure of 20 cm H2O and a PEEP of 5 cm H2O while changing CRS (10, 30, 60, 90, and 100 mL/cm H2O) and varying inspiratory time and expiratory time. Tracheal pressures were always lower (maximum 8 cm H2O during inspiration) or higher (maximum 4 cm H2O during expiration) than the pressures measured proximal to the ETT if zero-flow conditions were not achieved at the end of the breathing cycles. Dependent on CRS and the breathing cycle, tracheal pressures deviated from those measured proximal to the ETT under non-zero-flow conditions. Intratracheal pressure and pressure curve dynamics can differ greatly from the ventilator pressure, depending on the ventilator setting and the CRS. The small pressure sensor may be used as a measurement method of tracheal pressure via integration onto an ETT.

Time to Extubation Among ARDS Subjects With and Without COVID-19 Pneumonia.

Pneumonia from COVID-19 that results in ARDS may require invasive mechanical ventilation. This retrospective study assessed the characteristics and outcomes of subjects with COVID-19-associated ARDS versus ARDS (non-COVID) during the first 6 months of the COVID-19 pandemic in 2020. The primary objective was to determine whether mechanical ventilation duration differed between these cohorts and identify other potential contributory factors. We retrospectively identified 73 subjects admitted between March 1 and August 12, 2020, with either COVID-19-associated ARDS (37) or ARDS (36) who were managed with the lung protective ventilator protocol and required >48 h of mechanical ventilation. Exclusion criteria were the following: <18 years old or the patient required tracheostomy or interfacility transfer. Demographic and baseline clinical data were collected at ARDS onset (ARDS day 0), with subsequent data collected on ARDS days 1-3, 5, 7, 10, 14, and 21. Comparisons were made by using the Wilcoxon rank-sum test (continuous variables) and chi-square test (categorical variables) stratified by COVID-19 status. A Cox proportional hazards model assessed the cause-specific hazard ratio for extubation. The median (interquartile range) mechanical ventilation duration among the subjects who survived to extubation was longer in those with COVID-19-ARDS versus the subjects with non-COVID ARDS: 10 (6-20) d versus 4 (2-8) d; P < .001. Hospital mortality was not different between the two groups (22% vs 39%; P = .11). The competing risks Cox proportional hazard analysis (fit among the total sample, including non-survivors) revealed that improved compliance of the respiratory system and oxygenation were associated with the probability of extubation. Oxygenation improved at a lower rate in the subjects with COVID-19-associated ARDS than in the subjects with non-COVID ARDS. Mechanical ventilation duration was longer in subjects with COVID-19-associated ARDS compared with the subjects with non-COVID ARDS, which may be explained by a lower rate of improvement in oxygenation status.

Individual Changes in Respiratory Compliance Upon Immersion May Predict Susceptibility to Immersion Pulmonary Edema

BackgroundImmersion pulmonary edema (IPE) is a frequent diving accident, and it is the primary cause of hospitalization for young military divers during training. The objective of this study was to identify immersion-induced parameters predicting individual susceptibility to IPE.MethodsEighteen experienced male divers having completed at least 100 dives were recruited. Eight divers had previously been hospitalized for IPE (IPE), and the other ten had never developed IPE (non-IPE). The two groups were matched for age, BMI, and number of dives performed. Ventilatory function and overall compliance of the respiratory system (Crs) were measured on land and during head-out-of-water immersion. Subjects also performed 30 min of fin swimming in a channel at 33 m min−1. Following this exercise, the presence of extravascular lung water, revealed by ultrasound lung comets (ULC), was assessed.ResultsIn the whole group, the decrease in Crs upon immersion correlated with the immersion-induced alterations to expiratory reserve volume, ERV (r2 = 0.91; p < 0.001), inspiratory reserve volume, IRV (r2 = 0.94; p < 0.001), and tidal volume, Vt, changes (r2 = 0.43; p < 0.003). The number of ULC correlated strongly with immersion-induced changes in ventilatory function (r2 = 0.818; p < 0.001 for ERV, r2 = 0.849; p < 0.001 for IRV, r2 = 0.304; p = 0.0164 for Vt) and reduced Crs (r2 = 0.19; p < 0.001).The variations of ERV, IRV, and Crs at rest induced by head-out-of-water immersion and the number of ULC measured after swimming for 30 min were significantly greater in IPE subjects.ConclusionIn the face of similar immersion stresses, the extent of alterations to ventilatory function and the number of ULCs were very different between individuals but remained statistically correlated. These parameters were significantly greater in divers with a history of IPE. Alterations to pulmonary function and, in particular, to pulmonary compliance induced by head-out-of-water immersion, through their effects on work of breathing appear to allow the identification of divers with a greater susceptibility to developing IPE. Measurement of these parameters could therefore be proposed as a predictive test for the risk of developing IPE.

Comparison of the effects of open and closed aspiration on end-expiratory lung volume in acute respiratory distress syndrome.

Alveoli tend to collapse in patients with acute respiratory distress syndrome (ARDS). Endotracheal aspiration may increase alveolar collapse due to the loss of end-expiratory lung volume (EELV). We aimed to compare the loss of EELV after open and closed suction in patients with ARDS. This randomized crossover study included 20 patients receiving invasive mechanical ventilation for ARDS. Open and closed suction were applied in a random order. Lung impedance was measured using electric impedance tomography. The change in end-expiratory lung impedance end of suction and at 1, 10, 20, and 30 min after suction, was used to represent the change in EELV. Arterial blood gas analyses and ventilatory parameters such as the plateau pressure (Pplat), driving pressure (Pdrive), and compliance of the respiratory system (CRS) were also recorded. Less volume loss was noted after closed suction than after open suction (mean ΔEELI: -2661 ± 1937 vs. -4415 ± 2363; mean difference: -1753; 95% CI [-2662, -844]; P = 0.001). EELI returned to baseline 10 min after closed suction but did not return to baseline even 30 min after open suction. After closed suction, the Pplat and Pdrive decreased while the CRS increased. Conversely, the Pplat and Pdrive increased while the CRS decreased after open suction. Endotracheal aspiration may result in alveolar collapse due to loss of EELV. Given that closed suction is associated with less volume loss at end-expiration without worsening ventilatory parameters, it should be chosen over open suction in patients with ARDS.

Utilizing Spontaneous Ventilation Modes in Patients Underwent Corrective Surgery for Right Ventricular Outflow Tract Obstructive Congenital Heart Disease: A Crossover Study

Background: This study aimed to determine whether the hemodynamics of patients with right ventricle outflow tract obstructive congenital heart disease (RVOTO-CHD) improve after corrective surgery by changing the ventilation mode. Methods: Patients with RVOTO-CHD who underwent corrective surgery were enrolled in this study. Echocardiography and advanced hemodynamic monitoring were performed using the pulse indicator continuous cardiac output (PiCCO) technology in the pressure-regulated volume control (PRVC) mode, followed with switching to the pressure support ventilation (PSV) mode and neurally adjusted ventilatory assist (NAVA) mode in random order. Results: Overall, 31 patients were enrolled in this study from April 2021 to October 2021. Notably, changing the ventilation mode from PRVC to a spontaneous mode (PSV or NAVA) led to better cardiac function outcomes, including right ventricular cardiac index (PRVC: 3.19 ± 1.07 L/min/m2 vs. PSV: 3.45 ± 1.32 L/min/m2 vs. NAVA: 3.82 ± 1.03 L/min/m2, p &lt; 0.05) and right ventricle contractility (tricuspid annular peak systolic velocity) (PRVC: 6.58 ± 1.40 cm/s vs. PSV: 7.03 ± 1.33 cm/s vs. NAVA: 7.94 ± 1.50 cm/s, p &lt; 0.05), as detected via echocardiography. Moreover, in the NAVA mode, PiCCO-derived cardiac index (PRVC: 2.92 ± 0.54 L/min/m2 vs. PSV: 3.04 ± 0.56 L/min/m2 vs. NAVA: 3.20 ± 0.62 L/min/m2, p &lt; 0.05), stroke volume index (PRVC: 20.38 ± 3.97 mL/m2 vs. PSV: 21.23 ± 4.33 mL/m2 vs. NAVA: 22.00 ± 4.33 mL/m2, p &lt; 0.05), and global end diastolic index (PRVC: 295.74 ± 78.39 mL/m2 vs. PSV: 307.26 ± 91.18 mL/m2 vs. NAVA: 323.74 ± 102.87 mL/m2, p &lt; 0.05) improved, whereas extravascular lung water index significantly reduced (PRVC: 16.42 ± 7.90 mL/kg vs. PSV: 15.42 ± 5.50 mL/kg vs. NAVA: 14.4 ± 4.19 mL/kg, p &lt; 0.05). Furthermore, peak inspiratory pressure, mean airway pressure, driving pressure, and compliance of the respiratory system improved in the NAVA mode. No deaths were reported in this study. Conclusions: We found that utilizing spontaneous ventilator modes, especially the NAVA mode, after corrective surgery in patients with RVOTO-CHD may improve their right heart hemodynamics and respiratory mechanics. However, further randomized controlled trials are required to verify the advantages of spontaneous ventilation modes in such patients. Clinical Trial Registration: NCT04825054.

Comparison of Tritube™ tube and Evone® ventilator use with traditional narrow-lumen tube use in microlaryngeal surgery cases

Aim: To evaluate the feasibility and safety of the Tritube™ tube and Evone® ventilator and compare patients intubated using Tritube™ and ventilated with flow-controlled ventilation (FCV) using Evone® (TT–FCV group) to those intubated using a traditional microlaryngeal intubation tube and ventilated with volume-controlled ventilation (MLT-VCV group) in terms of perioperative parameters and outcomes during microlaryngeal surgery (MLS). &#x0D; Material and Method: A prospective observational design was conducted. This study was carried out in 6 (six) months between February 2022 and September 2022. After receiving their informed consent, 18 patients were randomly assigned to two groups. Patients older than 18 years, who were scheduled for elective MLS were included in the study. The closed opaque envelope method was used for randomization. The same standard anesthesia protocol was applied to all patients. The patients’ demographic parameters, American Society of Anesthesiology physical status (ASA), Mallampati and Cormack-Lehane scores, duration of ventilation, duration of surgery, hemodynamic parameters, ventilation parameters, and complications were recorded. &#x0D; Results: Twenty-one patients recruited for the study. Three of them regretted to participate to study. At the end 18 patients were analyzed. The mean age of population was 53(43-62). When the intraoperative respiratory and hemodynamic parameters of the patients were compared between the two groups, the regional cerebral oxygen saturation (rScO2) (p=0.020), tidal volume (p=0.005), compliance of the respiratory system (p=0.001), and post-extubation rScO2 (p=0.001) values were statistically significantly higher in the TT-FVC group compared to the MLT-VCV group. Right rScO2 (p=0.038), left rScO2 (p=0.047), and time to extubation (p=0.021) were statistically significantly lower in the TT-FVC group compared to the MLT-VCV group.&#x0D; Conclusion: According to the findings we obtained, utilizing Tritube™ and Evone® during MLS surgeries appears to be effective in terms of achieving safe airway management.

Early decrease of ventilatory ratio after prone position ventilation may predict successful weaning in patients with acute respiratory distress syndrome: A retrospective cohort study.

Previous studies usually identified patients who benefit the most from prone positioning by oxygenation improvement. However, inconsistent results have been reported. Physiologically, pulmonary dead space fraction may be more appropriate in evaluating the prone response. As an easily calculated bedside index, ventilatory ratio (VR) correlates well with pulmonary dead space fraction. Hence, we investigated whether the change in VR after prone positioning is associated with weaning outcomes at day 28 and to identify patients who will benefit the most from prone positioning. This retrospective cohort study was performed in a group of mechanically ventilated, non-COVID ARDS patients who received prone positioning in the ICU at Zhongda hospital, Southeast University. The primary outcome was the rate of successful weaning patients at day 28. Arterial blood gas results and corresponding ventilatory parameters on five different time points around the first prone positioning were collected, retrospectively. VR responders were identified by Youden's index. Competing-risk regression models were used to identify the association between the VR change and liberation from mechanical ventilation at day 28. One hundred and three ARDS patients receiving prone positioning were included, of whom 53 (51%) successfully weaned from the ventilator at day 28. VR responders were defined as patients showing a decrease in VR of greater than or equal to 0.037 from the baseline to within 4 h after prone. VR responders have significant longer ventilator-free days, higher successful weaning rates and lower mortality compared with non-responders at day 28. And a significant between-group difference exists in the respiratory mechanics improvement after prone (P < 0.05). A linear relationship was also found between VR change and compliance of the respiratory system (Crs) change after prone (r = 0.32, P = 0.025). In the multivariable competing-risk analysis, VR change (sHR 0.57; 95% CI, 0.35-0.92) was independently associated with liberation from mechanical ventilation at day 28. Ventilatory ratio decreased more significantly within 4 h after prone positioning in patients with successful weaning at day 28. VR change was independently associated with liberation from mechanical ventilation at day 28.

Characteristics and outcomes in extracorporeal membrane oxygenation support in COVID-19 patients: A nationwide cohort-study in Argentina

IntroductionOne of the great challenges during the COVID-19 pandemic was the management of ventilatory support. Extracorporeal membrane oxygenation (ECMO) was the main strategy for the management of refractory acute respiratory distress syndrome. ObjectiveRetrospective, multicentre cohort study of adult patients who required extracorporeal membrane oxygenation (ECMO) in participating centers. Clinical and paraclinical characteristics were recorded. A comparison was made between surviving and non-surviving patients. In addition, time from symptom onset to ECMO placement, time from mechanical ventilation, and cannulation were analyzed. Material and methodsRetrospective, multicentre cohort study of adult patients who required extracorporeal membrane oxygenation (ECMO) in participating centers. Clinical and paraclinical characteristics were recorded. A comparison was made between surviving and non-surviving patients. In addition, time from symptom onset to ECMO placement, time from mechanical ventilation, and cannulation were analyzed. ResultsTwenty-six patients were included in the analysis. Mortality during ECMO was 42.3% (n=11) and overall hospital mortality was 65.3% (n=17). The patient cohort did not differ in terms of sociodemographic characteristics and predictors of mortality at ICU admission between survivors and non-survivors. Mobile ECMO was performed in 10 patients, while 16 were cannulated in situ at the participating centers. The median time from symptom onset to ECMO was 14.5 days (IQR 10.7–21.5), 11 days (IQR 9.5–15.5) in the survivor group, and 17 days (IQR 12.5–27) in non-survivors. The median IMV time was 28.5 (IQR 13–38.25) days. Driving pressure (12 vs 10cmH2O; p<.01), compliance (37.2 vs 21.4ml/cmH2O; p<.01), and mechanical power (17.4 vs 11.3J/min; p=.051) of the respiratory system showed statistically significant differences when comparing survivors and non-survivors, during the 3rd day of ECMO support. ConclusionIn our cohort, mortality after ECMO and after 30 days of hospital stay, was 42.3%, similar to that stated on the extracorporeal life support organization (ELSO) COVID-19 registry dashboard. Information about patients with COVID-19 who required ECMO during the first wave in Argentina was provided in this analysis.

ABDOMINAL COMPRESSION IN END-STAGE FIBROTIC INTERSTITIAL LUNG DISEASE (ILD) IMPROVES RESPIRATORY COMPLIANCE

ABDOMINAL COMPRESSION IN END-STAGE FIBROTIC INTERSTITIAL LUNG DISEASE (ILD) IMPROVES RESPIRATORY COMPLIANCE

Incidence and Risk Factors for Blood Stream Infection in Mechanically Ventilated COVID-19 Patients.

It is widely known that blood stream infections (BSIs) in critically ill patients may affect mortality, length of stay, or the duration of mechanical ventilation. There is scarce data regarding blood stream infections in mechanically ventilated COVID-19 patients. Preliminary studies report that the number of secondary infections in COVID-9 patients may be higher. This retrospective analysis was conducted to determine the incidence of BSI. Furthermore, risk factors, mortality, and other outcomes were analyzed. The setting was an Intensive Care Unit (ICU) at a University Hospital. Patients suffering from SARS-CoV-2 infection and requiring mechanical ventilation (MV) for >48 h were eligible. The characteristics of patients who presented BSI were compared with those of patients who did not present BSI. Eighty-four patients were included. The incidence of BSI was 57%. In most cases, multidrug-resistant pathogens were isolated. Dyslipidemia was more frequent in the BSI group (p < 0.05). Moreover, BSI-group patients had a longer ICU stay and a longer duration of both mechanical ventilation and sedation (p < 0.05). Deaths were not statistically different between the two groups (73% for BSI and 56% for the non-BSI group, p > 0.05). Compared with non-survivors, survivors had lower baseline APACHE II and SOFA scores, lower D-dimers levels, a higher baseline compliance of the respiratory system, and less frequent heart failure. They received anakinra less frequently and appropriate therapy more often (p < 0.05). The independent risk factor for mortality was the APACHE II score [1.232 (1.017 to 1.493), p = 0.033].

Thromboelastography Profile Is Associated with Lung Aeration Assessed by Point-of-Care Ultrasound in COVID-19 Critically Ill Patients: An Observational Retrospective Study.

Background. To evaluate relationships between lung aeration assessed by lung ultrasound (LUS) with viscoelastic profiles obtained by thromboelastography (TEG) in COVID-19 respiratory failure. Methods. Retrospective analysis in a tertiary ICU in Rome, Italy. Forty invasively ventilated adults with COVID-19 underwent LUS and TEG assessment. A simplified LUS protocol consisting in scanning six areas, three per side, was adopted. A score from 0 to 3 was assigned to each area. TEG®6s was used to obtain viscoelastic hemostatic assay parameters which were compared to LUS score. Results. There was a significant inverse correlation between LUS score and static compliance of the respiratory system (Crs, rs −0.75; p < 0.001). We found a significant association between LUS and functional fibrinogen maximum amplitude (FF-MA): among 18 patients with LUS score ≤ 12, median FF-MA was 31 mm [IQR 28–39] whilst, among 22 patients with LUS score > 12, it was 46.3 mm [IQR 40–53], p = 0.0004. Median of the citrated recalcified kaolin-activated maximum amplitude (CK-MA) was 66.1 mm [64.4–68] in the LUS score ≤ 12 group, and 69.6 [68.5–70.7] when LUS score > 12, p < 0.002. Conclusions. The hypercoagulable profile as defined by elevated FF-MA and CK-MA may be associated with a low degree of lung aeration as assessed by LUS.

Increased respiratory dead space could associate with coagulation activation and poor outcomes in COVID-19 ARDS.

PurposeTo determine whether VDPhys/VT is associated with coagulation activation and outcomes.Materials and methodsWe enrolled patients with COVID-19 pneumonia who were supported by invasive mechanical ventilation and were monitored using volumetric capnography. Measurements were performed during the first 24 h of mechanical ventilation. The primary endpoint was the likelihood of being discharge alive on day 28.ResultsSixty patients were enrolled, of which 25 (42%) had high VDPhys/VT (>57%). Patients with high vs. low VDPhys/VT had higher APACHE II (10[8-13] vs. 8[6-9] points, p = 0.002), lower static compliance of the respiratory system (35[24–46] mL/cmH2O vs. 42[37–45] mL/cmH2O, p = 0.005), and higher D-dimer levels (1246[1050–1594] ng FEU/mL vs. 792[538–1159] ng FEU/mL, p = 0.001), without differences in P/F ratio (157[112–226] vs. 168[136–226], p = 0.719). Additionally, D-dimer levels correlated with VDPhys/VT (r = 0.530, p < 0.001), but not with the P/F ratio (r = −0.103, p = 0.433). Patients with high VDPhys/VT were less likely to be discharged alive on day 28 (32% vs. 71%, aHR = 3.393[1.161–9.915], p = 0.026).ConclusionsIn critically ill COVID-19 patients, increased VDPhys/VT was associated with high D-dimer levels and a lower likelihood of being discharged alive. Dichotomic VDPhys/VT could help identify a high-risk subgroup of patients neglected by the P/F ratio.

Effect of Driving Pressure-Oriented Ventilation on Patients Undergoing One-Lung Ventilation During Thoracic Surgery: A Systematic Review and Meta-Analysis.

BackgroundHypoxemia and fluctuations in respiratory mechanics parameters are common during one-lung ventilation (OLV) in thoracic surgery. Additionally, the incidence of postoperative pulmonary complications (PPCS) in thoracic surgery is higher than that in other surgeries. Previous studies have demonstrated that driving pressure-oriented ventilation can reduce both mortality in patients with acute respiratory distress syndrome (ARDS) and the incidence of PPCS in patients undergoing general anesthesia. Our aim was to determine whether driving pressure-oriented ventilation improves intraoperative physiology and outcomes in patients undergoing thoracic surgery.MethodsWe searched MEDLINE via PubMed, Embase, Cochrane, Web of Science, and ClinicalTrials.gov and performed a meta-analysis to compare the effects of driving pressure-oriented ventilation with other ventilation strategies on patients undergoing OLV. The primary outcome was the PaO2/FiO2 ratio (P/F ratio) during OLV. The secondary outcomes were the incidence of PPCS during follow-up, compliance of the respiratory system during OLV, and mean arterial pressure during OLV.ResultsThis review included seven studies, with a total of 640 patients. The PaO2/FiO2 ratio was higher during OLV in the driving pressure-oriented ventilation group (mean difference [MD]: 44.96; 95% confidence interval [CI], 24.22–65.70.32; I2: 58%; P < 0.0001). The incidence of PPCS was lower (OR: 0.58; 95% CI, 0.34–0.99; I2: 0%; P = 0.04) and the compliance of the respiratory system was higher (MD: 6.15; 95% CI, 3.97–8.32; I2: 57%; P < 0.00001) in the driving pressure-oriented group during OLV. We did not find a significant difference in the mean arterial pressure between the two groups.ConclusionDriving pressure-oriented ventilation during OLV in patients undergoing thoracic surgery was associated with better perioperative oxygenation, fewer PPCS, and improved compliance of the respiratory system.Systematic Review RegistrationPROSPERO, identifier: CRD42021297063.